2000

; RefNo. [ 1753 ]

2003

Ecological effects of the interaction between submerged aquatic vegetation and currents depend on the plants and their associated organisms as well as the large-scale transport of dissolved and suspended constituents near the canopy. Mathematical models or airflow within plant canopies were adapted to describe the water flow through and above meadows of aquatic eelgrass Zostera marina. The resulting model provided the vertical distribution of velocity and shear in a water column within the meadow, and it was developed to automatically conserve flow within the canopy. It was tested and calibrated with data from the laboratory and the field, and it performed adequately. The flow profile was nearly exponential within the canopy and logarithmic above it. The model was used to study how the eelgrass canopy affected the horizontal transport of conservative constituents. The most important finding was that the vertical distribution of a constituent determined whether the canopy will reduce or enhance its transport through the water column. This effect has direct implications for transport of nonconservative constituents such as dissolved oxygen, nutrients, organic carbon, and particulate pollen, larvae, plankton, and detritus. It also has direct implications for biological issues such as vertical distributions of photosynthesis and of recruitment of organisms on blades of grass while they are exposed to varying degrees of currents and shear.; RefNo. [ 2 ]

2050

; RefNo. [ 1755 ]

2000

In 1985, the Directorate of Fisheries (Bahrain) initiated a fishing log scheme to collect shrimp trawl fishery data. In the 1997-1998 season, fishermen where intructed to report on turtle catching incidences in standard fishing logs. The current work highlights the 1997-1998 fishing log information on turtle incidence. The percentage of boats reporting on turtle incidence ranged from 20.3 to 35.3% for different months. Fishermen use a single local name for all marine turtles found in Bahrain waters. This may indicate the abundance of a single species, which most likely is the green turtle. Turtles were reported in 12 out of the 20 grounds fished during the 1997-1998 season. The highest turtle incidence and fishing effort values were found in october 1997. Higher incidence rates were found in the green bouy, Aljarim, Tugailib, Mishtan, and Alshiek fishing areas. The highest total seasonal incidence was found in Qumais, which was the second highest in terms of fishing effort. Lowest incidence rates were found in january 1998. This study is the first attemp to asses turtle incidence in shrimp fishery in the Arabian Gulf Area.; RefNo. [ 1748 ]

2003

Tracer experiments with 13C-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98% 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48°50'N, 16°30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T. rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T. rotula, equivalent to 1 g algal C m-2 yr-1, was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77% of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95% of the individuals had taken up 13C from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52% of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of 13C tracers into the sediment. With regard to contradictory results from former 13C-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains.; RefNo. [ 3 ]

1999

; RefNo. [ 1760 ]

2003

; RefNo. [ 8 ]

2003

We measured particulate and dissolved organic carbon (POC and DOC), chlorophyll, oxygen, partial pressure of CO2, pH, total alkalinity (TAlk) and particulate inorganic carbon (PIC) during a late summer cruise in the eutrophic Loire estuary. These parameters reveal an intense mineralisation of organic matter in the estuarine maximum turbidity zone (MTZ) that results in oxygen deficits (down to 20% of the saturation level) and high CO2 oversaturations (pCO2 up to 2900 µatm). Several facts revealed the occurrence of carbonate dissolution in the Loire MTZ: large amounts of alkalinity were produced in the upper estuary, increasing its transfer to the ocean by 30%; the calculated saturation index showed a net undersaturation for aragonite and a slight undersaturation for calcite in the MTZ; and PIC decreased from 2.1% (% dry weight) in riverine suspension to 0.4% in the MTZ. A stoichiometric approach is used to assess the coupling between aerobic respiration and carbonate dissolution, where apparent oxygen utilisation, excess CO2, TAlk and dissolved inorganic carbon are compared quantitatively. About 20% of the CO2 generated by respiration was involved in carbonate dissolution. The loss of PIC at the river-estuary transition quantitatively corresponds to the amount of authigenic calcite precipitated upstream in the highly eutrophic river. This suggests that CO2 exchange with the atmosphere along the eutrophic river-estuary continuum is buffered by carbonate precipitation in the autotrophic river and its dissolution in the heterotrophic estuary.; RefNo. [ 11 ]

2002

Dolphins and sharks feed at times on the same food; however, the influence of these interactions on the feeding success of either predator has not been measured. I employed underwater video to record bottlenose dolphins Tursiops truncatus and silky sharks Carcharhinus falciformis feeding on the same school of fish, and for the first time measured food intake of free-ranging dolphins. Regression analyses showed that dolphin food intake diminished as the number of feeding sharks increased, but was unrelated to the number of dolphins feeding, size of the prey clump or duration of feeding events. The number of dolphins increased at the beginning of a feeding event in the presence of sharks but not in their absence. This increase apparently provided a benefit to dolphins since the number of sharks feeding was negatively related to the number of dolphins feeding. Other studies have indicated that risk of shark predation influences dolphin group size and habitat use. This study indicates that interspecific contests over food influence dolphin food intake and perhaps also dolphin group size.; RefNo. [ 12 ]

2001

Motivation: The eXtensible Markup Language (XML) is an emerging standard for structuring documents, notably, for the worl wide web. In this paper, the authors present XML and examine its use as adata language for bioinformatics. In particular, XML is compared to other languages, and some of the potential uses of XML in bioinformatics applications are presented. The authors propose to adopt XML for data interchange between databases and other sources of data. Finally the discussion is illustrated by a test case of a pedigree data model in XML.; RefNo. [ 1757 ]

2002

; RefNo. [ 1282 ]

2000

The reef fish assemblage at Orpheus Island, Great Barrier Reef, was examined using visual censuses and the ichthyocide rotenone. Small 3.5 m2 quantitative rotenone samples, using a fine-mesh net to enclose the site, were compared with visual-point censuses (prior to the placement of the net), random-point censuses and strip censuses. Furthermore, the fishes collected inside and outside the net were examined to determine the relative efficiency of enclosed versus open rotenone samples. Rotenone samples comprised 128 species in 28 families. Of these, only 49% of the species overlapped between the enclosed (inside net) and open (outside net) samples. Only 17.7% of the species in the enclosed rotenone sample were seen prior to collection. Rotenone samples reveal that visual censuses underestimated the abundance of small taxa. Overall, rotenone samples increased the estimated number of species by 40.4% and the total fish abundance by 50.1% (75.3% for fishes <50 mm). Biomass increased by less than 1.0%. However, through relatively high energetic demands, high turnover rates and their role as potential prey, small fish taxa may play a greater role in reef processes than previously assumed. The limits of visual censusing techniques are highlighted, emphasising the value of small, enclosed, intensive rotenone samples for providing reliable quantitative samples of small taxa.; RefNo. [ 13 ]

1999

Understanding how populations of marine species interact with their habitats for developing an effective conservation strategy. During its complex life history, the Caribbean spiny lobster (Panulirus argus) uses a variety of benthic marine habitats, but how habitat characteristics affect thei dispersal is unclear. To assess how habitat insularity affects the benthic dispersal of spiny lobsters, I compared lobster abundance, size class structure, and migration among insular mangorve and coral reef habitats that were surrounded by bare rubble fields or by seagrass meadows. Lobsters were significantly more abundant on mangrove and coral islands surrounded by seagrass. The size-class distributions of lobsters in these habitats have higher proportions of juveniles, whereas islands surrounded by sand and rubble had skewed distributions dominated by adult lobsters. Seagrass is known to serve as settlement habitat for larval recruits and is likely associated with the higher abundances of lobsters found in seagrass-isolated habitats. Immigration and emigration rates were three to four times higher on seagrass-isolated islands than on rubble-isolated islands, reflected in the significantly greater number of juveniles moving into and from seagrass-isolated islands. Rubble fields appeared to function as a barrier to benthic dispersal of for all lobsters except adults. Vegetated substrates may function as movement corridors for juvenile lobsters and may facilitate dispersal to areas containing new resources. The effects of insularity on a population may be lessened by the nature of the surrounding habitats if those habitats have important functional roles as larval settlement areas, foraging grounds, or movement corridors. Protection of insular habitats like coral reefs may be ineffective if related habitats like seagrass meadows are left unprotected. Conservation strategies for mobile benthic species need to incorporate the protection of areas with heterogenous habitats that are important to meet the changing habitat requirements in complex life cycles.; RefNo. [ 1 ]

2002

Explanations for the association between habitat patchiness and diversity in coral reef fish communities are often conflicting among studies, and no consensus has been reached. We investigated patterns in diversity and structure of fish communities associated with large and small coral patch reefs at Glover's Reef, Belize. The abundance of fish was greater on large reefs (mean size 2300 m2) than on small reefs (mean size 740 m2), but species richness was less consistent among the different sizes of reefs. Results from rarefaction analyses indicated that both species richness and species evenness were similar between a single large reef and 3 smaller reefs of equivalent total area to the large reef. Furthermore, the density of species on standardized sizes of reef habitat was similar or greater on small reefs than species density on large reefs. The nested subsets hypothesis predicts that species assemblages on small isolated habitat patches will constitute only a subset of the assemblage on a large patch. However, reef fish communities in our study did not show any nested patterns when they were ordered by species richness, reef size, or reef isolation. To further evaluate why the fish communities on small reef patches were so diverse, we compared the number of numerically rare species and the spatial segregation of species within large and small reefs. More rare species, including both transients and resident species, occupied the combined small reefs than the large reefs. A greater number of species occupied reef edge habitats than the reef top and thus contributed to greater species density on small patches with larger perimeter:area ratios. Diversity in coral reef fish communities may be associated with the spatial distribution of species over the physical structure of reef habitat, but these patterns may be highly scale-dependent.; RefNo. [ 15 ]

2001

; RefNo. [ 1756 ]

2002

We visually censused fishes along transects on the back-reef and adjacent lagoons of bank-barrier reefs at 6 sites on St. Croix, US Virgin Islands, to determine the extent to which coral reef fishes use lagoon habitats as nurseries. Fishes were recorded by size class (small, <3 cm; medium, 3 to 5 cm; large, >5 cm) on the back-reef, and on 5 lagoon habitat types: patch-reef, rubble, seagrass, algal plain, and sand. We examined densities of 4 focal 'species' (Acanthurus spp. [A. bahianus and A. chirurgus], Haemulon spp. [all species of the Haemulon genus], Sparisoma aurofrenatum, and Scarus iserti), and densities of all species combined to determine spatial and temporal patterns of habitat use. Although there was a general tendency for coral reef fishes to use lagoon habitats as nurseries, we discerned 2 patterns of habitat use: 1 group, exemplified by Acanthurus spp. and Haemulon spp., use lagoon patch-reef and rubble as nurseries in preference to back-reef and other lagoon habitats; in contrast, Sparisoma aurofrenatum and Scarus iserti preferentially use back-reef and, to a lesser extent patch-reef, as nursery, juvenile, and adult habitat. Temporal variation was greatest in the small size class and least in the large size class. Most settlement occurred during summer, which is when settlement in lagoon habitats was greatest, with a little settlement in winter in the back-reef habitat. For species that use lagoons as nurseries, lagoon habitats must provide advantages that offset the additional energy expense and predation experienced by both incoming larvae, as they cross over the reef and search for patch-reef and rubble, and juveniles, as they return to the reef during the juvenile-to-adult transition. Given the use of lagoon habitats as nurseries, there is a need for inclusion of lagoons in coral reef reserves.; RefNo. [ 17 ]

2003

; RefNo. [ 1723 ]

2001

Proponents of community conservation present it as a means of reconciling conservation and development objectives by ensuring that the interests of local people are taken into account in making trade-offs. Conservation critics see it as a challenge to the state led, scientific management that is necessary to guarantee the preservation of biodiversity.In this paper, we argue that community conservation is not one thing but many. It is evolving both as aconcept and as a practice that must be built on. It is not a project or 'policy' choice that can be simply aacepted or rejected. The key questions about community conservation are who shoul set the objectives for conservation policy on the ground and how should trade-offs between the diverse objectives of different interests be negotiated.; RefNo. [ 1758 ]

2001

; RefNo. [ 19 ]

2000

This paper argues that successful conservation of wetlands is fundamentally determined by the institutions and property rights associated with resource management decisions. Thus an understanding of property rights regimes, the constraints which they impose on users of wetlands resources, and the distribution of benefits of use among users and non-users are essential if the economic values of wetland ecosystems and functions are to be realised. We outline relevant theoretical perspectives on property rights and the sustainable utilisation of natural resources. We argue that wetland resources tend to have unique property rights regimes due to their ecological characteristics, namely, their multiple-resource characteristics, the indivisible nature of these resources, and the seasonal and cyclical nature of different wetland resource components. Case studies of property rights regimes in Indonesia and Vietnam are presented. These show that wetland resources are often managed as common pool resources, and that state appropriation of resources or the imposition of private property rights can contribute to unsustainable utilisation or conversion of wetlands to other uses.; RefNo. [ 21 ]

1999

; RefNo. [ 1761 ]

1996

The main objective of this first quantitative ecological survey of any bay in French Polynesia, is to present the spatial organization of the coral communities. Ten stations were surveyed on both sides of Opunohu Bay, located on the North Coast of Moorea. Diving observations allowed us to obtain the species composition, and coral coverage was estimated along linear transects on the three zones of the fringing reef along the shores of the bay: the reef flat, the reef crest and the reef wall. The presence- absence matrix as processed by a constrained clustering analysis. The results permit us to recognize three parts of the bay: 1) the bayhead were corals are almost absent; 2) the middle part occupied mainly by common species; and 3) the bay entrance with most diversed and well developed coral community, composed of all the species fount in the bay head and middle part, in addition to uncommon species. The spatial organizati0on is mostly congruent with the Miyadi concpt of "embayment degree". Nevertheless, some aspects 0f the species composition are expalined by the biogeographical isolation of french Polynesia and the salinity?turbidity stress which occurs after heavy rainfall.; RefNo. [ 1752 ]

2002

We analysed the interannual variability of the major reef communities (algae, corals and fishes) on the outer slope of the Tiahura sector on Moorea Island between 1991 and 1997, and examined the impacts of natural disturbances on these communities. Patterns of temporal variation and the response to natural perturbations were clearly different among the taxa examined. A sharp decrease in the percent cover of branching corals (Pocillopora and Acropora) followed cyclonic and bleaching events that occurred in 1991. After 1993, a slight increase in coral cover values was recorded, and can be interpreted as a sign of recovery. Despite a similar proportion of bleached colonies at the beginning of bleaching events in 1991 and 1994, the bleaching in 1994 had no significant impact on coral cover. This result demonstrates the importance of understanding the ecological history of reefs (i.e. the chronology of disturbances) in interpreting the specific impacts of a particular disturbance. The decline in coral cover was accompanied by an increase in the percent cover of turf algae, but surprisingly, the percent cover of macroalgae did not show any significant temporal variation during the 7 yr period. Thus, the decrease in the percent cover of corals, which opens up new substrate, does not always result in an increase in macroalgal cover. The temporal variation of the fish community was mainly characterized by (1) the high variability in the recruitment of juveniles, with a peak in 1991; (2) the slight increase in the density of adult species; and (3) the decrease in the density of corallivorous chaetodontid fishes from 1991 to 1994. Since corals were the only taxon directly affected by natural disturbances, they were consequently the cause of the indirect effects of these disturbances (i.e. increase in turf algae and decrease in chaetodontid fishes), and can therefore be regarded as the 'key component' of the outer slope reef communities in Moorea.; RefNo. [ 22 ]

2003

; RefNo. [ 23 ]

2002

; RefNo. [ 1749 ]

2003

Catchability patterns of western Mediterranean Nephrops norvegicus were studied in relation to depth and season by sampling animals during 4 continuous 24 h cycles of trawl hauls at 100 to 110 m and 400 to 430 m in October (near the autumn equinox) and June (near the summer solstice). Bottom light intensity was recorded between consecutive catches. Catch data were transformed into density estimates of animals emerging from their burrows. Results revealed a marked emergence rhythmicity: nocturnal with crepuscular peaks on the continental shelf, and diurnal on the continental slope. On the slope, peaks of catch occurred in phase with light intensity, whereas this did not happen on the shelf. In particular, both benthic environments presented diel fluctuations in light intensity that differed within several orders of magnitude. These data indicate a differential physiological adaptation of N. norvegicus eyes to local photic conditions, implying a revision of the optimum light intensity concept, already proposed in the literature. Emergence patterns were almost identical for males, females and berried females, and these were not size-dependent.; RefNo. [ 25 ]

2001

Solubilization of sediment-bound hydrophobic contaminants (HOCs) by gut fluids of deposit-feeding polychaetes greatly exceeds solubilization by seawater. We present evidence that digestive surfactants exert a central role in HOC desorption, and that the degree of in vitro solubilization by gut fluids is an excellent predictor of HOC absorption efficiency (AE) by the respective worm species. We compared in vitro solubilization of sediment-bound 14C-hexachlorobenzene (HCB) and 14C-tetrachlorobiphenyl (TCBP) by gut fluids of 2 deposit-feeding polychaete species, Nereis (Neanthes) succinea and Pectinaria (Cistenides) gouldii, to AEs measured in live worms by pulse-chase methodology. N. succinea desorbed 72% HCB and 79% TCBP in vitro (during 6 h incubations), and absorbed both compounds with 73% efficiency, while P. gouldii desorbed only 37% HCB in 6 h, and analogously absorbed only 37% HCB. Higher desorption and absorption efficiencies of N. succinea were accompanied by greater gut-fluid surfactancy and higher micelle concentration (determined by drop contact angle) compared to P. gouldii. Calibration of desorption efficiencies with a synthetic surfactant, sodium dodecyl sulfate (SDS), showed that N. succinea gut fluid desorbed a similar amount of HOC as a 1% (ca 3.5 mM) SDS solution, whereas P. gouldii gut fluid was equivalent to a 0.25% (ca 0.9 mM) SDS solution. Detailed analysis of the kinetics of HOC desorption (after 1, 45 and 360 min) showed that gut fluids from both polychaetes desorbed more than two-thirds of the bioavailable HOC within the first minute, suggesting that digestive desorption occurs rapidly and that gut-residence time has only minor influence on the degree of desorption or absorption of sediment-bound HOCs.; RefNo. [ 27 ]

2002

Grazing effects of amphipods were examined for 3 groups of diatoms (loosely attached cells, moderately attached cells and strongly attached cells) in Gamo Lagoon, Miyagi Prefecture, Japan. Diatom species with filamentous forms or low adhesive strength were susceptible to grazing, while those with stronger adhesion were less affected by grazing pressure. Seasonal trends for both amphipods and microalgae found on the macroalgae Gracilaria vermiculophylla showed high densities of amphipods and low densities of microalgae during warmer months (June to September) and vice versa in colder months (December to March). This inverse relationship between densities of amphipods and diatoms suggests a causal relationship and that effects of grazing pressure by amphipods on epiphytic diatom communities seem to be strong in Gamo Lagoon. A manipulative experiment (feeding pressure experiment) revealed that Melosira sp. and Nitzschia sp. were mostly selected by tube-dwelling species (Corophium uenoi and Grandidierella japonica), whilst Gyrosigma sp. and Melosira sp. were mostly selected by free-living species (Eogammarus possjeticus and Melita setiflagella).; RefNo. [ 28 ]

2003

Boat collisions with manatees (Trichechus manatus latirostris) account for about one-quarter ofmanatee deaths annually in Florida. This emphasizes the need to influence boaters’ behavior through an understanding of their knowledge, beliefs, attitudes, and behavioral intentions toward manatees and their conservation.We conducted a telephone survey of a random sample of boat users whose boats were observed in Tampa Bay, Florida. Five hundred and four boaters completed the survey, a cooperation rate of 55%. Respondents had a mean score of 6.2 on a 10-question knowledge scale, and supported manatee conservation efforts with a mean score of 3.84 on a 5-point support scale based on seven statements. Boaters indicated more support for increased public education than for stringent regulations such as speed and wake limits in sea grass areas, no-entry areas, or increased patrols. Greater knowledge about manatees was positively correlated with support for manatee conservation. To understand boating behaviors, we used the sociopsychological theory of reasoned action to analyze boaters’ disregard for speed zones. Results indicate a strong normative influence on boaters’ behavioral intention to follow speed zones, with respondents highly motivated to comply with law enforcement. The survey results provide a basis for recommendations about public communication interventions.; RefNo. [ 30 ]

2002

; RefNo. [ 31 ]

2001

; RefNo. [ 43 ]

2002

This study focuses on the seasonal changes in the Gulf of Aquaba, Red Sea, in nitrite concentration and their relationship with phytoplankton activity, which is mainly controlled by an alternation of water-column stratification with vertical mixing. Within the euphotic zone, during thermal summer stratification, nutrient depletion was severe, and no nitrite could be detected in the upper 70 m. However, during stratification, nitrite was always associated with the nutriclines and formed a deep maximum at the bottom of the euphotic zone. In contrast, nitrite accumulated in the mixed water column during winter, closely paralleling the development of phytoplankton biomass. In the Gulf of Aqaba, maximum nitrite accumulation occurred when winter mixing reached its greatest depth, which in turn was coincident with the height of the phytoplankton spring bloom. Thus, our field data suggest that accumulation of nitrite is associated with nutrient-stimulated phytoplankton growth. This hypothesis was supported by nutrient-enrichment bioassays performed concomitantly: only when phytoplankton growth was stimulated by nutrient additions, did nitrite accumulate in the water. In the bioassays, the time-course of nitrite accumulation closely paralleled the development of phytoplankton biomass during the incubation period. We therefore suggest that the accumulation of nitrite in the mixed water column during winter is due to excretion by algal cells. Our field and experimental data show that between 10 and 15% of the total amount of nitrogen entering the mixed-water column is released as nitrite by phytoplankton. Further, our field and experimental data support the hypothesis that nitrite excretion by phytoplankton has a significant role in the formation of the deep nitrite maximum (DNM) during stratification in summer. In the bioassays, phytoplankton cells excreted nitrite even when ammonia was the nitrogen source. This indicates a so far unrecognised physiological pathway involved in nitrite excretion by phytoplankton cells.; RefNo. [ 46 ]

2002

Monthly 18O records of 2 coral colonies (Porites cf. lutea and P. cf. nodifera) from different localities (Aqaba and Eilat) from the northern Gulf of Aqaba, Red Sea, were calibrated with recorded sea surface temperatures (SST) between 1988 and 2000. The results show high correlation coefficients between SST and 18O. Seasonal variations of coral 18O in both locations could explain 91% of the recorded SST. Different 18O/SST relations from both colonies and from the same colonies were obtained, indicating that 18O from coral skeletons were subject to an extension rate effect. Significant 18O depletions are associated with high extension rates and higher values with low extension rates. The relation between coral skeletal 18O and extension rate is not linear and can be described by a simple exponential model. An inverse relationship extends over extension rates from 1 to 5 mm yr1, while for more rapidly growing corals and portions of colonies the relation is constant and the extension rate does not appear to have a significant effect. We recommend that 18O values be obtained from fast-growing corals or from portions in which the isotopic disequilibrium is fairly constant (extension rate >5 mm yr1). The results show that interspecific differences in corals may produce a significant 18O profile offset between 2 colonies that is independent of environmental and extension-rate effects. We conclude that the rate of skeletal extension and the species of coral involved have an important influence on coral 18O and must be considered when using 18O records for paleoclimatic reconstructions.; RefNo. [ 47 ]

2003

Lipid content and lipid-class distribution in the northern krill Meganyctiphanes norvegica (M. Sars, 1857) was investigated in 3 contrasting (in terms of climatic and trophic conditions) areas: the Ligurian Sea, the Clyde Sea and the Kattegat. Seasonal differences in the lipid content of krill were closely related to food supply coupled with the krill reproductive state in both the Ligurian Sea and in the Clyde Sea. In the Kattegat, the lipid reserves of reproductive krill were low and probably used continuously over a longer reproduction period and successive spawning cycles. In the Ligurian and Clyde Seas, female krill lost 55 and 33% of their cephalothorax (CT) lipids through spawning. The content of triacylglycerol (TAG) and phosphatidylcholine (PC), both major lipids in the CT, were higher when food conditions were optimal at the 3 sites, and were correlated to chlorophyll a (chl a) concentration in the Ligurian and Clyde Seas. The influence of reproduction on lipid-class distribution in the Clyde and Ligurian Seas was expressed by a large decrease in PC and TAG throughout spawning, while in the Kattegat PC and TAG levels were low irrespective of the reproductive state. The relative influence of environmental and physiological factors on the lipid distribution of krill in the CT and abdomen (AB) among the 3 locations was evaluated using principal components analysis. In the CT, TAG and PC along with minor lipids were major discriminating factors and were strongly correlated to total lipid content and chl a concentrations. For reproducive krill, marked differences in the CT and AB indicated covariation between reproduction and trophic conditions. The influence of the physical environment on M. norvegica at sexual rest found expression in variation in the membrane lipids in the AB across the different temperature and salinity regimes at the 3 sites. The results are discussed in terms of adaptive mechanisms involving lipid distribution and metabolism developed by the species.; RefNo. [ 33 ]

2050

; RefNo. [ 1750 ]

2003

; RefNo. [ 35 ]

1982

; RefNo. [ 1751 ]

2002

The control exerted by different intensities and temporal inputs of small-scale turbulence on the balance between C production and respiration in planktonic communities has been studied by means of laboratory microcosms. The different turbulence conditions modified the temporal pattern of phytoplankton (chlorophyll a) and total biomass development. However, the differences between average values of total (after re-suspension) biomass were not statistically significant. Net primary production (NP) was significantly higher at intermittent turbulence (alternating turbulence and calm periods), with maxima coinciding with the turbulence periods. Respiration (R) was less sensitive to turbulence conditions, but on average was significantly higher under continuous turbulence. The relationships between analysed total particulate organic carbon (TPOC) and theoretical estimates of total organic carbon (according to the daily balance between NP and R) indicated that between 30 and 50% of NP could be released as dissolved organic carbon. The quotient between daily C production and R (indicative of auto- or heterotrophic conditions) was higher under turbulence conditions. Autotrophy lasted for longer periods of time under intermittent turbulence. These results confirm the importance of turbulence in the modulation of the trophic status of the system, opening new perspectives for the study of the mechanisms controlling the selection of planktonic food webs.; RefNo. [ 36 ]

2000

; RefNo. [ 1747 ]

2002

10. We present the results of experimental and descriptive field studies on the effects of dense sea urchin aggregations on seagrass beds in the Mombasa lagoon (Kenya). The study area was dominated by slow-growing seagrass, and supported an average sea urchin density of 1.6 m-2, mostly Tripneustes gratilla (90%). In the T. ciliatum meadows, 39% of the cover was heavily grazed by the sea urchins (more than 75% dead shoots), 23.4% was moderately grazed (19.8% dead shoots). We observed 5 aggregations (fronts) of T. gratilla in the study area, 4 of theses within the T. ciliatum meadows. These aggregations were linear in structure, with mean densities of 10.4 suare meters and left in their wake a trailing edge area of defoliated seagrass rhizomes. Grazing rates were measured in 2 ways: marked permanent quadrats along the front, and sea orchin addition experiments. The first method produced grazing rates 1.8+_ 0.43 shoots and the second produced slightly higher values of 5+-0.86 shoots. New shoot recruitment was estimated from the marked permanent quadrats in the fronts as 0.32 shoots. Simple models indicated that the return interval for the sea urchin grazing fronts was 99 or 34 mo, depending on the method used, and that T. ciliatum recovery time was 44 mo. We conclude that the sea urchin aggregations observed in the Mombasa lagoon control T. ciliatum density by grazing its exposed apical tips.; RefNo. [ 1746 ]

2000

The seasonal nutrient mass balance of the dominal seagrass of the Mediterranean, Posidonia oceanica (L.) Delile, was evaluated in NE Spain in order to test the hypothesis that the effect of seasonal nutrient imbalance can be reduced by the reutilization of internal nutrient pools. To this end, we investigated the seasonal and age-dependent variability of nitrogen and phosphorous concentration of the leaves, inferring from these data values of seasonal nitrogen and phosphorous incorporation, uptake, losses and retranslocation. Incorporation of nitrogen and phosphorous in leaves peaked in June and was lowest in September, thus following the seasonal growth pattern of the plant. Retranslocation of nitrogen and phosphorous was high from May to September and close to zero during the rest of the year. Losses of nitrogen and phosphorous were highest at the end of summer, associated with the major biomass losses. Nitrogen uptake by leaves reached maximum values in winter and was lowest during August-September, while phosphorous uptake was highest in spring and lowest in August-September. On an annual basis nitrogen and phosphorous uptake accounted for 60 and 41% of the total nutrient incorporation, respectively, while translocation of nutrients from old tissues accounted for the remaining 40 and 59%. Although roots and rhizomes function as sources of nutrients at the beginning of the summer, their contribution to the seasonal nutrient budget seemed to be minor.; RefNo. [ 941 ]

2001

We present the seasonal carbon (C) balance of the Mediterranean seagrass Posidonia oceanica (L.) Delile calculated from seasonal rates of C gain (photosynthesis), C loss (respiration) and growth. We compare our balance with the evolution of seasonal C reserves in order to determine the parameters (shoot:root biomass, reserve allocation, photosynthetic parameters, etc.) that influence the seasonal cycle of the plant. Additionally, we examine whether the annual C balance can be used as a valid tool for testing the vulnerability of seagrasses to light reduction. The seasonal whole-plant C balance showed alternate negative (from September to June) and positive (July and August) values. This trend was the result of the interplay among several seasonal factors such as irradiance, water turbidity, photosynthetic parameters, respiratory rates, shoot growth, within-shoot age distribution, and principally, the low photosynthetic:non-photosynthetic biomass ratio. The lack of significant correlation between seasonal growth and metabolic balance (C gain – C demand) did not permit the prediction of plant growth. Conversely, the seasonal pattern of carbon storage was consistent with the periods of positive and negative C balance. Consequently, reserve mobilization allows overwintering and re-growth under conditions of negative C balance. Using different calculations the annual C balance was found to be negative during 1993; this is in accordance with the carbohydrate interannual depletion and the shoot density decline. Since Posidonia oceanica is regressing in the Mediterranean, our carbon budget may notably contribute to future carbon models that can be essential tools for defining the minimum light requirements for survival. More insight into the functioning of some of the parameters that definitively influence this carbon budget (e.g.: the rhizome/root oxygen consumption and the O2 to C conversion) is needed to fully understand the vulnerability of seagrasses to light reduction.; RefNo. [ 37 ]

1999

This study evaluated the ability of Zostera marina L. (eelgrass) to balance the daily photosynthetic deficit by mobilization of carbon reserves stored in below-ground tissues during a period of extreme winter light limitation. A quantitative understanding of the mobilization process and its limitations is essential to the development of robust models predicting minimum light levels required to maintain healthy seagrass populations. Plants were grown in running seawater tanks under 2 light regimes. One treatment was provided with 2 h irradiance-saturated photosynthesis (Hsat) to produce sever light limitation, while control plants were grown under 7 h Hsat, simulating the typical winter time condition in Monterey Bay California, USA. Although plants maintained under 2 h Hsat were more severely carbon limited than plants grown under 7 h Hsat whole-plant carbon balance calculated from metabolic needs and growth rates was negative for both Hsat treatments. The eelgrass studied here responded to negative carbon balances by suppressing the production of new roots, depleting sucrose reserves, and effecting a gradual decrease in growth rate and an increase in the activity of sucrose synthase (SS, E.C. 2.4.1.13) in sink tissues in the terminal stages of carbon stress. The 7 h Hsat plants survived the 45 d course of the experiment while the plants grown under 2 h Hsat died within 30 d, even though one-third of their carbon reserves remained immobilized in the rhizome. Thus, extreme light limitation can prevent full mobilization of carbon reserves stored in below-ground tissues, probably through the effects of anoxia on translocation. Metabolic rates, particularly photosynthesis and respiration of the shoot, were unaffected by prolonged carbon limitation in both treatments. The patterns obeserved here can provide useful indices for assessing the state and fate of seagrass ecosystems in advance of catastrophic declines.; RefNo. [ 942 ]

2002

9. An assumption underlying the growing support for marine protected areas (MPAs) is that they meet conservation goals and provide economic benefits to fisheries and ecotourism. However, support for MPAs will be at risk if managers cannot asses whether various MPA objectives are being fulfilled. Current approaches to MPA management emphasize the need to evaluate performance criteria; however, there is little consensus criteria and their evaluation. We propose a marine protected area evaluation model (MPAEM), based on and modified from a multi disciplinary approach used to asses the sustainability of fisheries, called rapid appraisal of fisheries (Rapfish). The application os MPAEM was explored in a pilot study of MPAs located in different regions of the world. Results indicate that the MPAEM can be used to evaluate MPA management effectiveness. However, the manner in which the evaluation attributes are scored and ways of engaging user groups should be explored before MPAEM become part of the day to day management of MPAs.; RefNo. [ 1744 ]

2000

The natural surface water and shallow groundwater quality in the Ethiopian Rift is influenced by excessive input of fluoride and some inorganic chemical constituents such as Li, Sr, Pb, Cu and Hg from the deep groundwater system. The surface bodies are characterized by high fluoride, bicarbonate and chlorid concentration far above the recommended consumption limit. The quality of surface water in the Ethiopian rift in influenced by the complex geological activities, which increase the concentration of undesirable chemical constituents in the surface waters by transfer from deep groundwater in the form of thermal springs, geysers and fumaroles. In fact, the concentration of some of the aforementioned chemical constituents highly exceeds the consumption limits giving rise to serious health problems to the local population.; RefNo. [ 1743 ]

2001

The main threat to the surface water quality in Addis Ababa is environmental pollution derived from domestic and industrial activities. Due to the inadequacy of controlled waste management strategies and waste treatment plants, people are forced to discharge wastes both on open surface and within water bodies. Uncontrolled (improper) waste disposal has deteriorated the quality of surface water (streams, rivers, reservoirs) by changing the chemical, physical and organoleptic properties of water. Chemical analyses of surface and shallow ground water samples taken at various points along streams and different springs show that the level of unwanted chemical constituents such as nitrates and chromium, for example, are higher than the background level. Among the main causes are poor economy and lack of proper waste disposal system that lead the residents to dump wastes illegally within the water bodies. Important measures to alleviate the problem are to develop the environmental awareness of the residents, proper control on industries, establishment of a wide spread waste collection system and improved landfill technology.; RefNo. [ 1742 ]

1981

; RefNo. [ 1738 ]

2003

In southern California, native eelgrass Zostera marina L. and the invasive non-native mussel Musculista senhousia have dynamic complex interactions. Although high densities of M. senhousia inhibit the growth of eelgrass, mussel survival and growth decline with increasing eelgrass shoot density and patch size. The correlation of these eelgrass attributes with local concentrations of chlorophyll a and water flow speeds suggested that the mussels, which feed on phytoplankton delivered by water currents, might suffer food limitation inside large eelgrass beds. By supplementing phytoplankton to M. senhousia living in eelgrass, we confirmed this hypothesis: mussels grew 50% faster when food availability was enhanced. Lab and field experiments investigating the effects of food limitation on growth and reproduction of M. senhousia showed that mussels respond by reducing shell growth, and subsequently fecundity. We found no evidence that mussels reallocated resources preferentially to reproduction when food was limited. Our results highlight how the effects of anthropogenic perturbations that currently threaten eelgrass populations directly could be magnified by interactions with a non-native species. Eelgrass habitat fragmentation and increasingly frequent phytoplankton blooms resulting from coastal development and eutrophication have welldescribed direct negative effects on eelgrass. By increasing phytoplankton availability to M. senhousia, such perturbations also indirectly affect eelgrass by acting to enhance mussel survival and growth, magnifying the negative effects of the mussel on Z. marina.; RefNo. [ 41 ]

2001

Previous studies have proposed that seagrass habitats, by supporting diverse and abundant fish assemblages, are preferred by foraging dolphins in coastal systems. To test this hypothesis, we (1) examined the fine-scale behavior of bottlenose dolphins in relatively pristine and developed inshore sites near Clearwater Harbor, Florida, USA, and (2) used an otter trawl to sample potential fish prey in non-seagrass and seagrass habitats. In the pristine site, dolphins preferred dredged channel and spoil-island habitats, while least preferring shallow seagrass habitats. In the developed site, foraging dolphins preferred the natural channel habitat, but exhibited little further selection. Therefore, the hypothesis that dolphins prefer seagrass habitats while foraging was rejected. Feeding frequency was significantly associated with diel state, with foraging peaking at dawn and decreasing throughout the day. Dolphin group size was negatively correlated and nearest neighbor distance positively correlated with feeding frequency. Analysis of trawl data focused on the pinfish Lagodon rhomboides which dominates the diets of dolphins in west Florida. The relative abundance of pinfish was significantly greater and standard lengths significantly less in seagrass than in non-seagrass habitats. Dolphins therefore forage in non-seagrass habitats where fish prey is both larger and perhaps more available. Although seagrass habitats support greater abundance of smaller fishes, they also provide a structural refuge which obscures fishes both visually and possibly acoustically. Thus, the importance of seagrasses to the health of coastal dolphins is probably indirect, as seagrasses support fish populations on which dolphins rely.; RefNo. [ 40 ]

2001

An approach to poverty reduction in low-income countries known as the ‘sustainable livelihoods approach’ is applied to understanding the strategies of artisanal fisherfolk confronted by fluctuating fisheries resources. The livelihood approach is explained, and the insights it provides into conventional fisheries management policies in developing countries are explored. It is argued that both state-led management and some of the newer, community or territorial use-rights approaches, if predicated on an incomplete understanding of livelihoods, can result in management directives incompatible with both resource conservation and the social and economic goals of management.; RefNo. [ 42 ]

2004

We examined how the marine cottid fish Clinocottus acuticeps used vegetated microhabitats within an estuarine system in the Pacific Northwest, USA. C. acuticeps was more abundant and grew faster in microhabitats in algal beds compared with open microhabitats. Furthermore, the condition index (CI) increased in vegetated microhabitats and decreased in open habitats which, combined with the variability in growth measured in both habitats, suggests that fish may regulate their growth more narrowly when food resources and protective cover provided by the algal bed function as complementary resources. Reduced growth in open microhabitats may be a physiological response to increased predation risk. Additionally, giving-up densities (GUDs) were similar in both habitats, in both field and laboratory experiments, where fish foraged in the presence of predators and under different levels of protection by algae. These results, combined with the implications of the growth experiments, suggest that C. acuticeps utilizes a risk-reckless strategy in the face of a tradeoff between food and safety by maximizing food intake despite predation risk. Nevertheless, we maintain that the increased growth and lower predation risk associated with algae microhabitats imply that, ultimately, fitness may be higher in individuals that primarily use vegetated habitats.; RefNo. [ 44 ]

2000

Rates and pathways of organic matter decomposition were estimated in sediments of 6, 8 and 35 yr old Rhizophora apiculata plantations in the lower Mekong delta, Vietnam. Rates of total carbon oxidation (Tcox = average of CO2 gas fluxes from exposed sediments + ECo2 fluxes from submerged sediments) were slowest in the 8 yr old forest (mean Tcox = 17.1 mmol C m-2 d-1), with higher rates in the 6 yr old (mean Tcox = 48.1 mmol C m-2 d-1) and 35 yr old forests (mean Tcox = 53.7 mmol C m-2 d-1). In all 3 forests, sediments to a depth of 40 cm were acidic, with mostly positive redox potential; free sulfides and methane were not measurable in the pore water or across the sediment/water-air interface. Oxic respiration was the major decomposition pathway, ranging from 63 to 64% of Tcox in the 2 older forests to 94% of Tcox in the 6 yr old stand. Budget calculations suggest that most of the O2 flux was associated with chemical oxidation in sediments of the 2 youngest forests. Sulfate reduction was the second most important diagenetic pathway (range 0.2 to 13.0 mmol S m-2 d-1) and, on average, total rates increased with increasing forest age. Manganese reduction appeared to be a minor decomposition pathway in all 3 stands (range 1.0 to 2.8 mmol Mn m-2 d-1), and iron reduction was measurable only in the 6 yr old forest (0.9 +/- 0.6 mmol Fe m-2 d-1). Denitrification was measurable only in the 35 yr old forest (2.2 +/- 0.5 mmol N2 m-2 d-1) and 35 yr old forests (1425 +/- 92 Mmol N2 m-2 d-1). The molar carbon ratio of sediment respiration to forest net primary production (Rhetero/NPP) in the 6 and 35 yr old forests averaged 18 and 28%, respectively. These comparatively low mineralization losses, coupled with the lack of measurable denitrification at 2 of the 3 plantations, imply that these R. apiculata plantations are highly efficient at sequestering labile carbon and nitrogen into plant biomass and sediment pools.; RefNo. [ 943 ]

2002

; RefNo. [ 45 ]

2001

Patch dynamics of intertidal Pyura praeputialis (Heller, 1878) were studied in experimentally cleared plots at 3 vertical levels (upper, mid and lower P. praeputialis levels) and 3 sites within the Bay of Antofagasta, Chile. The sites corresponded approximately to the northern limit (Las Conchillas), the center (El Way), and the southern limit (El Lenguado) of the species geographic distribution in Chile. Replicated 40 × 60 cm quadrats were photographed periodically to follow patch re-colonization. Patch recolonization (recolonized area) followed a sigmoid curve and could be fitted at most sites and levels by applying maximum likelihood techniques to the asymptotic model: y = a/{1 + exp[–(x – b)/c]} where Parameters a and b are asymptotic percentage cover and time for 50% recovery respectively, and Parameter c defines the shape of the curve (growing phase). Among sites, the highest asymptotic values and fastest recovery times were observed at El Way, in the center of the species distribution. Among levels, the highest asymptotic values were observed in the mid P. praeputialis level quadrats. The perimeter of the patches increased and subsequently decreased as a function of recolonized area. Recruitment observations showed the process of recolonization to be related to the perimeter of the patch to be colonized rather than to the area available. Further more, the recolonization patterns could be predicted using the patch perimeter scaled by a linear coefficient. We believe that the mechanism of recolonization is most probably related to the settlement of recruits to the border of previously settled individuals, possibly mediated by intraspecific self-facilitation mechanisms.; RefNo. [ 49 ]

2003

The diving behavior of a medium-sized female sperm whale off the Kumano coast, Japan, was studied using a suction-cup-attached TDR (time depth recorder) tag. The tag remained attached to the whale for 62 h and recorded 74 dives deeper than 100m. The whale repeatedly dived for 30 to 45 min down to 400-1200m. Surface intervals were generally 10 min between dives, except for a period of 1.3 to 4.2 h spent at the surface every afternoon. The whale spent long periods of time at the bottom of dives, during which there was considerable variability in both depth and velocity data, with occasional bursts in velocity. These data suggest that sperm whales use an active search-and-pursue strategy while foraging. Assuming all dives with active bottom time were for foraging, this whale spent about 80% of its total time in foraging dives. Dives with little activity at depth were occasionally observed, which were probably for resting. Although dive parameters resemble those of northern bottlenose whales, dive profiles seem to be different, suggesting that these 2 deep diving cetaceans employ different foraging strategies.; RefNo. [ 50 ]

2000

During the past few dwcades, the forest area in Thailand marked decreased from 53% to 26% of the total land area during the period 1960-1995. The forest cover has been converted to other types of land use, such as farmland, urban areas, orchards etc. In this study attempts were made to analyze the process of deforestation in the Mae Klong Watershed research station (Lintin), Thongphaphum District, Kanchanaburi Province Thailand. Five ddifferent time series of areal photographs were interpreted and land use maps were made in 1954, 1969, 1974, 1986 and 1994 to evaluate the impact of anthropoenic forces on land use changes in rural Thailand. From aerial interpretation, we can classify land use into two main types; forest and agricultural land. Based on the land use maps of 1954 and 1994, the forest cover in mountainous areas had been less converted to other types of land use than that in flat areas. However, forests in mountainous areas were conyinuously degraded during the study period. On the other hand, forest land use in flat areas decreased gradually from 1954 to 1974, and rapidly in 1974 and 1994 while agricultural land use increased. The changes of the forest cover in the mountainous and flat areas indicate that tht the topographic factors are related to the changes of land use and land cover in the area. In flat areas, the increase of the number of households in the two villages was an important factor for the conversion of the forest area to agricultural land. Therfore anthropogenic factors directly affected land use and land cover changes in the study area.; RefNo. [ 1737 ]

2003

; RefNo. [ 1736 ]

2050

; RefNo. [ 1735 ]

2002

The Contingent Valuation Method (CVM) was used to obtain the willingness to pay (WTP) of households in the contiguous area of the Garonne River near Toulouse, France, and the willingness to accept (WTA) of households that currently own land on the banks of the river to provide a strip of riparian land for habitat preservation. Results for the WTP study indicated a relatively large difference in WTP between open and closed ended responses. When corrected for the substantial number of 0 observations, the WTP was reduced by about half. The WTA appears consistent with revenues generated from crops. Moreover, Many farmers who were already providing habitat preservation indicated a zero minimum WTA. Although the small number of WTA responses severely limits the ability to draw definitive conclusions, a comparison of the derived benefits (WTP) and costs (WTA) was made, which appeared to suggest the possibility of a favorable a benefit/cost ratio.; RefNo. [ 1734 ]

2002

On the western coast of the Atlantic, according to the literature, 2 distinct groups of Semibalanus balanoides occur with a distinct interface near the Miramichi Estuary, New Brunswick, in the Gulf of St. Lawrence. On each side of this interface, the groups are characterized by clinal variations for MPI (mannose-6-phosphate isomerase) and GPI (glucose-6-phosphate isomerase). The present study was carried out to determine whether selection occurs at this interface, to establish how early in the sessile life period it occurs and to examine the selecting forces involved. Reciprocal transplant experiments of newly settled individuals to both sides of the interface were carried out. No significant differences specifically linked to source or destination were observed in growth or fecundity for the 2 groups at the sites studied for either control or transplanted individuals. However, differences in survival were observed; individuals transplanted south of the estuary showed lower survival than individuals transplanted north. An allozyme analysis of barnacle survivors for MPI and GPI, 2 alleles whose frequencies are known to vary abruptly in this region, indicated a change of allele frequency in transplanted individuals. The transplants’ allele frequencies came to resemble those of adults from target sites, while no change occurred in transplanted individuals at control sites. Taken together with previous results, our study suggests that selection occurs very early in the newly settled individuals (spat).; RefNo. [ 52 ]

1999

Spores newly realeased from plurilocular sporangia of Ectocarpus siliculosus (Dillw.) Lyngb. Sporophytes were assayed for chemotaxis to nutrients and for settlement stimulation by nutrients. To enable these measurements with relatively small volumes and numbers of released spores, we developed a computer-assisted motion-analysis assay for spore chemotaxis and verified the results with a more standard, capillary tube chemotaxis assay. The presence of the nutrient gradient did not influence the swimming behavior of E. siliculosus spores in the motion-analysis assay, and likewise no chemotactic effect was measured in the capillary tube assay. Microplate settlement asssays previously utilized with bacteria and invertebrates were dapted for use with algal spores settled at higher rates on a hydrophobic plastic surface than on surfaces with either positively or negatively charged hydrophillic coatings. Nutrient mixtures had no effect on the rate of spore settlement on hydrophobic surfaces.; RefNo. [ 1733 ]

1981

; RefNo. [ 1802 ]

2002

; RefNo. [ 53 ]

2003

Despite the widespread occurrence of mixotrophic dinoflagellates, most research on cyst formation in dinoflagellates has focused on phototrophic organisms or on factors affecting phototrophic growth (i.e. light intensity and nutrient supply). Presumably, factors that stimulate cyst formation in mixotrophic organisms would be combinations of those factors that affect phototrophic and phagotrophic growth (such as limiting light intensity and limiting prey concentrations). The toxic dinoflagellate Pfiesteria piscicida is an interesting test case because it has a complex life history and is considered mixotrophic. Recently, a form of P. piscicida has been described that does not have the ability to produce toxins (termed ‘non-inducible’). The objectives of this study were to identify which life stages are likely to be present in a mixotrophic culture of ‘non-inducible’ P. piscicida and to determine the morphological differences based on fluorescent stain uptake. Also, we examined which combinations of adverse environmental factors (low light intensity and low prey concentrations) affect life stage transformations. In this culture, we observed 3 distinct life stages (a zoospore stage, and 2 cysts). One of the cysts (termed Cyst A) has a thick cell wall and appears to form from actively feeding zoospores regardless of light intensity. The second type of cyst (Cyst B) has a much thinner cell wall and only forms from recently fed zoospores maintained in complete darkness. During the experiment, encystment rates to either cyst were low, suggesting that encystment will not dramatically affect bloom dynamics on small timescales.; RefNo. [ 54 ]

2003

The carotenoid astaxanthin is a powerful antioxidant and a compound of vital importance for many marine organisms such as crustaceans and salmonids. Although astaxanthin deficiency may have serious consequences for ecosystem functioning, its origin and transfer in the food web have been little studied. Astaxanthin is produced by planktonic crustaceans, but these cannot synthesise carotenoid pigments de novo; they rely on the availability of astaxanthin precursors through the consumption of phytoplankton algae. We performed 4 laboratory experiments to test how the production of astaxanthin in wild pelagic copepod communities (mainly consisting of Acartia) is affected when different phytoplankton communities (unfertilised, fertilised with N and P, or fertilised with N, P and Si) are supplied as prey. We show that phytoplankton community composition and biomass have profound effects on the production of astaxanthin in calanoid copepods. When they were grazing on a diverse phytoplankton community with high biomass dominated by chlorophytes, dinoflagellates and diatoms with thin silica frustules, astaxanthin production in the copepods was highest. It was lower when the copepods were fed with low phytoplankton biomass or high biomass dominated by large heavily silicified diatoms; these diatoms were not consumed and grazing was mainly on prymnesiophytes. When the astaxanthin production was high, maximum astaxanthin content per copepod individual of about twice the initial level was reached during sunrise. These results suggest increased feeding activity and astaxanthin production during the night and utilisation of astaxanthin for photoprotection and other antioxidant activities during the day.; RefNo. [ 55 ]

2003

The objective of this study was to evaluate the potential of near infrared reflectance spectroscopy (NIRS) to estimate the botanical composition of seagrass mixtures in the stomach contents of dugongs more rapidly and cost-effectively than by conventional means. NIRS estimation of dietary composition is achieved by developing calibration equations that relate NIR spectra of samples to laboratoryderived values for botanical composition. Once calibration equations have been developed, these characteristics can be estimated for further samples from their spectra alone. We developed calibration equations using samples from the stomachs of 26 dugongs (from a total data set of 128 dugongs) and validated them against a further set of 14 stomach samples. Nine dietary components were identified, 5 of which made up less than 5% of the total diet. Acceptable calibrations were obtained for the major components of dugong diets: seagrass rhizomes (pooled across all species) and the leaves of the seagrasses Thalassia hemprichii, Syringodium isoetifolium and Cymodocea species. We did not attain satisfactory calibrations for minor (<10%) dietary components. NIRS is a valid method for obtaining rapid information on the main components of the dugong diet. With larger calibration sets and fresh samples it should also be able to provide information on minor dietary components. NIRS is applicable to dietary studies of marine herbivores and should thus be of value to marine ecologists generally.; RefNo. [ 56 ]

2002

A large river plume generated by anomalous precipitation and oceanic circulation associated with Hurricane Mitch was detected off Honduras in October 1998 using SeaWiFS ocean color images. This event provides the background for analyzing connectivity between coral reefs and land in the Meso-American reef system. We discuss the potential implications of such short-term events for disease propagation and nutrification, and their potential significance in evolutionary processes.; RefNo. [ 57 ]

2001

A series of local factors such as substrate structure, presence or absence of kelp forests and environmental variables play an important role in determining both the diversity and abundance of temperate reef fish assemblages. The presence of kelp forests has been shown to increase structural complexity, available shelter, and prey availability in the reef environment. This, in turn, may affect the structural organization of the fish assemblage. In this study, the diversity, abundance and trophic patterns of subtidal fish assemblages at 2 localities off the northern Chilean coast were analyzed. These localities differ markedly in their spatial structure: the subtidal substratum at Caleta Errázuriz is characterized by a sloping bedrock with large rocks and boulders and a kelp forest, while at Carrizal Bajo it consists of a sharply declining bedrock with few boulders and isolated kelp stands. We hypothesized that structurally highly complex habitats would exhibit higher diversity, abundance and a more complex trophic organization in terms of more functional groups and guilds of reef fish assemblages than less structured environments. Contrary to our hypothesis, we found similar species diversity and fish abundance at both localities. However, there were clear differences in species dominance, number of functional groups and trophic guilds. There were also marked differences in the trophic webs between localities. In the presence of kelp forest, both carnivores and omnivores consumed mainly benthic prey inhabiting the understory canopy, while in its absence carnivores fed on pelagic prey in the water column. Therefore, a more complex spatial structure would seem to support a more complex trophic organization with a greater degree of connectivity, as well as interaction between the species in a reef fish assemblage.; RefNo. [ 58 ]

2003

Paralomis granulosa Jacquinot is a commercially fished lithodid crab species living in subantarctic and cold-temperate regions of southern South America. Its larval stages (Zoea I, II, Megalopa) are fully lecithotrophic, developing in the complete absence of food from hatching through metamorphosis; first feeding occurs in the first juvenile crab stage. In laboratory rearing experiments conducted at constant 1, 3, 6, 9, 12, and 15°C, we studied rates of larval and early juvenile survival and development in relation to temperature. At 1°C, many larvae (52%) reached the Megalopa stage almost 2 mo after hatching, but all died subsequently without passing through metamorphosis. Larval development was successfully completed at all other temperatures, with maximum survival at 6 to 9°C. The time of non-feeding larval development from hatching to metamorphosis lasted, on average, from 24 d (at 15°C) to almost 4 mo (117 d, at 3°C). When the experiment was terminated 1 yr after hatching, the 3rd (3°C) to 8th (15°C) juvenile crab instar had been reached. The relationship between the time of development through individual larval or juvenile stages (y) and temperature (T) was described as a power function (y = a × Tb, or log[y] = log[a] + b · log[T]; the same regression model was also used to describe the temperature-dependence of cumulative periods of development from hatching. The wide thermal tolerance window for successful larval development (at least 3 to 15°C) and the broad geographic range of this species show that the early life-cycle stages of P. granulosa are cold-eurythermal. This physiological trait together with larval independence of food indicate that this lithodid crab species is well adapted to severe conditions of cold in combination with the food-limitation in subantarctic regions. Since similar traits have been also observed in other Lithodidae, we suggest that early life-history adaptations to low temperatures and low planktonic productivity may explain the high number of lithodid species occurring at high latitudes and in the deep sea, i.e. in conditions under which other Decapoda show strongly reduced diversity.; RefNo. [ 59 ]

1932

; RefNo. [ 1759 ]

1979

; RefNo. [ 60 ]

1994

; RefNo. [ 1906 ]

1999

; RefNo. [ 1963 ]

1999

; RefNo. [ 1718 ]

1999

; RefNo. [ 61 ]

1999

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2000

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2000

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2000

1. GOOS is being iplemented in the Pacific islands region by PacificGOOS, which was formed in Suva in 1998. In August 2000, in Apia, Samoa, PacificGOOS held a regional workshop on the development of a coastal Global Ocean Observing System (GOOS) for the Pacific region. This workshop aimed to raise the level of awareness about PacificGOOS and its value for sustainable development, to inform participants about recent coastal GOOS developmnents to begin forming a regional network to take forward the development of operational oceanography in the region, to broaden participation in PacificGOOS and to develop the oulines of some pilot projects to take forward the implementation of PacificGOOS. Three project outlines were developed, on: (I) coastal water quality; (ii) mariculture developments; and (iii) coral reef health. Partnerships were created to take forward the development of each project. Participants were introduced to the concept of the Agro float project and explored its significance for the Pacific as well as in the ways in which Pacific nations could participate in and assist in the implementation of the project.; RefNo. [ 1727 ]

2000

; RefNo. [ 1765 ]

2000

; RefNo. [ 64 ]

2000

; RefNo. [ 1764 ]

2000

; RefNo. [ 1766 ]

2001

; RefNo. [ 1768 ]

2001

; RefNo. [ 1870 ]

2001

GOOS is being implemented in the Pacific islands region by PacificGOOS, which was formed in Suva in 1998. In August 2000, in Apia, Samoa, PacificGOOS hels a regional workshop on the development of a coastal Global Ocean Observing System (GOOS) for the Pacific region. This workshop aimed to raise the level of awareness about PacificGOOS and its value for sustainable development, to inform participants about recent coastal GOOS developments, to begin forming a regional network to take forward the development of operational oceanography in the region, to broaden participation in PacificGOOS, and to develop the outlines of some pilot projects to take forward the implementation of PacificGOOS. Three project outlines were developed, on: (I) coastal water quality; (ii) mariculture developments; and (iii) coral reef health. Partnerships were created to take forward the development of each project. Participants were introduced to the concept of the Agro float project and explored its significance for the Pacific as well as the ways in which Pacific nations could participate in and assist in the implementation of the project.; RefNo. [ 1722 ]

2001

; RefNo. [ 66 ]

2001

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2001

; RefNo. [ 1767 ]

2001

; RefNo. [ 1732 ]

2002

; RefNo. [ 67 ]

2003

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2003

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2003

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2003

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2003

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2004

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2004

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2004

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2004

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2050

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2050

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2050

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2050

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2050

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2050

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2050

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2050

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2050

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2050

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2050

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2050

Hurricane, impact key feefs; RefNo. [ 1950 ]

2050

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2050

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2050

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2050

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2050

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2050

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7

2005

The Ocean Conservancy, a non-profit group that works with regional and federal fishery councils in the US toward managing fisheries responsibly, produced a first 'scorecard' to compare the sustainability of different US fisheries. Sustainability is represented on a percentage scale called 'success scores' (100% being best). They evaluated the use of 'best management practices' (e.g. are stocks assessed, is there overcapacity, are catches below targets, is bycatch monitored, etc.), and whether there is current overfishing taking place and if the stock had been overfished in the past. They presented the scores of several coastal fisheries in the US by region and by individual fishery, showing that, overall, the North Pacific region is currently being managed best and the Caribbean worst.; RefNo. [ 2024 ]

2002

Recent empirical research has examined the relationship between certain indicators of environmental degradation and income, concluding that in some cases an inverted U-shaped relationship, which has been called an environmental Kuznets curve (EKC), exists between these variables. Unfortunately, this inverted U-shaped relationship does not hold for greenhouse gas emissions. One explanation of the absence of EKC-like behavior in greenhouse gas emissions is that greenhouse gases are special pollutants that create global, not local, disutility. But the international nature of global warming is not the only reason that prevents de-linking greenhouse gas emissions from economic growth. The intergenerational nature of the negative impact of greenhouse gas emissions may have also been an important factor preventing the implementation of greenhouse gas abatement measures in the past. In this paper we explore the effect that the presence of intergenerational spillovers has on the emissions income relationship. We use a numerically calibrated overlapping generations model of climate economy interactions. We conclude that: (1) the intertemporal responsibility of the regulatory agency, (2) the institutional capacity to make intergenerational transfers and (3) the presence of intergenerationally lagged impact of emissions constitute important determinants of the relationship between economic growth and greenhouse gas emissions.; RefNo. [ 81 ]

2002

; RefNo. [ 82 ]

2001

The European Eel Anguilla anguilla L, reaches the Israeli coastline, ( the most Eastern part of the Mediterranean sea) through its annual migration, but in relatively small numbers, to enter the very few river systems of Israel. It is occasionally found in fishponds connected to the river and canal system. However, because of its lack of visible scales, eel is considered not kosher and therefore inedible for religious and traditional Jewish people. It is for this reason that there is only a short history of eel farming in Israel compared to the longer fish farming history of the country. To date, the only producer of eel in Israel is the Kibbutz Dan Fish Farm located in the most Northern part of the country. This farm receives good quality water from one of Israel's major water resources, the river Dan. Several hundred kg of glass eel are imported from England every spring. On arrival, they are stocked at densities of 25,000(ca 7-8 kg)/cu. M. They undergo acclimation to reach the nursing water temperature of 23 deg C, and are bathed for 6 hours inoxytetracycline daily for the first 3 days. Feeding on the cod roe starts the day after arrival and continues for 5 days, after which a mix of cod roe and dry eel already feed only on dry feed crumbs. In the first year of nursing, the eel grow from an average of 0.20 g to an average of 19 g with an average FCR of 1.36. However, only ca 15% of the stock reaches the zise of over 150 g, ready to be exported, by the middle of the second year of the culture. The remainder reaches an export size after 2 years of culture. At the size of 7-40 g, the eel are tyransferred from the nursery to a set of outside ponds, sized 40 cu m or 250 cu m for ongrowing. In these ponds, the eel are feed a paste feed, once or twice a day, depending on the season. The main export market for the eel( export size of 150 to 280 g) is The Netherlands. The current yield is 30 tons a year. If market prices improve, it is hoped to achieve a yield of 200 tons by the year 2002.; RefNo. [ 1771 ]

1994

Landings of Queen conch throughout the caribbean region are estimated on the order of 4,000mt with potential value of $40 000 000 (US). The resources is not utilized efficiently, and much variability exists within the region with respect to stock status and management. Little information is available on stock status, especially on deep water, and on the degree and effect of habitat destruction. The identification of critical habitats for recruitment and for juvenile growth and survival, with an understanding of processes affecting populations within and between these habitats is given high priority. Managemnt on both the local and iternational levels is needed and, considering the degree of uncertainty in stock status, should be conservative. Enforcement must be given emphasis and should be considered within the larger context of protecting coastal regions and all associated living resources. Mariculture has the potential to supplement fisheries landings and contribute to stock rehabilitation but considerable constraints to large scale production still exist. The greatest needs are in post larval growout, particularly the development of a cost effective artificial feed and the reduction of predation. Advances in research and management would be enhanced by an increase in communication technology transfer among scientists, between scientists and managers and fishermen Past experience has shown significant time-lags between the attainment of scientific information and its incorporation into management; with most stocks now intensively fished, failure to incorporate significant new information promptly could result to stock collapse.; RefNo. [ 1772 ]

2003

The effects of solar radiation, both visible and ultraviolet (UV-R, 290 to 400 nm), on the kelp Laminaria saccharina (L.) Lamour were examined in relation to depth distribution and tidal height in the Gulf of Maine. Despite the high attenuation of visible and UV-R, shallow subtidal L. saccharina exhibited significant decreases in midday measurements of steady-state quantum yields of Photosystem II (PSII) fluorescence compared to deeper conspecifics. Decreases in PSII quantum yields under low-tide conditions at midday were more pronounced and associated with higher coefficients of non-photochemical quenching than yields of the same algae measured at midday under high-tide conditions. Steady-state quantum yields in shallow algal populations had not recovered by early morning of the following day. Laboratory experiments were conducted to partition out the effects of high visible radiation versus UV-R effects on steady-state quantum yields observed in the field. Algae exposed to solar visible PAR (photosynthetically active radiation; 400 to 700 nm), PAR + UV-A (ultraviolet-A radiation; 320 to 400 nm), and PAR+UV-A+UV-B (ultraviolet-B radiation; 290 to 320 nm) treatments exhibited daily midday depressions in steady-state quantum yields, similar to those observed in field samples at low tide. The PAR+UV-A+UV-B treatment showed a significantly greater depression in PSII quantum yields than field samples at low tide, and took longer to recover at night. Algae exposed to the UV-R component of the spectrum also showed a significant decrease in gross primary production and contained less areal chlorophyll a than field samples, while nonphotochemical quenching (a measurement of the dissipation of excess excitation energy) was significantly higher during midday exposures to UV-B. Significantly greater concentrations of the UV-Babsorbing compound mycosporine-glycine, a mycosporine-like amino acid (MAA), were present in the shallow field and experimental PAR+UV-A+UV-B treated algae. Our results suggest that exposure to midday visible irradiances resulted in dynamic photoinhibition, while exposure to visible and UV-R irradiance in the Gulf of Maine results in both dynamic and chronic photoinhibition that causes a decrease in gross primary production of L. saccharina in shallow waters or under low-tide conditions.; RefNo. [ 83 ]

2004

The apparent use of marine and freshwater habitats by Anguilla australis and A. dieffenbachii was examined by analyzing the strontium (Sr) and calcium (Ca) concentrations in otoliths of silver eels collected from Lake Ellesmere, which is a shallow brackish-water coastal lagoon in New Zealand. The age and growth of these eels was also examined using their otolith annuli. Size and ages of females were greater than those of males for both species. Growth rates were similar among sex and species, but the highest growth rates were observed in eels that experienced saline environments. Line analyses of Sr:Ca ratios along a life-history transect in each otolith showed peaks (ca. 15 to 21 × 103 in A. australis, 14 to 20 × 103 in A. dieffenbachii) between the core and elver mark, which corresponded to the period of their leptocephalus and early glass eel stage in the ocean. Outside the elver mark, the Sr:Ca ratios indicated that eels had remained in different habitats that included freshwater (average Sr:Ca ratios, 1.8 to 2.4 × 103), areas with relatively high salinities (average Sr:Ca ratios, 3.0 to 7.4 × 103), and in some cases individuals showed clear evidence of shifts in the salinity of their environments. These shifts either indicated movements between different locations, or changes in the salinity of the lake. There were more individuals of A. australis that used areas with intermediate or high salinities, at least for a short time (85% of individuals), than A. dieffenbachii (30%). These findings suggest that these 2 southern temperate species may have the same behavioral plasticity regarding whether or not to enter freshwater or remain in marine environments, as has been recently documented in several northern temperate anguillid species.; RefNo. [ 85 ]

2003

A comparative study of the otolith microstructure of glass eels Anguilla celebesensis from the Indonesian and Philippine coasts determined the timing of metamorphosis and age at recruitment to freshwater habitats; 2 samples from Indonesia were analyzed and statistically compared with a previously published sample analyzed using the same techniques. Ages at metamorphosis and at recruitment were, respectively: 98 ± 7.2 d (mean ± SD) and 122 ± 7.2 d for specimens from the Poso River in Indonesia; 90 ± 13.6 and 112 ± 14.2 d for specimens from the Poigar River in Indonesia; and 124 ± 12.0 and 157 ± 13.7 d for specimens from the northern Philippines. The average duration of metamorphosis was very similar (15 to 17 d) in all specimens. A close linear relationship was found between age at metamorphosis and age at recruitment. These findings and the regional geography of the islands and ocean currents suggest that A. celebesensis has several spawning areas and potentially isolated populations in the region, as has been suggested for another, more widely distributed tropical anguillid, A. marmorata.; RefNo. [ 1774 ]

2003

An increased incidence of harmful algal blooms (HABs) has been reported in nearshore coastal waters, including economically important aquaculture sites worldwide. This has generated interest in using ecologically inert clays as a means of mitigating HABs at relatively shallow enclosed mariculture sites. This proposed mitigation measure assumes that flocculation and accelerated sedimentation of large algal cells (dinoflagellates) occurs with the application of clays. The objective of the current research was to characterize suspended clay-algal interactions and in situ particle size in a laboratory application of the phosphatic clay IMC-P (1.8 µm mean equivalent spherical diameter, ESD) to a simulated Heterocapsa triquetra (14.7 µm mean ESD) bloom. Flow speed was adjusted to provide 2 contrasting regimes (mimicking possible field conditions). This research was conducted in a recirculating flume and used a novel in situ device, the small volume particle microsampler (SVPM), for particle size characterization. Results indicated that 100% of the thecate dinoflagellate H. triquetra was removed in 48 h by IMC-P in a low-flow (<2 cm s1) regime, but remained in the water column in the high-flow (>13 cm s 1) regime. The mechanism for algal removal is equivocal since SVPM filter photographs indicated that clay aggregated to form particles >3 µm, but did not aggregate with algal cells under the experimental conditions tested. At this particle size, the clay aggregates become available for retention with 100% efficiency on the gills of suspension-feeding bivalves, which could be seriously affected by the increased particle flux to the bottom. The mechanism of cell removal by clays has not been identified; however, it may occur via direct effects of clay on cell surface properties and swimming ability. Further investigations on the removal mechanism are required to predict the fate of cells in a field application of clay.; RefNo. [ 90 ]

2001

Following the closure of 2 outfalls, changes in the number of species and abundance of intertidal organisms at 2 decommissioned outfalls were compared with control (sewage outfalls that remained in operation) and reference (natural) areas. Two intertidal levels (mid- and low-shore) were sampled 5 times over 2 yr following the closure of these outfalls. It was proposed that the number of species would increase and the abundance of green algae would decrease through time at the decommissioned outfalls, while no noticeable changes in the number of species and the abundance of green algae were predicted at the reference and control locations. The 4 outfalls (2 decommissioned and 2 controls) were analysed separately with an asymmetrical ANOVA to identify differences between the outfall and the average of their 2 respective reference locations. Non-metric multidimensional scaling ordination using Bray-Curtis similarity was used to identify differences between outfalls and reference locations in the structure of the assemblages at the 2 heights on the shore. During the first (6 mo after closure) and second sampling period, fewer species and greater abundance of green algae were observed at every outfall than at their respective reference locations in low-shore areas. In the subsequent sampling periods, the number of species at the decommissioned outfalls increased through time while there were consistently fewer species at the control outfalls. The opposite pattern was observed for the abundance of green algae (i.e., decreases through time at the decommissioned outfalls). Assemblages at control outfalls never clustered with their reference locations. At midshore levels, no pattern was observed at any sampling date. Furthermore, at the first time of sampling, the number of species was not smaller at the outfalls than at reference locations. These results suggest that sewage outfalls have little impact on the number of midshore species. The results of univariate analysis were similar to those from multivariate analyses. Assemblages of species in low-shore areas at the decommissioned outfalls were different from those at reference locations at the first sampling date, but became more similar by the last sampling date. Some exceptions were observed at the site closest to the point of discharge. Again no differences in abundances of organisms were observed at any time for any outfall. The results showed a recovery of the benthic assemblages in the low-intertidal zone after the closure of 2 sewage outfalls. Furthermore, this study supports the importance of using more than 1 reference and control areas to measure recovery of a site without ambiguity.; RefNo. [ 86 ]

2001

Public policy toward pesticide use in agriculture can benefit from data coming from models that integrate ecological and economic constraints into cropping decisions and pesticide use. Herein we use such a model to focus on the environmental and economic effectiveness of a specific set of tools used to promote sustainable agriculture with less pesticide runoff incentive-based instruments created by risk-indexed herbicide input-taxes. We measure risk by health advisory levels and by an ecological economic simulation model that estimates predicted exposure levels. We explore whether this innovative solution of herbicide input-taxes does better at reducing losses to farm net returns, and surface and groundwater loadings than quantity restrictions. Using the integrated CEEPES model, our results suggest that risk-indexed input taxes by information about individual herbicide exposure levels can be a cost-effective tool to reduce predicted groundwater exposures. No single policy, however, was efficient at simultaneously improving groundwater and surface water quality. Instead we construct an efficient policy set. We find exposure-induced taxes were most efficient for small percentage reductions in overall exposure, bans were efficient for medium reductions, and flat taxes were efficient for high reductions.; RefNo. [ 92 ]

2002

We determined mercury levels in internal tissues and feathers from corpses of Audouin’s Larus audouinii and yellow-legged gulls L. cachinnans michaellis, common terns Sterna hirundo and European shags Phalacrocorax aristotelis desmarestii, as well as from fish representative of trawler discards, collected at the Ebro Delta (NW Mediterranean) between March and July (seabird’s breeding season) in 1997 to 1999. The levels of mercury were significantly lower in epipelagic (Clupeiforms) than in demersal fish. When representation of each species in the discards is taken into account, the mean mercury concentration from this resource is more than double that of epipelagic fish (the main natural prey for most seabirds in the area). The shag was the only species with direct access to benthic fish, as it can dive to the seabed, and shags presented high levels of mercury even though they do not feed on discards. The other seabirds showed mercury levels in accordance with their seasonal use of discards. Audouin’s gull, which exploits discards extensively during the breeding season, had the highest levels in those tissues reflecting mercury intake during the breeding season (liver and 1st primary feathers). In contrast, the common tern makes little use of discards and presented the lowest levels of mercury. For those samples reflecting the intake of mercury during the winter (mantle feathers), when only the yellow-legged gull exploits discards extensively, this species presented the highest values. Audouin’s gull and the common tern showed similarly low concentrations of mercury for this period. We conclude that consumption of discarded demersal fish strongly influenced mercury contamination of surface-feeding seabirds.; RefNo. [ 93 ]

6

2003

The study provides a new technique based on the use of the “Box and Whisker Plot” designed to distinguish opportunistic and rare phytoplanktonic species. Presents an effective methodology for water characterization and can also be used as a qualitative tracer for detecting renewal processes of coastal marine ecosystems.; RefNo. [ 2054 ]

2001

In the late 1970s the American jackknife Ensis americanus (syn. E. directus) was introduced into the North Sea. The history of its dispersal along the coast is used to derive an estimate of the species’ mobility. On average, the population spread by 125 km per year to the north and, at the same time, by 75 km per year to the west, against the residual currents. Therefore, recruitment in a given area may depend on larvae produced some 125 km upstream while the offspring produced in the study area may recruit another 125 km downstream. As a consequence, the population dynamics cannot be explained from single-site sampling and even studies on local effects need knowledge of the population dynamics on a large spatial scale to distinguish between general trends and local peculiarities. For E. americanus in the North Sea a minimum longshore extension of the sampling area of some 250 km is suggested. Provided other benthic species with pelagic larvae have similar dispersal capabilities, community studies need a similar spatial scale. This implies that the number of distinguishable major communities is very limited in the coastal North Sea. To overcome the logistic difficulties in studying a sufficiently large area, a permanent network of institutes engaged in benthic population and community dynamics is recommended.; RefNo. [ 94 ]

2000

At a sandy beach site on the island of Sylt in the North Sea, the interstitial micro- and meiofauna has been studied by several investigators since the 1960's, and a total of 652 species living between the tide marks has been reported. Most of the effort was devoted to the free-living Plathelminthes ('Turbellaria'), which accounted for 32% of all species, followed by Nematoda (27%), Ciliata (11%, the smallest size-groups not included), Copepoda (10%), Gastrotrichia (7%), and 9 other major taxa. The species ratio of macrofauna to interstitial fauna was about 1:25 for the entire beach. The investigated shore consists of a steep upper slope from high to mid tide line (13 m), and a gentle lower slope from mid to low tide line (100 m horizontal distance). While the macrofauna gradually increased in species number from the beach face (8 species) towards low tide line (23 species), this was not the case for the diverse interstitial fauna. It attained a broad maximum of species richness at a 10 m wide terrace just below the steep slope of the beach face. Here an optimal balance may exist between organic supply, oxygen and water retention. Three hundred and fifty species per meter interval of the transect were recorded. From there species richness declined gradually towards the low tide line (230 species) and abruptly at the steep slope of the beach face (170 species). Similarity analysis indicates a threshold in species composition at the bend between the gentle and the steep slope, which is just above mide tide level. For marine interstitial fauna the mid shore provides a center of diversity.; RefNo. [ 944 ]

2000

; RefNo. [ 1775 ]

1999

; RefNo. [ 1036 ]

2001

; RefNo. [ 1776 ]

2000

This paper reports on the results of an investigation of management costs in the fisheries of Iceland, Newfoundland and Norway and discusses them in a more general framework. Management costs are defined as costs necessary to overcome the problems associated with common property. The question of whether management costs should be paid by industry is discussed, as is the likely e!ect of user pay on the efficiency with which management is provided. Since management has public goods characteristics, it is likely that there is an unavoidable role for government in providing these services. The question of who pays for it is separate, and recovering costs from industry has both effciency and optimal taxation aspects. A greater involvement in management by industry further raises the question of compatibility between the industry's interests and the public interest. Measured as percent of gross value of fish landings the management costs are by far highest in Newfoundland (15}25%), lowest in Iceland (about 3%), with Norway in the middle (about 10%). Management costs thus appear to be substantial and quite variable. This gives rise to three conclusions. First, when calculating optimal harvesting and investment paths one must take the management costs of implementing these paths explicitly into account. Second, what is the economic effciency of management? Could the same level of benefits be produced at lower costs? Third, can fisheries management expenditures of the magnitude discussed be justified in the sense that the benefits exceed the costs?; RefNo. [ 95 ]

2000

; RefNo. [ 96 ]

2002

The purpose of this paper is to investigate seascape biodiversity patterns along the Mediterranean and the Black Sea through the study of the benthic polychaete biogeography of the region. A set of non-parametric multivariate analyses and recently developed diversity indices were performed on the benthic polychaete inventories of the areas of the Mediterranean and the Black Sea. Both the numbers of species and the multivariate analyses demonstrate a west-east zoogeocline, shown by the decreasing number of species and by the multivariate similarity pattern of the areas. The performance of the ‘second-stage’ multi-dimensional scaling (MDS) shows, when species information is aggregated to genera, results belonging practically to the same similarity pattern, independent of the similarity coefficients utilized. The same similarity pattern is derived when species information is aggregated to the zoogeographical categories of amphi-Atlantic, Atlanto-Mediterranean, cosmopolitan and endemic species. BIO-ENV analysis reveals a large number of geographic, climatic and trophic variables to be highly correlated with the similarity pattern derived from the various taxonomic/ zoogeographical categories. The synergy, however, of the environmental variables is best reflected in the case of the endemic Mediterranean species. The latter category is considered as the critical zoogeographic category with respect to providing information on the evolutionary history of the taxon in the region. The application of the average taxonomic distinctness and the variation of taxonomic distinctness indices resulted in a diversity ranking of the areas, which appears to be independent of the number of species hosted in each area. However, this is not the case for the phylogenetic diversity (PD) index. Additionally, the former 2 indices indicate that the benthic polychaete species-pool, hosted in the Mediterranean and the Black Sea areas, may well serve as a useful basis for future comparisons in environmental assessment studies. Finally, results from the application of the area-diversity formula show that the equilibrium model can be applicable for the endemic benthic polychaetes of the region: the number of endemic species can be considered as a function of the degree of isolation of the area from the source region against the degree of within-area isolated habitats.; RefNo. [ 97 ]

2002

Fish farming is a biological production process dependent upon biological and environmental conditions. These constraints imp y that different fish farmers are likely to have a similar distribution of different sizes of fish over time. If there are no perfect substitutes for the different sizes of fish in the short-run, this production cycle can cause different relative price between the different sizes over the year. By studying prices for different sizes of salmon for the period 1992-1998 we show that such patterns exist. This can have important implications when studying aquaculture industries and markets.; RefNo. [ 1779 ]

2000

; RefNo. [ 1780 ]

2000

Previous studies have determined that Caribbean reef sponges of the genus Agelas are chemically defended from fish predation by brominated pyrrole alkaloids, and that the compounds responsible for this defense have been elucidated for 1 species, A. clathrodes. In this study, we expand our understanding of chemical defense in this common sponge genus to include the characterization of defensive metabolites in the tissues of A. wiedenmayeri and A. conifera. Bioassay-directed isolation of defensive metabolites was undertaken using fish feeding assays carried out in laboratory aquaria and in the field. A. wiedenmayeri contained the same 2 major metabolites as A. clathrodes, 4,5-dibromopyrrole-2-carboxylic acid (1), and oroidin (2), in addition to a small amount of bromoageliferin (7). The 2 major metabolites were present at higher concentrations in samples of A. wiedenmayeri than in A. clathrodes, and their relative concentrations were reversed, with A. wiedenmayeri on average containing more 4,5-dibromopyrrole-2-carboxylic acid (1) (2.0 mg ml1) than oroidin (2) (0.8 mg ml1). A. conifera contained a mixture of dimeric bromopyrrole alkaloids dominated by sceptrin (3), with <10% each of dibromosceptrin (5), bromoageliferin (7), dibromoageliferin (8), ageliferin (6), and bromosceptrin (4). Mean concentration of sceptrin (3) in sponge tissue was 5.3 mg ml1; this compound deterred feeding of reef fish in aquarium assays at 1.0 mg ml1, the lowest concentration assayed. Sceptrin (3) concentrations were higher in sponges collected in the southern Bahama Islands than in those collected in the middle Bahamas, but the reasons for this variation remain unclear. The structure-activity relationship of the pyrrole group was investigated by assaying derivatives of the active metabolites. Feeding deterrent activity of the molecule was enhanced by the addition of bromine to the pyrrole group, but not affected by exchange of the heteroatom from N to O or S. Combining an understanding of the structure-activity relationship of Agelas metabolites with an understanding of the variation in these metabolites across the genus may provide insight into the evolution of defensive chemistry in this highly successful taxa of pan-tropical sponges.; RefNo. [ 98 ]

2001

; RefNo. [ 1781 ]

2000

; RefNo. [ 1783 ]

2002

While evidence is mounting that larval reef fish are active participants in the process of dispersal and settlement, the sensory and behavioural mechanisms by which these fishes disperse and return from their oceanic phase to the reefs remain unknown. On One Tree Island (Great Barrier Reef, Australia), we tested freshly collected animals in a large choice-flume on the shore. Here, we present the first evidence that larval reef fish (primarily apogonids) approaching the time of settlement are capable of detecting differences between ocean and lagoon water and prefer lagoon water. We also demonstrate that they sniff actively with well-innervated noses and that attraction to lagoon water was not affected by warmer or colder temperatures. We conclude that they used chemical signals to orient toward lagoon water. Finally, we describe ebb tide plumes of lagoon water that extend many kilometers from reefs. Such plumes could provide chemosensory cues for dispersal and settlement stages of reef fish as they develop swimming efficiency. We argue that fishes may imprint to reef odour as embryos and/or early larvae and that this could facilitate both retention near the natal reef and navigation toward reefs from greater distances.; RefNo. [ 101 ]

2000

; RefNo. [ 1785 ]

1984

; RefNo. [ 1784 ]

2003

; RefNo. [ 102 ]

2000

Between the years 1989 and 1992, severe drought conditions occurred in the Thames estuary catchment, significantly reducing freshwater flows into the estuary and affecting estuarine water quality. Long-term data assembled for water quality between 1977 and 1992 were combined with invertebrate abundance data obtained from the intake screens of West Thurrock power station over the same period. This allowed an examination of the influence of drought-induced changes in water-quality parameters on the populations of the most abundant mobile estuarine invertebrates. For 8 invertebrate species, seasonal and monthly means for pre-drought (1977 to 1988) and drought (1989 to 1992) abundances were calculated and tested for significant differences. Time-series data were used to estimate regression models explaining observed variations in populations of Carcinus maenas, Crangon crangon and Gammarus spp. during both periods. Stability tests were used to establish significant differences in pre-drought and drought models. Significant mean seasonal and monthly differences were found for C. maenas and Gammarus spp. in both winter and summer, with significant summer differences being apparent for C. crangon and Palaemon longirostris. Regression analyses confirmed these results for the modelled species and highlighted the ignificance of drought-related changes in temperature for all 3 crustaceans, with dissolved oxygen being an additional significant variable for C. crangon. The reported significant changes in abundance of the studied species during drought conditions have important implications for the structure and dynamics of estuarine food webs, as C. maenas, Gammarus spp., and particularly C. crangon, are either important predators on invertebrates and juvenile fish or major food items for estuarine fish species.; RefNo. [ 103 ]

1992

; RefNo. [ 1786 ]

2004

Despite suspended solids being an important water-quality parameter in the regulatory process, very little is known about the risks of prolonged exposure to high concentrations of suspended solids in fish, especially marine species. In this study, the green grouper Epinephelus coioides, an important mariculture species with a wide geographic distribution, was exposed to various concentrations (0, 50, 100, 200, 1000 and 2000 mg l1) of suspended solids for 6 wk. The results showed that exposure was not lethal at environmentally realistic concentrations, and no changes in food intake, growth and RNA:DNA ratio were observed. However, damages to gill structure, including epithelium lifting, hyperplasia in the pillar system, and reduction of epithelial volume, were clearly evident, and strongly correlated with suspended solid concentration exposure. Despite the observation that serum osmolarity and haematocrit values did not change, Na+, K+-ATPase activities and chloride cells of the gill lamellae were altered, indicating that fish were experiencing osmoregulatory stress. Reduction in levels of free triiodothyronine (T3) in serum further confirmed that fish were experiencing physiological stress with suspended solids exposure. The overall results suggested that prolonged exposures can cause sub-lethal stress and compromise fish health, even though the high suspended solids we delivered were in concentrations that have been reported in coastal environments as not lethal to green grouper.; RefNo. [ 105 ]

1998

Despite suspended solids being an important water-quality parameter in the regulatory process, very little is known about the risks of prolonged exposure to high concentrations of suspended solids in fish, especially marine species. In this study, the green grouper Epinephelus coioides, an important mariculture species with a wide geographic distribution, was exposed to various concentrations (0, 50, 100, 200, 1000 and 2000 mg l–1) of suspended solids for 6 wk. The results showed that exposure was not lethal at environmentally realistic concentrations, and no changes in food intake, growth and RNA:DNA ratio were observed. However, damages to gill structure, including epithelium lifting, hyperplasia in the pillar system, and reduction of epithelial volume, were clearly evident, and strongly correlated with suspended solid concentration exposure. Despite the observation that serum osmolarity and haematocrit values did not change, Na+, K+-ATPase activities and chloride cells of the gill lamellae were altered, indicating that fish were experiencing osmoregulatory stress. Reduction in levels of free triiodothyronine (T3) in serum further confirmed that fish were experiencing physiological stress with suspended solids exposure. The overall results suggested that prolonged exposures can cause sub-lethal stress and compromise fish health, even though the high suspended solids we delivered were in concentrations that have been reported in coastal environments as not lethal to green grouper.; RefNo. [ 106 ]

2003

To investigate site fidelity and homing behavior in juvenile loggerheads (Caretta caretta, L.), a markrecapture study spanning four years (19982001) was conducted in Core Sound, N.C., USA. Each year of the study, approximately half of the turtles captured were tagged and released near the capture sites (n=207), while the remaining turtles were displaced 1520 km and released (n=198). Loggerheads in both groups were recaptured in equal proportions near the original capture sites and many individuals were also recaptured in subsequent years. These data imply that juvenile loggerheads often returned to their capture sites following displacement, because if turtles dispersed randomly or remained near their release sites, then fewer displaced turtles should have been caught again. Moreover, because turtles migrate out of North Carolina sounds each winter, turtles recaptured at the same locations in different years evidently returned to specific sites following long migrations. To further investigate homing behavior, a small number of displaced turtles (n=28) were tracked using radio telemetry following their release. Although transmitters detached from most turtles within a few days, analyses of initial headings showed strong orientation in the direction of the capture site. In addition, four turtles successfully tracked for longer periods of time all returned rapidly to the vicinity of the capture location and remained in the area. Taken together, the results of this study indicate that juvenile loggerheads exhibit fidelity to specific areas during summer months and possess the navigational abilities to home to these areas following forced displacements and long-distance migrations.; RefNo. [ 107 ]

2000

Surveys at the whole-lake scale take some time to carry out: several hours or several days. For logistic reasons, the sites are not sampled simultaneously or in a random sequence. Traditional limnological sampling methods require an appreciable amount of time at each site. Any sampling strategy that is not random or simultaneous introduces dependencies among the observations, which must be taken into account during the analysis and interpretation of the data. What is the real nature of the variation measured using a given sampling design? This question is approached using sites sampled by two boat teams during two consecutive days. Statistical modelling was used to partition the variation of zooplankton size-class data into environmental and spatial components. The conclusions reached after an analysis that did not control for the sampling design are erroneous and quite different from those reached when the effect of the sampling design (factors Day, Boat, and Hour) was taken into account. Clearly, when a significant effect of the sampling design is found, one must control for it during the analysis and interpretation of ecological variation.; RefNo. [ 1787 ]

2000

Surveys at the whole-lake scale take some time to carry out: several hours or several days. For logistic reasons, the sites are not sampled simultaneously or in a random sequence. Traditional limnological sampling methods require an appreciable amount of time at each site. Any sampling strategy that is not random or simultaneous introduces dependencies among the observations, which must be taken into account during the analysis and interpretation of the data. What is the real nature of the variation measured using a given sampling design? This question is approached using sites sampled by two boat teams during two consecutive days. Statistical modelling was used to partition the variation of zooplankton size-class data into environmental and spatial components. The conclusions reached after an analysis that did not control for the sampling design are erroneous and quite different from those reached when the effect of the sampling design (factors Day, Boat, and Hour) was taken into account. Clearly, when a significant effect of the sampling design is found, one must control for it during the analysis and interpretation of ecological variation.; RefNo. [ 1788 ]

2001

; RefNo. [ 1789 ]

2002

We studied the spatial variation in biotic variables of a Macoma balthica population. Systematic sampling was carried out over an environmentally heterogeneous intertidal bay of the St. Lawrence Estuary. Several biotic (density, body tissue and shell mass, reproductive effort, shell length and growth) and abiotic (intertidal level, sediment characteristics) variables were concurrently analysed to quantify the part of the variance accounted for by the abiotic factors and the part accounted for by density (density was also studied as an explanatory variable). Redundancy analysis and multiple regression were used. The variables examined were mapped to show the trends in their spatial variation. Density was highly variable, from 0 to 2700 ind. m–2, and was mainly positively related to the percentage of sand in the sediment. Most biotic variables were spatially variable, and the variables accounting for most of this variation were shore level and density. Body tissue and shell mass were negatively affected by increasing shore level and density. Shell length decreased with increasing shore level and increased with increasing pore water content. Reproductive effort was enhanced at high density.; RefNo. [ 108 ]

5

1999

This paper examined the effects of MPAs beyond simply reducing fishery mortality of target species. Theoretical studies have suggested that increased predator numbers within a reserve can lead to a trophic cascade, whereby taxa two or more trophic levels below a target species show a response to the change in management (see Paper 11 below). In the case examined, reduction in fish and invertebrate urchin-predators lead to increased urchin numbers and hence increased grazing pressure. Within the reserves, fish and invertebrate urchin-predators had increased in number and mean size, leading to a reduction in urchin numbers and an increase in macroalgal abundance. The increased macroalgal abundance within reserves compared to fished areas lead to higher levels of benthic primary production in reserves compared to fished areas. This suggests that the implementation of reserves can fundamentally alter energy partitioning within an ecosystem. Supporting evidence from other studies is presented and discussed.; RefNo. [ 2041 ]

2000

This paper introduces the papers of this Special Issue on Achieving Food Security in Central Asia. Identifying the current challenges, it enlists the information gaps and policy research needs for accelerating the reform process in the food, agriculture and natural resource sectors of the Central Asian Republics. The paper concludes by calling for identifying policies and institutional arrangements that facilitate economic reforms that will lead to poverty reduction, increased food security, and sustainable use of natural resources.; RefNo. [ 1790 ]

2000

This paper attempts to provide insights into poverty, food insecurity, and malnutrition in Central Asia in the period following independence, and presents the available evidence from household-level data in the Kyrgyz Republic. It finds that although some improvement has been made in recent years, significant levels of poverty, food insecurity, and child malnutrition still exist. The paper argues that, in the short run, efforts should be made to protect vulnerable groups by investing in information generation and building capacity to design and implement food security and nutrition policies and programs. Increasing the speed of policy reforms and investment in productivity-enhancing agricultural research and rural infrastructure are fundamental for long-tern sustainable development in Central Asia; RefNo. [ 1791 ]

1998

The response of mixed Southeast Asian seagrass beds to siltation was analyzed based on field data, a transplantation experiment and experimental manipulation of light availability in seagrass populations along a silt gradient at Cape Bolinao, The Philippines. Seagrass species diversity, shoot density and depth penetration declined with increasing amounts of suspended material and increasing water column light attenuation along the silt gradient. The seagrass species could be ranked according to decreasing tolerance to siltation as: Enhalus acoroides > Cymodocea serrulata > Halodule uninervis > Thalassia hemprichii > Halophila ovalis > Cymodocea rotundata > Syringodium isoetifolium. A gradual decline in shoot density and depth penetration of the different species along the silt gradient suggested that changes in the vertical light attenuation coefficient in the water column, primarily caused by differences in suspended inorganic solids, was the most important factor affecting seagrass performance. However, inconsistency among the species in response to increasing water depth, artificial shading and transplantation indicated that other factors, such as siltation-derived changes in sediment conditions, contribute to the sequential loss of seagrass species along the silt gradient.; RefNo. [ 945 ]

2000

; RefNo. [ 1796 ]

2003

While biodiversity in deep-sea soft sediments appears to be high, little is known about diversity levels on deep-sea hard substrates. To determine the contribution of potentially abundant whale-skeleton habitats to deep-sea biodiversity, we compare the local macrofaunal species richness and composition on 3 sulfide-rich whale skeletons to assemblages from vents, seeps, and other deepsea hard substrates. Based on rarefaction curves, whale skeleton diversity is higher than diversity in any other deep-sea hard substrate habitat. The average local species richness (185 spp.) on single chemoautotrophic whale skeletons approaches known levels of global cold-seep macrofaunal species richness (229 spp.), and exceeds the richness of the most speciose vent field known (121 spp.). Species richness on the whale skeletons is also substantially higher than on other deep-sea nonreducing hard substrates, such as manganese nodules and rocks. Richness levels approach those in deep-sea soft sediments and exceed some shallow-water hard substrates. This high species richness may be explained by unusually high trophic diversity on whale bones due to the presence of sulphophiles, generalized organic-enrichment respondents, whale-bone consumers, and background hard-substrate fauna such as suspension and deposit feeders. High species richness levels on whale skeletons and deep-sea sponge stalks suggest deep-sea hard substrates may harbor higher levels of diversity than previously recognized.; RefNo. [ 110 ]

2002

Despite extensive research into the coral bleaching phenomena there are very few data which examine the population biology of affected species. These data are required in order to predict the capacity of corals to respond to environmental change. We monitored individual colonies of 4 common coral species for 8 mo following historically high sea-surface temperatures on the Great Barrier Reef in 1998 to compare their response to, and recovery from, thermal stress and to examine the effect of bleaching on growth and reproduction in 2 Acropora species. Platygyra daedalea and P. lobata colonies took longer to bleach, longer to recover and longer to die. In contrast, Acropora hyacinthus and A. millepora colonies bleached quickly and most had either recovered, or died, within 14 wk of the initial reports of bleaching. Whole colony mortality was high in A. hyacinthus (88%) and A. millepora (32%) and partial mortality rare. In contrast, most colonies of P. daedalea and P. lobata lost some tissue and few whole colonies died. The mean proportion of tissue lost per colony was 43 ± 6.6 % and 11 ± 1.1 % respectively. Consequently, observed hierarchies of species susceptibility will depend critically on the time since the onset of stress and must consider both whole and partial colony mortality. Colony mortality was highly dependent on visual estimates of the severity of bleaching but independent of size. Growth rates of Acropora colonies were highly variable and largely independent of the severity of bleaching. A. hyacinthus was more susceptible to bleaching than A. millepora with 45% of surviving colonies gravid compared to 88%. High whole-colony mortality combined with a reduction in the reproductive output of surviving Acropora suggests that recovery to former levels of abundance is likely to be slow.; RefNo. [ 111 ]

2003

The depth range of coral species has often been attributed to post-settlement mortality reflecting different physiological tolerances of species along physical gradients, such as light and water movement. Consequently, the potential of habitat selection by larvae to contribute to these patterns has been largely ignored. To test whether larvae prefer substratum conditioned in the parental habitat, the larvae of 6 common coral species, with contrasting depth distributions, were introduced to aquaria containing settlement tiles conditioned at 2 and 12 m (shallow and deep), plus unconditioned tiles. Goniastrea aspera and G. retiformis, reef-flat species, settled on shallow tiles in densities 4 times greater than on deep tiles. Fungia horrida, a species locally restricted to deeper water, was 6 times more abundant on deep tiles. F. repanda, with a similar distribution, settled exclusively on deep tiles. Platygyra daedalea, a species with a wide depth range, settled preferentially on shallow tiles; however, this preference was much less pronounced than in G. aspera or G. retiformis. Leptoria phyrgia, another species with a wide depth range, was equally abundant on deep and shallow substrata. We conclude that the depth distribution of these species is influenced, in part, by substrate preferences of larvae at settlement.; RefNo. [ 116 ]

2002

Pilot whales Globicephala spp. have long been thought to be deep divers, yet little information is available on dive depths. During August 1999 we obtained detailed dive data from suction-cup-attached time-depth recorder/VHF radio tags deployed on 5 long-finned pilot whales G. melas. Pilot whales were tagged for short periods (average 5 h ind.1) in deep (>2000 m) waters of the Ligurian Sea, off the NW coast of Italy. During the day all 5 whales spent their time in the top 16 m of the water column, and visible surface activities consisted primarily of rest and social behaviors. Tags remained attached after dark on 2 whales and shortly after sunset both whales made several deep dives (max. 360 and 648 m). Velocity on these deep dives was greater than during shallow dives either during the day or at night, suggesting that these deep dives function primarily for foraging. Our results confirm the supposition that long-finned pilot whales can dive deep, particularly within 2 h after sunset, which is the time that vertically migrating prey become more readily available as they move closer to the surface.; RefNo. [ 112 ]

2001

A series of laboratory experiments was conducted to determine fertilization success in the commercial abalone Haliotis tuberculata L. Fertilization success is a function of sperm dilution, sperm-egg ratio, gamete age and the amount of time sperm and eggs are in contact. Sperm density required for optimum fertilization success in vivo, using 10 ml culture volume, was in the range 5 ´ 104 to 5 ´ 105 sperm ml1. When these experiments were repeated using 500 ml culture volume, results showed high levels of fertilization success across a far larger range of sperm dilutions with success >80% at 103 sperm ml1. Sperm-egg ratios of >100:1 have little effect on fertilization success, but below these levels this factor becomes significant. Viability of both sperm and eggs decreased with age so that no fertilization occurred after 2.5 h. Maximum fertilization success occurred after 30 min sperm-egg contact time. These data suggest that sperm limitation may severely compromise reproductive success in exploited populations of H. tuberculata.; RefNo. [ 117 ]

4

2004

This annotation is based on a presentation given by Andrew Bakun at IFM-GEOMAR, Kiel, Germany, 2. June 2006.

Aquatic ecosystems are complex adaptive systems characterized by non-linear feedbacks. They are different from terrestrial ones (human intuition does not work).

Pelagic ecosystems are often characterized by a wasp-waist, in the sense that the lower and upper trophic level consist of many species, but the level that feeds on zooplankton consists of only one or few species of small pelagic fishes (Clupeidae or Engraulidae). This is important because changes in abundance or migratory patterns of these species will not be 'buffered' by other similar species but rather affect the ecosystem as a whole.

The dynamics of small pelagics are not well understood. They may vary according to their own intrinsic dynamics. They are the lowest trophic level that moves voluntarily. Often they feed on the eggs and larvae of their predators and are thus able to hold the predators down if they themselves are superabundant.

Their abundance is not varying around a mean carrying capacity: they do not go extinct at low densities and they do not seem to be limited in upper numbers. Rather, they are characterized by boom-and-bust cycles at the scale of decades. Apparently they can survive at very low abundance (refuge), when they are of little interest to predators. This is a stable system because a) productivity exceeds mortality but b) the predators start feeding on them heavily as soon as their abundance increases (the predator pit), thus keeping them in the 'low abundance refuge'.

If, however, their production rate is increased or the predators are decreased by other factors, the small pelagics can pass the predator satiation point and increase in abundance. If their production rate now surpasses their mortality rate an outbreak in abundance occurs. In such high-abundance state they may cover huge areas where they are normally not seen.

Sardines and anchovies have different life-history strategies and may replace each other in different pelagic regime states. Sardines are migratory, batch-spawn in many places, and feed on micro- or phytoplankton in clear oceanic water. Anchovies are smaller, have coarser gill rakers and feed on zoo-plankton, e.g., in murky areas such as estuaries, plankton blooms or upwelling areas. They are non-(or less) migratory. Heavy fishing pressure on small pelagics can disrupt their migratory patterns or push their abundance below the level where they control the predators. This may lead to regime shift. Because of the complexitiy of interactions in the ecosystems the results of a regime shift can not be predicted. For example, fishing down small pelagics to bring back their predators may instead result in the outbreak of other species, such as other less-desired planktivorous fishes (known examples: gobies, trigger fishes, snipefishes) or jellyfish.

Coastal upwelling can be so strong that herbivorous zooplankton can not maintain itself in the core area of upwelling near the coast. Sardines can take their place and keep the system stable. If sardines are removed by overfishing, phytoplankton blooms remain uncontroled, sink to the bottom and cause bacterial decay and methan and H2S eruptions at huge scales: an upwelling system gone anoxic. Also, medusae and other species may experience abundance outbreaks. All of this seems to have happened in the Namibia system. Other upwelling areas are vulnerable to the same process as global warming intensifies upwelling. Methan is a strong greenhouse gas and thus this could be a self-enhancing feedback loop with dire consequences for the respective systems.; RefNo. [ 2129 ]

2000

Settlement and recruitment of echinoderms were measured in 2 adjacent habitats: a kelp bed (Laminaria longicruris) and an echinoid (Strongylocentrotus droebachiensis)-dominated barren ground at each of 2 sites in the rocky subtidal zone (5 to 10 m depth) off Nova Scotia. Settlement was measured using artificial collectors made of 0.05 m2 panels of plastic turf that were deployed 0.2 m (low) and 2.3 m (high) above the bottom in each habitat, and sampled bi-weekly from June to November 1992 to 1994. Distinct settlement pulses of ophiuroids (Ophiopholis aculeata and Ophiura spp.), asteroids (Asterias spp.) and an echinoid (S. droebachiensis) occurred between July and September of each year at both sites. Timing of settlement differed consistently among species in relation to differences in timing of spawning and larval development. The magnitude of each pulse varied between years and species, and the year of maximum settlement differed between species, suggesting that species-specific processes regulate settlement rather than general environmental conditions. Settlement of all species was greater at the more protected site, but between-habitat patterns were not consistent among species. Asteroids settled in greater numbers in and above kelp beds, whereas ophiuroids showed a trend toward greater settlement in the barrens. The echinoid S. droebachiensis also tended to settle more in barrens, although the difference was not statistically significant. This suggests that kelp beds do not exhibit a consistent or strong effect on settlement. Sampling settlement concurrently at different frequencies (3 to 48 d) gave different estimates of settlement, indicating a need for assessment of sampling artifacts (e.g. changes in collector quality, post-settlement mortality or migration) that can occur over longer deployment intervals. For most species sampled, settlement predicted recruit density in natural populations the following year. However, the strength of the relationship varied between species, probably because of differing postsettlement processes.; RefNo. [ 118 ]

2003

Knowledge of the natural pattern of spatial variation of the variables of interest is fundamental for designing effective sampling strategies to be used in surveys and monitoring programs. Unfortunately, little is known on patterns of spatial variation of structural, morphological and dynamic features of Posidonia oceanica, despite their increasing use as indicators of the status and/or trend of meadows. Here, variations in some such features (such as shoot density, leaf biometry, annual rhizome elongation and leaf formation) were examined on a hierarchy of spatial scales, ranging from cm within individual meadows, to meadows separated by 10 km, using independent full-nested analyses of variance. Overall, at least 3 variables showed significant variations in the mean values on each of the scales examined. Patterns of variability differed among individual traits. Most of the total variation, however, was on the smallest spatial scale examined (i.e. among replicates, shoots or quadrats). For some variables, a significant variation was also associated with the largest scale (i.e. among meadows). Collectively, the results indicated that patchiness in density, morphology and growth exists on a very local scale within P. oceanica meadows along the same isobath. This suggests that sampling designs and analyses which incorporate different spatial scales and appropriate replications should at least be considered in the future when planning large-scale and long-term surveys.; RefNo. [ 120 ]

2

2005

; RefNo. [ 1991 ]

2004

; RefNo. [ 122 ]

10

2005

A guide providing an approach to governance of fisheries and aquaculture that tries to adress the complexity of the subject. The book is meant for all people that are actively involved in fisheries governance. ; RefNo. [ 1985 ]

6

1999

This paper focuses on relationships between mangroves and coastal fish resources. mangroves can be considered as a particular case of an estuarine environment, and then address the broader issue of the relationships between tropical estuaries and fishery resources.; RefNo. [ 2055 ]

2002

; RefNo. [ 272 ]

2050

; RefNo. [ 1797 ]

2000

The following paper reviews recent developments in the methodology for valuing the role of wetlands in supporting economic activity. The main focus will be on mangroves serving as a breeding ground and nursery habitat in support of coastal and marine fisheries. As this particular ecological function of a mangrove system means that it is effectively an unpriced ‘environmental’ input into fisheries, then it is possible to value this contribution through applying the production function approach. The first half of the paper overviews the procedure for valuing the environment as an input, applied to the case of a wetland supporting a fishery. Both the ‘static’ Ellis Fisher Freeman approach and the ‘dynamic’ approach developed by Barbier and Strand, incorporating the intertemporal bioeconomic fishing problem, are reviewed. The second half of the paper discusses briefly two recent case studies of mangrove-fishery valuation. An application in South Thailand, which is based on the static Ellis Fisher Freeman model, and an application in Campeche, Mexico, which is based on the dynamic approach.; RefNo. [ 123 ]

2002

Over the past decade, blooms of the domoic acid (DA) producing diatom Pseudonitzschia have been responsible for numerous deaths of marine mammals and birds in Monterey Bay, California. Euphausiids (krill) are important members of the local zooplankton grazer community and comprise the primary diet of squid, baleen whales, and many seabirds. Krill are thus a key potential vector for the transfer of DA to higher trophic level organisms in Monterey Bay. A better understanding of the quantitative trophic interactions and body burden of DA in krill is required to predict whether they can act as an effective vector for this neurotoxin. Here we report results of toxin analyses and gut content examinations of krill Euphausia pacifica collected from Monterey Bay in 2000. Corresponding counts of toxic Pseudo-nitzschia species in the water and their cellular DA concentrations were also obtained at the collection sites. Toxin analysis by receptor binding assay demonstrated that DA in krill tissue varied between 0.1 to 44 µg DA equiv. g1 tissue (confirmed by tandem mass spectrometry), with levels corresponding to the abundance of toxic Pseudo-nitzschia species present in the water. The occurrence of Pseudo-nitzschia australis frustules in the digestive tract of E. pacifica verified that a toxic species of this diatom was an important part of their diet and thus implicated this phytoplankter as the source of DA. These findings provide compelling evidence for the role of krill as a potential transfer agent of the phycotoxin DA to higher trophic levels in marine food web.; RefNo. [ 124 ]

2003

The present study investigated the assemblage of fish species in an intertidal mangrove forest during high tide in a macrotide region. We describe the seasonal changes in the fish assemblage composition in relation to biomass, density, and species number in tidal creeks of the Furo do Meio, Caeté Estuary, Brazil. A total of 29 107 individuals of 49 species in 26 families were caught using a block net. Their total weight was 526 kg (total density 0.11 ind. m2 and total biomass 2.1 g m2). Analysis of the catch data showed that the number of species varied significantly between creeks, and that total fish biomass differed significantly between seasons. The densities and biomass of the 2 most important species, Cathorops pleurops and Colomesus psittacus, were significantly different between seasons. The densities and biomass of C. pleurops, Pterengraulis atherinoides, Pseudauchnipterus nodosus, and Stellifer naso showed significant temporal differences. Significant differences between creeks were observed in the density and biomass of Anchovia clupeoides and Rhinosardinia amazonica. The abundance biomass comparison (ABC) plots for the fish fauna in the creeks of the Furo do Meio showed that the dominant species increased in number and weight at the beginning of the rainy season. As a result of increased rainfall in March and April, salinity declined to values between 6 and 8 psu. At that time, the dominant species made up more than 60% of the total biomass and density and Hill’s index of diversity (N1) declined, whereas the number of species (N0) and evenness (E2) did not change. After April, rainfall decreased, and density and biomass returned to levels similar to those before the rainy season. The number of species and the density and biomass in the mangrove tidal creeks are compared with published data for other tropical and subtropical estuaries. Migration trends were inferred from the results of the seasonal fluctuations of density and biomass of the most important species in the Furo do Meio, and are compared with data from other studies in the main channel of the Caeté Estuary.; RefNo. [ 126 ]

2003

; RefNo. [ 1033 ]

2002

Three sympatric species of semi-terrestrial hermit crabs (Coenobita cavipes, C. rugosus and C. pseudorugosus) occur on SW Madagascar shores on the edge of a semi-desert. They have similar resource requirements, some of which are restricted, yet their populations are very abundant. All 3 species seek refuges, the type and extent of which were assessed in 5 size classes for each of the species at 6 sites. Refuge-use, principally burrowing, was governed by a series of factors: tidal range, individual size (mass), species identity, site, shade. Shell architecture did not, however, directly influence refuge-use. An existing ordination technique (detrended correspondence analysis, DCA) was modified by inserting refuge identities as ‘species terms’ to interpret the structure underlying multidimensional niche space. The results show that variability in the refuge suite sought by hermit crabs serves to partition niche space both overall at the species level, and on a site-by-site basis for each species. On high spring tides, the extent of burrowing (a strategy common to all 3 species) was reduced, and a DCA of this data set showed niche compression at this tidal phase. Whilst biologically mediated niche shifts are a well-established concept, the changing of niche overlap described here clearly differs, as it is temporally dynamic and physically (tidally) driven. Inclusion of intertidal and subtidal hermit crabs at the study site into a data matrix showed that most species were separated ecologically by 4 niche dimensions: shore zone, habitat type, shell type and refugial behaviour. Niche complimentarity was clear, as species which were similar in 1 or more dimensions (such as C. rugosus and C. pseudorugosus) differed in other dimensions. Refuge-use of Coenobita spp. hermit crabs (and equivalent clustering behaviour of intertidal species) seems, therefore, to be multifunctional. The behaviour appears crucial to environment extremity avoidance, but may be equally important in resource management through water conservation and shell-, habitat- and shore-zone-partitioning. The results indicate that the SW Madagascar hermit crab assemblage is a speciose guild with (5D) niche complimentarity and temporally dynamic niche overlap.; RefNo. [ 134 ]

2003

To see the ‘big pictures’, it seems increasingly clear that experimental design, data collection and analyses of ecological investigation need to be at multiple scales. This causes problems with data complexity, sampling (level) and independence. Many ecological programmes are currently conducting multi-scale investigation of organismal trends (e.g. diversity). In this study, by contrast, the assemblages analysed were the resources used by animals (rather than animals per se). Variability in shell use was studied in 5 members of a taxon (hermit crabs) from global to site spatial levels. The novel adaptation of an existing technique used 1-factor, 3-level ANOVA of Bray-Curtis similarity values based on ‘centroids’ for each scale. Similarity in the number of shells used, the proportional usage of shell types, shell diversity and other variables were examined at site (>10 m apart), locality (>1 km apart) and region levels (>1000 km apart). There was significant variability amongst scales and between regions in shell use of all species. For some species, observed variability differed with location, while in others the trend was similar in all 3 regions. Between 18 and 3 shell types were used by different study species with diversity (Shannon H’) values ranging from 2.54 to 0.1 and evenness values from 0.99 to 0.1. Shell use by hermit crabs was less similar (to each other) between regions than between the study hermit crab species. No significant spatial effects at any level were found on the proportion of damaged shells used by different species. The numbers of shell types used by hermit crabs had both a taxon-specific component and a global pattern. Data from the literature in combination with that from the present study showed Dardanus, Diogenes and Pagurus species used fewer shell types than Coenobita, Clibanarius and Calcinus species. No inter-oceanic patterns were evident in any genus. Shell numbers used by Clibanarius and Calcinus species both, however, exhibited distinct latitudinal clines. Adaptation of a novel technique has, thus, demonstrated global (and differential between scale) trends in resource use by a guild of animals, although interpretation of the mechanism or meaning underlying this is not straightforward.; RefNo. [ 135 ]

2003

In just 4 decades, marine litter has become abundant in northern oceans and seas and is increasing on even remote Southern Ocean island shores. The Southern Ocean was thought to be protected from rafting organisms by its freezing sea surface temperatures. Here we report on an assemblage of animals attached to a piece of plastic that was washed ashore on Adelaide Island, Antarctic Peninsula (68° S). The band of plastic was positively buoyant. At least 10 species belonging to 5 phyla were present on the plastic and the size of some indicated that it had been afloat for more than a year. Clearly it is possible for a range of animals to survive and grow in such an environment, and so exotic species could enter or leave the Southern Ocean.; RefNo. [ 138 ]

2000

Intertidal-zone hermit crab populations in the Quirimba Archipelago occur in high densities and many species overlap considerably in terms of spatial distribution and types of shell used. The suites of shells used by 5 mid- to supra-littoral hermit crab species were studied (using multivariate analyses) across 3 shore zones, 7 islands and several levels of mollusc fishing pressure. Potentially high intra- and inter-specific competition for resources in the Quirimba Archipelago hermit crab assemblages is alleviated by a degree of macrohabitat and shore zone separation but largely by significant partitioning of shell resources. The suite of shells used by each species was distinct, even if certain types were in common. The highest influence on shell usage was tidal height followed by shore-zone area and hermit crab identity. Where the spatial distributions are tighter (in the supralittoral), the resource (shell) partitioning is greater. Fishing pressure (and associated abundance of target-species shells) was generally unimportant, but 1 species, Coenobita cavipes, used harvested shells opportunistically in proportion to their availability. Shannon H’ and species-richness values of shells used increased with shore zone area in the upper shore zone but not in the supra-littoral zone. It is suggested that this was due to high fishing pressure on certain mollusc species making certain shells abundant for hermit crabs (shell middens were deposited on the supra-littoral zone). The results suggest a tight niche mosaic of the many hermit crab species in the Quirimba Archipelago.; RefNo. [ 137 ]

2003

Nitrogen metabolism in Enteromorpha intestinalis from 3 contrasting populations in the Auckland region, New Zealand, was investigated. The sites (intertidal flats at Laingholm in the Manukau Harbour and Mangemangeroa and rockpools at Waterfall Reef) were chosen as they provided a range of ammonium enrichment. Seawater at Laingholm had higher levels of ammonium and total inorganic nitrogen compared with the other 2 sites. However, mean nitrate levels in Mangemangeroa seawater were similar to those measured at Laingholm. Seawater at Waterfall Reef had the lowest concentrations of ammonium and nitrate. At all 3 sites, E. intestinalis was found high in the intertidal. At Laingholm, the ammonium-enriched site, plants were immersed for 90 min at high tide; during this period the plants took up sufficient ammonium to increase their nitrogen content by 10%. The higher levels of inorganic nitrogen in the seawater at Laingholm resulted in higher levels of tissue nitrogen, chl a and b, glutamine and asparagine, and lower nitrogen-specific rates of ammonium assimilation (measured in the laboratory in the presence of saturating concentrations of ammonium) in E. intestinalis at this site. There were strong positive correlations between seawater concentrations of ammonium and the level of glutamine and between levels of chl a and b and tissue nitrogen in E. intestinalis. The nitrogen-specific rate of ammonium assimilation decreased as the nitrogen content of the plant increased and reached a minimum value above a nitrogen content of 1 to 2% or a glutamine level of 5 µmol per g dry weight (DW). This glutamine level corresponded to a seawater ammonium concentration of 6 µM. The nitrogen-specific rate of ammonium assimilation provides a novel and important bioindicator of the link between the concentration of inorganic nitrogen in the environment and the nitrogen status of the plant.; RefNo. [ 139 ]

2000

; RefNo. [ 1798 ]

2003

We compared the antipredator mechanisms of 3 morphological ‘types’ of lobsters: slipper lobsters Scyllarides latus, spiny lobsters Palinurus elephas and clawed lobsters Homarus gammarus. These lobsters differ in the extent and effectiveness of their weaponry and armor, which we assessed by: (1) field tethering experiments that compared relative survival of intact and manipulated (clinging ability, antennae, or claws removed) lobsters in the face of predation, and (2) measurements of the breaking strength and thickness of the carapace of each species. Intact clawed lobsters suffered higher mortality than either intact slipper or spiny lobsters after both 4 and 24 h. At 24 h, intact spiny lobsters also had higher mortality than intact and manipulated slipper lobsters. The intact spiny and clawed lobsters suffered less predation after 4 h than the manipulated lobsters (lacking weapons); however, this advantage diminished or vanished by 24 h. This indicates that weapons provided some measure of protection in the short-term, which might be sufficient to allow the lobsters to escape from a predator using a strong abdominal tail flip. Triggerfish Balistes carolinensis were the primary predators on the lobsters. We also saw octopuses Octopus vulgaris feeding on lobsters, but these were never observed subduing a live lobster. ‘Punch’-tests (i.e. puncture tests) on the carapaces of each of the 3 species showed that slipper lobsters had stronger armor than either spiny or clawed lobsters, while the spiny lobster armor was intermediate in strength. These results suggest that the defensive strong armor of slipper lobsters is a more effective antipredatory mechanism than the offensive morphological weapons of the spiny and clawed lobsters.; RefNo. [ 142 ]

2003

The reductionist trend of equating sustainable development with sustained economic growth needs to be reversed. New accounts and balances help to operationalize the elusive notion of sustainability: they provide a coherent picture of the interaction between environment and economy. ‘Greened’ national accounts measure economic sustainability in terms of (produced and natural) capital maintenance; balances of material flows assess ecological sustainability as the dematerialization of production and consumption. Both concepts aim to preserve environmental assets, but differ in scope, strength and evaluation of sustainability. First results for Germany indicate weak sustainability of the economy; strong sustainability is not in sight because of insufficient reduction of material throughput. Attaining sustainability through integrated policies needs the support of share- and stakeholders of sustainable development.; RefNo. [ 143 ]

2002

I tested the importance of both total cover and cover quality to the foraging ability of large Fundulus heteroclitus fish in tanks. Total cover was measured as the combined areas of all the individual structures, viewed as shadows. I divided total cover by the bottom area of the tank to form Ct/At, an index that measures the total amount of structure available in a given area for prey to hide behind. Cover quality was measured as the width of each individual structure divided by the width of the individual prey organism (Cw/Pw). This index measures how visible a prey organism is when hiding behind an individual structure. Both of these complexity indices are dimensionless and potentially applicable to any habitat type and habitat scale. I predicted that prey survivorship should increase hyperbolically with increasing Ct/At, because increasing the amount of structure within a habitat increases the amount of the habitat blocked off from detection, but with diminishing returns. Past experiments demonstrated that increased Ct/At does increase prey survivorship, but the shape of the relationship was unclear. I also predicted that prey survivorship should increase hyperbolically with increasing Cw/Pw. I predicted this by simulating a prey organism hiding behind a flat structure being viewed by a predator from all potential angles. In this simple simulation, the ‘average amount of the prey hidden from view’ increased hyperbolically with increasing Cw/Pw to an asymptote of 0.5. I performed 2 experiments to test these ideas. In the first, I kept Ct/At constant between treatments and varied the width of the individual structures relative to the width of shrimp prey Paleomonetes spp. In the second experiment, I kept the inter-structural space widths nearly constant between treatments and varied Ct/At. The prey for the second experiment were mobile amphipods. I tested the hypothesis that survivorship and treatment were independent using log-linear models for both experiments. I found that there was no significant difference in survivorship between treatments for the Cw/Pw experiment, and there was a significant difference in survivorship between treatments for the Ct/At experiment. The relationship between Ct/At and prey survivorship appeared to increase hyperbolically, as predicted. Finally, I used the results of the Ct/At experiment, and results from a past study, to form a modeled regression equation of the survivorship surface for large F. heteroclitus feeding on amphipods for various levels of Ct/At and Sp/Pr (inter-structural space size/predator width). This equation was highly significant, and fit the data well. In this regression, amphipod survivorship increased hyperbolically with increasing Ct/At, and decreased sigmoidally with increasing Sp/Pr.; RefNo. [ 145 ]

6

2001

Uses the world vector shoreline to measure coastal complexity in a case study for Mexico. It uses a modification of the Angle measurement technique.; RefNo. [ 2056 ]

2002

The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors on squid presence were assessed using logistic regression analysis. During spring through fall, L. brevis was collected over a wide range of bottomwater salinities (17.9 to 35.0), bottom-water temperatures (8.1 to 29.6°C), bottom-water dissolved oxygen levels (1.9 to 14.6 mg O2 l1), and depths (1.8 to 29.9 m), but it was not present in trawls conducted during winter in. L. brevis, especially juveniles < 60 mm dorsal mantle length (DML), were abundant, frequently ranking in the upper 12% of overall annual nektonic trawl catches, and during the fall of some years, ranking second to anchovies. The probability of catching a squid increased in Chesapeake Bay at higher salinities and water temperatures, and was much greater in normoxic than in hypoxic waters; these variables had a profound influence on both annual and seasonal variability in distribution. Salinity had the largest influence on squid distribution, with squid being completely absent from the bay when salinity was <17.9 and most abundant in the fall when salinity was highest (despite declines in water temperature). Squid were most prevalent at depths between 10 and 15 m. The results of this study suggest that L. brevis is an important component of the Chesapeake Bay ecosystem when salinities and water temperatures are within tolerance limits and that unlike other squids, L. brevis may be well-equipped for an inshore, euryhaline existence.; RefNo. [ 147 ]

2002

Identical contingent valuation studies of willingness-to-pay (WTP) for improvements in coastal water quality were conducted in the town of Jaco and city of Puntarenas on the Pacific Coast of Costa Rica. Several common hypotheses for benefit transfer reliability were tested for the transfer of WTP estimates between the two communities, as well as between districts within Puntarenas. This study finds no basis for the claim that the reliability of benefit transfer increases with proximity between the study site where WTP estimates are taken from, and the policy site estimates are transferred to. The claim that transfer of WTP adjusted by the benefit function outperforms transfers of unadjusted or simple income-adjusted WTP is rejected for this particular study. Results also show that census-type socio-economic site characteristics are necessary, but not sufficient to explain site-specific differences in WTP. The trade-offs in designing valid and reliable benefit transfer studies with transferable results are discussed.; RefNo. [ 148 ]

2000

An experiment was conducted to optimise rooting in stem cuttings of the mangrove tree species Bruguiera parvi¯ora, Cynometra iripa, Excoecaria agal- locha, Heritiera fomes and Thespesia populnea. Cuttings were girdled or non-girdled and treated with the auxins indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and naphthalene-acetic acid (NAA) and amylase, IAA- oxidase, peroxidase and polyphenol oxidase activities were measured. The best rooting performance (in terms of root number) was in stem cuttings of E. agallocha followed by C. iripa and H. fomes when treated with IBA + NAA. IAA and IBA combinations were more effective in T. populnea and B. parvifolia. Variations in rooting response were markedly re¯ected in amylase, IAA-oxidase, peroxidase and polyphenol oxidase activ- ities. Sharp increases in amylase and polyphenol-oxidase activities were associated with enhanced rooting in E. agallocha, C. iripa and H. fomes. On the contrary, lowered IAA-oxidase and peroxidase activities favoured rooting in T. populnea and B. parvi¯ora. A higher number of roots occurred in pre-girdled cuttings in comparison to non-girdled cuttings.; RefNo. [ 149 ]

2004

To study the effects of sublethal doses of mercury on corals, colonies of Porites astreoides (Lamarck) were exposed to nominal concentrations of 0.01, 0.1 and 0.5 mg Hg l1 using semi-static, chronic bioassays for up to 15 d, with HgCl2 administered by pulses every 3 d (mean concentration in the water was 0.004, 0.037 and 0.180 mg Hg l1, respectively). While total Hg in the corals was directly proportional to Hg exposure, analysis of the different coral compartments (polyps, zooxanthellae and skeleton) showed that zooxanthellae and the skeleton accumulated Hg in direct relation to Hg exposure, but polyp tissue accumulated more Hg at 0.1 than at 0.5 mg Hg l1. This suggests saturation of Hg only in polyps and/or activation of mechanisms of detoxification. Within a colony, the Hg concentration per unit area of coral surface differed between ompartments as follows: zooxanthellae > polyp > skeleton. Colonies exposed to the highest Hg concentration accumulated 1.738 µg Hg cm2, 89% of which was found in zooxanthellae, 7% in polyps and 4% in the skeleton. Polyp biomass (dry weight and protein content), zooxanthellae biomass (cell density and protein content), and pigment concentration per unit area of coral surface decreased with Hg exposure. The bioconcentration factor ([Hg] in organism/[Hg] in water) was inversely related to the Hg concentration in water. The capacity of zooxanthellae and the skeleton to concentrate Hg and the decrease in zooxanthellae density support the hypothesis that polyps may divert Hg to these 2 coral compartments as a detoxifying mechanism.; RefNo. [ 151 ]

2004

A simple but novel experiment is described examining the impact of interviewer appearance upon stated willingness to pay (WTP) for an environmental good. This test consists of an interviewer wearing either formal or more casual clothing. This analysis is interacted with a cross cutting treatment examining the impact well known of adding information on certain of the less familiar attributes of the good in question. Face-to-face interviews are employed to collect a sample of respondents who are randomly allocated to one of the four treatment permutations described by our interviewer appearance and information change study design. Our analysis suggests that both altering the appearance of an interviewer and changing the degree of information provided can have significant impacts upon stated WTP. Furthermore this effect is heightened when both effects are running in parallel. We argue that such findings are to be expected given the highly interactive nature of face-to-face interviewing but note that this serves to provide a cautionary note regarding the complex array of influences at work when members of the public are asked to express preferences regarding goods for which they have not previously provided monetary values.; RefNo. [ 153 ]

2001

Bivalve molluscs can acquire diarrhetic shellfish poisoning (DSP) toxins via ingestion of toxigenic dinoflagellates. The dynamics and fate of DSP toxins were investigated in the bay scallop Argopecten irradians exposed to cells of the epibenthic dinoflagellate Prorocentrum lima, a known producer of DSP toxins, in controlled laboratory microcosms. Toxin parameters determined were uptake and detoxification rates, and anatomical compartmentalization. Toxins in tissue and algal extracts were analyzed by liquid chromatography-mass spectrometry (LC-MS). No mortalities occurred and feeding inhibition was not observed for juvenile and adult bay scallops during the 2 wk exposure to P. lima cells. Clearance rates were similar for scallops exposed to equivalent biovolume cell concentrations of toxigenic P. lima and the non-toxic diatom Thalassiosira weissflogii; however, absorption efficiency of organic matter was significantly lower with a diet of P. lima than T. weissflogii. Although DSP toxin concentrations in viscera of bay scallop exceeded commonly accepted regulatory levels (0.2 µg g1 whole tissue) within 24 h of exposure to P. lima, after 2 wk of exposure total DSP toxin retained in scallop tissues was <1% of the total toxin ingested over the same period. Most of the total toxin body burden was in the viscera (76%); however, in adult scallops a significant portion was associated with gonadal tissue (12%). Toxin levels were relatively low in gill, mantle and adductor tissue (<12% of total toxin body burden). During the depuration period, rapid release of DSP toxins from scallops indicated that toxins were poorly bound to all tissues, with the exception of the viscera. Detoxification of viscera consisted of a rapid loss of weakly bound toxin components within the initial 3 d of depuration, followed by a much slower release of the remaining toxin at a rate of 8.4% d1.; RefNo. [ 154 ]

2004

Human activities continue to eliminate of degrade wetlands that provide rich habitat for many species. Compensatory mitigation, including creation of new wetlands, restoration of previously degraded wetlands, or preservation of existing wetlands, is one policy option that seeks to maintain no net loss of wetland habitat. Public support of wetland mitigation is essential because the public incurs the cost for many mitigation projects in the form of higher taxes. Therefore, public preferences should be considered when decisions are made about wetland mitigation options. We used a contingent-choice survey in Rhode Island to identify factors affecting public support for different types of compensatory wetalnd mitigation. Results were based on 640 survey responses. The amount of wetland lost during the original development project had no significant effect on the preferred mitigation alternative. Preferences for preservation, restoration, and no-action alternatives varied according to respondent's gender, education, and income. Certain general considerations applied, however, regardless of mitigation type. Respondents were willing to incur increases in taxes and fees for most mitigation projects. The larger the mitigation project and the lower the cost, the more likely it was to gain public support. The presence of endangered species contributed to public support, but less significantly than public access. Public access can be critical to public support, particularly if the size of the wetland is small or the cost is high. If the cost of providing public access, such as a boardwalk or viewing tower, is relatively small, the gain in public support for mitigation expenditures may well allow a substantial expansion of the area involved in mitigation projects and thus a greater increase in the amount of habitat conservation.; RefNo. [ 155 ]

2001

; RefNo. [ 1799 ]

2003

North Atlantic right whales were instrumented with suction-cup mounted, time-depth recorders (TDR) during the summers of 2000 and 2001 to examine their diving and foraging behavior. Simultaneous observations of temperature, salinity and the vertical distribution of their principal prey, Calanus finmarchicus stage 5 copepodites (C5), were obtained along each whale’s track with a conductivity-temperature-depth instrument (CTD) and an optical plankton counter (OPC). Right whale feeding dives were characterized by rapid descent from the surface to a particular depth between 80 and 175 m, remarkable fidelity to that depth for 5 to 14 min and then rapid ascent back to the surface. The average depth of dive was strongly and positively correlated with both the average depth of peak C. finmarchicus C5 abundance and the average depth of the bottom mixed layer’s upper surface. Significantly longer surface intervals were observed for reproductively active females and their calves when compared to other individuals, indicating that this critical segment of the population may be at increased risk of ship strikes owing to their diving behavior. Ingestion rates calculated from TDR and OPC data exceeded estimated daily metabolic requirements for most of the tagged right whales; however, short deployment durations and uncertainty in metabolic rates make it impossible to judge whether individual right whales were obtaining sufficient energy to meet the metabolic costs of reproduction. Improvements in attachment durations and the development of novel methods to estimate the metabolic rates of large whales in situ are required to determine whether right whale reproduction is limited by insufficient food resources.; RefNo. [ 160 ]

2003

Simultaneous visual and oceanographic surveys were conducted in the lower Bay of Fundy and in Roseway Basin of the SW Scotian Shelf during the summers of 1999 to 2001 to investigate the physical and biological oceanographic factors associated with North Atlantic right whale occurrence. Sightings of right whales were recorded along predetermined transects through each region, while both in situ and remotely sensed oceanographic measurements were collected. Sampling with plankton nets and an optical plankton counter confirmed that right whales in these regions feed on Calanus finmarchicus copepodite stage 5 (C5). Spatial variability in right whale occurrence was associated with water depth and the depth of the bottom mixed layer. C. finmarchicus C5 aggregated over the deepest water depths in both regions, and within these areas, right whales occurred where the bottom mixed layer forced discrete layers of C. finmarchicus C5 to occur shallower in the water column (allowing more efficient foraging). Annual increases in right whale occurrence appeared to be associated with decreases in sea surface temperature (SST) in both regions; however, this observation merits caution in light of the short duration of the study (3 yr). There was also evidence to suggest that both spatial and interannual variability in right whale occurrence in Roseway Basin may be associated with SST gradient, a proxy for ocean fronts.; RefNo. [ 158 ]

2003

Temporal variability in the distribution and abundance of North Atlantic right whales Eubalaena glacialis and their copepod prey, late-stage Calanus finmarchicus, was monitored at an oceanographic station in Grand Manan Basin of the lower Bay of Fundy for 29 h on 2 separate occasions. The vertical distribution of C. finmarchicus was measured at 1/2 h intervals with an optical plankton counter (OPC) and at 6 or 12 h intervals with a MOCNESS. Right whale abundance was estimated from periodic point scans. Late-stage C. finmarchicus exhibited diel vertical migration in the upper 100 m of the water column, but the bulk of the population remained at depths below 100 m throughout both the day and night and was likely in diapause. Diel vertical migration is unlikely to be influenced by right whales, but may instead be motivated by abundant, near-surface food resources and avoidance of visual predators. Right whale sighting rate was correlated with OPCdetected C. finmarchicus fifth copepodite (C5) abundance at mid-depths (90–140 m); variability in both right whale sighting rate and C. finmarchicus C5 abundance in this depth stratum appeared to have similar periodicity to that of the tide. Energetic considerations suggest that right whales continue to feed on deep, diapausing layers of C. finmarchicus during the night, but the occasional presence of exploitable near-surface concentrations of C. finmarchicus suggests that nighttime near-surface feeding might sometimes occur.; RefNo. [ 159 ]

2001

Joint production is suggested as one of the conceptual foundations of ecological economics. The notion of joint production springs immediately from the application of thermodynamics, and has a long history in economic analysis. Considerations of joint production give rise to philosophical concerns relating to responsibility and knowledge. The concept of joint production is easily comprehensible, and is also constitutive and supportive of a range of concepts current in ecological economic thought.; RefNo. [ 1800 ]

2003

Invasive alien marine species threaten biodiversity,marine industries (including fishing and tourism) and human health,and unlike oil spills only get worse with time. While some progress is being made internationally on the 10,000 species estimated to be in transit around the world in the ballast water,effective solutions are a long way off; meanwhile the majority of vectors is being ignored. A systematic approach to invasive alien marine species is required to target the means and location of the most effective management actions. Cooperation among regional trading partners will be essential to effectively manage the threat.; RefNo. [ 161 ]

1997

; RefNo. [ 1801 ]

2002

This field study had 2 objectives: (1) to test predictions from laboratory studies on growth and feeding behaviour in a comparison of 2 oyster species from the same estuary in NSW, Australia; and (2) to compare the feeding behaviour of these oysters with published accounts of other bivalve species from elsewhere. The predictions were that Pacific oysters Crassostrea gigas would feed and grow more quickly along with a greater metabolic efficiency than Sydney Rock oysters Saccostrea glomerata. Measurements were made at 3 sites in the Port Stephens estuary, NSW, and the predicted differences between species were confirmed. For both species, growth was quicker from March to May than from May to July (1999). Feeding was also faster in March and May than in July. Absorption efficiency was maintained at a relatively constant level over the experimental period by a compensatory response to changes in the organic content of the ingested material. Selection and absorption efficiencies for nitrogen altered over time, holding nitrogen absorption relatively independent of the nitrogen content of the food. Simple equations were fitted to the data to describe feeding behaviour as a function of properties of the diet, and these equations used to compare these oysters with relationships for other bivalves in the literature. A few such equations may be used to predict net absorption of food energy by oysters in the field, based on measurements of food only. At one rather coarse level, there are basic similarities between bivalve suspension feeders regarding feeding behaviour and its relation to growth. At a more detailed level, differences in physiological responses to diet may help in the interpretation of differences in growth, such as have been observed here for 2 oyster species growing in the same habitat. The competitive advantage enjoyed by C. gigas over S. glomerata is due to faster rates of feeding, particularly at higher food concentrations, and greater metabolic efficiencies of both feeding and growth.; RefNo. [ 163 ]

2002

The potential relationship between ecological versatility and local distribution and abundance for 5 species of triggerfish was examined at Kimbe Bay, Papua New Guinea. The abundances of juvenile and adult Balistapus undulatus, Melichthys vidua, Rhinecanthus verrucosus, Sufflamen bursa and S. chrysopterus were quantified in a range of habitats along a typical coral reef profile. Four of the 5 species displayed distinct and relatively narrow distributions across the reef profile, with the fifth species, B. undulatus, being broadly distributed across all zones and depths, and the most abundant species. For each species, the spatial distribution of juveniles closely matched that of adults and juvenile densities were greater in species with more abundant adults. A detailed description of depth distributions of individuals indicated that shallow species had narrower depth ranges. In terms of microhabitat use, B. undulatus was the most generalised species, occupying all the microhabitats that were identified. The other 4 species were specialised to varying degrees on different microhabitats. Results from this study provide the first detailed description of patterns of distribution and abundance, habitat use and ecological versatility in triggerfish. Distribution and abundance could partially be explained by differences in the degree to which each species is specialised, both in terms of depth and microhabitat selectivity. Hence, versatility in depth and microhabitat use may play an important role in determining the local distribution and relative abundance of coral reef fishes.; RefNo. [ 164 ]

2002

Present-day patterns in pelagic biodiversity are the result of the interaction of many factors acting at different scales. Developing an understanding of the processes that regulate the diversity of oceanic ecosystems is thus challenging. In this study, diversity of calanoid copepods was decomposed into species associations by means of the recent ‘indicator value method’ and multivariate analyses. For the first time, at an oceanic basin scale and with a spatial resolution approaching the mesoscale, species associations of calanoid copepods have been identified. Nine species associations were determined and have enabled us, (1) to improve the ecological partitioning of this region, and (2) to identify the main factors that regulate pelagic biodiversity in this area. It is shown that temperature, hydrodynamics, stratification and seasonal variability of the environment are likely to be the main factors contributing to the ecological regulation of diversity of calanoid copepods. The similar geographical pattern evident between currents/water masses and the species associations suggest that the species groups may be used as an environmental indicator to evaluate long-term changes in the marine environment related to climate change and other increasing human-induced influences.; RefNo. [ 165 ]

2003

Seasonal abundance, volume, size distribution and carbon content of transparent exopolymeric particles (TEP) were examined in 2 hydrologically distinct sites in the NW Mediterranean (NWM) Sea: a coastal (Point B, Villefranche Bay) and an offshore (DYFAMED, France, JGOFS) site. TEP concentration varied from 0.2 to 2.2 × 105 particles ml1, and was higher offshore. The TEP pool was low during the winter mesotrophic period and increased after the spring bloom, remaining relatively high throughout summer at both sites. The increase in TEP abundance during the oligotrophic period was relatable to nitrate limitation and a decline in primary production. TEP formation in spring was associated to a nanoflagellate bloom, while the build-up of a large pool of TEP in summer occurred in the presence of a phytoplankton community dominated by picoplankters and during strong thermal stratification, limiting vertical sedimentation. In the NWM Sea, when the TEP carbon pool (TEP-C) is high, it may represent up to 22% of the total organic carbon, and reach down to 1% when it is low, suggesting that the particles play a significant role in the carbon cycle. In the NWM Sea, the trophic status of the system and the composition of primary producers control TEP formation. Hydrological processes appear to be of primary importance in governing seasonal TEP distribution.; RefNo. [ 167 ]

2001

We present a methodology to model water, heat, and dissolved oxygen budgets on short time scales within a shallow estuarine environment using limited local water quality and climatic data. A tidally restricted eutrophic pond in Elkhorn Slough, California, experiences extreme diel dissolved oxygen (DO) variations during warm sunny days and neap tidal cycles. Empirical relationships between biological metabolism (measured as DO variations) and physical parameters are derived using time-series hydrographic data from the site. A simple box model predicts the time-series structure of water depth, water temperature, and DO concentrations within the pond as a function of the tidal cycle and local climate over 10 to 15 d simulation periods. Parametric analyses illustrate applications of the model to predict thermal and geochemical responses to hydrologic, chemical, and climatic alterations to the system. This study also initiates preliminary investigations of the fundamental processes influencing DO dynamics within a natural wetland environment, and could be used to explore the potential response to various physical and chemical alterations prior to restoration or management adjustments. Future box models of wetland geochemistry should include carbon and nutrient budgets to create a more sensitive model, and to allow more rigorous evaluations of the role decreased nutrient inputs would play in alleviating eutrophic conditions.; RefNo. [ 168 ]

2003

; RefNo. [ 172 ]

2003

We investigated daily and annual variation in the marine habitat selection of marbled murrelets Brachyramphus marmoratus (Alcidae) in the nearshore California Current System at scales of 10 to 100 km of coastline. We addressed 2 general questions: (1) how do murrelets select habitat while facing dramatic and often rapid variation in oceanographic conditions and prey availability; and (2) does selection vary between meso- (10 to 100 km) and fine- (<10 km) scales. Marine transects were performed during 1999 and 2000 to survey murrelets and prey-fish schools, and to collect data on physical oceanography. We predicted that habitat selection would vary with upwelling intensity and prey availability: prey-aggregating mechanisms should be more important under low upwelling scenarios when cool, productive water is more limited, and murrelets should forage closer to nesting habitat when prey availability is high. This was generally the case, as murrelets selected cooler locations when upwelling was low and locations closer to nesting habitat when upwelling was high. Interactions among variables were important; murrelet habitat selection for prey and fronts changed among different sea surface temperatures (SSTs), distance to nesting habitat, upwelling intensity, and overall prey availability. Scale-dependent selection for prey patches (fish schools) and fronts occurred within larger-scale selection for SST or distance from nesting habitat. Additional scaledependent effects of prey availability were revealed by small-scale surveys in an area of high prey density. In this case, murrelets selected cool water (higher quality habitat) when prey availability was low and were associated with prey schools when prey availability was high. Additional large-scale surveys from 1996 to 2000 revealed that these patterns also manifested themselves on a longer temporal scale. Murrelets occurred farther from nesting flyways in years when spring upwelling was low and during the 1998 El Niño Southern Oscillation (ENSO) when local food webs were depressed and numerous other seabird species failed to reproduce.; RefNo. [ 170 ]

2002

We studied the mercury contamination of 13 species of seabirds breeding on Bird Island, South Georgia, in 1998. Total mercury concentrations in body feather samples of birds caught at their breeding colonies were determined. Among the species, grey-headed albatross (8933 ng g1) and southern giant petrel (7774 ng g1) showed the highest, and gentoo penguin (948 ng g1) the lowest body feather mercury concentrations. Mercury levels were negatively correlated with the proportion of crustaceans (mainly krill) in the species’ diets, suggesting that the trophic level is the most important factor in explaining the variation of mercury concentrations in Antarctic seabirds. In 4 species studied for age effects among adult birds (grey-headed and black-browed albatross, northern and southern giant petrel), no age-dependent variation in mercury levels was found. Sex differences were also assessed: female gentoo penguins had lower mercury levels than males, which may be related to the elimination of part of the mercury body burden by females into eggs. In contrast, northern giant petrel males had lower levels than females, which may be related to a higher consumption by males of carrion from Antarctic fur seals. In grey-headed albatrosses, mercury levels were 113% higher than in 1989, when this species was investigated at the same site, indicating a possible increase in mercury pollution of the Southern Ocean during the last decade.; RefNo. [ 169 ]

2050

; RefNo. [ 1803 ]

1998

Photosynthetic rates of seagrasses have until recently been measured as gas exchange of chamber-enclosed leaves mainly in the laboratory, and in situ measurments under natural conditions are scarce. In this work we explore the possibility of measuring such rates by pulse amplitude modulated (PAM) flourometry, using a newly developed underwater device. This was done by first comparing photosynthetic O2 evolution (net photosynthesis corrected for dark respiration) with rates of electron transport (ETR) derived from flourescence measurements of the effective quantum yield of photosystem II multiplied with the estimated photon flux of photosynthetic active radiation absorbed by this photosystem. In the field, ETRs were then measured both as rapid light curves (RLCs) and by in situ point measurements under ambient light during the day. Photsynthetic O2 evolution showed a linear relationship with ETR within a range of irradiances for the Mediterranean seagrass Cymdocea nodosa, while the tropical Halophila stipulacea and a temperate intertidal population of Zostera marina exhibited decreasing O2 evolution rates relative to ETRs at high irradiances. These differences are likely due to photorespiration, which is absent in C. nodosa. The molar ratio between photosynthetic O2 evolution and ETR within the range of their linear relationship was found to be 0.3 for C. nodosa, which is close to the theoretical stoichiometric ratio of 0.25, but was higher and lower for Z. marina and H. stipulacea, respectively. Point measurements of ETR in the field showed good agreements with rates derived from RLCs for H. stipulacea and Z. marina, but values varied greatly between repliocate measurements for C. nodosa at high irradiances. It is speculated that this variation was partly due to light-flecks caused by waves in the shallow water where these measurements were done. In all, this work shows that PAM flourometry can efficiently yield photsynthetic rates for seagrasses in the laboratory, without the typical lag experienced by O2 electrodes, as well as in situ under natural conditions which are not disturbed by enclosures.; RefNo. [ 946 ]

2003

Traditional statistical methods for testing for differences between vertical plankton distributions are invalid if the distributions are patchy. This Note describes a statistical test for differences in vertical plankton distributions in the presence of patchiness when replicate samples are available. An illustration involving a test for day/night differences in the vertical distribution of the copepod Calanus pacificus is presented.; RefNo. [ 173 ]

2002

Recent studies modelling back-calculated birth date distributions of pelagic juvenile (0-group) cod Gadus morhua have indicated differential regional spawning components in waters off the west, north and east coasts of Iceland, in contrast to traditional paradigms of stock structure. The relative proportions of pelagic juvenile cod that were estimated to originate from these regional spawning components were hypothesized to influence recruitment and vary in response to the inflow of Atlantic water from the main spawning grounds off the southwest coast to the main nursery grounds off the north coast. We examine this hypothesis by analyzing annual (1971 to 1998) coastal current data in relation to the total relative abundance, mean total length, and proportions of pelagic juvenile cod that were estimated to originate from the main spawning component off the southwest coast of Iceland. Additional variation in environmental (temperature, salinity, and zooplankton biomass) and spawning stock biomass (SSB) effects were also examined in relation to the 0-group variables and recruitment at Age 3 to enable a detailed analysis of the stock-recruitment relationship. The coastal current index was the most dominant covariate affecting the spawning origins and recruitment of cod in Icelandic waters. The freshwater-induced coastal current provided a predictable transport mechanism for pelagic eggs and larvae derived from the main spawning component off the southwest coast to the main nursery grounds off the north coast. In years when the coastal current were strong, more abundant and larger pelagic juveniles derived from the main spawning component were found on the main nursery grounds, typically resulting in corresponding years of good recruitment. Differentiating the interplay of the physical environment with that of a spawning stock is fundamental to understanding recruitment variability in marine fish stocks.; RefNo. [ 174 ]

2004

We examined the invertebrate assemblages associated with macroalgal canopies in the Mingan Islands (northern Gulf of St. Lawrence, eastern Canada) in the summer and fall of 2001. Invertebrates were sampled in patches or beds of 4 species of macroalgae (Alaria esculenta, Agarum cribrosum, Desmarestia viridis and Ptilota serrata) as well as in adjacent urchin barrens. Multivariate analyses of the invertebrates on the algal fronds, those on the underlying substratum, and the 2 groups together demonstrated differences in invertebrate assemblages among all 5 habitats. A. esculenta sheltered the most distinct invertebrate community due to the domination of the substratum under this alga by the blue mussel Mytilus edulis. Differences among other canopy types were due to differences in invertebrate assemblages both on the algal fronds and on the substratum. A manipulative experiment involving the removal of the canopy of the 2 most abundant macroalgae, A. esculenta and A. cribrosum, was carried out to examine their effects on mussels. Recruitment of mussels onto ceramic tiles varied among treatments and was greatest in the A. esculenta zone with greater, but non-significant, recruitment under the canopy. The growth of mussels from early July to October was higher in the A. cribrosum zone than the A. esculenta zone. However, there was no effect of the algal canopy in either zone. Our study demonstrates that the local diversity and distribution of benthic invertebrates is intimately associated with macroalgae, and reinforces the need for detailed sampling and analyses for assessing distributional patterns.; RefNo. [ 175 ]

2001

; RefNo. [ 176 ]

2004

While the species level effects of marine reserves are widely recognized, community level shifts due to marine reserves have only recently been documented. Protection from fishing of top predators may lead to trophic cascades, which have community-wide implications. Disease may act in a similar manner, regulating population levels of dominant species within a community. Two decades of data from the Channel Islands National Park Service’s Kelp Forest Monitoring database allowed us to compare the effects of fishing and urchin disease on rocky reef community patterns and dynamics. Different size-frequency distributions of urchins inside and outside of reserves indicated reduced predation on urchins at sites where fishing removes urchin predators. Rocky reefs inside reserves were more likely to support kelp forests than were fished areas. We suggest that this results from cascading effects of the fishery on urchin predators outside the reserves, which releases herbivores (urchins) from predation. After periods of prevalent urchin disease, the reef community shifted more towards kelp forest assemblages. Specific groups of algae and invertebrates were associated with kelp forest and barrens communities. The community dynamics leading to transitions between kelp forests and barrens are driven by both fishing and disease; however the fishery effect was of greater magnitude. This study further confirms the importance of marine reserves not only for fisheries conservation, but also for the conservation of historically dominant community types.; RefNo. [ 1713 ]

2002

; RefNo. [ 1804 ]

2003

Very little is known about how periodic hypoxic intrusions into shallow, nearshore habitats influence local migration patterns of mobile species such as the blue crab Callinectes sapidus. These hypoxic events may cause direct and indirect mortality of crabs as well as alter their distribution and abundance patterns. We used biotelemetry techniques with concurrent hydrographic measurements to monitor movement responses of free-ranging crabs to the spatiotemporal ynamics of hypoxic upwelling events. Shallow areas (<1.7 m depth) were rarely hypoxic (<1% of the time) and should offer refuge for mobile organisms that avoid low dissolved oxygen (DO) concentrations during hypoxic upwelling events within the Neuse River Estuary (NRE), North Carolina, USA. Free-ranging blue crabs generally attempted to avoid hypoxic water (<4 mg l1) by moving inshore towards higher DO concentrations; however, crabs were unsuccessful at moving to normoxic water (>4 mg l1) after exposure to hypoxia during upwelling events. Furthermore, telemetered crabs sometimes remained within severely hypoxic water (<2 mg l1) for several hours. We discuss potential behavioral mechanisms that may explain these surprising results and compare the movement response of our individuals to the population-level movement responses inferred from trawling studies. To better understand the impacts of episodic hypoxic upwelling events on local blue crab populations, future studies need to identify the mechanisms blue crabs use to detect hypoxia and to orient towards more suitable (i.e. normoxic) habitats. Our results suggest that the movement responses of individuals to disturbance events can be used to predict changes in the distribution and abundance patterns of local populations.; RefNo. [ 180 ]

2003

Episodic hypoxic events in estuaries can alter the trophic dynamics of important benthic predators. During hypoxic upwelling events mobile predators may reduce their feeding activity as they migrate to relatively shallower, oxygenated water, and may reinvade deep-water habitats during relaxation of hypoxia to exploit vulnerable infaunal prey (e.g. clams and polychaete worms) that have reduced their burial depth in response to hypoxia. We used biotelemetry techniques with concurrent measurements of dissolved oxygen (DO) to monitor the feeding and movement responses of free-ranging blue crabs Callinectes sapidus to episodic hypoxic upwelling and subsequent relaxation events within the Neuse River Estuary (NRE), North Carolina, USA. Although telemetered crabs fed in hypoxic water with DO concentrations as low as 1.01 mg l1, percent feeding occurrence declined slightly when crabs were exposed to mild (DO = 2 4 mg l1) and severe hypoxia (DO <2 mg l1), relative to normoxic concentrations (DO > 4 mg l1). Crabs reduced the proportion of time spent feeding during hypoxic upwelling conditions except for the most severe events when DO dropped rapidly from normoxia to severe hypoxia. The proportion of time crabs spent feeding did not increase and crabs did not reinvade deeper water habitats during relaxation events, as was hypothesized. These results are somewhat inconsistent with previous studies and we suggest that crabs may have fed on prey other than benthic infauna, or that upwelling events may not have lasted long enough to cause infauna to migrate close enough to the sediment surface to be vulnerable to predation by blue crabs. Our study highlights the importance of examining the complex interaction between the hydrodynamics of episodic events and various behaviors (e.g. feeding and movement) when trying to understand the impact of these events on estuarine trophic dynamics.; RefNo. [ 178 ]

2003

We evaluate the use of the Bartholomew Sp/Pr index with reference to the collection of information to be used in index calculation and interpretation. Through examination of hypothetical structural arrangements, we address issues related to determining the spacing between structures which are non-uniformly distributed. We also utilize fieldcollected data to examine how measures of inter-structural spacing may vary when (1) 2 different field methods are used and (2) measurements of the same structures are made over different spatial scales. Using a mangrove prop-root system, measures of inter-structural spacing within 2900 m2 areas using a 100 point confined arc method were obtained, as were small quadrat samples conducted within the same sites using the confined arc and nearest neighbor method. In small quadrat sampling, mean between-root distances using the arc method were nearly 20% less than those obtained from the 900 m2 plots. The greatest difference in spacing easurements, and accordingly Sp values, was recorded when the confined arc and nearest neighbor methods were applied to the same inter-structural spaces. Our combined results illustrate that quantification of spatial arrangement can vary with both method and scale of measurement and suggest that across-study comparisons using the index developed by Bartholomew et al. (2000, Mar Ecol Prog Ser 206:4558) will be difficult to interpret unless the same method of structural complexity measurement is employed, and similar spatial arrangements are compared.; RefNo. [ 181 ]

2001

; RefNo. [ 1806 ]

2002

The persistence of phase shifts from coral-dominated to macroalgae-dominated communities following disturbances has been largely attributed to reduction of herbivores and eutrophication on tropical coral reefs. The influence of reduced herbivory and increased nutrients and their combined interactions on the colonization of crustose coralline algae (CCA) and fleshy algae onto settlement tiles was studied for effects on community structure. Cages were used to manipulate herbivory, and slowrelease fertilizer was used for nutrient enrichment. The responses of the following variables were measured at 2 adjacent reefs in Guam, Mariana Islands: percentage cover of CCA, fleshy algal biomass, coral recruitment, and sediment load. Fleshy algal biomass and sediment were greatest on tiles where herbivores were excluded, whereas CCA were most abundant on tiles exposed to herbivores. Nutrients did not have a significant effect on fleshy algae; however, CCA had a lower level of increase in response to increased nutrients at 1 site. Coral recruitment was low; therefore, preferential settlement to substratum type was indeterminable. This study demonstrates that herbivory, in particular, can have a marked effect on the initial composition of the benthic community, even over a relatively short time span. Moreover, the inverse relationship between CCA and both fleshy algae and sediment has implications for the recruitment of organisms with reliance on CCA.; RefNo. [ 182 ]

2001

In most organisms relative locomotor speed body lengths per second [bls1]) is inversely proportional to body size. The ability of late stage reef fish larvae to achieve swimming speeds of over 40 bls1 is consistent with this general scaling relationship. However, this relationship does not extend to smaller larvae which are not fully developed. Maximum critical swimming speeds appear to be limited by both developmental stage and size. At 7 mm total length when settling, the unusually small larvae of anemonefishes are able to sustain speeds of 49 bls1. This probably approaches the maximum limit for sustained aquatic vertebrate locomotion.; RefNo. [ 185 ]

2000

; RefNo. [ 1807 ]

2000

; RefNo. [ 1808 ]

2001

Analyses of spatial pattern in populations and assemblages along distinct environmental gradients are common in ecology. Few studies have examined whether these patterns are consistent at a hierarchy of spatial scales, despite increasing evidence indicating that spatial variability is not scale independent. In this study I have investigated the general model that much of the variation on rocky sea shores occurs across the vertical gradient, unless major physical attributes of the habitat change. This model was contrasted with 2 alternative models that incorporate patchiness at different scales: either vertical variation is larger than horizontal variability at small but not at large scales of horizontal spatial variability or there is no characteristic scale at which vertical variation is larger than horizontal variability. In order to distinguish among these alternatives, I compared variability in abundance of organisms across heights on the shore on rocky coasts in the north-west Mediterranean, with estimates of horizontal variability obtained at different scales, ranging from the scale of the patch (among quadrats 10s of cm apart) up to the regional scale (among shores 100s of km apart). Results indicated that vertical and horizontal variability were comparable in magnitude at the smallest spatial scale, while horizontal variability was generally larger when measured at scales of 100s to 1000s of m. When multivariate patterns in the structure of assemblages were examined, there was more vertical than along-shore variation at small (10s to 100s of cm) but not at large (>1000s of m) spatial scales. Univariate and multivariate analyses also revealed that much of the horizontal variation was among quadrats 10s of cm apart. These results indicated that any description of spatial pattern in abundance for organisms living on rocky sea shores in the NW Mediterranean must contemplate both vertical and horizontal sources of variation, regardless of the scale investigated. It is concluded that failure to recognise the importance of sources of variation other that those expressed by the most obvious gradients detracts from potentially important causal processes hindering progress in ecological understanding.; RefNo. [ 186 ]

2001

Anthropogenic disturbances affect natural populations and assemblages by interacting with fundamental ecological processes. Field experiments simulating the effects of human activities at the appropriate spatial and temporal scales are useful to understand these interactions and eventually to predict their ecological consequences. In the Mediterranean, low-shore habitats of rocky coasts are often dominated by canopy algae Cystoseira spp., but these species are requently replaced by assemblages of turf-forming algae and mussel beds. We propose that anthropogenic disturbance is the proximate cause of loss of Cystoseira in the Mediterranean, and that the disappearance of canopy algae causes an increase in cover of turf-forming species in disturbed habitats. Two hypotheses were investigated to test this proposition: (1) canopy algae will be dominant in relatively pristine habitats while turf-forming algae will be more abundant in urban areas, and (2) removal of canopy algae in unpolluted areas will result in the development of assemblages similar to those found in urban areas. We tested the first hypothesis by comparing patterns in abundance of Cystoseira and turf-forming algae at a number of locations in urban areas and in areas far from distinct sources of anthropogenic disturbance in the northwest Mediterranean. The second hypothesis was tested by conducting a largescale manipulative experiment, involving the experimental removal of Cystoseira and several spatial and temporal repetitions of the manipulation. Turf-forming algae were always dominant in urban areas where Cystoseira was nearly absent. In contrast, canopy algae often dominated rocky shores in relatively pristine areas of the northwest Mediterranean. The removal of Cystoseira generally caused an increase in the percentage cover of turf-forming algae and a decrease in the abundance of invertebrates. These changes were already evident 4 mo after manipulation and were consistent at the spatial and temporal scales examined in the study. Assemblages in cleared patches were qualitatively similar to those occurring where Cystoseira was naturally absent, but quantitative differences in the relative abundance of several taxa were still evident by the end of the study. These results support a causeeffect relationship between anthropogenic disturbance and loss of Cystoseira in the northwest Mediterranean and allow for quantitative predictions of the indirect consequences of disturbing canopy algae for the whole understory assemblage. Management options aimed at conserving these plants should simultaneously preserve other components of the assemblage.; RefNo. [ 187 ]

2003

The autobranch bivalve Bathypecten vulcani is a peri-hydrothermal vent ‘living fossil’; as such, it is of particular interest both with respect to its trophic strategy and with respect to its particle processing mechanisms. These aspects are investigated through a study of the gill using scanning electron microscopy and mucocyte mapping. B. vulcani possesses a flat, homorhabdic gill, which lacks the morphological specializations associated with endosymbiont presence. Abfrontal and latero-frontal cilia, frontal tract differentiation, organic inter- or intrafilamentar junctions, an ascending lamella on the external demibranchs, and ventral particle grooves are all absent. The lack of latero-frontal cilia in this homorhabdic gill points to direct particle capture on the frontal tracts, a novel mechanism in adult bivalves. The abundant mucus-particle masses on the ventralmost frontal surfaces, which first come in contact with incoming water currents, together with an extremely high density of acid (AM) and acid-dominant (ADM) mucopolysaccharide-secreting mucocytes, suggest that particle capture is initially effected in this zone. The presence of antero-posteriorly oriented mucus cords in the gill arch indicate that transport on the gill is first dorsal, then anteriorward to the buccal region. An increasing postero-anterior gradient in mucocyte numbers and volumes suggests that transfer to the labial palps occurs via an exposed mucus bridge. These findings are the first substantiated representations of primitive autobranch particle processing, prior to the evolution of ventral particle grooves, latero-frontal cilia, or the heterorhabdic condition. It thus serves as a starting point for the understanding of the evolution of particle processing mechanisms in the basal pectinid condition, as well as in contemporary autobranch bivalves.; RefNo. [ 188 ]

1999

The pseudolamellibranch is the only main bivalve particle processing system whose mechanisms of pseudofeces rejection on the mantle have not been elucidated. To this end, the entire mantle surface and underlying tissue characteristics were investigated in the oysters Crassostrea virginica and C. gigas, using scanning electron microscopy and histology, as well as observations of particle transport on half-shell preparations. Pseudofeces transport is effected by short simple cilia atop specialized radial ridges, which extend from the gill-mantle junction near the adductor muscle to the mantle edges. The histology of the ridges is characterized by a densely-ciliated pseudostratified epithelium and numerous acid mucopolysaccharide (AMPS)-containing mucocytes, and differs markedly from that of the inter-ridge regions which present a cuboidal epithelium containing few mucocytes and isolated tufts of long simple cilia. In contrast to the pseudofeces transport (infrabranchial) region of the mantle, the suprabranchial mantle region is uniformly and densely ciliated, and devoid of ridges. The sparse ciliation of the inter-ridge region and the counter-current beat of the ridge cilia (presumably isolated to varying degrees from the pallial flow by the mucus-particle rafts involved in mucociliary transport) indicate that the maintenance of pallial flow is accomplished almost exclusively by the gill and the suprabranchial mantle ciliation in these 2 species. Pallial pseudofeces rejection mechanisms to date are summarized for the 4 main bivalve gill systems, which may be grouped into 3 categories: (1) pallial transport with vertical elevation accomplished via composite cilia (homorhabdic filibranchs and eulamellibranchs), (2) pallial transport with vertical elevation accomplished via mantle ridges (pseudolamellibranchs), and (3) voidance via valve clapping (heterorhabdic filibranchs).; RefNo. [ 1810 ]

2001

This paper explores the nature of conflict and how institutional failure may be a primary cause of conflict over natural resources. Typologies for studying conflicts are reviewed and a typology specific to tropical fishery conflicts is proposed. Using data fromthree tropical fisheries, it shows how conflicts emerge and how they are managed.1 The paper concludes that local level management of conflict can be successful, but, without proactive support from higher levels of government the underlying causes of conflict are unlikely to be removed in the long term.; RefNo. [ 189 ]

2003

This paper presents a new non-invasive technique for measuring sediment O2 uptake that, in its concept, differs fundamentally from other methods used to date. In almost all natural aquatic environments, the vertical transport of O2 through the water column toward the sediment surface is facilitated by turbulent motion. The new technique relies on measuring 2 parameters simultaneously and at the same point in the water above the sediment: the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating O2 concentration using an O2 microelectrode. From these 2 parameters, which typically are measured 10 to 50 cm above the sediment surface for a period of 10 to 20 min and at a frequency of 15 to 25 Hz, the vertical flux of O2 toward the sediment surface is derived. Based on measurements performed under actual field conditions and comparisons with in situ flux-chamber measurements, we believe that this new technique is the optimal approach for determining O2 uptake by sediments. The technique is superior to conventional methods as measurements are done under true in situ conditions, i.e. without any disturbance of the sediment and under the natural hydrodynamic conditions. Furthermore, this technique can be used for bio-irrigated or highly permeable sediments, such as sands, where traditional methods often fail. While this paper only focuses on O2 uptake by sediments, the technique can also be applied to other solutes that can be measured at a sufficiently high temporal resolution.; RefNo. [ 190 ]

2002

; RefNo. [ 1812 ]

2000

; RefNo. [ 1814 ]

6

2004

Describes the use of expert knowledge to map fishing grounds; RefNo. [ 2057 ]

2002

Knowledge of the critical levels for key environmental variables that are likely to cause bleaching in reef corals is of fundamental importance in conducting risk assessments of potential climate-change effects on coral reefs. Such knowledge can also be used to provide early warning of mass bleaching events. A number of factors have contributed to the difficulty in determining critical levels for coral bleaching. These factors include the fact that multiple stressors may be involved in bleaching, the duration of stress required to elicit a bleaching response varies with temperature, and bleaching triggers are known to be variable in space, time and by species. In this study, I identify sea surface temperature (SST) as the most important parameter for predicting coral bleaching from 4 possible environmental variables collected over 10 to 12 yr from weather stations at 2 locations on the Great Barrier Reef (GBR): temperature, wind speed, solar radiation and barometric pressure. Predicted bleaching-response curves are constructed from high-resolution in situ temperature records and historical observations of coral bleaching for 13 locations. These curves approximate reef-wide stress-response thresholds for bleaching of thermally sensitive (and often dominant) coral species. Distinct spatial trends exist in the thermal sensitivity of coral populations that correspond with position across the shelf and latitude in the case of mid- and outer-shelf reefs. This suggests that considerable thermal adaptation has taken place over small (10s of km) and large (100s to 1000s of km) spatial scales. Bleaching curves for inshore reefs do not correspond with latitude and are more variable, reflecting greater local-scale variability in temperature regimes.; RefNo. [ 192 ]

1999

; RefNo. [ 1816 ]

1999

; RefNo. [ 1815 ]

2004

Detailed mapping of coral bleaching events provides an opportunity to examine spatial patterns in bleaching over scales of 10 s to 1,000 s of km and the spatial correlation between sea surface temperature (SST) and bleaching. We present data for two large-scale (2,000 km) bleaching events on the Great Barrier Reef (GBR): one from 1998 and another from 2002, both mapped by aerial survey methods. We examined a wide range of satellite-derived SST variables to determine which one best correlated with the observed bleaching patterns. We found that the maximum SST occurring over any 3-day period (max3d) during the bleaching season predicted bleaching better than anomaly-based SST variables and that short averaging periods (36 days) predicted bleaching better than longer averaging periods. Short periods of high temperature are therefore highly stressful to corals and result in highly predictable bleaching patterns. Max3d SST predicted the presence/ absence of bleaching with an accuracy of 73.2%. Largescale (GBR-wide) spatial patterns of bleaching were similar between 1998 and 2002 with more inshore reefs bleached compared to offshore reefs. Spatial change in patterns of bleaching occurred at scales of 10 s km, indicating that reefs bleach (or not) in spatial clusters, possibly due to local weather patterns, oceanographic conditions, or both. Approximately 42% of reef bleached to some extent in 1998 with 18% strongly bleached, while in 2002, 54% of reefs bleached to some extent with 18% strongly bleached. These statistics and the fact that nearly twice as many offshore reefs bleached in 2002 compared to 1998 (41 vs. 21%, respectively) makes the 2002 event the worst bleaching event on record for the GBR. Modeling of the relationship between bleaching and max3d SST indicates that a 1 C increase would increase the bleaching occurrence of reefs from 50% (approximate occurrence in 1998 and 2002) to 82%, while a 2 C increase would increase the occurrence to 97% and a 3 C increase to 100%. These results suggest that coral reefs are profoundly sensitive to even modest increases in temperature and, in the absence of acclimatization/adaptation, are likely to suffer large declines under mid-range International Panel for Climate Change predictions by 2050.; RefNo. [ 193 ]

2003

; RefNo. [ 1817 ]

1999

This article reports on state coastal zone management (CZM) effectiveness in meeting the national goal of protecting natural shoreline resources. The research focuses on efforts to protect beaches, dunes, bluffs, and rocky shores. This study concludes that state CZM programs are effective overall in addressing the protection objective of the Coastal Zone Management Act of 1972 (CZMA). This conclusion recognizes that the CZMA requires states to balance competing needs and demands such as protection of natural resources from hazards and overdevelopment, promotion of recreational use, and respect for private property rights. Determination of CZM program effectiveness is based on process indicators and case examples. Outcome indicators were too sparse to allow an outcome effectiveness determination. All coastal states and territories use a wide variety of tools and processes to achieve resource protection, including regulatory, planning, state land management, acquisition, nonregulatory, and research tools. Regulatory tools are the most significant tools employed nationwide, because the majority of the oceanfront shoreline is in private ownership and is subject to significant shoreline change and development pressures. Over 60 significant upgrades to coastal management programs have been implemented over the years to protect natural shoreline resources. Process indicators of effectiveness show increased resource protection from CZM efforts. Of the 29 coastal states and territories studied, most (23) employ setbacks from the shoreline to provide a natural buffer between development and the water. All (27) but a few regulate shoreline activities to protect critical habitat and minimize adverse impacts on resources. All (28) but one regulate shoreline stabilizations to minimize adverse impacts on beach systems. Most (23) restrict pedestrian and vehicular access to channel human encroachment along boardwalks or dune crossovers, minimizing dune destabilization and impacts on fragile resources. All (28) but one use planning tools to designate and protect specific shoreline resources. Within state coastal parks, most (25) have designated natural protection areas and guided accessways. Many (21) have acquired additional coastal land holdings. Almost half use boardwalks or dune crossovers to protect dune vegetation and minimize adverse impacts on natural resources, and sand fencing and dune creation to restore the natural function of damaged dune systems. Over half (17) use beach nourishment to recreate eroding recreational beaches. Greater attention is needed to document on-the ground results of CZM resource protection efforts through in-depth case studies and long-term monitoring of resource indicators of program success.; RefNo. [ 195 ]

1999

; RefNo. [ 1818 ]

2004

Sharks may have an important role in marine ecosystems in relation to populations of fish and invertebrates at lower trophic levels. Fishery management plans stress the need for an ecosystem approach, but few quantitative studies on the foraging ecology of sharks have been published. Stomach contents and catch data of early life stages of Atlantic sharpnose Rhizoprionodon terraenovae, blacktip Carcharhinus limbatus, finetooth Carcharhinus isodon, and spinner sharks Carcharhinus brevipinna taken from fishery independent surveys in Apalachicola Bay, Florida, USA, were examined to test for overlap in resource use. Young-of-the-year Atlantic sharpnose sharks were found to feed mainly on shrimp, juveniles on sciaenids, and adults on clupeids. Young-of-the-year blacktip sharks were found to feed mainly on sciaenids, whereas juveniles fed on clupeids. The primary prey of young-of-the-year and juvenile finetooth and spinner sharks was clupeids. Eight of 10 prey size-selectivity tests showed neutral selection. Compared to relative prey sizes published for teleost piscivores, Atlantic sharpnose and finetooth sharks consume relatively small-sized prey while blacktip sharks consume relatively large prey. Regardless of maturity state and species, diet overlap was high for species-life stage combinations that are similar in size; however, species-life stages did not show significant habitat overlap. Prey categories shared by similar-sized species may not be limiting, although shark species may have alleviated competition pressure by partitioning the resource of time or space.; RefNo. [ 196 ]

6

1996

Use of GIS and users input to plan the management of a coastal zone in Italy.; RefNo. [ 2058 ]

2004

This study presents (1) the first annual time-series recorded for any marine system of the weekly variability in rates of production (P) and dissolution (D) of biosilica (BSiO2) and (2) the first evidence of the end of the year-round dominance of diatoms in the Bay of Brest, a well-mixed anthropogenically nitrate-enriched macrotidal ecosystem, typical of western Europe. In coastal waters, silicic acid (Si(OH)4) availability depends on both external inputs and internal recycling. We quantified the contribution of internal recycling through experiments conducted from April 2001 to April 2002 in the surface waters of SOMLIT-Brest station at the outlet of the bay. From spring to mid-summer, diatoms dominated successive microphytoplankton blooms and, since they require Si(OH)4 to construct their frustules, the concentration of Si(OH)4 in surface waters was severely reduced at this time, relative to winter (mean 1.62 µM); BSiO2 concentration and production and dissolution rates were high, averaging 1.26 µmol l1, 0.96 µmol l1 d1 and 0.40 µmol l1 d1, respectively. From mid-summer to mid-fall, non-siliceous phytoplankters predominated, and the mean surface-water concentration of Si(OH)4 was 4.67 µM. BSiO2 concentration and production and dissolution rates were low, averaging 0.69 µmol l1, 0.10 µmol l1 d1 and 0.04 µmol l1 d1, respectively. The summer shift from diatom to dinoflagellate dominance was likely under bottom-up control. The Bay of Brest, with D:P ratios averaging 0.43 during the productive period, is intermediate between coastal upwelling systems, where new production usually predominates (0.1 < D:P < 0.25), and oceanic oligotrophic systems, in which regenerated production usually predominates (D:P ~ 1.0).; RefNo. [ 197 ]

2001

This paper surveys data obtained during 3 decades (1969–1999) of monitoring the macrobenthic fauna of a 50 km2 tidal-flat area in the Wadden Sea (Balgzand) and compares the annual figures with similar long-term data series from other parts of the Wadden Sea (Groningen, Norderney). Despite enormous year-to-year variability in annual recruitment of particularly the bivalves, total biomass values were remarkably stable. Detailed data are presented on the annual variability in recruitment success of the 4 most important bivalve species of the Balgzand area (Cerastoderma edule, Macoma balthica, Mya arenaria, and Mytilus edulis). Together these 4 species usually accounted for more than half of the total zoobenthic biomass and largely governed its year-to-year fluctuations. Recruit numbers of the 4 species observed in 27 summers showed similar relationships with the character of the foregoing winter. Such relationships were also observed in other Wadden Sea areas in The Netherlands and Germany. These common relationships resulted in a certain synchrony of recruitment success between the species (within areas) and between areas (within species). Thus, over vast areas (hundreds of km), bivalve recruit densities were generally (though not invariably) high after severe winters and low after mild winters. The resulting strong year-to-year variability in recruit numbers (with standard errors exceeding long-term means) was only just passed on to subsequent total-biomass values for the following 3 reasons: (1) the biomass of any species was generally composed of more than 1 year class, (2) the various species did not reach their maximal biomass at the same age (time elapsed after recruitment), and (3) feedback mechanisms (enhanced reduction of numbers at high abundance) were effective in some species.; RefNo. [ 198 ]

2002

Macrocrustaceans and juvenile demersal fish were sampled in spring of 1997 in the surf zone of an exposed sandy beach on the Belgian coast. Three consecutive 24 h cycles were sampled to investigate tidal, diurnal and semi-lunar distribution patterns within the epibenthic community. Multivariate statistical techniques and 3-way ANOVA were used to evaluate the effects of the environmental variables measured. The most important variable correlated with the variation in epibenthic catch density was the state of the tide (ebb and flood), but light intensity (day and night) was also important. The individual catch density of several species differed significantly over the three 24 h cycles. Despite the strong turbulent conditions of the site studied, clear tidal (e.g. the brown shrimp Crangon crangon, juvenile plaice Pleuronectes platessa) and diurnal (e.g. juvenile sole Solea solea and clupeids, caught mainly during the night/day respectively) periodicities of many macrocrustacean and demersal fish species were observed. Nevertheless, the extremely turbulent conditions of the surf zone possibly affect the behaviour of many species (e.g. juvenile brown shrimp are not able to bury themselves as the water retreats). To investigate whether the high dynamics of the surf zone suppress the ability of juvenile plaice to actively search for food, stomach contents were analysed. Also, the interaction with potential prey was investigated: the hyperbenthic fauna was sampled simultaneously and macrobenthic data were available from the literature. Clearly, the Belgian sandy beaches are used as a feeding ground by I-group plaice. An opportunistic utilisation of available food resources is suggested. I-group plaice migrate high up the beach during the flood tide to profit from the rich macrobenthic intertidal area, while the 0-group feeds mainly on the most abundant hyperand macrobenthic organisms from somewhat deeper water. The presence of the 0-group in the intertidal area is possibly linked to refuge for predators or influenced by the strong surf zone currents.; RefNo. [ 199 ]

2000

; RefNo. [ 1819 ]

2004

; RefNo. [ 200 ]

2002

Maintaining the integrity of differentiated genomes in marine organisms needs efficient isolation mechanisms, because planktonic larval dispersion provides contacts between taxa. Habitat specialisation is interesting in this respect, because it can both prevent interspecific crosses (each taxon reproduces in its own habitat) and eliminate hybrids (typically less fit than a parental taxon in each habitat). The contact zone between smooth-shelled mussels Mytilus edulis and M. galloprovincialis in Europe is a good example, as allozyme genotypes typical of both taxa seem to segregate into different habitats. However, allozymes may be selected directly and it is not known whether the same pattern can be extended to the whole genome. Here, we used 6 presumably neutral PCR markers to investigate habitat specialisation, focussing on the Bay of Quiberon, a small region in the midst of the contact zone between the 2 taxa. Confirming allozyme findings, our results indicate that habitat specialisation is apparent at the genomic scale, as M. edulis-like genotypes are found in sheltered or open-sea sites under freshwater influence, whereas M. galloprovincialis-like genotypes occupy exposed sites. Hybrid (or mixed) populations are found in open-sea or sheltered areas without freshwater influence. Therefore, habitat specialisation does contribute to the interspecific barrier. However, this mechanism seems insufficient to completely prevent the mixing of the 2 genomes, as mixed populations exist and provide opportunity for further hybridisation. Large gametic disequilibria within hybrid populations indicate the existence of restrictions to genetic exchange between the 2 taxa, even within a single habitat. Habitat-independent isolation mechanisms must, therefore, exist in addition.; RefNo. [ 201 ]

1989

; RefNo. [ 1820 ]

2003

In populations of species that are able to reproduce both sexually and asexually, there may be local differences with regard to the relative importance of the 2 modes of reproduction. Studies of plant species with such a life history have shown that the contribution of sexual reproduction to population maintenance may be lower at the geographical margins, with genotypic diversity often used as an indicator of the relative importance of vegetative and sexual reproduction. This hypothesis was examined in a collection of samples of eelgrass Zostera marina (a marine flowering plant) from its eastern Atlantic southern limit (Ria Formosa, Portugal). Samples from 12 sites were genotyped using 9 microsatellite loci to compare within-site clonal and genetic diversity, and among-site distribution of genetic diversity, with previously published values from central sites. Sites within the Ria Formosa had lower clonal diversities (mean = 0.29, range = 0.07 to 0.68) than the central sites (mean = 0.86, range = 0.33 to 1.00), lower levels of expected heterozygosity (He = 0.423 vs 0.486) and exhibited heterozygote excesses rather than deficits. Similarly, genetic differentiation was found to be much greater in the Ria Formosa, with the FST of 0.233 being over 10-fold greater than that reported for populations in the Baltic Sea. Results from this study were consistent with previous findings of reduced sexual reproduction, genotypic diversity and among-population gene flow at species limits.; RefNo. [ 202 ]

2003

Laminaria digitata is the dominant species of the dense, continuous kelp stands in the English Channel and on the Atlantic coasts of France, where it is harvested for its high quality alginates. However, in spite of its ecological and economic importance, our knowledge of the level and organisation of genetic diversity in this species is scant. Here, using comprehensive hierarchical sampling and 7 microsatellite loci, we explored the roles of dispersal strategies, current regimes and habitat discontinuities in shaping genetic structure of L. digitata populations. Our results show that continuous, non-fragmented forests of L. digitata were genetically differentiated at distances greater than 10 km, despite the absence of clear population boundaries. Furthermore, a pattern of isolationby- distance indicated that gene flow occurred preferentially among adjacent populations following a stepping-stone model. In addition, we analysed the direction of migration using assignment tests and found that currents appeared to play a minor role in orienting gene flow, except in the Gulf of Saint Malo gyre. In contrast, habitat discontinuities were found to accentuate genetic differentiation and resulted in reduced genetic variation of isolated stands. In the context of a otential over-exploitation of kelp stands in Brittany, this study suggests that the existence of neighbouring populations can be vital to maintaining high levels of gene flow and thus, genetic diversity in this species.; RefNo. [ 203 ]

2000

; RefNo. [ 1821 ]

2002

Recent empirical studies have tested the hypothesis of an Environmental Kuznets Curve (EKC) focusing primarily on the relationship between per capita income and certain types of pollutant emissions. Given the stock-nature of many pollution problems, emissions only partially account for the environmental impacts. Moreover, almost all of the studies have given consideration to little more than income levels as explanatory variables. This paper empirically tests the hypothesis of the EKC existence for a stock-sensitive indicator, that is, the percentage of protected area (PA) within national territory. It does theorize that economic growth is a necessary condition in order to better address environmental issues. But it also stresses that other variables (income distribution, education, information accessibility) may play a fundamental role in determining environmental quality. Contrary to other studies that mainly focus on the calculation of the income level corresponding to the transition point, this paper is more concerned with the calculation of environmental quality corresponding to that transition point, that is, the minimum level of environmental quality that a country is willing to accept. This paper highlights the idea that if the transition point is determined primarily by income level, social policies determine the level of environmental quality corresponding to that point.; RefNo. [ 204 ]

2001

We subjected seedlings of Zostera marina L. to High (72%), Medium (23%), and Low (10%) daily irradiance (mean daily PAR of 24.4, 7.9, and 3.3 E m2 d1 respectively) over 12 wk. We measured plant response in terms of survivorship, lateral shoot production, morphology, growth rate, photosynthesis and respiration, and leaf pigment concentration. Decreasing the light available to eelgrass seedlings from 72 to 23% resulted in a reduction of lateral shoot formation, lower plant biomass, and longer and wider leaves. Shoot area, growth rate, and pigment concentrations remained similar. A reduction of incident light to 10% decreased survival to 74% and had a negative effect on shoot growth, size, and above- and belowground biomass. Pigment concentrations increased with respect to seedlings raised at medium light. In general, the responses of seedlings to reduced light are similar to those reported for mature Z. marina. Rapid expansion of seedling patches can only occur at irradiance levels greater than 7.9 E m2 d1. Morphological changes resulting from exposure to mean daily PAR levels of less than 8 E m2 d1 such as thinner leaves and low belowground biomass, have serious implications for decreased seedling survival in the field.; RefNo. [ 205 ]

2002

Determination of photosynthetic production in plant communities is essential for evaluating plant growth rates and carbon fluxes in ecosystems, but it cannot easily be derived from the photosynthetic response of individual leaves or thalli, which has been the focus of virtually all previous aquatic studies. To evaluate the regulation of aquatic community production, we measured the photosynthetic production of thallus parts and entire communities of Fucus serratus (L.) of different density and spatial structure exposed to varying photon flux density and dissolved CO2 concentration. Photosynthetic production in relation to photon flux density differed considerably between entire communities and individual thallus parts. No light saturation occurred in the communities, and all photosynthetic variables such as light compensation point, efficiency of light utilisation at low light and maximum production at high light depended on community density. Therefore, while the determination of the production of individual algal thalli is useful for evaluating differences in acclimatisation and adaptation between species and stands, it is not useful for evaluating production rates for entire plants and communities. Maximum gross production of F. serratus followed a hyperbolic curve at increasing community density, reaching a maximum of 30 µmol O2 (m2 ground area)1 s1 at a leaf area index (LAI) of 8 to 10. Maximum net community production in the light was attained at an LAI of 6 to 8, while the maximum in a natural day-night cycle is attained at an LAI of 5 to 6. Maximum gross production was about 3-fold lower in F. serratus communities than in terrestrial communities in forests, grasslands and crops. Manipulating F. serratus communities to a more vertical structure increased light penetration and gross production in the communities, implying that canopy structure had a profound influence on community production and that a non-optimal distribution of light is likely to be the main reason for the lower maximum gross production rates in aquatic than terrestrial plant communities.; RefNo. [ 206 ]

10

2002

A compendium on the main principles of international law concerning the protection of the environment. It includes a comprehensive chapter on the conservation of marine living resources and biodiversity, providing a detailed introduction into the subject. ; RefNo. [ 1982 ]

2002

The concentration of contaminants usually decreases with increasing distance from a point-source disturbance, so sampling to detect ecological impacts is usually done at 1 spatial scale, often at regular intervals from the point of discharge. There is, however, concern that the choice of an inappropriate scale will cause failure to detect impacts or failure to identify and estimate the size of impacts. In this study, the putative impact of a shoreline sewage outfall on the abundance of green ephemeral algae and gastropods was sampled at 2 spatial scales (tens of metres and several kilometres from the point of discharge) in order to determine whether the ecological impact of effluent was comparable across these, as would be expected if the abundance of species follows the gradient of contaminants. Such sampling also enabled the putative impact of this outfall on the spatial variability of taxa to be examined at 3 spatial scales: (1) among quadrats in the site with the outfall compared to variance among quadrats in other sites on the shore with the outfall; (2) among quadrats in non-outfall sites on the shore with the outfall compared with variance among quadrats in sites on control shores; (3) between non-outfall sites on the shore with the outfall in comparison to among sites on the control shores. A greater abundance of Enteromorpha spp. was found close to the outfall than further away at both spatial scales. Patterns in the abundance of many other taxa differed between the 2 spatial scales of sampling. The density of the limpet Patelloida latistrigata was much greater close to than far from the outfall, when considered on a large spatial scale. At the smaller scale among sites on a single shore, the impact was completely reversed densities were much smaller close to than away from the outfall. Variances, like abundances, did not always follow the gradient of contaminants and different patterns were often seen at different spatial scales. Thus, putative impacts should be sampled on multiple spatial scales using nested sampling designs. Where this is not possible, the spatial scale at which an impact might be detected or interpreted needs to be clearly stated because the generalisation that a disturbance has a similar impact at all spatial scales relevant to the population being studied cannot be made without explicit tests.; RefNo. [ 207 ]

1999

The aim of the present study was to investigate whether tropical intertidal seagrasses were better adapted to tolerate dessication than subtidally growing seagrasses. To do this, the photsynthetic performance of 8 seagrass species, growing from the upper intertidal to the shallow subtidal in Zanzibar, East Africa, was studied during the event of air exposure and the subsequent rehydration. Photosynthetic efficiencies were measured by pulse amplitude modulated (PAM) flourometry as effective electron quantum yields a photosystem II (Y) since it had recently been shown that this measure parallel rates of O2 evolution for several species under a defined irradiance. Contrary to our expectations, it was found that the shallow intertidal species were in general more sensitive to dessication than the deeper species. This was expressed both as a faster decline in Y at decreasing water contents and as an inability to regain full photosynthetic rates during rehydration following even mild dessication, as compared with the deeper-growing species. One exception was the subtidally growing Syringodium isoetifolium, which was very sensitive to dessication. The 2 species which grow highest up in the intertidal zone, Halophila ovalis and Halodule wrightii, may not dessicate much in situ during low tide because the leaves lie flat on the moist sand and, for the latter species, overlap one another so as to minimise water loss. Thus, it seems that dessication tolerance is not a trait which determines the vertical zonation of tropical seagrasses. Rather, it is hypothesized that the ability to tolerate high irradiances, as well as to benefit from high nutrient inputs from the shore, allows the shallow species to occupy the uppermost intertidal zone.; RefNo. [ 947 ]

2002

We sampled larval fishes along cross-shelf transects off Granite Canyon, California, USA, during the upwelling seasons of 1993 and 1994 to determine whether coastal upwelling fronts affect the cross-shelf distribution of larval rockfishes Sebastes spp. during the earliest period of planktonic life. Rockfish larvae occurred in relatively high densities near surface fronts and were distributed in patches oriented along sloping pycnoclines contiguous with surface fronts. Qualitative comparisons between observed distributions of larval rockfishes in relation to hydrographic structure and predictions from models of plankton distributions at convergent fronts support the hypothesis that convergent circulation contributes to observed distributions. Our results indicate that (1) coastal upwelling fronts influence larval rockfishes at an earlier life history stage than has previously been documented, and (2) the influence of upwelling fronts on distributions of larval rockfishes is similar to the influence of hydrographic fronts on distributions of larval fish reported for a variety of oceanographic settings. In light of the plausible effects of upwelling fronts on larval transport and ecology, our findings suggest that upwelling fronts merit further investigation for their potential role in translating variability in upwelling dynamics into fluctuations in recruitment to coastal rockfish populations along the west coast of North America.; RefNo. [ 209 ]

2000

The pelagic juvenile stage of sea turtles is poorly studied. We present a growth model and estimates for duration of the pelagic juvenile stage for loggerhead sea turtles Caretta caretta in the North Atlantic based on length-frequency analyses and sizes of young-of-the-year stranded in the Azores. The size-specific growth model is a monotonic, nonlinear, declining function. The growth model is consistent with growth rates calculated from recaptures of tagged loggerheads. Loggerheads leave the pelagic habitat and recruit to neritic habitats over a range of sizes from 46 to 64 cm curved carapace length (CCL). From this size range and the growth model, we estimate the duration of the pelagic stage varies from 6.5 to 11.5 yr. Nonparametric smooths of the size frequency distributions of loggerheads in pelagic (n = 1692) and neritic (n = 1803) habitats intersect at 53 cm CCL, which is equivalent to an 8.2 yr duration for the pelagic stage. More growth data from loggerheads <2 yr old would strengthen the database for our growth model and perhaps lengthen our estimates of the duration of the pelagic stage. Incorporating our estimates for duration of the pelagic juvenile stage into the stage-based population model developed for North Atlantic loggerheads would have a major effect on estimates of population growth.; RefNo. [ 212 ]

2003

Green turtles Chelonia mydas in the Atlantic undergo a complex series of developmental migrations, moving long distances among foraging grounds. The study of the ecology and demography of these foraging populations is hampered by a lack of estimates of survival probabilities for immature stages. In addition, for all species of sea turtles, estimates of survival probabilities have repeatedly been identified as the greatest requirement for improving models of population dynamics and plans for the management and conservation of these endangered and threatened species. We use data from long-term capture-mark-recapture studies of 2 sampling populations of immature green turtles in the Bahamas Union Creek, Great Inagua from 1978 through 2001, and Conception Creek, Conception Island from 1989 through 2001 to generate estimates of annual survival probabilities. We employ a joint analysis of live-recapture and dead-recovery data (Burnham model) to generate estimates of true survival and permanent emigration probabilities for the Union Creek sampling population. Because fewer dead-recovery data were available for the Conception Creek sampling population, we used a Cormack-Jolly-Seber modeling approach to estimate an apparent annual survival probability of 0.680, which confounds mortality and permanent emigration. Our best estimate of true annual survival probability for Union Creek green turtles, protected from humaninduced mortality, is 0.891. High survival probabilities in immature stages are necessary for species such as sea turtles with long lifespans and late sexual maturity to maintain stable populations. After green turtles emigrated from Union Creek, annual survival probability declined to 0.761 as the turtles were no longer protected from human-induced mortality, demonstrating the negative effect of this mortality on the future of green turtle populations in the Caribbean. This study reports the first application of the joint analysis of live-recapture and dead-recovery data to sea turtle populations and demonstrates the advantages of this modeling approach.; RefNo. [ 213 ]

1999

The green turtle (Chelonia mydas) population that nests at Tortuguero, Costa Rica, is the largest in the Atlantic by at least an order of magnitude. Surveys to monitor the nesting activity on the northern 18 km of the 36-km beach were initiated in 1971 and extended to the entire beach in 1986. From the survey data, we estimated the total number of nesting emergencies on the northern 18 km for each year from 1971 through 1996. Evaluation of the trend in nesting emergences indicated a relatively consistent increase from 1971 to the mid-1980's, constant or perhaps decreasing nesting dueing the late 1980s, and then resumption of an upward trend in the 1990s. Evaluation of trends in sea turtle nesting poulation requires many years of data because of the large degree of annual variation in nesting numbers. The trends reported in this study must be evaluated with caution for several reasons. First, if the mean number of nests deposited by each female each year (clutch frequency) varies significantly among years, changes in the number of of nesting emergences among years could reflect changes in the number of nesting females, clutch frequency, or both. Second, we only assessed the trend in one segment of the population (mature females), which may or may not represent the trend of the entire green turtle population, and which, because of late maturity, ,may not reflect changes in juvenile mortality for many years. Third, survey frequency, and thus confidence in annual estimates, varied among years. The upward population trend must be assessed from the perspective of the catastrophic decline that the Caribbean green turtle populations have experienced since the arrival of Europeans. If careful management is continued in Costa Rica and adopted throughout the region, the collapse of the Caribbean green turtle population-which seemed imminent in the 1950s-can be avoided.; RefNo. [ 210 ]

2000

; RefNo. [ 1822 ]

2001

Fishing acts like a predator; it alters the extent of competition and allows the coexistence of competitive species. To test this hypothesis, several component elements are addressed. The variability of biomass in demersal fish communities is analysed to seek evidence that biotic interactions play a role in community dynamics. Spatial segregation as a result of a fishery's removal in several communities is analysed to test whether there are differences in coexistence or segregation. Previous studies of the demersal fish community of the Scotian Shelf revealed that the coefficient of variation for total biomass over time was lower than that for individual species. Similarly, as shown in this paper, variability of biomass in the demersal fish assemblages of the Bay of Biscay and the Gulf of Lions (France) are characterized by the same patterns. This pattern is interpreted as the effects of interactions between species (predation, competition) that involve energy limitation within the systems. Also, spatial segregation among species is related to fishing intensity. First, differences in spatial segregation between the Bay of Biscay and the Gulf of Lions, as measured by the slopes of the species area curves, are significant. Spatial segregation decreases from the least harvested systems to the most harvested ones when data from several systems are compared. These analyses indicate that biotic interactions play a significant role in the dynamics of demersal fish communities and that decreases in the spatial segregation of species can be associated with increased fishing. These results are consistent with the hypothesis that fishing and predation have similar effects on fish communities.; RefNo. [ 1823 ]

1999

Causes of spatial variation in recruitment of the surfgrass Phyllospadix torreyi were explored. Recruitment of seedlings in this dominant, late succesional seagrass is dependent on the presence of host plants (mainly branched algae), which serve as substrates for seed attachment and anchor the seedling during its early growth stages. Field observations indicated that attachment of seeds and seedlings to host plants was not always proportional to abundance of host plants. To explore mechanisms causing this pattern we measured seed attachment to 7 algal species and surfgrass in the laboratory under 3 water flow regimes. Laboratory experiments were conducted using a flow tank designed to produce oscillatory flow. The primary objectives of our laboratory experiments were to determine the relative seed catching ability of different host species, and the extent to whichthe seed catching efficiency of a host varied with flow velocity. The flow tank experiments revealed significant effects of both host species and flow regime, and no significant interaction between host species and flow. Seed attachment to all species was was greatest at a moderate flow(max. velocity 85 cm s-1) flows. Seed attachment was highest on the intertidal red algaChondracanthus canaliculatus (Harv.) Guiry and the subtidal coralline alga Lithothrix aspergillum Gray. Differences in seed attachment among the remaining 6 species were generally small; on average these plants collected about half as many seeds as C. canaliculatus and L. aspergillum. Data collected from field surveys were generally consistent with results obtained in the laboratory. The field abundance of host species having high seed-attachment potential in the laboratory explained a significant amount of spatial variation in seedling density at 3 of 4 intertidal sites (numbers of seedlings at 2 subtidal sites were very low and precluded similar analyses). Nontheless, a substantial amount of variability in seedling recruitment remained unexplained by the abundance and species composition of host plants. Data obtained from standardized seed collectors placed in the field were consistent with this observation as the numbers of seeds attached were highly variable both within and among sites. This suggested that factors influence seed production, dispersal and seedling survivorship also contribute to spatial variability in the density of seedlings in nature.; RefNo. [ 948 ]

2004

Marenzelleria sibling species Types I and II are characteristically distributed within the salinity gradient of the Elbe estuary. For the first time F1-hybrids between the 2 Marenzelleria species were found. Type I inhabits mainly the isoosmotic/hyperosmotic range, while Type II and the F1-hybrids prevail in the hypoosmotic range. A sympatric occurrence could be inferred in salinity ranges from 3.3 to 12.3 ppt. Marenzelleria sibling species Type II has been found for the first time in the North Sea (Elbe estuary). The influence of salinity on the distribution of Marenzelleria spp. Was examined by laboratory experiments. In a time-course experiment with salinity changes from 10 to 25 ppt and from 25 to 10 ppt, respectively, enzyme activities and free amino acids were determined. The activities of alanine aminotransferase, aspartate aminotransferase, and glutamate dehydrogenase were always higher in Type I than in Type II. A salinity increase from 10 to 25 ppt resulted in a faster increase of the concentrations of D,L-alanine, glycine, serine, glutamate and threonine in Type I. The biochemical results showed that the capacity of cell volume regulation could be involved in the different spatial distributions of the 2 sibling species.; RefNo. [ 214 ]

2003

The paper sketches out a theoretical framework for analysing the interplay between eco-efficiency, cognition and institutions. It derives from analytical shortfalls of the prevailing literature, which features strongly engineering and business economics, by using insights from New Institutional Economics, from Cognitive Science and, partly, from Evolutionary Economics. It emphasises the role cognition and institutions play in the adoption of ‘green’ technologies by firms. A cognitive perspective derives from recent research on simple heuristics and context-based rationality; it is proposed that those findings can serve to analyse decision-making of individual actors respectively firms and, thus, should complement economic analysis. A second proposition is that eco- fficiency and normative rules such as a Factor Four strongly rely upon institutions, i.e. the ability of institutions to evolve over time and the development of those institutions that are most appropriate to enhance technological change. In this regard, business institutions and competition are crucial, but regulatory needs remain in order to safeguard continuity of knowledge creation. The framework allows for an analysis why overall adoption of eco-efficiency still can be considered relatively slow and why some markets and firms are far ahead. As a brief case study the article reflects upon German waste law’s ability to enhance eco-efficiency.; RefNo. [ 216 ]

1998

; RefNo. [ 270 ]

6

2005

A compilation of the extensive range of shoreline indicators that have been reported in the literature. Strengths and limitations of the more common proxy shoreline features are highlighted. Recent advances that use automated image-processing techniques ability to gain a better process-based understanding.; RefNo. [ 2059 ]

2001

An extensive survey of nitrogen forms and phytoplankton of the euphotic zone on the northern Spanish shelf was made in March 1992. Dissolved inorganic nitrogen (DIN) included nitrate, nitrite and ammonium, which were determined by colorimetric analysis. Dissolved organic nitrogen (DON) was determined by persulfate oxidation of filtered seawater. In addition, particulate nitrogen, chlorophyll a, sestonic proteins and primary production measurements were carried out at selected stations. Surface waters in the western region (Galicia) were characterized by the presence of Eastern North Atlantic Central Water of subtropical origin (ENACWt). This water mass extended over the southern Bay of Biscay (Mar Cantábrico) where large phytoplankton accumulations occurred. Chlorophyll a concentration and primary production rates measured in the Mar Cantábrico were significantly higher than in Galicia. DON reached concentrations of up to 10 mmol m3 in phytoplankton rich areas, particularly in the eastern part of the southern Bay of Biscay, where primary production was also high. Positive correlations were found between DON and particulate nitrogen, and between chlorophyll and primary production, while a negative correlation was found between DON and DIN. On average, dissolved nitrogen was ca 95% of total nitrogen, and DON formed from 52% (Galicia) to 61% of total nitrogen (Mar Cantábrico). The average concentration of DON in the Mar Cantábrico (7.82 mmol N m3) was almost double that of Galicia. Using salinity as a conservative tracer, DON was partitioned and the excess DON (DONexcess) compared to the expected concentration resulting from mixing between continental water and ENACWt at each depth was computed. We found lower correlation values between DONexcess and phytoplankton biomass and production than between total DON and these variables, which suggests an uncoupling between phytoplankton and DON production and the participation of microplanktonic grazers in the release of DON in surface waters. However, considering nitrogen stocks integrated in the euphotic zone in each region, DONexcess accounted on average for only 7% of total nitrogen in Galicia, while in the phytoplanktonrich Mar Cantábrico it accounted for 26%. This suggests that phytoplankton spring blooms are one of the main sources of organic matter in this pelagic ecosystem.; RefNo. [ 217 ]

2002

Sea otter Enhydra lutris populations were severely affected by the 1989 ‘Exxon Valdez’ oil spill in western Prince William Sound, AK, and had not fully recovered by 2000. Here we present results of population surveys and incorporate findings from related studies to identify current population status and factors affecting recovery. Between 1993 and 2000, the number of sea otters in the spill-area of Prince William Sound increased by about 600 to nearly 2700. However, at Knight Island, where oil exposure and sea otter mortality in 1989 was most severe, no increase has been observed. Sea otter reproduction was not impaired, and the age and sex composition of captured otters are consistent with both intrinsic reproduction and immigration contributing to recovery. However, low resighting rates of marked otters at Knight Island compared to an unoiled reference area, and high proportions of young otters in beach cast carcasses through 1998, suggest that the lack of recovery was caused by relatively poor survival or emigration of potential recruits. Significantly higher levels of cytochrome P4501A (CYP1A), a biomarker of hydrocarbons, were found in sea otters at Knight Island from 1996 to 1998 compared to unoiled Montague Island, implicating oil effects in the lack of recovery at Knight Island. Delayed recovery does not appear to be directly related to food limitation. Although food availability was relatively low at both oiled and unoiled areas, we detected significant increases in sea otter abundance only at Montague Island, a finding inconsistent with food as a principal limiting factor. Persistent oil in habitats and prey provides a source of continued oil exposure and, combined with relatively low prey densities, suggests a potential interaction between oil and food. However, sea otters foraged more successfully at Knight Island and young females were in better condition than those at Montague Island. We conclude that progress toward recovery of sea otters in Prince William Sound is evident, but that in areas where initial oil effects were greatest, recovery may be constrained by residual spill effects, resulting from elevated mortality and emigration. It is evident that internal reproduction and immigration of juveniles has been the primary means of population recovery, as opposed to broad scale redistribution of adults from outside affected areas. The result is a recovery period protracted by long-term spill effects on survival and emigration and intrinsic limits to population growth.; RefNo. [ 218 ]

2001

; RefNo. [ 1824 ]

2002

; RefNo. [ 219 ]

2001

; RefNo. [ 1825 ]

2003

The bioaccumulation of cadmium in the oyster Crassostrea gigas originating from a clean (Bourgneuf Bay) and a chronically Cd-contaminated area (Gironde estuary) experimentally exposed to 109Cd-labeled bulk seawater (dissolved and particulate pathways combined) was examined over 21 d. A single-component first-order kinetic model describing the behavior of the bioaccumulation factor (BAF) throughout the experiment showed that the estimated Cd BAF at 21 d was 47% higher for oysters originating from the contaminated estuary than for oysters from the clean area, suggesting an influence of the previous chronic exposure to Cd contamination in the estuarine environment. From the experimental results, the potential adaptive mechanism suggested cannot be attributed to a reduction in Cd permeability but rather to a higher Cd turnover due to the synergy between lysosomes and metallothioneins which, through chelation, are responsible for the reduction in bioavailability and toxicity of cd in oysters. The lower BAF observed for soft parts of oysters previously exposed to chronic Cd contamination corresponded to a faster response to the experimental Cd contamination due to the presence of pre-existing metallothioneins induced by the Cd present in the estuarine environment. Furthermore, based on a 2-component exponential loss kinetic model, Cd complexation to metallothioneins and lysosomes was probably responsible for the slow turnover in the long-term compartment of loss (biological half-life, Tb1/2 = 495 and 198 d for the Bourgneuf and the Gironde oysters, respectively). Of the total Cd accumulated, 40 to 60% was in the soluble form and 30 to 40% of this fraction had been detoxified by the Gironde oysters through chelation to metallothioneins or to lysosomes, which means that approximately 12 to 24% of the total Cd accumulated was potentially bioavailable to humans through oyster consumption. However, through depuration, it was also more efficiently eliminated from oyster soft parts (the edible portion) previously exposed to Cd than from control oysters. Therefore, in the light of these results, it is suggested that the way in which regulatory thresholds of Cd in oysters are presently calculated should be reconsidered and should take into account the level of Cd already detoxified by the oysters through complexation processes.; RefNo. [ 220 ]

2003

We measured diet composition, prey preferences and feeding rates of Acartia spp., an abundant copepod group in San Francisco Bay. Monthly incubations with Acartia feeding upon the natural planktonic assemblage were conducted during spring 2000 at 2 locations: South Bay (SB, lagoonal estuary) and San Pablo Bay (SPB, partially mixed estuary). Prey assemblages in SB and SPB were always dominated by nanoplankton, however Acartia never consumed cells <10 µm in either location. Overall abundance >15 µm was always higher in SB, comprised primarily of autotrophic cells (diatoms and pigment-containing flagellates). The assemblage in SPB was typically dominated by heterotrophic prey (ciliates and small non-pigmented flagellates). Acartia consumed a diverse diet but were highly selective for motile prey, especially ciliates and nanoflagellates. Acartia selectivity for individual prey taxa was strongest during periods of high food abundance, consistent with optimal foraging theory. In SB at least 50% of Acartia diet consisted of autotrophic biomass (diatoms, flagellates and the autotrophic ciliate Mesodinium). Ingestion rates were low and accounted for only 6.3% of body carbon per day, except during the March bloom, when Acartia ingested diatom biomass at 217 ng C copepod 1 h 1, or 188% of body carbon per day. In SPB Acartia diets were dominated by heterotrophic prey >10 µm, with ciliates and non-pigmented flagellates always >60% of total biomass consumed. Ingestion rates were lower than in SB (typically equivalent to 2.2% of body carbon per day), but in the April bloom Acartia increased consumption of heterotrophic flagellates to 121 ng C copepod 1 h 1, or 101% of body carbon per day. These results indicate that protozoans provide an essential nutritional supplement for San Francisco Bay copepods, especially in SPB, and that bloom periods may be important for copepod production and, in turn, higher trophic levels.; RefNo. [ 221 ]

2002

Among species in which fragmentation is an important mode of asexual reproduction, mechanisms that facilitate fragmentation should be advantageous. The Caribbean gorgonian Plexaura kuna readily fragments on reefs of the San Blas Islands, Panama, to form aggregations of genetically identical colonies. To understand the mechanics of fragmentation and the role of structural properties, the force required to break branches was measured on live colonies in the field, and morphology, flexibility, and strength of the axial skeleton were measured in laboratory experiments. Young’s modulus, used as a measure of stiffness, was higher in P. kuna than in many other gorgonians and significantly varied among clones, ranging from 2.859 to 6.073 GN m2. This level of variation indicates that drag should vary among clones due to ifferences in their flexibility. Of the morphological traits measured, coplanar constrictions influenced the force required to break a branch while anti-planar constrictions and branch anisotropy did not. The modulus of rupture, a measure of the strength of the branch, significantly varied among clones of P. kuna, ranging from 50.87 to 92.58 MN m2. Using hydrodynamic theory we predict that the 55% variation in skeletal strength is sufficient to produce variation in fragmentation rate among clones. The stiffness of the skeleton of some colonies may prevent bending and shedding of drag resulting in failure due to the weakness of the skeleton. Clonal variation in flexibility and strength provides a mechanism through which selection may act to favor fragmentation and clonal growth.; RefNo. [ 222 ]

2003

Nutrient enrichment in oligotrophic tropical waters is considered one of the main causes for coral reef degradation. In the present study, the impacts of net-pen fish-farming in the Gulf of Eilat, Red Sea, on coral biology were evaluated by investigating survival, growth and gonad development in 2 common branching coral species. From 10 Acropora eurystoma genotypes (colonies) 200 branches were collected and suspended for 7 mo from PVC plates adjacent to a commercial fish farm. They grew 3 times faster than a similar set of branches taken from the same 10 colonies and suspended on PVC plates at a non-enriched reference site. The increase in branch weight and volume was 2.7 and 4.3 times greater, respectively, at the fish farm than at the reference site. Survival rates were 100% at both sites. Nubbins of Stylophora pistillata deployed on plates at the 2 sites initially (first 4 mo) grew more rapidly at the reference site, but after 13 mo, the vertical extension levels were significantly larger at the fish-farm site (19.2 ± 6.1 vs 16.3 ± 4.6 mm, respectively). The average number of oocytes polyp1 and the number of polyps with developing testes in mature S. pistillata colonies were significantly higher at the fish farm than at the reference site. It is suggested that nutrients released from intensive mariculture may not necessarily lead to the demise of coral reefs, as is commonly presumed.; RefNo. [ 223 ]

2003

Populations of the greater blue crab Callinectes sapidus throughout the Gulf of Mexico, as far north as South Carolina, USA, are infected by the rhizocephalan barnacle Loxothylacus texanus. Larvae are non-feeding and have approximately 3 d from the onset of metamorphosis from their naupliar stage to successfully encounter and recognize a host before their nutrient stores are depleted. The female cypris and kentrogon stages are the initial infective agents. Chemical cues, like those used by free-living barnacles to identify settlement sites, appear to be important in the identification of potential hosts by this parasitic barnacle. The cypris larvae of L. texanus settle in response to carbohydrate or glycoprotein cues found in the epicuticle layer of C. sapidus exoskeletons. These cues are associated with the epicuticle layer only, not the biofilm associated with the carapace. In fact, the carapace biofilm and lipid-based compounds found in the outer layer of the epicuticle appear to afford crabs some protection against settlement by L. texanus.; RefNo. [ 224 ]

2002

While larval supply patterns play a major role in determining the distribution and abundance of reef fishes at a range of spatial and temporal scales, events occurring in the weeks after settlement may also significantly alter the demography of a juvenile population. I monitored over 2 summers the arrival of new recruits of 6 species of benthic damselfish onto continuous and patch reef habitat in One Tree Island lagoon. Each species had specific habitat preferences, and most showed some form of patchiness in spatial and temporal distribution at settlement; however, this was most likely a result of group settlement rather than habitat patchiness. Tagged recruits of Pomacentrus amboinensis remained within 1 m of their settlement site for at least the first 36 d on continuous reef, while known individuals of other species also moved little during this period, suggesting that disappearances were likely to be due to mortality. Mortality of recruits varied among species, years and habitats (patch vs continuous reef), and consequently spatial distributions of fish changed after settlement at the scale of 10s of metres (within-site) and several kilometres (among 8 sites). The spatial patchiness in distributions was not consistent among species, sites or years, suggesting that spatial variation in substrate did not have a major effect on settlement variation at this scale. These results show that the settlement signal may be obscured in the first few weeks post-settlement, and that lessfrequent censuses, commonly used as proxies for high-frequency monitoring of settlement, may not accurately hindcast spatial or temporal patterns of settlement.; RefNo. [ 1474 ]

2002

Large-scale bleaching events are major disturbances to coral health and community structure, but may also affect other coral reef taxa, such as fishes. In 1997-1998, wide-spread coral bleaching and mortality occurred across the Great Barrier Reef, caused by increases in sea surface temperatures resulting from El Niño Southern Oscillation. As part of this event, in February-March 1998, there was extensive bleaching within One Tree Island lagoon (southern Great Barrier Reef), such that almost 12 mo later there was a significant reduction of live coral cover at some sites. We monitored the distribution of adults and recruitment of damselfishes (Pomacentridae) to sites within One Tree Island in 1993-1995 and in 1999. Fish species that normally associate with live corals showed relatively lower recruitment at bleached sites compared to the same sites pre-bleaching or to recovered sites and, as a result, species diversity and assemblage structure of recruits changed. Compared to 1993/1995 densities, adult Pomacentrus wardi, P. moluccensis and Chrysiptera rollandi densities dropped at bleached sites, but not at unbleached sites. While P. moluccensis directly associate with live corals, the other 2 species do not. This study has demonstrated that indirect effects of bleaching can include changes in assemblage structure of reef fish adults and recruits.; RefNo. [ 225 ]

2000

The spatial and temporal patterns of distribution of new settlers of 23 species of damselfish (Pomacentridae) within One Tree Island lagoon, southern Great Barrier Reef (GBR) were measured for 3 summers to assess the persistence of spatial patterns of recruitment. Overall recruitment was 3 times higher in 1993/1994 than 1994/1995, and 1.5 times higher than 1999. In general, recruitment decreased towards the lagoon centre, even though habitat availability was not lower there on average, suggesting that most fish settled at outer sites as they were advected from adjacent waters. There was also great variation in numbers of recruits among outer sites. Patterns of recruitment to continuous reef and patch reef habitats also differed among species, suggesting habitat selection at this broad level. For example, Pomacentrus nagasakiensis was primarily found on patch reefs, while P. moluccensis was largely found on continuous reef. One site (Shark Alley) received the highest number of recruits of most species during the study, and this pattern has been observed in studies since 1975. Despite interannual variability in abundance of potential settlers and differences in the habitat preferences of some species, therefore, some sites on the reef can receive relatively high numbers of settlers over decadal time scales. This consistency of spatial pattern may be due to local topography and oceanography at Shark Alley, which appear to favour the input of potential settlers. The availability of live coral may also be important, but species which showed no preferences for live cover also recruited at high levels at this site. The attributes of Shark Alley were compared with those at other sites. Overall, sites that clustered on the basis of oceanographic and habitat features also had similar recruitment, suggesting that these features may be useful in predicting recruitment hotspots on reefs elsewhere.; RefNo. [ 1827 ]

2002

; RefNo. [ 1828 ]

2001

; RefNo. [ 1829 ]

2000

; RefNo. [ 1830 ]

2002

; RefNo. [ 1831 ]

2000

Seagrass meadows are among the most diverse coastal ecosystems in the Baltic Sea. There is, however, an apparent lack of quantitative data on functional aspects of these systems, such as plant-animal interactions. We tested the importance of seagrass density and morphology for benthic infaunal recruitment in a 2 mo (June/July 1997) field-experiment with both bare and vegetated (3 densities of artificial Ruppia maritima and Zostera marina) colonization trays with azoic sediment. These artificial seagrass patches were placed at 3 m depth in an unvegetated area of a sandy bottom seagrass site on the Åland Islands, northern Baltic Sea. Faunal succession was followed by SCUBA diving and core sampling with 10 to 20 d intervals. The data showed strong effects of seagrass complexity and wind disturbance on (1) physical processes such as accumulation of drifting algae, particle trapping and sediment binding, (2) development of community parameters (abundance, species richness, diversity) and (3) species-specific colonization patterns. Our data further demonstrated the importance of post-settlement events for distribution of juvenile macrofauna (e.g. resuspension or transport by means of drifting algae), and showed negative and positive effects of wind-mediated disturbance in low- and high-complexity habitats, respectively. It is concluded that wind disturbance may act as a mechanism creating and maintaining high animal diversity in seagrass meadows.; RefNo. [ 226 ]

7

2004

Review on sea urchin fisheries management with emphasis on North America. Authors assess various approaches to management in the context of biological reference points. They indicate that the implementation of a limit reference point based on lifetime egg production would be desirable for fishery management of this kind of invertebrates.; RefNo. [ 2030 ]

2001

; RefNo. [ 1834 ]

2001

; RefNo. [ 1832 ]

2003

Horseshoe crab Limulus polyphemus eggs are laid on sandy estuarine beaches, and subsequently develop into first instar (trilobite) larvae that emerge into the plankton before settlement. To obtain estimates of early survival, we collected data on the densities of trilobite larvae within intertidal sediments on a beach in Delaware Bay, New Jersey, and the densities of post-settlement juveniles, through the first 4 instar stages, on the adjacent tidal flats. Over the course of the spawning season in 1999, there were some 761 000 live trilobites produced within a 1 × 3 m band of intertidal beach. Losses (mortality + emigration) were highest during the brief planktonic phase or shortly after settlement to the benthos; we estimated that about 97.5% of the live trilobites on the beaches were lost during their transition to epibenthic trilobites on the intertidal flats. Newly settled horseshoe crab juveniles were not dependent on a specific sediment type, but tended to be more abundant close to shore. After settlement, there was about a log-fold decrease in juvenile density with each molt from the second through the fourth instar. Overall, only about 3 larvae per 100 000 remained as fourth instar juveniles on the tidal flats at the end of their first summer. Our ability to extrapolate future adult year-class strengths based on young-of-the-year densities is limited, because 9 to 10 yr are required for horseshoe crabs to reach sexual maturity.; RefNo. [ 227 ]

2000

Between January 1995 and August 1996, suspended matter and zooplankton were sampled at different locations in a mangrove ecosystem located in the Gautami Godavari estuary and adjacent Kakinada Bay (Andhra Pradesh, India). Suspended matter was sampled at 13 different stations, and was found to have a highly variable carbon stable isotope composition, with d13C values ranging overall between 30.94 and 19.18, and a highly variable elemental (C:N) composition. Our data suggest that the phytoplankton component has a seasonally and spatially variable d13C signature, which is surpressed by the terrestrial signal but may at times fall in the same range as the d13C of the allochtonous matter. It is argued that the phytoplankton d13C decreases after the onset of the monsoon rains, most likely due to the 13C-depletion of the DIC pool caused by the microbial respiration of the allochtonous organic matter. At each of the 4 sites selected for concurrent zooplankton sampling, the zooplankton showed a much wider range of d13C than did the suspended matter, with overall d13C values between 30.14 and 16.45. In addition, spatial differences in average d13C were much more pronounced for zooplankton than for total suspended matter. These data indicate that zooplankton feed on a component of the suspended matter pool, which has more pronounced seasonal and spatial d13C variations than the total suspended matter. Thus, despite the large amounts of terrestrial and mangrove detritus present in the water column, the locally produced phytoplankton appears to be a more important carbon source for the zooplankton.; RefNo. [ 228 ]

2002

Nitrogen limits plant growth in most salt marshes. As foliar N-uptake makes a significant contribution to the overall N-requirements of submerged plant species such as (e.g.) seagrasses, we tested if foliar N-uptake was also significant in Spartina anglica Hubbard, a species that dominates the lowest, regularly flooded areas of salt marshes in the SW Netherlands. Foliar N-uptake was compared for plants from 2 estuaries with contrasting N-loads in their water column. N-uptake was quantified by (1) flooding detached leaves in test tubes, (2) spraying leaves still attached to the plants, and (3) flooding whole plants, with solutions containing either 15NO3 or 15NH4 +. We found that detaching the leaves from the plant underestimated NH4 + uptake by between 30 and 50%. Higher salinity also reduced foliar N-uptake. Uptake rates were higher for NH4 + than for NO3, as has been found for many submerged and terrestrial angiosperms and marine algae. Methodology also had a major effect on the uptake rate, with flooding of intact plants yielding higher uptake rates than spraying attached leaves. However, in general, foliar N-uptake rates were low at the NO3 and NH4 + concentrations that are actually present in the tidal waters during the growth season, and may at most contribute to around 10% of the growth requirement. This percentage is much less than for seagrasses, but in line with data for some terrestrial systems. We conclude that in contrast to seagrasses, foliar N-uptake does not form a significant contribution to the overall N-requirements of S. anglica. This low N-uptake capacity of the S. anglica leaves appears to be a consequence of adaptations to survive tidal flooding.; RefNo. [ 229 ]

2003

Using temperature as an independent variable, we were able to explain some 43 and 49% of the variance in the specific absorption coefficient of phytoplankton (a*)) at wavelengths 443 and 676 nm, respectively, for some 1187 samples collected over a broad range of oceanographic regimes. Through examination of ancillary data, we demonstrate that our results are consistent with the view that the size structure and taxonomic composition of phytoplanktonic communities are regulated by physical processes, for which temperature is often a suitable proxy. Results obtained from multiple-linear regression analysis showed that by using temperature and chlorophyll a concentration, both of which can be retrieved by remote sensing, a larger proportion of the residual variance in a* could be explained than if chlorophyll a concentration were used alone. Furthermore, as a single independent variable, temperature could explain nearly an equal proportion of the variance of a* as chlorophyll a. These results show clearly the potential of using satellite-derived temperature data to improve retrieval of phytoplankton biomass from remotely sensed data on ocean colour.; RefNo. [ 230 ]

2003

The need to better understand the linkages and interdependencies of socio-economic and coastal environmental dynamics has taken on a more deliberate role in the development and assessment of Integrated Coastal Management world-wide. The analysis and establishment of indicator-driven programs to assess change in coastal and watershed systems have increasingly moved to stress socio-economic forcings and impacts. This article serves to review the need for and provide an assessment of important frameworks designed to foster such integration. It argues that the evolution of the Driver Pressure State Impact Response (DPSIR) framework, now in broad use, provides an essential contribution.; RefNo. [ 232 ]

2002

Predators face decisions about which prey to include in their diet in order to maximize fitness. The foraging tactics used to capture prey and the resulting profitability of prey influence these decisions. We present the first evidence of prey-dependent foraging tactics and prey profitability in a free-ranging pinniped. We studied 39 adult male harbour seals Phoca vitulina at Sable Island, Nova Scotia using an animal-borne video system. Each male wore the camera system for 3 d during which 10 min video samples were recorded every 45 min from 06:00 h, resulting in approximately 3 h of videotape per male and a total of 1094 capture attempts of identified prey. Males foraged mainly on sand lance Ammodytes dubius and flounders (Pleuronectids), but salmonid and gadoid fishes were occasionally pursued. Foraging tactics differed among and within prey types based on differences in prey behaviour. Sand lance was both a cryptic prey, when in the bottom substrate, and a conspicuous schooling prey. Seal swimming speed, handling time and capture success differed between cryptic and conspicuous sand lance. The highest capture success and handling time was recorded for flounders. Estimated profitability, i.e. net energy intake per unit time, also differed with prey type and prey size. Our results suggest that diet selection may have important implications on the foraging energetics of pinnipeds.; RefNo. [ 231 ]

2003

The re-colonisation of a site used for the extraction of sand and gravel for ca. 25 years off the southeast coast of the UK was examined 4 years after the cessation of dredging. Effects of different levels of dredging intensity on the rate of macrofaunal re-colonisation were investigated. Values of abundance and total numbers of species were significantly lower (p<0.05) in an area most recently exposed to the highest level of dredging intensity compared with samples taken from an area of low intensity, and those from a reference site. Differences between previously dredged sediments and the reference location were due to the reduced abundance of a range of macrofaunal species characterising nearby sediments. Multivariate measures of community structure also indicated that there were significant differences (p<0.01) between the macrofaunal assemblages in the areas exposed to different dredging intensities. Sediment from the area exposed to the highest dredging intensity contained proportionally more sand than other sampled sediments. The extent to which dredging intensity contributed to these differences was difficult to determine owing to the absence of any baseline data. Despite this, univariate and multivariate analyses indicated a strong relationship between macrofaunal community structure and dredging intensity at this site. Correlation analyses also demonstrated that the predominant influence on the macrofaunal community was that of the level of dredging that took place in 1995, the last year that the licensed site was dredged heavily. Preliminary observations indicated that the fauna remained in a perturbed state some 4 years after cessation of dredging. Therefore, relatively rapid ‘recovery’ rates, commonly cited as 2–3 years for European coastal gravelly areas, should not be assumed to be universally applicable. Implications for the future management and scientific study of marine aggregate extraction arising from preliminary observations on the physical and biological status of this site are discussed together with the options for selecting a reference site in the absence of baseline information.; RefNo. [ 1835 ]

2001

; RefNo. [ 1833 ]

10

1999

A collection of essays covering international law issues relating to sustainable development, with a special focus on the utilisation of marine living resources and the protection of the marine environment. It includes topics such as 'The development of the legal regime of high seas fisheries', 'International fisheries law since Rio: the continued rise of the precautionary principle', and 'Towards long-term sustainable use: some recent developments in the legal regime of fisheries'.; RefNo. [ 2051 ]

2003

Multiple ichthyoplankton surveys of Placentia Bay, Newfoundland during the spring and summers of 1997 and 1998 indicated that both passive and active processes contribute to spatial pattern in pelagic eggs and larval fish. Distribution patterns of pelagic eggs and early larvae in coastal Newfoundland waters were consistent with passive drift during development, but older larvae were associated with areas of high production. Recently hatched larvae from pelagic spawners decreased in size throughout the spawning season, reflecting seasonal decreases in egg diameter. Larvae from demersal eggs increased in size over the same time period, possibly reflecting retention and growth. Lloyd’s index of patchiness calculated for pelagic eggs generally increased during development, suggesting passive retention. Patchiness decreased after hatch, then increased at approximately 10 mm. We hypothesize that the observed spatial patterns in older larvae, seasonal size increases in larvae from demersal eggs, and ontogenetic changes in patchiness reflect active processes. Predator patchiness, ontogenetic changes in spatial patterns, and published larval consumption rates support the hypothesis that mortality did not generate this pattern. Furthermore, mean crowding of capelin larvae by potential prey increased with development. Increases in patchiness during late larval development coincided with the size at which swimming ability was predicted to exceed ambient flow. This pattern suggests that larger larvae may actively contribute to their spatial distribution. We conclude that swimming ability and behaviour become increasingly important in determining spatial distribution patterns as pelagic larvae develop.; RefNo. [ 233 ]

2003

Small-scale habitat complexity, including that caused by biological structures, is an important factor in structuring benthic communities and also sometimes in increasing biodiversity. The aim of this study was to determine if hydroid colonies have an effect on the composition of benthic communities in the Irish Sea, and if so, which components of the fauna are affected. Forty-six seabed core samples were taken by divers from two sites off Port Erin, Isle of Man, Irish Sea. Half of these were centred on hydroid colonies, half were not. All taxa retained by a 63-lm sieve from the cores were identified and counted. Community composition and diversity were compared between hydroid and non-hydroid cores using multivariate and univariate methods. Benthic communities were significantly different between the two sample groups. This was almost entirely due to the presence of sessile and mobile epifaunal taxa in the hydroid cores. The tube-building amphipod, Ericthonius punctatus, was particularly abundant attached to the hydroid stems. Infauna was not significantly different between the two groups. Upright sessile epifauna may play a particularly important role in the Irish Sea as a settlement substrate for juvenile scallops (Pecten maximus and Aequipecten opercularis), which are an important fishery resource in this area. The 11-year closure of an area to dredging has not only enhanced scallop stocks but has had the added benefit of enhancing habitat complexity and biodiversity.; RefNo. [ 234 ]

6

2001

The combination qualitative and quantitative research approaches through a concrete example: a social impact assessment of the rock lobster fishery in Tasmania, Australia. In addition, how the research was applied politically by people outside the academy.; RefNo. [ 2060 ]

2003

Hector’s dolphin (Cephalorhynchus hectori) is small New Zealand delphinid with a coastal distribution. Within a strip of 1 km from shore, the present study quantified the habitat used by the dolphins n=461 groups) over a 19-month period (216 field days with 966 survey hours) by recording the abiotic factors sea surface temperature (SST), water depth and water clarity. Resource selection functions were used to distinguish the properties of 461 ‘‘used’’ sites (dolphins present) from 425 ‘‘unused’’ sites (no dolphins present) in six different study areas. Most dolphins were encountered in waters <39 m depth, with <4 m Secchi disk visibility and >14C temperature. The preference of Hector’s dolphins for warm and turbid waters was tested using eight models. Water depth, water clarity, SST and the study area explained dolphin presence to a very significant degree (p<0.001), and the model allowed the creation of probability plots for a variety of combinations of the variables. Habitat selection by dolphins differed between study areas, particularly between east and west coasts, in summer (December-February) and winter (June-August). Dolphin abundance appeared to change seasonally in some study areas, possibly due to a more offshore distribution of their prey in the winter, with its lower SSTs. This was so especially in summer (the main reproductive season), when dolphins (frequently with calves) occupied shallow and turbid waters, whereas in winter less use was made of this habitat.; RefNo. [ 235 ]

1998

The amount of terrestial protection achieved for biodiversity through designation of no-take public wilderness areas in the United States is much greater than no-take protection in the nation's National Marine Sanctuary System. With the exception of a small area in the Florida Keys, no permmanent reserve in the United States protects marine biodiversity from commercial fishing with gear that has strong effects on marine habitats and which has been identified as one of the major threats to marine biodiversity. A recent national poil has shown that public support does exist for conservation of the marine environment and protection of marine biodiversity. The New England region provides examples of the obstacles that such support may face in regions with a long history of commercial exploitation of marine species. I discuss the overall influence that the commercial fishing industry in New England has had on marine conservation efforts in the region, contrast the public's perception of marine versus terrestial wildlife species, and describe the nature of the media's coverage of the commercial fishing industry and fisheries management issues in the region. I propose the creation of a national no-take marine wilderness preservation system as a way to achieve protection of marine biodiversity as a separate goal from sustainable fisheries management in New England and other, similar regions in the United States.; RefNo. [ 236 ]

2003

Reproductive output (RO) is commonly used as a proxy for reproductive effort (RE) among Brachyuran crabs and other marine invertebrates, and so far no attempt has been made to incorporate the cost of brooding into RE to obtain a more reliable estimate of reproductive investment, nor to compare it along a temperature (latitudinal) gradient. We compared RO among 3 sites (ca. 20, 30 and 40° S, reflecting mean annual sea-surface temperatures of 18, 14 and 10°C, respectively), and the cost of brooding (oxygen provision) at those temperatures, in order to obtain a more reliable pattern of reproductive investment along an extended latitudinal gradient. A total of 187 brooding females of Cancer setosus were collected to estimate RO. Fecundity, volume and weight of the embryos, and embryo losses were also estimated. Laboratory experiments were carried out at the characteristic temperatures of those sites (acclimating females from central Chile) to determine (1) patterns of oxygen provision to the embryos, (2) patterns of brooding behavior, and (3) to quantify the cost of embryo ventilation. Optic fibers, video recording and respiration chambers were used to meet these goals. Results showed that (1) RO, (2) fecundity, and (3) volume and weight of embryos varied with latitude, and that temperature affects (1) period of embryo ventilation (oxygen provision) events, (2) flapping frequency, (3) embryo losses throughout the brooding period, and (4) cost of embryo ventilation per unit of time. While RO increased with latitude, the cost of embryo ventilation decreased with temperature, suggesting a trade-off between investment in eggs and the cost of providing oxygen to the embryos at different temperatures (latitudes). This pattern may not be exclusive to Brachyuran crabs, but may also apply to other marine invertebrates since oxygen limitation during early development occurs in other brooding species.; RefNo. [ 240 ]

2001

One of the most documented generalisations in sandy beach ecology is the trend for species richness of macroinvertebrates to decrease along a morphodynamic gradient from the dissipative to the reflective condition. This widely documented pattern remains unexplained, because the responsible ecological factors and underlying biological processes are still unknown. It has been proposed that swash condition, which changes significantly along the morphodynamic gradient, is the key limiting factor underlying this biological pattern. In this study, I suggest that 2 other physical factors could also be involved: sediment grain size and erosion-accretion dynamics. This proposal is supported by a 2 yr study of 12 sandy beaches in Chile, which showed that grain size becomes coarser, erosion-accretion dynamics more intense, and swash frequency and velocity increase as morphodynamic conditions change from dissipative to reflective extremes. I propose that these 3 environmental factors, although physically interrelated, may have independent influences on different biological processes or species. I suggest therefore that the reduction of species towards the reflective extreme is caused by increasing environmental severity, which is generated by the action (of at least) the 3 physical factors mentioned above. This proposal constitutes the hypothesis of ‘multicausal environmental severity’, which agrees with the large interspecific variability in the life history and ecological traits of sandy beach communities, since it admits that species with different characteristics could be controlled by different limiting factors. Thus, the present hypothesis provides a more general and flexible framework for investigating the relationship between species richness and morphodynamics in sandy beaches.; RefNo. [ 241 ]

2003

The saltmarsh–mangrove interface generally constitutes the landward boundary for the grey mangrove Avicennia marina var. australasica, the most widespread species on southeast Queensland shores. A. marina produces buoyant propagules, which are dispersed by tidal waters, only infrequently transported to saltmarsh by the highest spring tides. We predicted that runnelling, a form of habitat modification for mosquito control, transports and deposits mangrove propagules to saltmarsh because the runnels carry low-amplitude tides that would not normally inundate higher regions of the marsh. To test this, groups of marked A. marina propagules were released at three runnelled saltmarshes in southeast Queensland during high-amplitude, flooding and low-amplitude, non-flooding tidal events. The distance propagules were transported from their original starting positions on the saltmarsh–mangrove interface was measured and analysed to detect differences among groups at different distances from runnels. Groups of propagules released within 10 m of a runnel were always transported significantly further from the starting position and further up the saltmarsh shore after both flooding and non-flooding tides than any other groups. In addition, the pattern of stranding on saltmarsh for significantly different groups was closely associated with the path of runnel construction so that propagules were located either in the runnel or in depressions linked to the runnel that had been isolated mosquito-breeding pools prior to runnelling. Observations of A. marina plants at other runnelled sites suggest that propagules transported by runnels can establish and develop to maturity, at least in depressions and runnels, in saltmarsh. The fact that runnels transport propagules to regions of the saltmarsh beyond their normal limits of dispersion suggests a possible advantage for landward extension of the intertidal distribution of A. marina at runnelled sites and should be considered in saltmarsh management and mosquito control programmes in southeast Queensland.; RefNo. [ 1836 ]

2003

Two methods traditionally employed to investigate functional diversity in marine benthic ecosystems are relative taxon composition analysis, which interprets changes in the distribution of taxa in terms of the characteristics they exhibit, and trophic group analysis, which investigates differences in feeding mechanisms between assemblages. An alternative approach, biological traits analysis, considers a range of biological traits expressed by organisms to assess how functioning varies between assemblages. This study compares biological traits analysis to the relative taxon composition and trophic group approaches. Biological trait scores were assigned to a range of epibenthic invertebrate taxa from the southern North Sea and eastern English Channel and differences in the relative proportions of these traits were investigated using multivariate methods. The traits important in differentiating stations were attachment, flexibility, body form, mobility, feeding method and life habit. Such assemblages were spatially heterogeneous and there was no obvious distinction between different geographical sectors. This contrasted with the results of the relative taxon composition approach, which showed broad patterns in assemblage distribution in the eastern English Channel and southern North Sea. The biological traits approach provided information on a larger variety of ecological functions than the other techniques and revealed very different relationships between assemblages. It highlighted a greater diversity of assemblage types and was resistant to large-scale biogeographic variation. Therefore, it is potentially more useful than the traditional approaches for assessing ecosystem functioning on both large and small scales in benthic environments.; RefNo. [ 242 ]

2002

13C fractionation effects in an experimental food chain were determined by performing a series of mesocosm experiments with the copepod Temora longicornis and using flagellates as food. The bulk copepods were enriched in 13C by 1.2 to 2.3 and the CO2 respired was enriched by 0.8, compared to the isotopic composition of the food. Faecal pellets, however, were strongly depleted in 13C by 4.3 to 11.3, in isotopic mass balance with the 13C enrichment of the copepod body and of the respired carbon dioxide. Compound-specific carbon isotope analyses indicated that solvent extractable sterols and alkenones were isotopically light in carbon in both the copepod body and in the faecal matter. These lipids reflected the isotopic nature of the consumed food, indicating that they are not fractionated in the copepod. The residual fraction of the faecal pellets (after extraction) showed the largest isotopic change, being depleted in 13C by about 16 compared to the same fraction in the diet. Curie point pyrolysis analyses indicated that proteins were the major constituents of this residual material from both the copepods and their faecal pellets. When food sources of different isotopic composition were alternately supplied to the copepods, the faecal pellet residue showed a relatively slow turnover rate compared to the alkenones, which were completely egested by the copepods. A similarly slow turnover rate was observed in the residual material from copepods, suggesting that it must be proteins that are being fractionated by the copepod T. longicornis. The low 13C value of faecal pellets adds another variable to the stable carbon isotopic signature of particulate organic carbon in the pelagic environment.; RefNo. [ 243 ]

2003

A combination of biophysical modelling and data analysis is used to infer some important aspects of the southwest Nova Scotia (Canada) Bay of Fundy (BoF) ecosystem with respect to the first year of life of Browns Bank (BB) haddock. One of the main observations in this ecosystem is that adult fish found in the BoF region consistently exhibit a larger length-at-age than fish found in the BB region. This is generally thought to be due to drift and retention processes acting during the early life stages, with the larger fish assumed to be the result of settlement in a more favourable temperature and food environment downstream in the BoF. Also, while BB is considered to be an important juvenile nursery ground and the source for the smaller southwest Nova (SWN) fish, the existence of the larger BoF fish suggests a downstream nursery ground. To date, no analysis has been made regarding the whereabouts of such a nursery ground. The assumption of a favourable temperature and food environment in the BoF is investigated. The result of this analysis suggests that the small ‘inshore’ region off of Yarmouth, Nova Scotia, is the best settling ground. An Age-1 capture probability map is constructed from 30 yr of Canadian research vessel (RV) survey data. This map shows 3 regions where juvenile haddock are found BB, the inshore, and upstream (northeast) of BB. The average pelagic juvenile concentration field derived from the biophysical model predicts that BB and the inshore region are preferred settling grounds. A habitat suitability map, based on surficial sediment type, shows that the observed settling grounds coincide with preferred haddock sediment type. Finally, it is shown that the upstream Age-1 fish most likely come from larvae that drifted downstream from the Western Bank haddock spawning ground, and that BB likely acts as a potential source for the Georges Bank haddock stock. Thus, the combination of biophysical modelling and analysis of fisheries data provides evidence of the metapopulation structure of haddock stocks on the Scotian Shelf/Gulf of Maine.; RefNo. [ 244 ]

2001

‘Casitas’ are artificial habitats that mimic large crevice-type shelters sought by juvenile Caribbean spiny lobsters Panulirus argus. Despite the widespread use of casitas for lobster fishing in the Caribbean, the ecological performance of casitas is not yet fully understood. We examined the mode of operation of casitas in a habitat-limited population of juvenile P. argus in the reef lagoon at Puerto Morelos, Mexico. The density of juveniles in the reef lagoon was estimated with transects as 11 ha 1. After the transect surveys, a year-long baseline study on the lobster population, consisting of 13 visual censuses, was conducted at 9 fixed sites, each of area 100 × 100 m (1 ha). All lobsters were juveniles (10.7 to 56.5 mm carapace length, CL), and only 12% measured >35 mm CL. No movement of tagged lobsters was recorded among sites. Overall density in the 9 sites was 5.0 ha 1, but density varied widely in space and time. Two groups of sites were evident: a group of 5 sites with virtually no lobsters (NL sites), and a group of 4 sites with lobsters (WL sites). Lobster density was related to the abundance and size of natural shelters in each site. Casitas were deployed in 2 of the 4 WL and 3 of the 5 NL sites (treatment sites), and further bimonthly censuses were conducted in all sites for an additional year. Despite temporal variations, lobster density in both WL and NL treatment sites increased significantly compared to control sites and to their respective baseline values. The mean size of lobsters and the biomass of all lobsters became gradually larger in treatment sites compared to control sites and to the baseline study, but both mean size and biomass fluctuated in time. These results support the hypothesis that artificial habitats increase the abundance and biomass of lobsters in habitat-limited environments, and the notion of an attraction-production continuum effect of casitas on lobsters.; RefNo. [ 245 ]

2000

Marine turtles are globally endangered and subject to numerous conservation and management initiatives, yet many aspects of their life histories remain undescribed. All populations subject to investigation have been shown to have temperature dependent sex determination, and data in a number of cases have suggested that the sex ratio of hatchling production may be highly female biased. To date, the green turtle Chelonia mydas has been little studied in this respect. We recorded the temperature in 18 green turtle clutches laid at Alagadi Beach, Northern Cyprus using automated intra-nest recording devices. The temperatures experienced within these clutches ranged from 26.7 to 34.1°C with mean temperature ranging from 29.8 to 32.5°C. No regular diel thermal cycle was observed. Incubation periods at this site decreased as the season progressed and ranged from 43 to 60 d (n = 231; 1993 to 1998). In comparison to other published studies regarding temperature dependent sex determination in this species, these data are strongly suggestive of a highly female biased hatchling sex ratio. This hypothesis was partly confirmed utilising histological sexing of hatchlings found dead in nests (>99% female in 1998, n = 231). From these data we estimate that the pivotal incubation period for this population is ³56 d and the pivotal temperature as below 29.2°C. Using a conservative assumption that 100% males are produced by nests with incubation periods ³56 d and 100% females are produced by nests with shorter incubations, for the years 1993 to 1998, we estimate that at least 86 to 96% of hatchlings produced at this site were female.; RefNo. [ 247 ]

2002

There has been a dramatic increase in jellyfish biomass over the eastern Bering Sea shelf since the early 1990s, which was previously hypothesized to have been triggered by changing climate and ocean conditions. We examine the hypothesis that the presence of these large carnivores has affected fisheries resources, either through direct predation on larval stages, or through competition for zooplankton prey. In this paper, we explore the impact of this jellyfish increase on zooplankton and fish communities based on field data on the composition of the jellyfish community, and the abundance, size, stable isotopic signatures, and feeding habits of the principal scyphomedusae in the region. These data, together with those on zooplankton biomass, are used to estimate the ecosystem impacts of this increase. The center of jellyfish biomass has shifted from the SE Middle Shelf Domain in the early 1980s to the NW in the late 1990s. In recent years, the species composition of large medusae caught in trawls was dominated (>80% by number and >95% by weight) by the scyphozoan Chrysaora melanaster. Dense aggregations of this species occupied the water column in daytime between 10 and 40 m. Their food habits consisted mainly of pelagic crustaceans (euphausiids, copepods, amphipods), although other jellyfish and juvenile pollock were also consumed. Based on stable isotope ratios, the trophic level of this scyphozoan is equivalent to, or higher than, that of Age 0 pollock. Preliminary estimates showed that medusae have a moderate grazing impact on zooplankton in the area around the Pribilof Islands; C. melanaster was estimated on average to consume seasonally about one-third of the standing stock and 4.7% of the annual production of zooplankton in this region. Daily consumption of Age 0 pollock was estimated to be 2.8% of the standing stock around the Pribilof Islands during 1999. A hypothesis for the increase in jellyfishes observed in the eastern Bering Sea, based on release from competition from planktivorous forage fishes, is proposed.; RefNo. [ 248 ]

2004

Seasonal availability of phosphate was assessed by the examination of P pools and turnover times of orthophosphate on 6 cruises between October 2001 and August 2002 in the upper water column (0 to 120 m) of the oligotrophic SW Pacific Ocean near New Caledonia (21° 30’S; 167°E). While the soluble reactive phosphate (SRP) concentration was below the analytical chemical detection limit (30 nM) in summer and fall, it reached detectable values in winter and spring. The annual mean depth-integrated (0 to 100 m) SRP pool was 6.8 mmol m2 (SD = 3.9, n = 6). Particulate phosphate (PP) and soluble non-reactive phosphate (SNP) pools were, respectively, 1.7 (SD = 0.3, n = 6) and 23.0 mmol m–2 (SD = 4.8, n = 6). A strong seasonal variation of turnover times (T) of orthophosphate was observed (0.17 to 19 d) in the upper water column, with shorter values in summer and fall. Indirectly estimated orthophosphate concentration ([PO4]), based on turnover time measurements, ranged from 56 to 118 nM in winter to 0.3 to 0.8 nM in fall. A seasonal P sufficiency in spring and winter T > 100 h; [PO4] > 20 nM) and a strong deficiency in summer (T < 15 h; [PO4] < 2 nM) and the beginning of fall (T < 5 h; [PO4] < 1 nM) occurred. This P deficiency was larger than at the ALOHA station in the North Pacific Ocean. Primary production and phosphate availability followed the same seasonal pattern. In this iron-rich area known to sustain high N2 fixation rates, phosphate may appear as a key factor controlling carbon production.; RefNo. [ 249 ]

2003

In reality, individuals differ from one another. Some of this can be attributed to genetic differences, but much is due to environmental effects. Even neighbouring cells will have differing histories and may be in differing physiological condition in consequence. Many of the processes governing cell-growth are non-linear functions of the cell’s physiological state. This, together with the possibility that each cell will be in a unique physiological state, implies that it is not possible reliably to infer the population-level growth rate from the product of population abundance and an individual growth-rate derived on the basis of the average physiological characteristics of the local population. Unfortunately, this is precisely the assumption that is implicit in the vast majority of phytoplankton models which take no account of local-scale physiological structure in the phytoplankton population. Here, we present an individual-based population model of phytoplankton dynamics. This model utilises the Lagrangian Ensemble method to take account of local-scale physiological structure in the population. We make comparisons of the predictions of this model when run as a truly individual-based model or in a manner mimicking a model having no representation of local-scale population physiological structure. The results suggest that, under realistic environmental conditions, individuals in close proximity to one another can indeed be in substantially different physiological condition. More importantly, failure to take proper account of this variability results in differences of more than 30% between the predictions of standing crop and productivity made by the structured-model descriptions of the same underlying biology.; RefNo. [ 250 ]

2001

We conducted field surveys of rocky intertidal communities at 18 sites distributed between 29°S and 36°S on the coast of central Chile in order to document broad patterns of functional and trophic group abundance and evaluate their association with oceanographic features. Results showed that the main sessile components of the landscape throughout the region were kelps (16%) and crustose algae (48%) in the low intertidal zone, while mussels beds (30%) and corticated algae (32%) dominated the mid-intertidal zone. Geographic trends in abundance across the entire region varied from no clear regional patterns for some groups (e.g. barnacles), to smooth gradients increasing or decreasing toward higher latitudes for others (kelps and ephemeral algae) and to an abrupt switch from dominant to scarce northward of 32° S in 1 group (mussels). Significant among-site negative correlations were detected between the abundances of most algal functional groups and between mussels and barnacles. Herbivore density was negatively correlated with kelp and corticated algal cover, and positively correlated with crustose algal abundance. These correlations reinforce the notion that local biological interactions can partially account for the among-site variability in functional group abundance. We assessed the influence of mesoscale oceanographic features through satellite image analyses, by classifying the study sites as either strongly or weakly influenced by coastal upwelling. At sites strongly influenced by upwelling, we found significantly higher cover of kelps in the low intertidal zone and of corticated algae in the mid-intertidal zone. Cover of ephemeral algae in the mid-intertidal zone was significantly lower at sites strongly affected by upwelling. Contrary to predictions of bottom-up community regulation models, we found no significant differences in abundance of sessile filter feeders (mussels or barnacles), herbivores or carnivores. A significant proportion of the regional variation in abundance in some of the most abundant functional groups within each tidal level was associated with the latitudinal gradient in annual mean sea surface temperature (SST). We detected a significant correlation between SST and the abundance of kelps and crustose algae in the low intertidal zone, and mussels and ephemeral algae in the mid-intertidal zone. The abrupt change in the abundance of mussels in the mid-intertidal zone at about 32° S may indicate a similarly abrupt change in biological or environmental conditions. Lack of significant correlation between the abundance of mussels and other functional groups suggests that biological interactions may not be responsible for this geographic discontinuity. We suggest that oceanography may be largely involved in the geographic variability detected in patterns of community structure. Recent remote sensing studies documenting oceanographic discontinuities around the 32°S zone support our suggestion. Our results highlight the need for further experimental and oceanographic studies in areas where strong biophysical gradients are observed. Such areas may well reflect the existence of steep oceanographic gradients sensitive to large-scale environmental forcing.; RefNo. [ 251 ]

2002

The nature of the plant-animal interaction between wood-boring isopods and the red mangrove Rhizophora mangle L. has been controversial, with discussion ranging from the damage caused by the isopod being detrimental to beneficial for the mangroves they attack. Initiation of lateral roots by the mangrove in response to isopod burrowing has been one of the most commonly cited examples as support for the concept of beneficial herbivory. In this study, the possibility of root repair as a response of Rhizophora to burrowing by Sphaeroma terebrans Bate was evaluated. Previously burrowed prop roots were tagged in the field and the fate of all burrows followed over 14 wk at a site in Upper Tampa Bay, Florida. Results demonstrated that the most common response of the mangrove was to repair abandoned isopod burrows, with 99% of all tagged roots and 66% of all monitored burrows showing signs of repair. Lateral root production occurred at a lower frequency (32% of roots). Similarly, transect surveys performed in Upper Tampa Bay and 2 additional locations (Anna Maria Island and Weedon Island) indicated a high incidence (57 to 82%) of attacked aerial roots showing signs of burrow repair. Again, lateral root production was less commonly noted on transects (13 to 25% of the roots surveyed). Initiation of lateral roots and burrow repair were not mutually exclusive responses and all instances of lateral root production were in conjunction with repair. Our results demonstrate that the most common response to damage is the replacement of root tissue rather than the stimulation of new tissue production.; RefNo. [ 252 ]

2004

; RefNo. [ 949 ]

2000

The main objectives of the paper are to (1) give an overview of the state of the art of environmental value transfer, (2) discuss its prospects and potential role in CBA as a decision-support tool, and (3) provide further guidelines for proper use and application. Environmental value or benefit transfer is a technique in which the results of studies on monetary environmental valuation are applied to new policy contexts. The technique is controversial, not least because of academic and political reservations over the usefulness and technical feasibility of economic valuation tools to demonstrate the importance of environmental values in project or programme appraisals. Testing of environmental value transfer so far has been unable to validate the practice. Taking into account the conditions set out in the literature for valid and reliable value transfer, most transfers appear to result in substantial transfer errors. This paper discusses why and addresses the question of which factors may have been overlooked. It is argued that the problem is much more fundamental than previously acknowledged. Strict guidelines in terms of quantitative adjustment mechanisms to valid value transfer are meaningless if the more fundamental issue of differences in the very nature of the values elicited is not addressed at the same time.; RefNo. [ 253 ]

1999

; RefNo. [ 255 ]

2004

; RefNo. [ 257 ]

2003

In previous work, we reported that embryos of Calanus finmarchicus exposed to artificial ultraviolet-B (UV-B) radiation exhibited high wavelength-dependent mortality. The strongest effects occurred under exposures to wavelengths below 312 nm and, at the shorter wavelengths (<305 nm), UV-B-induced mortality was strongly dependent on cumulative exposure (i.e. dose). In the experiments reported here, we tested (for C. finmarchicus) the principle of reciprocity that is, was the effect of cumulative UV dose the same regardless of the dose rate at which it was delivered? Dose rate had no discernible effect on the proportion of live C. finmarchicus nauplii recovered from eggs exposed to 3 different UV doses: reciprocity held. The doses and dose rates administered were ecologically relevant. However, the issue of UV dose versus dose-rate effects on marine organisms requires further investigation at a broad range of dose and dose rates and for different exposure durations, preferably under natural sunlight.; RefNo. [ 256 ]

2002

The shallow-water reef coral Goniastrea aspera Verill 1865 has previously been reported to demonstrate differences in within-colony susceptibility to bleaching at elevated sea temperatures; parts of the colony which are exposed to the highest solar radiation are more thermotolerant than areas which are less exposed. In this paper, we show that at elevated experimental sea temperature the ‘high light’ surfaces lose fewer symbiotic algae, have lower levels of oxidative stress, higher levels of host antioxidant-enzyme copper zinc superoxidase dismutase (CuZnSOD), and host heat-shock proteins 60 and 70, compared to the less exposed surfaces. In addition, ‘high light’ surfaces show less chronic photoinhibition and greater Photosystem II (PS II) recovery potential when exposed to high irradiance at ambient sea temperature. In contrast, no differences were noted in algal defences (e.g. antioxidant enzymes and stress protein production, and xanthophyll cycling) either at elevated or ambient temperatures. These results are noteworthy because they suggest that corals which acclimatise to high irradiance can, as a result, develop increased thermotolerance which may prevent bleaching at high sea temperatures. Importantly, they also demonstrate the significance of the host tissues in maintaining the intact symbiosis of G. aspera under thermal stress.; RefNo. [ 260 ]

2002

Abstract Individual zooxanthellate corals vary in their susceptibility to bleaching, caused by the loss of symbiotic algae in response to increased temperatures and solar radiation. In 1995 at Phuket, Thailand, the west face of colonies of the massive coral Goniastrea aspera displayed bleaching in January-March, mediated by high solar radiation. By May, when sea temperatures were anomalously high but solar radiation much reduced, the east sides preferentially bleached. Cores from the east faces of corals exposed to elevated temperature under low irradiance in a laboratory experiment also bleached in response to elevated temperature. The algae in G. aspera were Symbiodinium sp., and the rDNA (both ssu and ITS regions) sequences did not differ between the east and west faces, indicating that the bleaching responses cannot be attributed to genetic factors in the symbiotic algae of the type described in other coral species. It is concluded that, in this system, bleaching is shaped by experience, and that the algae may acquire cross-protection against bleaching from solar to temperature stresses. The impact of experience on bleaching susceptibility may become increasingly important in shaping coral responses to temperature and solar radiation stresses in the coming decades.; RefNo. [ 262 ]

1997

; RefNo. [ 1837 ]

2001

This paper outlines an approach to natural resource management that incorporates multiple objectives for protected area management within a decision-making framework. Both regulators and other major stakeholders are directly incorporated into the approach to enhance decision-making processes. We call this approach trade-off analysis. The approach uses a framework based on multi-criteria analysis (MCA) but involves stakeholders at all stages. This holistic approach is appropriate for multiple use, complex systems such as marine protected areas (MPAs), where many different users are apparently in conflict and where linkages and feedbacks between different aspects of the ecosystem and economy exist. The paper applies trade-off analysis to the case of Buccoo Reef Marine Park (BRMP) in Tobago. Stakeholder analysis is undertaken, and social, economic and ecological criteria identified. The impacts of four different development scenarios are evaluated for these criteria. Stakeholders are asked to weight different criteria and then the outcomes of different stakeholder weightings in the MCA are used to explore different management options. For BRMP, the MCA suggests consensus around development options characterised as limited tourism development for the area surrounding the park in association with the implementation of complementary environmental management. The approach has been used to enhance stakeholder involvement in decision-making and develop consensus-based approaches to management of the MPA.; RefNo. [ 259 ]

2000

Overconsumption of natural resources is frequently portrayed as a significant environmental threat. This paper addresses overconsumption from the individual level, discussing the problems associated with identifying overconsumption and identifying general approaches that can he used to reduce consumption. A behavioral approach to understanding resource consumption is presented, with the existing literature reviewed as it applies to this approach. Using this framework, we identify key issues requiring empirical attention and note the important contribution that ecologists, economists, and other behavioral scientists can make in research and intervention efforts aimed at reducing resource consumption. By discussing what is known to be effective in reducing consumption and some questions that remain unanswered, this review aims to assist researchers and those designing intervention programs in developing programs and policies that reflect the behavioral complexities associated with reducing resource consumption.; RefNo. [ 258 ]

2000

; RefNo. [ 1838 ]

2002

The present study assessed the effect of seawater ammonium enrichment on survival and growth of the seagrass Zostera noltii Hornem. Ammonium enrichment had an inhibitory effect on shoot, rhizome and root elongation rates, as well as on primary production. The inhibitory effect was partially alleviated by phosphate addition. The frequency of ammonium pulses also affected growth negatively, with a maximum effect at both low and high pulse frequencies. Similar results were obtained when the experiment was run in the field during a winter trial. However, when the field experiment was repeated in spring at higher mean temperature and irradiance levels, opposite results were obtained, with ammonium enrichment causing a substantial increase in growth rates and productivity. These responses were related to the internal balance of non-structural carbohydrates (especially sucrose) with respect to C and N cell metabolism. Thus, there was a mobilisation of sucrose in both above- and belowground tissues to meet C increased demands arising from ammonium assimilation in winter, with sucrose concentrations reaching critical levels in relation to the total internal C pool. In contrast, sucrose accumulated in the tissues when ammonium pulses were applied in spring, indicating an enhanced C turnover that was able to meet the increased demands arising from ammonium assimilation into organic N compounds.; RefNo. [ 263 ]

2003

The effects of macroalgae blooms on seagrasses were assessed by shading Zostera noltii Hornem. with Ulva rigida C. Agardh mats under laboratory and field conditions. In the laboratory, where there was no direct contact between U. rigida and Z. noltii, leaf, rhizome, and root elongation rates, as well as gross production, declined as a function of U. rigida layers, causing a mobilization of non-structural carbohydrates in both above- and belowground tissues to meet carbon demands. However, when shading was performed in the field, where direct contact exists between Z. noltii and U. rigida, Z. noltii responses were not proportional to the number of Ulva layers. Elongation rates and gross production were reduced by U. rigida shading, with the lowest values under 2 Ulva layers, while there were no significant differences between controls and 4 U. rigida layers. This suggests another Ulva effect occurs besides shading. To test the likely effect of dissolved organic carbon (DOC) derived from U. rigida, Z. noltii plants were cultured under light limitation with radioactive dissolved organic carbon (DO14C) released by U. rigida. Plants cultured under a full DO14C load showed a significant enhancement of growth. The DO14C disappeared from the culture medium during the first 4 d of culture as a linear function of external DO14C concentration. This was coupled to a linear increase of radioactive particulate organic carbon (PO14C) in aboveground tissues, while a substantial part of this PO14C was allocated in belowground tissues. Overall, the PO14C incorporated in Z. noltii plants represented ca. 20 to 25% of the DO14C which had disappeared. Therefore, a net transfer of DO14C from U. rigida to Z. noltii has been documented. Other additional possibilities, such as a light quality effect or other kind of signals (i.e. growth factors), are discussed.; RefNo. [ 264 ]

2001

We assessed the impacts of antrhpogenic threats on the 93 protected areas in 22 tropical countries to test the hypothesis that parks are and effective means to protect tropical biodiversity. We found that the majority of parks are successful at stopping land clearing, and to a lesser degree effective at mitigating logging, hunting, fire, and grazing. Park effectiveness correlates with basic management activities such as enforcement, boundary demarcation, and direct compensation to local communties, suggesting that even modest increases in funding would directly increase the ability of parks to protect tropical biodiversity.; RefNo. [ 265 ]

2001

Mass coral bleaching is currently viewed as a major threat to the long-term health of coral reef communities. Here we quantify coral bleaching in Palau coincident with the 1997/1998 El Niño Southern Oscillation event and with local sea surface temperature of 31 C, which were 1.0-1.25 C higher than long-term, satellite-derived climatological maximum monthly means for the region. We sampled nine sites, including protected lagoon and fringing reefs, vertical reef walls and exposed barrier reefs. The percentage of living scleractinian coral tissue that was bleached was 53.4 +- 6.2 (range: 32.3-79.3, n = 8 sites) at 3-5 m depth and 68.9 +- 6.2 (45.7-91.7, n = 6 sites) at 10-12 m and did not differ significantly between depths. The overall mean percent cover of bleached scleractinians was 18.9 +- 1.5 (mean +- SE, n = 9 sites), while the cover of healthy corals was only 15.6 +- 2.0. Nearly half (48%) of 946 surveyed colonies belonging to 20 scelractinian taxa were totally bleached. Overall the results indicate that the 1998 coral bleaching episode in Palau was relatively severe and widespread across depths, sites, habitats, and coral taxa.; RefNo. [ 267 ]

2002

Declines in the seagrass Zostera marina L. in estuaries and lagoons have been attributed in part to reductions in irradiance reaching the seagrass blades. Epiphytes growing on Z. marina have the potential to attenuate a large fraction of the light that would otherwise reach the blades. This problem has previously been studied by measuring light penetration through homogenized epiphytic slurries or through glass slides fouled with epiphytes. However, the latter may not represent the natural succession or species composition found on live Z. marina leaves and the former does not preserve the structure of the epiphytic complex. Further, past studies have not measured attenuation across the full range of epiphytic densities found in the field. In this study, we measured light penetration across a wide range of epiphytic densities by holding scraped and unscraped Z. marina blades over a submerged light sensor. Results compared well with past studies at low epiphyte densities, with strong reductions in light penetration as density increased. However, at higher densities, penetration leveled off to a relatively constant value as the epiphytes floated out from the edges of the blade. Studies using slurries did not capture this phenomenon and thus predicted decreasing penetration down to 0%.; RefNo. [ 268 ]

2002

Recent evidence suggests that cleaner fish Labroides dimidiatus effectively control parasite densities on client reef fish that actively visit them to have parasites and dead or infected tissue removed. These findings support the hypothesis that clients benefit from cleaning. However, they do not show how cleaners reduce the parasite load of their clients. Cleaners could selectively feed on parasites or parasite removal could be a side product of cleaners foraging indifferently on the client surface, resulting in the removal of healthy mucus and scales also. To investigate cleaner fish foraging behaviour, we infected individuals of the surgeon fish Ctenochaetus striatus, with parasitic monogeneans on one body side, while the other body side was parasite free. We then allowed these clients to interact with L. dimidiatus. We found that the duration of interactions depended on parasite load, and that cleaners spent both more time and took more bites per time unit on the infected than on the uninfected side. Our data thus support the idea that parasite abundance determines food patch quality for cleaners. The overall outcome of cleaning interactions is thus likely to benefit the clients.; RefNo. [ 269 ]

2002

The potential for competition to influence the population dynamics of bluefish Pomatomus saltatrix and striped bass Morone saxatilis through interactions at the juvenile stage was examined. Habitat and diet utilization were compared between juvenile striped bass and bluefish in 3 New York Bight marine embayments. Juvenile bluefish and striped bass were seldom captured together during the summer and early fall, suggesting low habitat overlap at the scale of a beach seine haul. Diet overlap was also low; age-0 bluefish (spring- and summer-spawned cohorts) had a more piscivorous diet than age-0 and age-1 striped bass. A 60d laboratory growth experiment tested for interference competition between age-0 bluefish (spring-spawned) and age-1 striped bass fed fish prey in mixed- and single-species treatments. In the growth experiment, bluefish grew significantly faster than striped bass; however, within a species, there was no significant difference in growth between the mixed- and single-species treatments. Additionally, long-term field-monitoring data showed that annual estimates of growth rate for bluefish and striped bass were not correlated with annual estimates of their potential competitor’s density. These field and laboratory data provide no evidence for competitive interactions between juvenile striped bass and bluefish.; RefNo. [ 271 ]

2000

Since 1992, coastal researchers at the University of North Carolina at Wilmington have been documenting the impacts of human recreational use on Masonboro Island, a component of the North Carolina National Estuarine Research Reserve, and the subsequent natural processes that mitigate these impacts. Both short-term and long-term natural mitigational processes were identified. The effects of these processes were found to be much more rapid than similar impacts on typical terrestrial settings. However, careful examination of the data suggests that both physical location of the impact site and natural variability of weather patterns and events play a role. Management implications of these findings are proposed.; RefNo. [ 274 ]

2002

Difficulties associated with manipulating plankton in situ have limited the ability of investigators to assess among-habitat variation in predation risk for plankton. We used plankton tethering units (PTUs) to tether zooplankton in a variety of reef and seagrass habitats, and used field and laboratory assays to test PTUs for tethering artifacts. Tethering did not affect the survivorship of 5 species of plankton (sizes <1 to 6 mm), indicating that the method works with a range of planktonic organisms. We then used the reef mysid Mysidium columbiae in additional assays and found that: (1) mysids remained on PTUs unless they were attacked by predators; (2) PTUs did not prevent planktivorous fishes from consuming tethered mysids; (3) untethered mysids commonly evaded predators, while mysids on PTUs did not; (4) the same types of predators consumed untethered and tethered mysids in the field; and (5) fishes were neither attracted to nor repelled from PTUs. We used PTUs and mysids to assess predation risk for plankton over various coral reef or seagrass habitats. Risk of attack varied among habitats and was correlated with abundance of planktivorous fishes. On the reef, attack rates were most intense over a topographically complex reef ledge, less intense over the less structurally complex center of the reef, and least intense over a structurally simple sand plain. Within the seagrass bed, attack rates were highest at the edge of the bed and less intense to the center of the seagrass bed and over an adjacent sand plain. Thus, attack rates at these sites varied tremendously over small spatial scales (meters).; RefNo. [ 275 ]

2002

In proximity of shelters, grazing by sea urchins plays a fundamental role in establishing and maintaining areas dominated by encrusting corallines. Much attention has been given to the effects of urchins on algal assemblages in shallow subtidal reefs, but few studies attempted to clarify the role played by encrusting coralline algae in this system. It has been shown that encrusting corallines are able to reduce settlement of potential competitors, suggesting that they do not rely on grazing by herbivores to prevent swamping by erect algal species. In shallow subtidal reefs of the Mediterranean Sea, the sea urchins Paracentrotus lividus and Arbacia lixula are the main herbivores, whose grazing commonly leads to a mosaic of areas dominated alternatively by encrusting corallines and turf-forming algae. This study aims to separate the effects of urchins and encrusting corallines on the re-colonisation of encrusting coralline dominated patches (barren habitat) by surrounding erect algal species (turf-forming algae). Different hypotheses were tested by means of multivariate and univariate analyses. The multivariate hypothesis was that the algal assemblage developing when encrusting corallines and urchins are simultaneously removed would be more similar to that establishing in stands of turf-forming algae, than that developing when none or only 1 of the 2 factors is manipulated. The univariate hypotheses tested were: (1) that there is a negative effect of sea urchins and encrusting corallines on the re-colonisation of barren areas by surrounding turf-forming algal species and (2) that the effects of encrusting corallines are weaker than those of urchins, but that they operate in the same direction. These hypotheses were tested by means of an orthogonal manipulation of urchins and encrusting corallines. At each of 3 study sites, 2 replicate barren patches were assigned to each of these treatments: (1) +corallines+urchins; (2) +corallines urchins; (3) corallines+urchins; (4) corallines urchins. The results suggest that the occurrence of areas dominated by encrusting corallines on shallow subtidal reefs in the northwest Mediterranean is not simply the result of grazing by sea urchins on turf-forming species. The removal of encrusting corallines also affected the abundance of dominant algal species and determined the development of an algal assemblage resembling those occurring within stands of algal turfs. The effects of the removal of urchins on turfforming species were generally positive, while those of encrusting corallines varied from negative (Padina pavonica) to positive (Acetabularia acetabulum and filamentous algae). Therefore, the role played by encrusting corallines in maintaining alternative habitats on shallow subtidal reefs should be taken into account, thus avoiding the overestimation of the effects of grazing by sea urchins.; RefNo. [ 276 ]

2001

San Miguel Bay is a large embayment along the Pacific coast of southeast Luzon, Philippines. The estuarine ecosystem therein is described through a mass-balance model that includes 16 functional groups (state variables), representing over 200 exploited fish and commercial invertebrate species, the energy (feeding) fluxes among them, and the multispecies catch of the fisheries, which pit artisanal fishers, using a wide range of gear, against trawl operators. The parameterization of the model is described in some detail, as are the implications of the ecological and fisheries interactions thus described. The discussion emphasizes the need for regulating the competition between the two sectors of the fisheries, whose present trajectories tend toward further degradation of the San Miguel Bay ecosystem.; RefNo. [ 1839 ]

2001

Intensive shrimp ponds are hypereutrophic ecosystems with high nutrient loading rates. The contribution of sediment nutrient fluxes to nutrient cycling in shrimp ponds was studied. Benthic processes were quantified using benthic chambers (clear and dark) on the sediment of intensive shrimp ponds at 3 farms. The ponds contained 2 distinct sediment zones: an outer zone of sand and rubble swept clean by the action of paddlewheels and other aerators (65 to 85% of the pond area), and an inner zone where settled particulate matter formed a sludge pile. The high nutrient loads, in the form of formulated feed, coupled with high sediment deposition resulted in an anoxic sediment in the pond center with a low respiratory quotient (oxygen:carbon dioxide ratio). The carbon dioxide effluxes were 2- to 4-fold higher than oxygen consumption. The highest nutrient flux rates from the sediment were those of ammonium (NH4 +), particularly in the inner sludge zone (up to 182 mmol m2 d1). Inferred denitrification efficiency was low (<2%), particularly in the inner sludge zone. Denitrification rates, as measured by the acetylene block method, confirmed this. Denitrification may be limited by nitrate (NO3) availability. It is unclear why NO3 concentrations were low, but nitrifiers either may have been inhibited by pond conditions or were unable to become established due to the routine water discharges to maintain adequate water quality. Fluxes of urea and PO4 3 were also low. This study shows that low rates of nitrogen loss from denitrification, relative to the high nitrogen inputs, results in high NH4 + concentrations in the water column. The discharges of pond water mean that sediment processes in shrimp ponds ultimately affect the nitrogen loads discharged into the aquatic environment, exacerbating the potential for eutrophication caused by shrimp farming activities.; RefNo. [ 277 ]

2000

The number of personal watercraft (PWC) used in coastal and inland waterways has increased recently, potentially disturbing people, "sheries activities, and wildlife and recreational resources. In 1997 we examined the behavior of nesting Common Terns as a function of exposure to PWC and other boats. PWCs traveled faster than motorboats near nesting islands, and came closer to birds. The number of terns that flew up in response to PWCs was greater than to motorboats. On one long-studied tern island, the terns su!ered nearly total reproductive failure in 1996 and 1997. Because of these adverse e!ects, an educational and enforcement campaign was initiated in 1998. Public meetings included presentations by scientists, marine police, state conservation o$cials, PWC associations, marina owners, and the general public. In addition, an educational campaign was aimed at local PWC rental businesses and docks, and additional signs were posted around tern nesting islands. These measures proved e!ective: PWC tra$c around the nesting islands was reduced, most PWCs that passed the tern nesting island did not venture outside the channel, and most PWCs reduced their speed. Although these measures did not eliminate the problem, they reduced the disturbance to the birds in 1998 and 1999, allowing increased reproductive success, representing a successful co-management program.; RefNo. [ 278 ]

2001

; RefNo. [ 1840 ]

2002

Single-celled, symbiotic, dinoflagellate algae known as zooxanthellae form associations with many shallow-water tropical marine invertebrates. Local ecological factors, particularly light levels, are known to influence algal type and distribution within hosts. Here I investigate whether biogeographic factors are similarly important in a convenient model, the zoanthid Palythoa caesia (Dana, 1846). Algal genotypes from P. caesia specimens from the eastern and western Indian Ocean were determined by restriction analysis and sequencing of the small subunit RNA gene, following PCR amplification with algal-specific primers. RFLP results indicate 2 common algal genotypes in the east, but only a single genotype in the west. Results from sequencing suggest further geographic patterning, with restricted geographic distribution of clades from the Seychelles, Sulawesi and Thailand.; RefNo. [ 279 ]

2003

In addition to the commonly used chemical defense mechanism against predation, sessile organisms such as terrestrial plants, soft corals and seaweeds are known to have a physical defense mechanism comprising structural elements made of lignin, CaCO3, silica, etc. Most sponges have siliceous spicules that play a key role as skeletal elements. To date, there has been no evidence to show that these spicules also play a role in defense against predation. It is known that low nutritional value of a prey may make it less susceptible to predation. The siliceous spicules found in sponges are indigestible to predators and so sponges that produce large amounts of these spicules may be less susceptible to predation due to their low nutritional value. In the present study, we tested the physical defenses of 6 Red Sea sponge species and 6 Caribbean sponge species against the generalist Red Sea wrasse Thalassoma klunzingeri. Physical defense of the 6 species collected in the Red Sea was also tested using the Caribbean wrasse T. bifasciatum. The spicules of 4 out of the 6 Red Sea sponges deterred predation by T. klunzingeri. Two out of the 6 Caribbean sponges were found to deter predation by T. klunzingeri. In assays conducted in the Bahamas on the Caribbean wrasse T. bifasciatum, only 1 Red Sea sponge species, Suberites clavatus, was found to be physically defended by its spicules. A positive correlation was found between the size of the spicules and their ability to deter predation by T. klunzingeri. Only spicules larger than ~250 µm deterred predation. On the other hand, T. bifasciatum seemed to be deterred based on reduced nutritional quality resulting from high concentration of spicules in a sponge, irrespective of their size. The combination of Crella cyatophora spicules and crude chemical extract deterred predation to a greater extent than that observed for each defense mechanism separately. This finding most probably indicates an additive mechanism of defense used by this sponge species.; RefNo. [ 733 ]

2003

Among marine invertebrates, sponges produce the largest number and diversity of novel secondary metabolites, some of which are used as defenses against predation. Seventeen abundant Red Sea sponge species were assayed for their ability to deter predation by 2 common Red Sea generalist predators: the fish Thalassoma klunzingeri and the sea urchin Diadema setosum. In addition, 17 common Caribbean sponge species were tested against both the Caribbean wrasse T. bifasciatum and the Red Sea wrasse T. klunzingeri. Among the 17 Red Sea species tested, 7 (41%) deterred T. klunzingeri. Extracts from the 17 Caribbean sponge species spanned a range of activities, from highly deterrent to highly palatable, when tested against both fish predators. Extracts were either deterrent to both fish species or palatable to both, suggesting that there are general responses by fish predators to deterrent sponge metabolites, regardless of geographic origin. Of the 17 Red Sea sponge species, 11 (65%) produced extracts deterrent to the sea urchin Diadema setosum. The same 7 species that deterred fish also deterred sea urchins, with 4 additional sponge species affecting only the sea urchins. Sea urchins were either deterred by different metabolites than fish or are more sensitive and thus are deterred by the same metabolites but at lower concentrations. Extracts from endosome and ectosome layers of 6 Red Sea sponges showed no difference in their ability to deter predation by T. klunzingeri and D. setosum, contrary to the prediction of the optimal defense theory.; RefNo. [ 280 ]

2001

; RefNo. [ 1843 ]

2001

; RefNo. [ 1842 ]

2000

Outplanting of hatchery-reared juvenile abalone has received much attention as a strategy for enhancement of depleted natural stocks. Most outplants attempted to date appear to have been unsuccessful. However, based on genetic analyses of a population sample taken in 1992, it has recently been suggested that a 1979 outplanting of red abalone Haliotis rufescens, on the south side of San Miguel Island (California, USA), was successful and probably sustained the fishery there through the 1980s. We resampled the San Miguel population in 1999 and found no genetic signature of the outplants. Allelic frequencies in our 1999 sample closely resemble those observed in a pre-outplant 1979 southern California sample and two 1999 northern California populations. All genotypic frequencies were in Hardy-Weinberg expected proportions. We also assessed mtDNA diversity at San Miguel and found it not to differ from that of 2 robust northern California populations of H. rufescens. Our results suggest that either the composition of the San Miguel abalone population changed rapidly between 1992 and 1999, or the genetic anomalies attributed to hatchery source for the 1992 sample were due to sample degradation or other laboratory artifacts. Since we lack samples from the 1992 collections, we cannot directly test which explanation is valid. However, several lines of reasoning call into question the earlier conclusion of outplant success.; RefNo. [ 281 ]

2002

Planktonic copepods exhibit rapid escape behavior in response to hydrodynamic disturbances. Small disturbances of brief duration were produced by a piezoelectric transducer moving a small cylinder. The escape responses of free-swimming adult males and females of the copepods Acartia tonsa and A. lilljeborgii were recorded using high-speed video and quantified using computerized motion analysis techniques. Response latency, swimming speed, acceleration and turning rate during escape behavior were measured. Acartia spp. typically respond within 4 ms to a hydrodynamic disturbance with multiple power strokes of the swimming legs. Each stroke and recovery is of ca. 7 ms duration with maximum speeds often exceeding 500 mm s1 and minimum speeds between strokes rarely falling below 100 mm s1. Acceleration during initial escape usually exceeds 100 m s2. Escapes often begin with rapid reorientation away from the source of the disturbance, with maximum turning rates of about 30° ms 1. Significant differences were found between the kinetics of escape responses of adult male and female copepods of each species, with males having greater maximum speeds and accelerations, and females having longer duration jumps. Significant differences were also found between males and females of the 2 species, with A. lilljeborgii exhibiting greater speeds and more rapid acceleration than the smaller A. tonsa.; RefNo. [ 283 ]

2004

Grey seals Halichoerus grypus were sampled in the Faroe Islands archipelago during the summers of 1993 to 1995. Concentrations of Cd, Cu, Hg, Se and Zn were measured in the liver, kidney and muscle of 68 seals. All elements except Zn exhibited lowest concentrations in the muscle. The liver contained the highest concentrations of Cu, Hg, Se and Zn, while the kidney contained the highest Cd concentrations. However, trace element concentrations within the tissues were influenced by sex and age. Thus, females had clearly higher Cd concentrations than males. Age was the most important factor influencing the concentration of Cd, Hg and Se in the liver, and of Cd and Hg in the kidney. A strong positive correlation between Cd, Hg and Zn in the kidney suggests the presence of a detoxification process involving metallothionein proteins. Similarly, a strong positive correlation between Hg and Se and a molecular Hg:Se ratio close to 1 in the liver suggests a demethylation process leading to the formation of mercuric selenide granules. High Hg concentrations could be related to fish consumption by the grey seal, but a piscivorous diet could not be responsible for the very high Cd concentrations. This suggests that the seals’ diet changes during the year, and may include a significant proportion of cephalopods in seasons other than summer. Finally very high Cd concentrations in grey seal tissues compared to other grey seal populations also suggest that the Faroe Islands are subject to sub-arctic influences.; RefNo. [ 284 ]

1999

Ontogenic changes in the behavior, spatial distribution, or habitat use of a species are presumably adaptations to ecological forces that differ in their effect on various life stages. The New Zealand rock lobster Jasus edwardsii is one of several species that exhibits dramatic ontogenetic shifts in sociality and spatial distribution, and we tested whether such changes are adaptive. We first sruveyed several natural populations of J. edwardsii to document size-specific differences in aggregation. To determine if chemical cues dishcarged by conspecifics promote aggregation for certain ontogenetic stages, we tested the responsiveness of lobsters of 3 ontogenetic stages (early benthic juvenile, juvenile, and subadult) to the chemical cues produced by conspecifics of different sizes. Finally, we tethered lobsters of different ontogenetic stages along and in groups to test the effect of lobster size and aggregation on mortality. Our results offer compelling evidence that pre-reproductive J. edwardsii undergo an ontogenetic change on sociality that alters their spatial distribution and survival. Our field surveys show that J. edwardsii are solitary as early benthic juveniles and become social and aggregate as they grow larger. We then demonstrate, using laboratory experiments, that there is a size-specific increase in the response of pre-reproductive J. edwardsii to the chemical cues of larger conspecifics which facilitates these ontogenetic changes in aggregation. Finally, our tethering results confirm that this change in social condition is selectively advantageous: aggregation does not increase the survival of small lobsters, but larger lobsters survive better in groups. Thus, in this study we demonstrate the linkage between ontogenetic changes in the spatial distribution of a species, the behavioral process that creates the pattern, and the selective advantage conferred by these developmental changes.; RefNo. [ 950 ]

2000

Over $3.5 billion were spent toward nutrient controls in the Chesapeake Bay watershed between 1985 and 1996. These expenditures were based on cost-shares between federal, state, local, and private sources and should be considered conservative. A comparison of point and nonpoint nutrient control expenditures in the Bay basin showed that about 50% of the funds were directed toward agricultural best management practices and 45% were allocated for point source nutrient reductions and combined sewer overflows (20% and 25%, respectively). The remainder was spent on various other estuarine-targeted programs. Maryland was responsible for 79% of the total expenditures, 16% was expended by Virginia, and the remainder was attributable to the District of Columbia and Pennsylvania (4% and 1%, respectively). The most costly basin was the Patuxent (over $125 per kilogram of total nitrogen removed) and the least costly was the Eastern Shore of Virginia, where the cost was just under $21 per kilogram of nitrogen removed. For the control practices examined, the analysis found that nutrient management was the least costly. Animal waste control and low tillage were the second and third most economical nutrient management strategies. Significant reductions were achieved from point sources for both total nitrogen (16%) and total phosphorus (53%) by 1996. Virtually all of the large reduction in point source phosphorus was a result of the phosphorus detergent ban implemented basinwide in the late 1980s. Nonpoint source nutrient reductions were more modest. An approximate 12% reduction in phosphorus was accompanied by an 8% reduction in total nitrogen loadings. Despite these nutrient reductions, no significant improvements in bottom-dissolved oxygen levels were detected along the Bay mainstem during the warmer months, and the mouth of Chesapeake Bay showed marginally significant degradation during the 11-year period. It was determined that dissolved oxygen conditions were influenced more by nitrogen than phosphorus reductions and that nutrient controls aimed at the mid-Bay region had the greatest potential for improving low dissolved oxygen conditions in the Bay’s bottom waters.; RefNo. [ 285 ]

2002

Cities are complex and dynamic entities. They are also nodes in spatial economic, social and political geographical networks. They are focal points for many of the concerns that underlay current debates about sustainable development. The aim of this paper is to focus on the local environmental effects of urbanization and to consider ways in which they may be effectively treated within the confines of an isolated city context and more generally when urban areas are seen as part of a wider economic system. Particular attention is focused on information systems of all types and on feedback mechanisms (including automatic mechanisms) which help, in particular, the integration of economic and environmental considerations at the urban level. The underlying question being posed is that of deciding on the role that urban indicators (both economic and environmental) can play in assisting to improve the management of cities. The points made are general and conceptual rather than being of a quantitative and empirical nature. There is no effort to try and provide comment on the existing indicators which various urban actors use in their efforts to manage urban affairs.; RefNo. [ 286 ]

2002

Bottom-water hypoxia (2 mg l1 dissolved oxygen [DO]) greatly modifies the benthic habitat of estuaries, depending upon spatial extent, duration, and frequency. Bottom-water hypoxia often develops under conditions of density stratification, which inhibits vertical mixing, and warm temperatures, which enhance biological oxygen demand. Long-term, mid-channel data from the Neuse River Estuary in North Carolina permitted evaluation of how stratification and temperature combined to affect DO concentrations at the bottom. Salinity stratification (S) and water temperature (T) explained respectively 30 and 23% of the variance in bottom-water DO concentrations. The amount of salinity stratification required to induce bottom-water hypoxia declined with increasing water temperature. About 80% of observed hydrographic profiles exhibited bottom hypoxia when S exceeded 5 psu and T exceeded 20°C. Using cross-channel hydrographic surveys as verification, we derived a general set of methods to estimate the lateral extent of low-DO bottom water from midchannel hydrographic profiles. The method involves cross-estuary and along-estuary extrapolation based on assumption of a flat oxycline. Occasional violation of this assumption resulted in modest overestimation in cross-channel extent of low DO. Application of this method produced estimates ranging from 0 to 116 km2 of bottom area (0 to 42% of the estuarine study area) exposed to hypoxia over all sample dates in summer 1997. The maximal bottom area exposed to hypoxia corresponded closely with an independent estimate of the area (100 km2) that experienced almost complete mortality of Macoma spp. clams, the key benthic resource for demersal fishes and crabs. Consequently, mid-channel hydrographic profiles taken along the mid-channel of the estuary can be employed to assess the spatial scale of bottom habitat degradation due to hypoxia.; RefNo. [ 287 ]

2000

Coral reef community structure has remained remarkably stable over a 10 yr period within a small protected marine area despite repeated hurricane impacts. Local community dynamics have been highly variable, however. Sites that were destroyed by disease in the 1970s are showing little or no recovery, while sites less than a kilometre away that were devastated by Hurricane Hugo in 1989 are recovering well. Strong coral recruitment has occurred in shallow, exposed areas that showed the greatest hurricane impacts, and these areas are now more species rich than in 1988, although coral cover has not reached pre-hurricane levels. Coral colony survivorship has been high throughout most of the study area. Partial mortality rates were elevated for several years following Hurricane Hugo, but significant whole coral-head mortality only occurred during periods with hurricane impacts and only at the most exposed sites. Overall, the coral community has proved resilient to closely repeated major hurricane impacts. From a single case study we cannot attribute this resilience to the relatively low level of human impacts, but grazing fish populations have apparently remained high enough to keep macroalgae in check despite the mass mortality of the herbivore Diadema antillarum in the 1980s.; RefNo. [ 288 ]

2003

Site-selection algorithms are used in reserve design to select networks of sites that maximize biodiversity, given some constraints. These algorithms are based on a snapshot of species occurrence, and they typically aim to minimize the area or cost needed to represent all the species once or a few times. Most of these algorithms ignore the question of how well species are likely to persist in the set of selected sites in the long term. Furthermore, the role of the unselected habitat in biodiversity persistence has received no attention in this context. We used a theoretical approach to evaluate the long-term performance of reserve networks in preserving biodiversity by using a model of spatiotemporal population dynamics (a metapopulation model). We compared extinction rates of species in reserve networks in two situations: when all sites remain suitable habitat for the species and, conversely, when the habitat in the unselected sites is lost. We made this comparison to explore the significance of unselected sites for spatial population dynamics and for the continued presence of species in the reserve network. Basic site-selection algorithms are liable to perform badly in terms of biodiversity maintenance because the persistence of species may be strongly dependent on sites not included in the reserve network. Our results support recent calls for the integration of spatial population modeling into reserve network design. Advances in metapopulation theory provide tools that can be used for this purpose.; RefNo. [ 289 ]

1994

; RefNo. [ 1844 ]

2004

Random, stratified, systematic and adaptative sampling designs were analyzed comparatively using data of benthic invertebrate abundance in the mudflats of the Tagus estuary. Intensive core sampling was performed in spring and summer of 1996, in an area of 4 m2. Estimates determined from sub-sets of samples chosen using the various designs were compared. The mean values of the density estimates obtained by the various sampling designs and sample sizes differed significantly, and the main variation trends also differed according to species. For species with low abundace, i.e. Polydora ciliata and Sphaeroma monodi, the estimates obtained by random sampling (RS), systematic sampling (SyS) and stratified sampling (SS) were similar to the real density value, while those that resulted from the adaptive sampling (AS) design tended to overestimate density in the majority of cases. A different pattern was obtained for the abundant species, i.e. Streblospio shrubsolii and Scrobicularia plana. For these species, the mean values of the estimates obtained by RS, SyS and SS were similar and presented a negligible bias, although their variances were usually high. AS designs produced strongly biased estimates, although with low variance. The mean values of these estimates were considerably lower than the true mean density value. Comparison of the mean variance estimates for the sample sizes considered for each sampling design with the RS variance estimates revealed that the lowest variance ratios were obtained with SS designs.; RefNo. [ 290 ]

7

2002

A 'traffic light' approach to assessing whether a fishery is within the acceptable boundaries of its biological reference points in order to apply 'holistic' management measures is discussed. Several indicators of fishery sustainability are assigned either red, yellow or green depending on whether they are inside, close to, or far outside acceptable limits. Then management measures, such as closing the fishery, are proposed based on how many red, yellow and green lights there are for said fishery.; RefNo. [ 2025 ]

7

2004

The author provides an overall review of the use and application of indicators and reference points in management of fisheries resources. He emphasizes the importance of monitoring a range of ecosystem and fishery characteristics, and the need for integrate multiple indicators and limit reference points into harvest rules and other decisional infrastructure. Two approaches are mentionated: the various driving forces-pressure-state-impact (DPSIR) frameworks and the traffic light approach (TL).; RefNo. [ 2031 ]

2002

Elkhorn Slough, a small estuary in central California, receives nutrient inputs from agricultural and other non-point source runoff. To evaluate the effect of nutrient loading on ecosystem processes, rates of sediment oxygen consumption, benthic nutrient fluxes, pore water ammonium (NH4 +), dissolved inorganic phosphate (DIP) and sulfide (S2) concentrations were measured at 5 sites several times each year between 1998 and 1999. Two sites near the head of the slough receive direct runoff from agricultural fields, while the sites in the middle reaches and mouth receive direct runoff from grasslands and woodlands. Sites receiving agricultural runoff usually had high water column concentrations of dissolved inorganic nitrogen and chlorophyll a (50 µM and 30 µg l1, respectively). High precipitation in the winter of 1998 caused low salinities in the slough at that time. In general, salinity and nutrient concentrations were inversely correlated. Sites receiving agricultural runoff had high pore water NH4 +, DIP and dissolved S2 concentrations, particularly in the summer. Oxygen penetration int o sediments was the greatest at the sites adjacent to grasslands and woodlands, and least at the sites receiving high nutrient runoff. Sediment oxygen consumption was 4 times greater at sites near agricultural fields than the site near the mouth, while NH4 + flux out of sediments was between 4 and 20 times greater at agricultural sites than at non-agricultural sites. This study suggests that high nutrient runoff has primarily a local rather than estuary-wide effect on sediment biogeochemical processes in Elkhorn Slough, perhaps due to longer water residence time at the head of the slough compared to the mouth.; RefNo. [ 291 ]

2003

Grazing can be a substantial loss factor for harmful algal blooms (HABs) and a possible cause of their termination. There is, however, a considerable gap in our knowledge of the relative grazing impact of the different components of the planktonic community on a red tide. In this study, we examine the importance of grazing control on a naturally occurring bloom of the toxic dinoflagellate Alexandrium minutum. We estimated the grazing impact of microzooplankton (by the dilution method) and copepods (by 24 h incubations with cultured populations of Acartia grani and Oithona davisae) on a bloom of A. minutum. Grazing by microzooplankton (0.84 d1) was equal to and even exceeded A. minutum growth rates (0.79 d1). On the other hand, copepod impact on the A. minutum population was not significant, although they were actively feeding on the dinoflagellate, which accounted for 78 and 86% of the daily carbon intake of A. grani and O. davisae, respectively. Even if these results were extended to the highest realistic copepod abundance attainable in the area, the grazing impact on highly concentrated HABs would not be sufficient to significantly reduce the algal concentrations. In summary, grazing by microzooplankton can represent an important factor for the regulation of HABs.; RefNo. [ 292 ]

2003

Changes in biomass and elemental composition (dry mass, W; carbon, C; nitrogen, N; hydrogen, H) were studied in the laboratory during complete larval and early juvenile development of the southern stone crab Paralomis granulosa (Jacquinot). At 6 ± 0.5°C; total larval development from hatching to metamorphosis lasted ca. 56 d, comprising 2 demersal zoeal stages and a benthic megalopa, with mean stage durations of 5, 11 and 45 d, respectively. All larval stages of P. granulosa are lecithotrophic, and first feeding and growth were consistently observed immediately after metamorphosis to the first juvenile crab stage. Regardless of presence or absence of food, W, C, N, and H decreased throughout larval development. Also the C:N mass ratio decreased significantly, from 7.2 at hatching to 4.2 at metamorphosis, indicating that a large initial lipid store remaining from the egg yolk was gradually utilised as an internal energy source. In total, about 68% of the initial quantities of C and H present at hatching, and 44% of N were lost during non-feeding larval development to metamorphosis. Approximately 10% of the initially present C, N and H were lost with larval exuviae, half of which was lost in the megalopa stage alone. Hence, metabolic biomass degradation accounted for losses of ca. 59% in C and H, but for only 33% in N. Most of the losses in C and H reflected metabolic energy consumption (primarily lipid degradation), while ca. 1/4 of the losses in N and 2/3 of those in W were due to larval exuviation. Complete larval lecithotrophy is based on an enhanced maternal energy investment per offspring, and on energy-saving mechanisms such as low larval locomotory activity and low exuvial losses. These traits are interpreted as bioenergetic adaptations to food-limited conditions in subantarctic regions, where a pronounced seasonality limits the period of primary production.; RefNo. [ 293 ]

2003

The RNA, DNA, and protein content of larval cod Gadus morhua reared in the laboratory at 3 temperatures and 3 densities of prey was measured. The data were used to define a quantitative relationship between RNA/DNA ratio (R/D), water temperature (T), and protein-specific growth rate (SGR, % d1). The nucleic acid content of each larva was determined with both a 2-dye flow-injection fluorometric assay (FIA) and a 1-dye/1-enzyme fluorometric microplate assay (MFA) in order to calibrate each methodology. The resulting equations were: SGR = 3.65 R/D + 1.02 T 13.05 for FIA, and SGR = 4.03 R/D + 0.88 T 11.16 for MFA. Measured growth rates ranged from negative (8% d 1) to 20% d 1. Water temperature and larval R/D explained 37 to 39% of the variability in the observed growth rate. The models are applicable over temperatures ranging from 2.5 to 9.5°C and can be used to determine short-term growth rates of cod larvae collected from both the laboratory and field.; RefNo. [ 294 ]

2003

Only recently have managers and scientists begun to collect age and growth information necessary for effective management of tropical marine ichthyofaunal communities. The majority of studies that have taken place in the tropics have focused on the Pacific Ocean, primarily on Australia’s Great Barrier Reef. In this study, otoliths were collected from 2 pomacentrids at 5 locations in the tropical western Atlantic, and examined for their ability to provide information on age. The collection sites for these 2 species, Stegastes planifrons and S. partitus, represent different ranges of annual temperature variation. Otoliths were examined for the presence of clear and interpretable increments as well as timing of increment formation. Annual increment quality varied between species and between regions, with the trend being decreasing clarity with decreasing temperature range. However, interpretable increments were discovered in areas with as little as a 3°C annual water temperature fluctuation. Marginal increment analysis of S. planifrons otoliths revealed that increments formed on the otoliths were deposited once a year during the spring or early summer, suggesting that pomacentrids in the tropical western Atlantic may be aged using the same techniques as in other tropical regions and temperate environments. Counts of annual increments revealed that S. planifrons was significantly longer-lived than predicted by other methods. Information on age and growth collected for reef fishes in studies such as this should provide managers with the life-history information needed to assess population stability and production. This information will be more difficult to obtain in low-latitude regions of the tropical western Atlantic.; RefNo. [ 295 ]

2003

Mussel Mytilus edulis cultivation on intertidal flats affects the invertebrate community, often adversely, and this may have detrimental consequences for shorebirds. Here we present the results of an experimental study to quantify the effects of intertidal mussel cultivation on shorebirds. A study area of 4.32 ha, comprising experimental plots and control plots, was laid out in summer 1999 on the mudflats of the Menai Strait in Wales. Regular counts throughout winter of 1999/2000 established pre-cultivation patterns of bird usage. Mussels were laid in the experimental plots in April 2000 and bird usage in these plots and the controls was monitored over the 2 subsequent winters. Although no species were lost from the experimental plots, the bird assemblage in them changed. This reflected variation in the distribution of the 5 most abundant species. However, none of these key species declined in abundance following the laying of mussels. Curlew Numenius arquata and redshank Tringa totanus increased in abundance, although, unexpectedly, oystercatchers Haematopus ostralegus did not. At this study site, commercial mussel cultivation may have beneficial effects, not just for the birds that eat mussels, but also for other species that can take advantage of the associated changes to the benthic fauna and habitat complexity. However, features of conservation interest at other localities may mean that bottom cultivation of mussels will have detrimental rather than beneficial effects. The environmental effects of proposals to initiate or expand bottom cultivation of mussels need to be assessed on a case-by-case basis.; RefNo. [ 296 ]

2003

This study evaluates the influence of different states of energy balance, positive and negative, on the accumulation and utilisation of energy reserves during the period of gonad development in the clam Ruditapes decussatus (L.). Our results show a clear sexual differentiation in the biochemical composition of the clams. The differences were associated with gonad development and were particularly evident in proteins and lipids. These findings imply that separation of the sexes for studying variations in the biochemical composition of sexually developed specimens is essential, and thus questions the results of previous studies in which both sexes were analysed simultaneously. Gonad development occurs under conditions of both positive and negative energy balance, and permits the development of a model of the utilisation of reserves during gonad development, which is closely linked to the clam’s energy balance. Under conditions of positive energy balance, the amount of food ingested provides sufficient energy for both metabolic consumption and the accumulation of reserves. The absolute value of all biochemical components increases, in particular for lipids in the case of female clams, with no evidence of consumption of glycogen and other carbohydrates or their conversion into lipid reserves. Conditions of negative energy balance lead to a moderate degree of organic weight loss in the clams. Glycogen and other carbohydrates are rapidly consumed, falling to almost a quarter of initial values, whilst protein and lipid levels remain constant in females. Lipid values decrease slightly in males. Finally, under situations of extreme nutritive stress (when energy reserves are scarce) there is a loss of all biochemical components in a specific order of priority. Most of the glycogen and other carbohydrates are consumed initially (a decrease of 61 and 74%, respectively), followed to a lesser extent by lipids in males (40%) and then proteins (between 20 and 25%). In females, there was no lipid loss until the majority of the carbohydrates and part of the proteins had been consumed, indicating that lipids constitute the reproductive reserve par excellence in this species.; RefNo. [ 297 ]

2001

; RefNo. [ 1845 ]

2003

Many types of zooplankton contain large proportions of lipids. Usually, these lipids represent energy storage compounds, but it has also been suggested that lipids play a role in buoyancy regulation. Lipids are thought to determine the overwintering depth of large calanoid copepods, and it has been widely assumed that these organisms overwinter at some ‘depth of neutral buoyancy’. However, lipids are generally more compressible, and have a larger thermal expansion than seawater. This means that any depth of neutral buoyancy will be inherently unstable. Model results show that the ascent rates attributable to this instability are small at depth (where temperature changes are small), suggesting a simple way for animals to remain at depth while overwintering. However, model results also show that the buoyant properties of a copepod (or any small plankter) are extremely sensitive to its relative biochemical composition. This presents problems to maintaining vertical position, but may also be useful for vertical migrations.; RefNo. [ 298 ]

2003

The economic and legal implications of the interrelationship between carbon sequestration programs and biodiversity are analyzed. Firstly, the current treatment of this issue under the Framework Convention on Climate Change process is presented. Secondly, the implications of carbon incentives for existing forests are studied (basing the analysis on an extension of the Hartman model including carbon sequestration and biodiversity values). Then, the expected influence of this policy on decisions about which type of forest to use for afforestation and reforestation is discussed. An optimal control model is used to analyze the choice between two types of forests: (i) one with high timber and carbon sequestration values but lower, or negative, biodiversity values; and (ii) one with lower timber and carbon sequestration benefits, but with high biodiversity values. Finally, the relationship between the Kyoto process and the Convention on Biological Diversity is investigated, to assess whether or not the latter is expected to have any influence on the outcomes obtained in the analysis above. Results show that creating economic incentives for carbon sequestration may have negative impacts on biodiversity, especially for afforestation and reforestation programs.; RefNo. [ 299 ]

2003

This paper investigates the effectiveness of reputation in inducing a polluting firm to self-regulate its emissions when consumers have imperfect information. In particular, we ask to what extent must consumers reward and punish the firm before it chooses self-regulation as its dominant strategy?We find that if payoffs in the stage game are such that both the consumer and the polluting firm have beliefs that are consistent with each others’ behaviors, then the firm has a positive probability of playing clean in each period of a finite game. Further, we find that a weak reward/punishment scheme may have an adverse effect on the environment, and that there are both environmental and welfare gains associated with strengthening the scheme.; RefNo. [ 300 ]

2003

Six bottom-trawl cruises, undertaken in spring 1994 to 1999 along the Spanish Mediterranean coastline, sampled pandalid shrimps from 30 to 800 m depth. Data analysis yielded a description of the distribution patterns of the 4 most common species (Plesionika heterocarpus, P. martia, P. gigliolii, P. edwardsi) over an area of 45 331 km2. We analysed abundance of juveniles and adults by partial correspondence analysis (pCCA) in order to determine the effect on distribution of depth (as an overall estimate of temperature, salinity, turbidity and other variables), time (among-survey variability) and space (geographical location). The main null hypothesis we explicitly evaluated is that species composition remains constant along the Spanish Mediterranean coastline after controlling for depth and time. A significant (8.2%) effect of geographical location was found. Hauls located in the central zone of the sampling cruises (Valencia: Ibiza Channel) showed an intermediate relative abundance of all species. By contrast, the samples from northern and southern zones showed a large relative abundance of P. martia and P. heterocarpus, respectively. This pattern may be related to environmental specificity of the hydrodynamic conditions in the Ibiza Channel, dynamic topography characteristics linked to the canyons in the North Catalan zone, and surface production inputs, as found in the North Alborán zone (southern zone), where the main species (P. heterocarpus) exhibited the shallowest bathymetric distribution. Although discrimination between depth preferences of juveniles and adults (with adults being located deeper) is already known on a local scale, our results extend this pattern to the entire Spanish Mediterranean coastline and across all the species studied.; RefNo. [ 301 ]

2000

; RefNo. [ 1846 ]

2003

The interest for wetlands is increasing, not only because of the possibility of a cost-efficient uptake of nutrients, but also because wetlands can be designed to provide other services. What values that are supplied depend largely on the design. There are numerous different design options, and different actors may promote different alternatives. Whether we want to design a wetland for nutrient retention alone, or one that also serves other interests, policy makers need information about the value of different options. Conducting a choice experiment, we are able to identify attributes that increase and decrease citizens perceived value of wetlands. Using a random parameter model we find that biodiversity and walking facilities are the two greatest contributors to welfare, while a fenced waterline and introduction of crayfish decrease welfare.; RefNo. [ 303 ]

2003

The phenomenon of terrestrial mammals as predators in marine intertidal communities, and thus as agents of energy transfer from sea to land, is poorly understood. We review here the evidence for terrestrial mammals intentionally entering the ocean shore at low tide in order to prey on living marine invertebrates, fish, algae, and seagrasses. We introduce the term ‘maritime mammals’, defined as coastal mammalian predators that utilize living intertidal energy resources and transfer these resources to the land. We document 135 records of predation among 45 species of terrestrial mammals in 8 orders feeding in marine intertidal zones. Most predation events are by carnivores (59%, mostly by raccoon, mink, black bear, and Arctic fox), followed by rodents (20%) and artiodactyls (14%). Maritime mammals occur on all continental coastlines of the world except Antarctica. Most records are from the Eastern North Pacific Ocean, with 21 species of maritime mammals. Twelve maritime mammal species occur in the Western North Atlantic Ocean, and 8 maritime mammals are known for the Eastern South Pacific Ocean. These 3 regions account for 42% of the diversity of maritime mammals. A total of 228 different prey taxa are known to be consumed, representing 12 phyla of marine organisms; 2/3 of these taxa are bivalve and gastropod mollusks, crabs, and fish. Introduced populations of 17 species of mammals have been recorded as maritime predators; 15 of these are recorded on islands where endemic mammals were absent or rare. Maritime mammals are widespread globally, with often repeated cases of predation being observed for the same species. We suggest that predation by maritime mammals is a rarely studied, rather than rare, phenomenon, and maritime mammals are thus a largely overlooked guild of intertidal predators. Quantitative field observations (using techniques such as infrared night vision, radiotelemetry, and stable isotope analysis) and experimental studies (using exclosures, or by taking advantage of the removal of insular introduced mammal populations) are required. The importance of intertidal resources in supplying energy to terrestrial populations of many species of mammals world wide may have been underappreciated.; RefNo. [ 304 ]

2003

Populations of horseshoe crabs Limulus polyphemus are widely distributed from Maine to the Gulf of Mexico, are commercially harvested, and are thought to have decreased in abundance in recent decades. To provide information needed to manage exploited populations of horseshoe crabs, we conducted comprehensive field sampling in a major shallow estuary containing preferred habitat for horseshoe crabs. The data we obtained are the first to comprehensively define abundance, determine sex ratios of horseshoe crabs across an entire estuary, and estimate cohort-specific growth and mortality of juvenile and adult horseshoe crabs. We found that juveniles were more abundant and suffered greater mortality than adults. Adults were largely found on the sediment surface, but 20% were buried shallowly in sediments. The male:female sex ratio in juveniles was 1.4:1, but the adult sex ratio was 2.3:1. Juveniles grew faster than adults, and adult crabs may plausibly molt as frequently as once per year rather than have a terminal molt. Spawning appeared to span late March to mid-July, and juveniles hatched at semilunar intervals during Year 0 and grew to 16.6 ± 0.9 mm prosomal width by the start of Year 1. The distinct semilunar cohorts of Year 0 coalesced into annual cohorts after Year 0. Females deposited large numbers of eggs, but only 0.001% survived to the end of Year 0, and approximately 78% of these juveniles reached adulthood.; RefNo. [ 305 ]

2001

Echinoderm regeneration provides a convenient and tractable test to monitor the effects of persistent micropollutants on the developmental physiology of marine animals. Regeneration involves crucial and sensitive biological processes (cell proliferation, morphogenesis, differentiation, tissue renewal) that make it an ideal tool to assess micropollutants at the tissue and cellular level. Our results provide evidence that the regenerative response in the crinoid Antedon mediterranea is especially sensitive to PCBs and that exposure to these chemicals induces significant variations in timing and modality of arm regeneration. Prolonged exposure to low concentrations of Aroclor®1260 (14 ng l 1 of total PCBs), typical of moderately polluted coastal zones, results in abnormal arm growth in terms of both gross morphology and microscopic anatomy. In terms of tissue/cellular aspects the main modifications are: accelerated growth of the regenerate; massive cell migration/proliferation; hypertrophic development of the coelomic canals; and, extensive rearrangement of differentiated tissues of the stump. The anomalies observed in the developmental regenerative processes appear to be compatible with a pattern of pseudo-endocrine activities.; RefNo. [ 307 ]

2000

; RefNo. [ 1847 ]

6

1986

A summary of the Application of Digital Remote Sensing Techniques in Coral Reef, Oceanography and Estuaries; RefNo. [ 2061 ]

2050

Multiple datasets show that marine biodiversity reaches global maxima in the Indo-Malay-Philippines archipelago. Analysis of distribution data for 2,983 species reveal a pattern of richness on a finer scale and identifies a peak of marine biodiversity in the central Philippine Islands and a secondary peak between peninsular Malaysia and Sumatra. This pattern is repeated in diverse habitat and higher taxa classes, most rigorously for marine shorefishes, supporting geohistorical hypotheses as the most general unifying explanations. Specific predictions based on area of overlap, area of accumulation, and area of refuge hypothese suggest that present day eastern Indonesia, or Wallacea, should be the center of marine biodiversity. Process suggested by these three hypothese contribute to the diversity in this region and are also likely explanation for the secondary center of diversity. Our study indicates, however, that there is a higher concentration of species per unit area in the Philippines than anywhere in Indonesia, including Wallacea. The Philippine center of diversity is consistent with hypothese that this area experienced numerous vicariant and island integration events and these hypothese warrant further testing. Special attention to marine conservation efforts in the Philippine is justified because of the identification of it as an apicenter of biodiversity and evolution.; RefNo. [ 1019 ]

2000

; RefNo. [ 1849 ]

2002

Food resource partitioning and some trends in the feeding ecology of 13 species of fishes inhabiting the slope of the Catalan Sea (western Mediterranean) were examined. Specimens were collected from 1987 to 1991, using bottom trawls at depths between 1000 and 2250 m. Prey selection was also examined in relation to data collected in the same area on 2 potential prey compartments for fish, the benthopelagic macrofauna suprabenthos or hyperbenthos and the megafaunal decapod crustaceans. Thus, the possible connections with prey availability within the benthic boundary layer (BBL) were also analysed. The size of available food resources was the most important factor responsible for food resource partitioning, both by depth stratum and season. The importance of the variable predator size is also evidenced. Most of the deep-sea demersal fish species inhabiting the Catalano-Balearic slope often consumed a variety of available resources in their diets, mainly comprising suprabenthos, but also infauna or planktonic prey. Thus, the BBL macrofauna constitute an important part of the available food exploited, with the range of the prey consumed increasing for the largest predators. A significant trend to increase dietary H’ values within the depth interval where each species attained its maximum abundance was observed. Some (positive) prey selection upon certain prey groups was detected depending on the fish species: sharks, Alepocephalus rostratus and Nettastoma melanurum preferentially preyed on decapods, siphonophores and pyrosomids; Polyacanthonotus rissoanus, macrourids, Lepidion lepidion and Cataetyx alleni preyed upon suprabenthic peracarid crustaceans; and only Bathypterois mediterraneus preferentially consumed copepods, the numerically dominant group in the bathyal BBL. Resource partitioning was high among the fish assemblage analysed in relation to the generally low dietary overlap values recorded. Overall, dietary overlap values among fish species decreased with increasing depth.; RefNo. [ 308 ]

2000

; RefNo. [ 1850 ]

2004

Ocean sunfish Mola mola are a seasonally common inhabitant of southern Californian waters, and comprise the largest bycatch component (29% of total catch) of the California drift gillnet fishery for swordfish. We used temperature and depth-sensing acoustic transmitters to quantify the fine-scale movement patterns of ocean sunfish near Santa Catalina Island, California. Eight ocean sunfish were tracked continuously over 24 to 72 h periods, during which oceanographic data were collected every 2 h. Geographical position and depth of tracked fish were analyzed in relation to oceanographic data and time of day. Ocean sunfish traveled a mean distance of 26.8 ± 5.2 (±SD) km d 1. Horizontal movements were characterized by a significant decrease in rate of movement (ROM) during the first 6 h of night (median ROM = 0.76 km h1) (SD = 0.31) as compared to the remaining nighttime period (median ROM = 1.00 km h1)(SD = 0.39), whereas daytime ROM (median ROM = 1.22 km h1) (SD = 0.58) was significantly higher than either nighttime period. Horizontal movements were highly directional, with angular concentration values (r) as high as 0.765 over the duration of entire tracks. Nocturnal vertical movements were confined to the surface mixed layer and thermocline, while diurnal vertical movements were often characterized by repeated dives below the thermocline. A significant relationship was found between maximum dive depth and the post-dive period spent in the mixed layer, suggesting that ocean sunfish may behaviorally thermoregulate between deeper daytime dives. The observed depth-distribution patterns of ocean sunfish indicate that lowering the depth of gillnets in the water column could significantly reduce bycatch of this species in the California drift gillnet fishery.; RefNo. [ 309 ]

2001

The present study assesses the contribution of dark carbon fixation to the primary production in the oxic/anoxic interface of a shallow estuarine environment that develops a salt-water wedge with the presence of sulfide. Primary production was partitioned into oxygenic photosynthesis, anoxygenic photosynthesis and dark fixation. The results show the importance of dark fixation in the oxic/anoxic interface with values higher than 5 mg carbon fixed per cubic meter and per hour in some cases. The average rate of primary production in the dark during the anoxic season for the Ebro River salt wedge resulted in 42 mg C m 2 d 1 in the interface. This represents at least twice the contribution of oxygenic photosynthesis to the primary production in such interface. Because this process is probably important in other salt-wedge or highly stratified estuaries with oxic/anoxic interfaces containing sulfide, the estimates of carbon fixation made so far for these systems may have been underestimated, and should therefore be revised taking into account the contribution of dark processes.; RefNo. [ 310 ]

2004

Engineer species transform ecosystems due to their own growth, constitute an integral part of altered environments, and provide new habitats for other species, thus affecting biodiversity and the ecosystem. On rocky shores inside Antofagasta Bay (Northern Chile), the alien ascidian Pyura praeputialis, an engineer species, creates broad belts and dense 3-dimensional matrices that modify the intertidal habitat structure. In all, 116 species of macro-invertebrates and algae inhabit this habitat, compared with the 66 species inhabiting adjacent intertidal rocky shores which lack P. praeputialis. Of the 145 species recorded at the seascape scale (encompassing both mid-intertidal habitat), 55% were found exclusively in intertidal P. praeputialis matrices. Along the coastal gradient, patterns in b-diversity emerge due to the addition of a new set of species to the community inhabiting the P. praeputialis matrices and, to a lesser extent, from spatial turnover. We found differences in the shape of the species frequency distribution between the communities inhabiting the engineered and non-engineered mid-intertidal habitats. However, within the same habitat type, there was no difference in the species frequency distribution between functional groups. Occurrence of macro-algae was not affected by habitat type, but occurence of macro-invertebrates increased significantly in P. praeputialis matrices. P. praeputialis increases species richness at local and seascape scales by providing a novel mid-intertidal habitat which is used by mobile and vagile macro-invertebrates that otherwise would remain excluded from this intertidal level.; RefNo. [ 311 ]

2001

; RefNo. [ 1851 ]

2003

A multidisciplinary approach amenable to automation and involving digital techniques in conjunction with detailed taxonomical observations and molecular genetic analyses was used to assess the phenotypic and genetic variability of 3 harpacticoid copepods previously identified as Cletocamptus deitersi. C. deitersi may be the most problematic species among congeners due to its intraspecific morphological variability. Specimens of C. deitersi collected from inland and coastal habitats in Alabama, California and Louisiana were analyzed to determine the degree of separation between specimens. Levels of extreme genetic differentiation at both mitochondrial and nuclear loci and incipient but congruent morphological differences among specimens of the 3 populations strongly suggest that each genetic lineage belongs to a different species. Discrimination among species was also detected using a digital correlation method invariant to position and rotation. This analysis involved an algorithm using the square module of the fast Fourier transform. Digital images of specimens from the 3 populations were processed to obtain their diffraction patterns. To discriminate among species, all diffraction patterns were correlated with a special filter containing different random fixed views of each species. Results indicate that new identification methods of microscopic organisms could be developed to reduce the amount of time of direct observation. In order to build these methods on a solid taxonomic validation, it is necessary to implement a multidisciplinary approach in which expertise in taxonomy, molecular biology and digital processing work in conjunction to maximize their reliability and precision.; RefNo. [ 312 ]

2001

; RefNo. [ 1085 ]

2000

; RefNo. [ 1970 ]

2000

Many seagrass species can be found in different stages of meadow formation, from recently established patches to fully developed meadows. However, little is known about how the fate of seagrass production (i.e. herbivory, decomposition, export and carbon storage), and its ecological implications, vary across meadow development. Here we examine the fate of production of the seagrass Cymodocea nodosa (Ucria) Ascherson across increasing stages of meadow formation in a Spanish Mediterranean coastal lagoon, Alfacs Bay. Differences in time elapsed since seagrass establishment explained only a modest fraction of the variability in the fate of production, with most production routes ranging over 1 order of magnitude for any given time. However, on the whole, leaf consumption by herbivores increased by 5-fold, and decomposition and export of detrital leaves by almost 2-fold from young (i.e. 0 to 2 yr since seagrass establishment) to old (i.e. 5 to 7 yr since establishment) stages of meadow formation. Below-ground decomposition also increased by almost 1 order of magnitude from young to old stages. These results indicate that longer-established C. nodosa patches transfer greater fluxes of production to consumers, and should thus support greater levels of secondary production. Moreover, seagrass biomass and detritus increased by 3-fold from young to old stages, showing that longer-established patches may act as greater sinks of organic carbon. These results suggest that generalizations about the extent of carbon storage and secondary production maintained by seagrasses must consider the stage of meadow formation typically exhibited by the species concerned.; RefNo. [ 313 ]

1999

A comparison of Gulf of Riga soft-bottom macrofauna in 1993–1996 with earlier studies shows that significant changes have taken place. Successively higher biomass values were found during the 1960s–1980s. This change reflects the changes of nitrate concentrations in the water. The total biomass in the 1990s was slightly higher than during the 1970s, but only about half the value of the 1980s. Abundance and biomass of Monoporeia affinis have decreased by over 50% between the 1980s and the 1990s. The decrease was extreme in deeper areas, while in shallower areas the species increased. For Macoma balthica, there were higher abundance and biomass values in the 1980s than in the 1970s. Since the 1980s abundance has increased slightly, while the biomass has nearly halved. During the 1970s and 1980s, annelids made up less than 25% of the abundance and 1% of the biomass. The arrival of Marenzelleria viridis in 1988 changed the picture drastically. This is now the most abundant species; it is found all over the gulf, and its share in abundance and biomass has increased to 42 and 12%, respectively. Annual production of macrozoobenthos was about twice as high during the 1980s as during the 1990s. Community annual turnover rates were estimated at approximately 0.5 for both periods; RefNo. [ 1852 ]

2002

Public and private demands for sustainable development put pressure on firms to develop strategies that include environmental concerns. Environmental effects from products often appear as externalities, outside the legal boundary of the producing company. These companies often possess the best competence to optimise the total life cycle environmental performance of its products. They are, however, neither obliged nor stimulated enough by policy incentives to do so from a sustainable development perspective. The policy instruments used today are mostly of a control-and-demand type, i.e. they do not create sufficient incentives to go further than hedging over set requirements. Environmental concerns and tightened environmental policy parameters have mostly been associated with the notion of additional costs and thus a restriction on economic performance. However, since the mid 1990s, several papers have called for corporate win win situations as well as instruments giving up-stream incentives for change, but not enough abatement of environmental impacts has emerged in reality. Perhaps this is due to the lack of proper connection between economic theory on the one hand, and incentive advocating articles and instruments on the other. We propose a concept for trading of product life cycle (PLC) emission rights, based on property rights and transaction cost theories considering the problem with asymmetric information over the value chain. The initial financial impacts from such PLC instruments are shown to be significant for the system provider, since emissions and resource use become production costs. This provides economic incentives to take an increased responsibility for information flow as well as initiatives for product innovations.; RefNo. [ 315 ]

2000

Chemical defenses that are rapidly activated in response to injury have been reported in numerous species of vascular plants, but activated chemical defense has been demonstrated for only 1 genus of seaweed. To investigate the frequency of potential activated chemical defenses in seaweeds and to determine if there are geographic differences in the frequency of theses, we conducted urchin and fish feeding assays using chemical extracts from 42 species of temperate or tropical seaweeds that were damaged immediately before extraction in organic solvents (= the potentially activated extract) or placed in organic solvents before they were damaged (= the non-activated extract). Seven species exhibited changes in palatability consistent with activated defenses while 4 species became more, rather than less, palatable if they were damaged 30 s before extraction. Frequency of activation did not vary geographically. Seventeen percent of tropical species (4 of 24) and 17% of temperate species (3 of 18) exhibited changes in palatability that were consistent with activation of chemical defenses. Thin-layer chromatography of lipid-soluble extracts indicated that damaging the thallus prior to extraction caused noticeable chemical changes in 70% of the species evaluated. Investigations of algal chemical defenses thus need to consider the effects of injury during herbivore attacks and the effects of extraction methodology on the types of, and concentrations of, metabolites discovered in seaweeds.; RefNo. [ 317 ]

2000

The lack of population dynamic information for most species of stony corals is due in part to their complicated life histories that may include fission, fusion and partial mortality of colonies, leading to an uncoupling of coral age and size. However, some reef-building corals may produce compact upright or free-living individuals in which the above processes rarely occur, or are clearly detectable. In some of these corals, individual age may be determined from size, and standard growth and population dynamic models may be applied to gain an accurate picture of their life history. We measured long-term growth rates (up to 2.5 years) of individuals of the free-living mushroom coral Fungia granulosa Klunzinger, 1879 at Eilat, northern Red Sea, and determined the size structure of a population on the shallow reef slope. We then applied growth and population models to the data to obtain estimates of coral age, mortality rate, and life expectancy in members of this species. In the field, few F. granulosa polyps suffered partial mortality of >10% of their tissues. Thus, the majority of polyps grew isometrically and determinately, virtually ceasing growth by about 30–40 years of age. Coral ages as revealed by skeletal growth rings were similar to those estimated from a growth curve based on field data. The frequency of individuals in each age class on the reef slope decreased exponentially with coral age, indicating high mortality rates when corals were young. The maximum coral age observed in the field population (31 years) was similar to that estimated by application of a population dynamic model (30 years). Calculated rates of growth, mortality and life expectancy for F. granulosa were within the range of those known for other stony corals. Our results reveal a young, dynamic population of this species on Eilat reefs, with high turnover rates and short lifespans. Such information is important for understanding recovery of coral reefs from disturbances, and for application to the management of commercially exploited coral populations.; RefNo. [ 1854 ]

2001

; RefNo. [ 1855 ]

2001

The brooded larva of Ostrea chilensis is not an obligate lecithotroph, as has often been supposed, because it removes particles from the mantle cavity of the parent oyster. The ingestion of exogenous particles by the larva becomes apparent when the shell length of the veliger is approximately 290 µm, the same stage at which the velar ciliature is also visible for the first time. Experiments using red plastic marker particles showed that gut retention time in brooding oysters was significantly greater (10 to 11 h) than in non-brooding oysters (8 h), providing a mechanism for more efficient use of the ingested food. Although there was no significant difference in gut retention time between oysters brooding early and late larval stages, the late brooders eliminated most of the faeces earlier than the early brooders. Experiments using 14C-labelled algae demonstrated a shorter gut retention time in the larva (6 h) than in the non-brooding adult (10 h). Faeces from larvae contained relatively more chlorophyll a and less phaeopigment than faeces from brooding adults. The data suggest that the digestive system of the larva is much less efficient than that of the adult. Following the introduction of larvae previously fed 14C-labelled algae into the pallial cavity of the brooding parent, the radiolabel was detected in the faeces of the adult, suggesting that the parent may ingest faeces produced by the larvae. The increase in gut retention time by the adult during the brooding period and the ingestion of larval faeces compensate for the high energy costs associated with the brooding process.; RefNo. [ 318 ]

2002

The gastropod Crepidula fecunda feeds in 2 distinct ways: grazing of the substrate and suspension feeding. The taenioglossan radula plays a role in both processes. In the former, the radula rasps the surface, and the material is immediately ingested. This means of food acquisition is mainly used by motile individuals, i.e. juveniles and adult males. Adult females are sessile, and are only able to rasp the area beneath the head region, severely limiting the amount of food acquired. Females brooding egg capsules are even more restricted, since the area normally grazed is occupied by the capsule mass. The second mode of feeding, suspension feeding, is exhibited by late juveniles and all adults. Suspended particles are captured in mucous nets on the ventral and dorsal surfaces of the single gill lamella. The entrained particles, loosely bound in mucus, are transported by ciliary action to the distal tips of the filaments, which are bulbous. The material accumulates in 2 mucous strings which traverse the ventral surfaces of the filaments at right angles to the filaments along the entire length of the distal margin of the gill. These strings coalesce into a single, thicker string, which is transferred at intervals to a food canal in the neck, where it is twisted into a compact, mucous cord by a spiral action of the neck canal musculature. The cord is moved through the neck canal to the buccal region, where it is grasped by the radula and ingested. Some material from the gill does not enter the neck canal but is carried by ciliary tracts to a modified region in the mantle, the food pouch, where it is compacted into a mucous ball, which is picked up by the radula and either ingested or rejected as pseudofaeces. In the case of rejection, the ball is pushed to the shell margin by the radula and lips. In C. fecunda food material is stored on the gill, allowing the radula time to undertake other tasks such as rasping the substrate and handling the mucous ball in the food pouch. This dual feeding mechanism diversifies the food and probably increases its nutritional value.; RefNo. [ 320 ]

2003

Current thinking on protected area management in developing countries seeks to build upon the recent international experiences with community management and Integrated Conservation and Development Projects (ICDPs). Private and community management frequently cannot provide the non-market values associated with free-ranging populations of large predators and other mammals in a natural ecosystem. This paper proposes an international civil service including these components: (a) objective rating criteria, (b) additional points for developing country citizenship and/or place of birth, (c) salaries comparable to similar professional positions in North American and European countries, (d) higher fees for foreign visitors, (e) local and regional scholarships for primary, secondary, and tertiary education, (f) financial support to host governments, and g) international promotion of ecotourism in developing countries.; RefNo. [ 322 ]

2003

A global market in seafood disperses many live organisms to distant locations. These organisms can be released into environments of the new locations, here they can establish reproductive populations. The risks of such introductions remain poorly resolved. We therefore surveyed bivalves (oysters, mussels, and clams) that are commercially available as seafood in the western United States. Twenty-four of the 37 available marine and estuarine bivalve species are nonindigenous. Eleven of these 24 nonindigenous species have established, self-sustaining populations in northeast Pacific environments. Three of the remaining 13 nonindigenous species have been introduced outside their natural ranges elsewhere in the world. We estimated the risks of some of these species being introduced by performing binomial probability analyses on these data. Our results suggest that there is a significant risk of introducing live seafood species into northeast Pacific ecosystems. Efforts to warn distributors and consumers to screen imported seafood species for invasiveness, to monitor estuaries and coastal ecosystems for early detection, and to develop rapid-response plans for containing new invaders are warranted.; RefNo. [ 323 ]

2003

In Lake Nabugabo, Uganda, a small satellite of the equatorial Lake Victoria, approximately 50% of the indigenous fish species disappeared from the open waters subsequent to establishment of the introduced predatory Nile perch ( Lates niloticus ). However, several of these species persisted in wetland refugia. Over the past decade, Nile perch in Lake Nabugabo have been intensively fished. Herein we report a resurgence of some indigenous species in open waters. In a multiyear study, we used annual transects in inshore and offshore waters of exposed (no wetland) and wetland habitats to document the pattern of resurgence. In 1995, haplochromine cichlids were largely confined to inshore areas, particularly wetland ecotones, and were rare in Nile perch stomachs, as were most other indigenous species. By 2000 haplochromine cichlids were abundant in inshore and offshore areas of both exposed and wetland transects. Several indigenous noncichlids also reappeared in the main lake, including three of the four original mormyrid species. Between 1995 and 1999, there was a dramatic increase in the proportion of haplochromines in the diet of Nile perch. When haplochromines were rare (1995), Nile perch switched from an invertebrate-dominated diet to piscivory at a large size (30 cm total length). In 2000, however, Nile perch were strongly piscivorous by 5-10 cm total length. The pattern of faunal loss and recovery in Lake Nabugabo demonstrates the importance of refugia in providing the seeds of resurgence and provides a model with which to understand some changes in Lake Victoria.; RefNo. [ 324 ]

2003

Intertidal seawalls are increasingly being built in urban estuaries, fragmenting and replacing natural intertidal shores. Many species of animals and plants live on seawalls. Previous work in Sydney Harbour has shown that common species live on seawalls and rocky shores, but vary in their relative abundances according to height on the shore and location. The potential value of seawalls to provide viable intertidal habitat will depend on their ability to support the full diversity of intertidal species, including those that are relatively rare. This study examines the diversity of animals and plants at 2 heights on rocky shore and seawalls, at 4 locations in Sydney Harbour, using presence/absence measures in an intensive sampling schedule in each habitat. The total number and types of taxa found were very variable within and among locations, but clear patterns arose when the data were combined (800 quadrats in each habitat). With few exceptions, algae and sessile animals were similarly distributed across habitats, but approximately 50% of the mobile animals were not found on seawalls. In addition, rocky shores had a greater proportion of rare taxa (only found in 1 or very few quadrats). Of the shared taxa, patterns of occurrence were similar on the 2 structures. Potential reasons for these patterns are discussed and ways to improve seawalls as a habitat for mobile animals are proposed.; RefNo. [ 321 ]

1999

Reductions in fishing mortality within no-take coral reef marine reserves can produces gradients in the density and size of fishes across reserve boundaries. Such boundaries may be affected by other factors, however, including differences in habitat quality between reserve and non-reserve areas and the movement of fish across reserve boundaries.To examine the effects of protection from fishing mortality and of habitat quality on an assemblage of exploited reef fishes, we measured the spatial patterns of fish density and size on fringing reefs near the boundary of the Barbados Marine Reserve (Barbados, West Indies) and statistically controlled for habitat correlates of fish density and size. Reserve sites supported a higher total density and size of fishes than non-reserve sites. Most species had a non-significantly higher mean density and size at reserve sites. The density and/or size of many species were correlated with the depth, rugosity, and/or substrate composition of sites. After statistically controlling for the effects of habitat correlates , the difference in total density between reserve and non-reserve sites remained significant, and the mean densityand size of most species remained non-significantly higher at reserve sites. Neither the mobility of species nor their vulnerability to capture by Antillean fish traps was correlated with their relative difference in density or size between reserve and non-reserve sites. Spearfishing target species had a significantly higher relative difference in size between reserve and non-reserve sites than non-target species. Protection from fishing mortality and higher habitat quality appear to contribute to the increased density and size of fishes on study reefs in the Barbados Marine Reserve, and this difference is not compromised by emigration from the reserve.; RefNo. [ 951 ]

2000

; RefNo. [ 1857 ]

6

1999

Presents the development of a framework fo a spatial decision support systems to be used in the web; RefNo. [ 2062 ]

2003

The South China Sea (SCS) is an oligotrophic marginal sea in the tropical-subtropical western North Pacific. Its warm, stratified and nitrate depleted water is an ideal habitat for the nitrogen- (N) fixing cyanobacteria Trichodesmium. Its abundant presence was not revealed, however, by our results, compiled from 7 cruises conducted between 2000 and 2002 in the northern SCS covering 2 springs (March), 3 summers (June to July) and 2 falls (October). Averaged Trichodesmium density in the surface water was 77 × 103 trichomes m3 with great spatial and temporal variations. No definite spatial distribution pattern was recognizable. Its depth- (0 to 60 m) integrated abundance was much lower in the springs (57 to 1360 × 103 trichomes m 2) than either in the summers (480 to 19 229 × 103 trichomes m 2) or falls (667 to 21 308 × 103 trichomes m 2). This might be attributed to the relatively shallower nitracline and lower water temperature in the spring than the warm seasons. The year-round abundance was positively related to (p < 0.05) both nitracline depth and surface water temperature. In the warm seasons when the surface temperature ranged between 27.1 and 31.3°C, only the nitracline depth was significantly related to the Trichodesmium abundance. Nitracline depth that was greater in the Kuroshio water compared to the SCS water also plays a decisive role in controlling the Trichodesmium abundance in the 2 regions, being greater in the Kuroshio than in the SCS. A sediment trap system deployed near the Luzon Strait in the SCS collected Trichodesmium samples as deep as 374 m. It showed a maximum downward flux of Trichodesmium at 24.69 × 103 trichomes m 2 d 1 in September and decreased to <1 × 103 trichomes m 2 d 1 from December to March. The sinking rate, when expressed as percentage of the integrated abundance, was 0.1 to 0.3 and 0.05% for the warm and the cold seasons, respectively. Despite its surface dwelling nature, Trichodesmium showed a downward flux when it was transported from the Kuroshio to the SCS where it became dissipated.; RefNo. [ 325 ]

2003

Cleaner fish on coral reefs can have a significant impact on the diversity and distribution of their fish clients. Understanding the factors affecting the distribution of cleaners themselves therefore becomes an important consideration for elucidating the mechanisms controlling coral reef fish community structure. We hypothesised that obligate cleaner fish, which rely almost exclusively on ectoparasites gleaned from clients, should be more abundant in areas rich in their preferred prey, namely parasitic gnathiid isopod larvae. We tested predictions from this hypothesis on 2 spatial scales in the Caribbean: among reefs within Barbados, and among 6 islands spanning the Greater and Lesser Antilles. As predicted, densities of coral-dwelling cleaning gobies Elacatinus spp., which are active cleaners, were higher in areas of high rates of emergence of gnathiid larvae from the benthos. This relationship was not observed in sponge-dwelling cleaning gobies, which rely mainly on nonclient- gleaned food sources. The density of coral-dwelling cleaners was also correlated with client density, but contrary to our prediction was not related to ectoparasite loads of a common reef fish client. Cleaning goby abundance is more likely to be a consequence than a cause of ectoparasite availability, since cleaning goby recruitment is usually linked to factors related to foraging, and territorial clients do not preferentially settle near cleaning gobies. Whether the link between cleaner abundance and ectoparasite availability is mediated through differential recruitment or differential survival of cleaners in parasite-rich and parasite-poor areas remains to be determined.; RefNo. [ 327 ]

2003

Many direct costs of parental care have been described for teleost fishes, including reduced body weight, body fat and immune condition. However, few studies have focussed on the indirect consequences of reproduction. In this study, we investigated such consequences in the longfin damselfish Stegastes diencaeus (Jordan & Rutter), a territorial reef fish in which the males provide parental care of eggs. More specifically, we examined patterns of spatial distribution of males and females in relation to substratum suitability for the establishment of nest sites and the consequences of spatial distribution for ectoparasite burden and cleaner-seeking activity. The territories of males and females differed significantly in a number of habitat features. Breeding males, with a nest site present in their territory, were found mainly at the periphery of reef patches, near sand, where vertical substratum suitable for nest sites is present, whereas females and non-breeding males were found in the centre of patches. Cleaning stations occupied by the cleaning gobies Elacatinus evelynae and E. prochilos were also located in peripheral areas, thus, in general, breeding males were closer to cleaning stations than females. Damselfish that were closer to cleaning stations visited them more frequently. During nest-guarding periods, males visited cleaning stations less frequently than during non-guarding periods, but this was not concomitant with an increase in ctoparasite loads during nest-guarding periods. Damselfish in peripheral territories had significantly lower ectoparasite numbers than those situated in the centre of reef patches. These results are consistent with a lower exposure of peripheral damselfish to ectoparasites. These intersexual differences in territory position, proximity to and use of cleaning stations, and ectoparasite loads are indirect consequences of sex differences in reproductive-resource requirements. Such interactions between breeding systems, distributional ecology and other aspects of non-reproductive behaviour are undoubtedly widespread, and their consideration could enhance our general understanding of reef-fish ecology.; RefNo. [ 326 ]

2003

The diet of the onychoteuthid squid Moroteuthis ingens was investigated through stomach content analyses of 72 individuals collected aboard a trawler targeting Patagonian toothfish Dissostichus eleginoides in the upper slope waters of the Kerguelen Archipelago. M. ingens is primarily piscivorous (67% by number and 87% by reconstituted mass), although the diet also includes squids (12 and 12%, respectively) and crustaceans (21 and <1%, respectively). The main fish prey were the paralepidid Arctozenus risso (28% by reconstituted mass), the gempylid Paradiplospinus gracilis (24%) and various myctophids. M. ingens preyed also upon conspecifics (cannibalism, 6%), and the euphausiid Euphausia triacantha was the main crustacean item. Most of the prey are pelagic organisms performing diurnal migration, suggesting that the benthopelagic M. ingens catch them when they are near the bottom during the day. In turn, M. ingens is a prey for several species of top predators, including D. eleginoides and air-breathing vertebrates. M. ingens thus contributes to carbon export from the pelagic environment to the benthos and from the ocean to the atmosphere as carbon dioxide expired by birds and mammals.; RefNo. [ 328 ]

2004

Using top predators as biological samplers, we collected information on the poorly known but ecologically important cephalopod fauna of the Southern Ocean. A total of 4527 cephalopod beaks were identified from stomach contents of Patagonian toothfish caught in slope waters at Crozet and Kerguelen Islands (Indian Ocean). Main prey were the squid Gonatus antarcticus and Kondakovia longimana at both localities, Taonius sp. B (Voss) and Slosarczykovia circumantarctica at Crozet, and Chiroteuthis veranyi and Mastigoteuthis psychrophila at Kerguelen. Fish diet together with the feeding habits of sharks and seabirds show that at least 36 and 38 different cephalopod species inhabit Crozet and Kerguelen waters, respectively. Oegopsid squid dominate the assemblages (29 and 32 taxa at Crozet and Kerguelen, respectively) over octopods (7 and 5 taxa), 1 species of sepiolid occurring at Kerguelen. These rich communities include pelagic squid, benthopelagic cirrate octopods and a few endemic benthic octopodids. The results emphasize the importance of onychoteuthids and gonatids in the nutrition of top consumers in the Southern Ocean and they shed new light on the role of chiroteuthids, mastigoteuthids and cirrate octopods in the trophic web of the marine ecosystems.; RefNo. [ 329 ]

2002

The 1983-84 Caribbean-wide mortality of the long-spined sea urchin Diadema antillarum Philippi was followed by a 2nd mortality event during 1991 in the Florida Keys. Pre-mortality sea urchin densities were up to 5 ind. M 2 and the large scale decline of D. antillarum is considered to be 1 factor affecting community dynamics of Florida Keys reefs. During 1999-2000, we surveyed 125 sites using a stratified random sampling design in shallow-water coral reef and hard-bottom habitats. Strip transects were sampled to assess density, habitat utilization and size structure patterns among habitat types, regional sectors and between fished and protected areas. Nearly 17 yr after the mass mortality, D. antillarum has not recovered to pre-1983 levels, with current densities no greater than 0.05 ind. M 2, and small test sizes (1 to 2 cm) dominate. Other sea urchins such as Eucidaris tribuloides (Lamarck) and Echinometra viridis Agassiz show density and habitat distribution patterns similar to historical observations.; RefNo. [ 330 ]

2000

Groupers (Pisces: Serranidae) of littoral environments of warm-temperate and tropical regions have experienced intense fishery exploitation. Indicators of intense fishing include declines or change in abundance, size, spawning aggregations, and species composition. Surveys of grouper were carried out from 1995 to 1997 in the Florida Keys, central Bahamas, southeastern Cuba, and the southeastern Dominican Republic to illuminate patterns in species composition, abundance, and size, along a gradient of relative fishing pressure. We assumed that the diversity, composition, density, and size would serve as indicators of fishing pressure in these areas. The study locations included 2 national parks and a national marine sanctuary, and were categorized as: (1) intensively fished with little or no management for groupers (southeastern Cuba, southeastern Dominican Republic), (2) intensively fished with numerous gear and effort regulations (Florida Keys), (3) lightly fished with some gear and effort regulations (northern and southern Exuma Cays, Bahamas). On each site 10 to 20 strip transects (20m x 5 m) were surveyed in water of 1 to 20 m depthover rocky hard-bottom habitats for density and size of grouper. Nine grouper species (2 Cephalopholis spp., 4 Epinephelus spp., and 3 Mycteroperca spp.) were documented among all areas. Results show that areas where grouper fishing was relatively light had greater numbers of species, density, and biomass, particularly for larger species such as Nassau grouper E. striatus. Classification of groupers by 3 life history categories or growth strategies (small, intermediate, and large) indicated significant differences in density and biomass among study areas. The density and biomass of larger grouper species were significantly greater in the no-take marine reserve and lightly fished areas than in the more intensively fished areas. In 3 of the areas characterized as intensively fished, one of which has several grouper fishery regulations, grouper density and biomass were dominated by small, non-targeted species such as the graysby C. cruentatus and the coney C. fulva. This pattern may indicate a second-order effect of fishing, indicative of potential changes in competition of predation. No-take marine fishery reserves represent a viable means to protect grouper resources, simplifying enforcement relative to complex catch and effort regulation, but also potentially alleviating the need to gather fisheries-dependent data.; RefNo. [ 953 ]

2001

; RefNo. [ 333 ]

2000

Some Age-0 males of the protandrous pandalid shrimp Pandalus latirostris Rathbun mature in their first year, and the proportion of these early maturing males (EMMs) in a population varies both locally and annually. Two laboratory experiments and 2 field observations were conducted to clarify the factors affecting the occurrence of EMMs. The first experiment showed that EMMs needed to grow fast until the breeding season and began producing sperm at about 14 mm carapace length. Individuals with an AMP (length of the endopod/length of the appendix masculina) value above 40 were defined as EMMs. In the second experiment, the effects of food amount, hatching date and maternal size on growth at Age-0 were examined. Food amount strongly affected the early growth. A difference in hatching date of >2 wk caused a large difference in body size of juveniles; this difference was maintained until the breeding season 3 mo later. Large females spawned larger larvae than small females, but the size difference between larvae from large females and those from small females decreased with time. Field observations showed that at one site in Saroma Lagoon, Hokkaido, Japan, hatching occurred over a 1 mo period. In 1996/1997, we found no obvious differences of size distribution of Age-0 individuals and the occurrence of EMM as a function of location in the lagoon or year. These results may have been caused by slow growth, because water temperatures in the lagoon were much colder in 1996/1997 than during 1987 to 1995. We conclude that the occurrence of EMMs is closely related to various environmental factors in shallow waters. Therefore, the proportion of EMMs may fluctuate both locally and annually. This study shows that a small difference in juvenile growth over a short period can alter the subsequent life history of P. latirostris.; RefNo. [ 334 ]

2003

Recently, winter upwelling events off western Iberia have become more frequent. This may affect the production and survival of sardine eggs and larvae through increased offshore transport. By analysis of RNA:DNA ratios, we investigated the impact of winter upwelling events on the larval condition of Sardina pilchardus larvae as a function of oceanographic conditions and food availability. Larvae were collected on a research cruise off northern Portugal in February 2000. Environmental parameters such as wind, water temperature, salinity, microzooplankton biomass and daily egg production of the calanoid copepod Calanus helgolandicus were also measured. The mean RNA:DNA ratios were relatively high, indicating that almost all larvae collected were in good condition. This was in agreement with the high microzooplankton biomass and high daily egg production of the copepod C. helgolandicus recorded during the same period. No adverse effects of upwelling causing offshore transport of larvae into poor feeding areas could be demonstrated because of the presence of a stratified warm plume with consequent high food production.; RefNo. [ 335 ]

2002

The largest zone of anthropogenic bottom water hypoxia in the Western Hemisphere occurs seasonally in the northern Gulf of Mexico between the Mississippi River delta and the coast of eastern Texas. This zone of hypoxia reaches its greatest extent in the summer months and is a consequence of seasonal stratification of the water column combined with the decomposition of organic matter derived from accelerated rates of primary production. This enhanced productivity is driven primarily by the input of inorganic nitrogen from the Mississippi River. There are 3 likely sinks for fixed nitrogen within this zone of hypoxia: sequestration in the sediment, dispersion and dilution into the Gulf of Mexico, and denitrification. We assessed potential denitrification rates at 7 stations in the zone of hypoxia during the summer of 1999. Those data are compared with bottom water nitrate, ammonium and dissolved oxygen (DO) concentrations. No denitrification was observed in the water column. Denitrification potential rates in the surface sediments were unexpectedly low and ranged between 39.8 and 108.1 µmol m 2 h 1. The highest rates were observed at stations with bottom water DO concentrations between 1 and 3 mg l 1. Denitrification activity was significantly lower at stations where DO was lower than 1 mg l 1 or higher than 3 mg l 1. Nutrient data for these stations demonstrate that as anoxia is approached, the dominant species of nitrogen shifts from nitrate to ammonium. The shift in nitrogen species suggests competition between microbial populations in the sediment community. The lower denitrification rates at stations with bottom water DO <1 mg l 1 may be due to nitrate limitation or an increase in the competitive advantage of microorganisms capable of dissimilatory nitrate reduction to ammonium (DNRA). Suppression of denitrification at low DO by any mechanism will increase the residence time of bioavailable nitrogen. This trend could act as a positive feedback mechanism in the formation of hypoxic bottom waters.; RefNo. [ 336 ]

2003

In Southampton Water the copepod Acartia bifilosa presents a diapause reproductive strategy, where there is a switch from subitaneous to diapause egg production around May, prior to the species’ disappearance from the water column between June and October. The effect of temperature and photoperiod on the production of diapause eggs by A. bifilosa was studied in an attempt to determine the primary cues for its summer diapause. A parallel study on the effect of temperature on metabolic efficiency of A. bifilosa and the non-diapause species A. discaudata, defined by the species’ ‘scope for growth’ (SfG), was examined as a potential, ultimate reason behind the diapause stage. photoperiod was identified as the primary proximate cue that induced diapause in A. bifilosa, and this response was temperature-mediated. Diapause was triggered by a 13:11 h light:dark photoperiod (day length), corresponding to a late-April photoperiodic regime, and resting eggs were produced even at temperatures as low as 5°C. A very low number of diapause eggs were, however, also produced after 6 d at a 12:12 h light:dark photoperiod at elevated temperatures between 14 and 20°C, but the mean percentage produced was significantly less (p < 0.05) than under the longer day lengths. The ultimate cause of the over-summering strategy of A. bifilosa is currently unknown, but the SfG assay indicated that at 10°C, SfG was twice that at 20 or 5°C, and so it may diapause to avoid the higher temperatures in summer. This pattern contrasted with the SfG of A. discaudata, which suggested a simple, positive relationship with temperature. In the field, competition is greatly reduced in the winter months, so A. bifilosa has a better chance of survival, even with its lower SfG.; RefNo. [ 337 ]

2001

; RefNo. [ 1859 ]

2000

; RefNo. [ 1858 ]

1999

In February 1998, Jasus edwardsii larval catches off the east coast of New Zealand were binomial in size and stage of development. Mid-stage larvae (presumed to be from the 1997 cohort) appeared to be contained within a large permanent eddy found offshore, known as the Wairarapa Eddy. Late-stage larvae (1996 cohort) have a different distribution from the mid-stage larvae, being found closer inshore of the eddy. Pueruli (also 1996 cohort) were found well inshore of the eddy. Surface currents derived from TOPEX/ Poseidon altimeter measurements of sea level are used to simuilate larval concentrations. The numerical simulations show that the different distributions of the 3 groups cannot be explained on the basis of advection alone. Mid-stage concentrations appear to be well described by passive drift alone, but the simulations suggest some mechanism inducing shoreward transport is needed for both pueruli and late-stage phyllosomas. Observed puerulus concentrations are best matched by adding a shorewards-directed speed of 8 to 10 cm s-1 for between 1 and 3 wk before the date of the cruise. Late-stage phyllosoma concentrations are best matched by adding speeds of 4 to 6cm s-1. Sustained shorewards swimming speeds of 8 to 10 cm s-1 are well within the estimates of swimming speed that have been reported elsewhere for pueruli. To our knowledge, extended directed horizontal swimming has not been reported for phyllosomas, yet in the final stage, the pleopods are almost as well developed as they are in the pueruli. These final stage larvae could well use forward pleopod propulsion, in conjuction with exopodal setai beating, to allow them to swim.; RefNo. [ 954 ]

2003

Two species of rock lobster (Palinuridae) are commonly found in coastal waters around both New Zealand and Australia. Both species have a relatively long larval phase, which raises the question of how populations can be maintained in regions where the mean flow advects larvae away from the coast. Previous work shows that Jasus edwardsii is genetically indistinguishable between Australia and New Zealand, whereas Sagmariasus verreauxi may be genetically different between the 2 countries. Satellite altimeter data are used here to test the hypothesis that Australia acts as a source of larvae for some New Zealand populations, and to investigate if there is a physical mechanism for the apparent lack of gene flow for S. verreauxi. A Lagrangian approach is used in which the western Tasman Sea is seeded with numerical drifters to build up a statistical summary of the likely distribution of larval trajectories. Ignoring biological factors, about 9% of J. edwardsii and about 2% of S. verreauxi larvae might be expected to arrive in New Zealand waters within their respective larval lifetimes. An order-of-magnitude estimate shows that even with extremely high mortality, these rates are high enough for trans-Tasman larval flow to contribute to and possibly maintain some New Zealand populations. Larval flow across the Tasman Sea should be sufficient to maintain trans- Tasman genetic homogeneity in both species. We suggest that 1 reason that S. verreauxi may not be genetically homogenous is that in order to arrive in New Zealand within 1 larval lifetime, they have to cross the Tasman Sea north of the productive Subtropical Front where there is not enough prey to sustain them.; RefNo. [ 338 ]

2002

Since the early 1920s, ecologists studying a variety of taxa have observed a positive relationship between the number of species and area sampled. The purpose of this study was to examine species-area relationships in coral reef fish assemblages in a tropical marine ecosystem and to determine what factors influence this relationship on isolated patch and continuous reefs. A positive relationship between the log (species richness of reef fish) and log (coral reef area) was observed, where area explained 66 to 96% of the variation in species richness. At smaller spatial scales patch reefs contained significantly more, approximately 35% more, species than continuous reefs. However, the slope was significantly greater for continuous reefs, and consequently at larger spatial scales the number of species was similar to that of patch reefs. Explanations are given for the observed variation between the slopes of species-area curves reported here and those of other studies. These include an influence from the 3-dimensional nature of reef systems, the lack of quantification at sufficient spatial scales and the potential role of habitat richness. Multiple forward stepwise regressions indicated that 80.2% of the variation in species richness on continuous reefs was explained by a suite of microhabitat variables, whereas for patch reefs only 55.7% of the variation was explained by these same variables. Of the variables, microhabitat richness was found to explain the greatest amount of variation in species richness for both continuous and patch reefs even though the species-area relationships differed significantly.; RefNo. [ 339 ]

2003

The structure and dynamics of reef fish assemblages on small patch reefs in the Caribbean (St. Croix, US Virgin Islands) were compared with those studied previously (Sale et al. 1994) on the Great Barrier Reef (One Tree Reef), Australia, in order to test whether assemblage structure and function are consistent despite overall taxonomic differences. St. Croix reefs were monitored over 5 yr (1991 to 1996), while those at One Tree Reef had been monitored for 10 yr (1977 to 1986). Analyses of species richness and abundances for individual patch reef assemblages revealed considerable change in assemblage structure between censuses. Specifically, number of individuals and species varied among summer and winter censuses, with summer censuses generally showing greater numbers. Among years but within a season, there was significant variation in the number of individuals (summer and winter) and species richness (summer only) at St. Croix, while only species richness varied yearly (summer and winter) at One Tree Reef. In addition, when the proportional abundances of species observed on each patch reef were compared among censuses on the same patch reefs but at different times (measured as Czekanowski similarity values), results indicated that faunal similarity declined with increasing length of interval between censuses. The mean, betweencensus Czekanowski similarity values for individual assemblages were 0.56 and 0.59 for St. Croix and One Tree Reef, respectively. These results suggest that there is substantial temporal change in assemblage structure at both locations. Species in each location were classified into 12 trophic guilds in order to determine whether the assemblages at St. Croix and One Tree Reef showed similar trophic structure despite different species present. Results indicated that guild structure varied among censuses in both locations and that average guild structure differed substantially between these locations. At St. Croix, diurnal and nocturnal planktivores were proportionately more important, while site-attached herbivores, wide-ranging grazing herbivores, wide-ranging browsing herbivores, sedentary carnivores, and demersal planktivores were proportionately more important on the Australian patch reefs. Results confirm that comparable assemblage dynamics occur for patch reef assemblages at St. Croix and One Tree Reef. However, there are also clear differences in structure and dynamics in these 2 locations, despite the very similar physical and hydrographic habitats occupied.; RefNo. [ 340 ]

2002

; RefNo. [ 1860 ]

2003

The parrotfish Sparisoma viride is an abundant and ecologically important member of the tropical NW Atlantic reef fish fauna. Sagittal otoliths of 417 individuals were analysed to estimate age-based demographic variables at 4 localities (Lee Stocking Island, Barbados, Los Roques Archipelago and the San Blas Archipelago) spanning 14° of latitude. The sampling localities ranged from an area protected from trap- and net-based reef fisheries (Los Roques) to an area supporting a dense human population and sustained trapping and spearing for reef fishes including S. viride (Barbados). Examination of sectioned sagittal otoliths from each locality revealed regular increments in the sagittal matrix. A preliminary validation at San Blas was consistent with these increments being annual check marks. These increments provided estimates of age structure, maximum longevities and mortality rates for the 4 study populations of S. viride. Von Bertalanffy growth functions fitted to each size-at-age plot generated similar growth curves from 3 of these 4 localities. The exception was Lee Stocking, where fish grew faster and reached a substantially larger size than those from the other 3 localities. Further analysis of the growth curves demonstrated that the differences between Lee Stocking and the other localities were attributable to more rapid growth over the first 4 yr of life. Agebased growth curves derived from the Los Roques population were very similar to a size-based curve generated by an independent study on S. viride carried out in Bonaire, adjacent to Los Roques. Maximum longevities for all 4 of our populations varied from 7 to 9 yr. Mortality rates generated from catch curve analysis were also similar among localities and suggest that maximum life spans do not exceed 12 yr. This result differs from that obtained at Bonaire, where repeated censuses of tagged fish suggest 30 yr maximum longevity. Abundances of S. viride varied 3-fold among localities, being highest at Los Roques (protected from reef fishing), lowest at Barbados (high fishing) and Lee Stocking (low fishing). Thus our age-based study suggests that S. viride is a relatively short-lived fish with consistent demographic parameters over a range of localities, latitudes and fishing intensities.; RefNo. [ 341 ]

2003

The biochemical composition of the chaetognath Parasagitta elegans from the hyperbenthic zone of Conception Bay, Newfoundland, was determined from April 1997 to June 1998. Lipid and carbohydrate levels (% dry weight) were relatively high in the spring and summer and low in the fall and winter. Conversely, the relative protein level was low in the spring and summer and high in the fall and winter. Carbon level was generally high in the spring and summer of 1997 but low from fall to the following spring, whereas inorganic ash level showed the opposite seasonal trend. Lipid and carbohydrate levels and the C/N ratio were positively correlated with chaetognath maturity stage, while protein levels were negatively correlated with chaetognath maturity. These results indicate that P. elegans were lipid- and carbohydrate-rich while maturing during spring and summer, and that immature individuals were protein-rich while achieving somatic growth during fall and winter. This increase in the levels of lipid and carbohydrate occurred when mature copepods increased in the spring and summer rather than when total abundance of copepods increased in the fall. Thus, it appears that food quality rather than quantity affects the biochemical levels and reproductive cycle of P. elegans. In addition, the maximum abundance of adult copepods occurred 3 wk after the peak of the spring bloom, and the maximum relative abundance of mature P. elegans occurred 3 wk later. This suggests that there is tight coupling of energy transfer from primary producers to carnivorous hyperbenthic chaetognaths following the spring phytoplankton bloom in Newfoundland coastal waters. Therefore, seasonal variation in the biochemical composition of P. elegans in the hyperbenthic zone of Conception Bay is closely related to its reproductive cycle and to food quality. Furthermore, it is clear that the chaetognath reproductive cycle is synchronized with the massive energy input from the annual spring phytoplankton bloom.; RefNo. [ 342 ]

2002

To investigate effects of thermal effluents from a coastal power station on bacteria and heterotrophic nanoflagellates (HNF) in adjacent coastal waters, surface distributions of bacteria and HNF and interrelations between microbial and environmental variables were studied in November 1998 and July, August and November 1999 near Hadong Power Station, Korea. In addition, manipulation experiments with treatments of high temperature (40°C; temperature in the cooling system of the power station) and additions of hypochlorite and dilution experiments of thermal effluents with intake seawaters were carried out. Water temperature in the discharge-channel was always 5 to 10°C higher than the ambient temperature, but bacterial production, HNF abundance and grazing rates on bacteria, as well as chlorophyll a concentrations, were always lower here and increased with distance from the power station. Manipulation experiments showed that addition of hypochlorite had much more deleterious effects on bacteria and HNF (95 to 98% inhibition of bacterial production and 25 to 45% decrease in HNF abundance at 0.13 ppm of residual chlorine) than high temperature (9 to 39% inhibition of bacterial production but no inhibition of HNF abundance at 40°C). Dilutions of thermal effluents from the outlet and condenser tube with intake seawater would bring <0.03 ppm of residual chlorine, but inhibitory effects of thermal effluents on bacterial production and HNF grazing activity (23 to 69% inhibition of bacterial production and 31 to 36% inhibition of HNF grazing) were shown, indicating inhibitory potential of chlorination by-products in the discharged water on coastal microbes. Analyses of horizontal distributions of microbial variables, manipulation and dilution experiments gave consistently similar results of inhibitory effects of thermal effluents on bacteria and HNF. Our work suggests that a microbial ecological approach is useful in estimating influences of thermal pollution on microbes in aquatic environments.; RefNo. [ 343 ]

2001

; RefNo. [ 1861 ]

2001

; RefNo. [ 1862 ]

2000

; RefNo. [ 1863 ]

2000

This paper outlines the evolution of an approach to building multimedia database applications for research and learning in an Australian university. This has involved an ongoing collaboration between the library, as database developer, together with research scholars and course managers, as application directors and discipline consultants. The paper provides details of three particular projects, the Australian Zooarchaeology image database, the fourteenth century music database and Audio Visual online. Each application has used the technological infrastructure provided by the library to develop unique and successful approaches to research and learning. All, in different ways, take advantage of the many new multimedia capabilities of the WWW and suggest that such an approach could be developed into a working model for building sustainable quality multimedia Web resources for research and learning.; RefNo. [ 1864 ]

7

2000

The fishing-in-balance (FIB) and Odum’s 24 attributes for describing the state of an ecosystem based on its maturity are explored. The FIB describes the effect of ‘fishing down the food web’ by relating the tropic level of a catch to the biomass of the landings. Using the default that 10 of energy from one trophic level is transferred to the next, the fishery is ‘in balance’ when catch levels increase by a factor of 10 as the average TL of the fishery is reduced by one. The FIB index is applied to fisheries in the Gulf of Thailand and the North Atlantic to show different trends in relationship to different levels of ecosystem degradation resulting from overfishing.; RefNo. [ 2022 ]

2050

; RefNo. [ 1865 ]

2002

; RefNo. [ 1866 ]

2001

A predetermined schedule of sanctions and regulations that reflect both scientific knowledge of resources and the preference and judgments of resource users in the community may provide a useful guide for management decisions involving complex coastal resource systems. Such a schedule can be implemented by constructing scales reflecting public judgments of the relative importance of adverse impacts on resources, or of activities causing such impacts. The importance scales can then be used to assess existing regulations and current management priorities and to serve as a guide for revisions and changes to current practice, for the design of new policy, for rationalizing regulatory controls, and for determining damage awards and other deterrence sanctions. The resulting evolution of a schedule can improve the consistency of resource use with community preferences by, for example, prescribing more severe restrictions on what are widely agreed to be more serious harms and lesser controls on less important ones. The application of this approach is demonstrated using Ban Don Bay, Thailand,; RefNo. [ 344 ]

2003

This paper presents the results of a cost-benefit analysis of a conservation program for the Pentro horse. This horse breed has been reared for millennia in a Southern Italian wetland where it is now strongly tied to the traditions of the region, but presently faces extinction as only 150 horses have survived. Horse herds live in a wild state, characterising in a remarkable manner the landscape of the wetland. This results in a flow of social benefits that the market value of this breed fails to capture. The benefits from a conservation program for this currently unprotected local breed is estimated in a contingent valuation study, while a bio-economic model is used to estimate the costs associated with its in situ conservation. The results show that the benefit/cost ratio is, in the worst scenario, equal to 1.67, thus justifying a conservation policy. This combined approach could be useful to support policy-making for conservation in regions with a long history of breeding domestic animals.; RefNo. [ 345 ]

2050

; RefNo. [ 1022 ]

1995

; RefNo. [ 1867 ]

6

1996

A comprehensive analysis of coastal zone problems, interactions threats and management strategies.; RefNo. [ 2063 ]

2004

We examined the effects of shade from multiple kelp canopy layers (surface Macrocystis pyrifera canopy, understory Pterygophora californica canopy), both individually and in combination, on an understory algal assemblage in a central Californian kelp forest. The removal of both kelp canopies resulted in a dense recruitment of the understory brown alga Desmarestia ligulata that formed a third canopy layer, which significantly decreased bottom light and the abundance of understory red algae. We subsequently created an additional canopy treatment by removing this third canopy layer. In general, the understory red algae fluctuated seasonally with winter swell intensity, changes in kelp canopy cover, and grazing; and although species richness increased significantly with increased bottom light, red algal bottom cover did not respond significantly to the canopy clearings until 2 yr after the canopies were initially cleared. Red algal cover within the Pterygophora canopy treatment was similar to that in the control treatment. In the absence of Pterygophora, the Macrocystis canopy treatment and ‘no canopy’ treatment were found to have greater red algal cover and species richness. Individual understory species were rare, which resulted in small effects sizes and thus low statistical power. However, when grouped post hoc, according to how they responded to the canopy clearings (i.e. response groups), we were able to detect canopy treatment effects as much as 1 yr earlier. This method identified that some understory red algae adapted to areas of canopy removal (light-adapted), and others adapted to a variety of light regimes (shade-tolerant). We were able to classify the light-adapted algae into 2 subgroups: the high-light species and the intermediate- light species. Although this method of grouping was done post hoc, our results indicate that it may provide the clearest assessment of how understory algae respond to shading from kelp canopies.; RefNo. [ 346 ]

2000

The process of developing and implementing decision rules resolved a mixed-stock herring fishery crisis in Cape Breton, Nova Scotia, Canada. The fishery occurs in an area which receives a large migrating stock on a set of smaller local stocks. A purse seine fleet follows the migrating stock into the area as part of their autumn and winter fishery. Little is known about the smaller local stocks which are harvested as by-catch in the seiner fishery and in directed inshore fisheries by local boats. A situation of constantly shifting regulations during the 1996 fishing season led to a series of incidents that included a wharf occupation and prevention of seiner offloading. As a result of these conflicts it was decided to develop decision rules that would allow the fishery to continue in a safe manner and would clearly identify the information and analyses needed to change the rules. The decision rules were developed by using computer simulations to estimate exploitation rate scenarios on each stock component. These simulations determined the following general guidelines for the decision rules. First, if fishing occurs where mixing of schools from stocks is random and proportional to their abundance, then average exploitation rates will be equal among stocks but exploitation rates will be more variable on the smaller stock(s). Second, if fishing occurs where small stocks are concentrated, then exploitation rates will be higher on the small stocks. A combination of data analysis and computer simulations was used to develop decision rules concerning catch allocations, when and where to start fishing, and size of fish to catch. The decision rules were formulated in a series of workshops and stock assessment review meetings attended by industry, managers, and scientists. This process was successful because it broke down barriers among these groups and used quantitative general guidelines to develop the decision rules. The process is readily transferable to other fisheries and provides a means of avoiding or resolving fisheries management crises; RefNo. [ 1868 ]

2003

This paper uses the case study of a recently designated marine protected area (MPA) in Indonesia to demonstrate the range of institutional and cultural obstacles which hinder effective resource management and which serve to highlight the suitability of collaborative approaches to management. The study explores the implications of recent constitutional reform in this regard and presents evidence supporting the case for enhanced efforts to promote co-management of Indonesia’s MPAs.; RefNo. [ 347 ]

2001

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplanktonderived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5 questions that will guide coastal science in the early 21st century: (1) How do system-specific attributes constrain or amplify the responses of coastal ecosystems to nutrient enrichment? (2) How does nutrient enrichment interact with other stressors (toxic contaminants, fishing harvest, aquaculture, nonindigenous species, habitat loss, climate change, hydrologic manipulations) to change coastal ecosystems? (3) How are responses to multiple stressors linked? (4) How does human-induced change in the coastal zone impact the Earth system as habitat for humanity and other species? (5) How can a deeper scientific understanding of the coastal eutrophication problem be applied to develop tools for building strategies at ecosystem restoration or rehabilitation?; RefNo. [ 348 ]

1999

; RefNo. [ 349 ]

2003

; RefNo. [ 282 ]

2001

Most cnidarian-microalgae symbioses exhibit some degree of specificity in host-symbiont pairing. Among taxa with aposymbiotic larvae, specificity must be established each generation. Newly settled polyps of the gorgonians Plexaura kuna and Pseudoplexaura porosa rapidly acquired zooxanthellae, in both laboratory and field settings. Initial zooxanthella acquisition by polyps was non-selective and did not reflect adult host specificity. When placed in shallow backreef and forereef habitats, and on the deep forereef, newly settled polyps naturally acquired zooxanthellae belonging to Symbiodinium clades A, B and C (based on restriction fragment length analysis of small subunit ribosomal DNA). Over time the taxonomic diversity changed such that by 3 mo, the majority of polyps (77%) harbored only algae belonging to Symbiodinium clade B, the same algal clade found in the adult hosts. A survey of naturally occurring juvenile gorgonians (those 10 cm or less) showed that all contained only algae belonging to Symbiodinium clade B at this life history stage. These data are the first to characterize the early ontogenic change in zooxanthella diversity and confirm models of specificity in cnidarians in which a broad group of dinoflagellates initially enter the host followed by an change in algal genotypes that leads to the specificity observed in the adult host.; RefNo. [ 350 ]

2003

The mechanisms and sites of processing and selection of large natural algal particles were studied in the oyster Crassostrea gigas, which possesses a heterorhabdic pseudolamellibranch gill type. Endoscopic observations of processing 1000 cells ml 1 suspensions of the pennate diatoms Pleurosigma planctonicum and Rhizosolenia setigera were performed, as well as endoscope-directed sampling of 100 cells ml 1 mixed suspensions of intact (25%) and empty (75%) 150 × 200 µm Coscinodiscus perforatus. Video endoscopy was used to observe processing on the gill and to allow in vivo sampling of contents of the dorsal and ventral particle tracts, while pseudofaeces was collected from the individual flow-through chambers. Selection indices were calculated for empty C. perforatus at each processing site. Only those P. planctonicum orientated in a dorso-ventral position could enter the principal filaments (PF) for delivery to the dorsal acceptance tract. R. setigera almost never entered the PF, being prevented by its curved and twisted shape. Visual counts of intact versus empty C. perforatus were done on samples from the ambient medium, ventral and dorsal particle tracts, and pseudofaeces. They showed that the percentages of intact and empty cells in both the dorsal and ventral particle tracts were identical to those initially presented (Kruskal-Wallis test; p > 0.05). In contrast, the pseudofaeces contained over 98% empty cells (Kruskal-Wallis test; p 0.001, degree of selection ranged from +29 to +34%). These results show that (1) large natural particles within the size range naturally encountered by C. gigas may only be subjected to qualitative selection on the gills if their shape and dimension allow them to enter the PF, and (2) the site of selection for particles unable to enter the PF is not the gill, but rather the labial palps. Selection sites and mechanisms in heterorhabdic bivalves should therefore be studied over the entire range of naturally available particle sizes. Given the periodic dominance of large diatoms in coastal temperate waters, the labial palp processing site could be of considerable importance in the dynamics of seston flow in oysterdominated ecosystems.; RefNo. [ 351 ]

2004

The aragonite skeleton of massive reef-building corals contains a record of the oceanic environment in which they grow. However, reading of the record requires understanding of how it is archived, a process complicated by the elaborate skeletal construction and seasonal growth patterns that characterize many species. In this study, we assess the utility of the massive brain coral Diploria labyrinthiformis as an archive of sea surface temperature (SST) variability in the western North Atlantic. In situ staining of live colonies combined with microscale analysis of skeletal chemistry indicate that D. labyrinthiformis grows throughout the year on Bermuda and records the full annual cycle of SST variability. However, skeleton accreted during the summer is overlain (thickened) by skeleton accreted during the subsequent fall and winter. As a result, conventional coarse sampling for 18O enables seasonal 18O cycles to be resolved but these do not capture the full amplitude of the annual SST cycle. Our data show that the shallow gradient of the 18O-SST regression equation derived for D. labyrinthiformis ( 0.113 ºC 1) relative to the expected 0.22 ºC 1 for marine skeletons results from dampening of the summertime peak in 18O. In contrast, skeleton accreted during the winter is not thickened and wintertime 18O captures the interannual wintertime SST variability at this site. Using SIMS ion microprobe to analyse strontium to calcium ratios (Sr/Ca), we avoided the hickening deposits and were able to resolve the full amplitude of the annual Sr/Ca cycle. The Sr/Ca-SST relationship obtained for D. labyrinthiformis ( 0.0843 mmol/mol ºC 1) corresponds to that derived from fast-growing tropical reef corals. X-ray intensity ratios, used as a proxy for skeletal density, reveal the expected seasonal changes associated with growth banding as well as variability on interannual and decadal timescales. These variations are well correlated with wintertime SST variability in the subtropical gyre and may be a valuable proxy thermometer for the North Atlantic.; RefNo. [ 352 ]

2001

This paper evaluates the economic and environmental impacts of three alternative landscape scenarios created by a team of landscape architects, following input from an interdisciplinary team of researchers. In the first scenario, the main objective was to increase production and profitability of commercial agriculture with environmental objectives given secondary weight. In the second scenario, water quality improvements were the main objective with secondary objectives being financial health of the agricultural sector and maintenance and restoration of biodiversity. In the third scenario, maintenance and restoration of native biodiversity was the main objective with secondary weight given to the financial health of the agricultural sector and water quality. We evaluate the degree to which the economic and environmental objectives can be achieved together or involve tradeoffs. We found that some changes in land use or agricultural practices result in environmental improvements on certain dimensions in addition to making economic sense. But most changes in land use or agricultural practice do not bring uniform environmental improvement. There may be difficult tradeoffs between different components of environmental quality in addition to tradeoffs between economic and environmental objectives.; RefNo. [ 1873 ]

2004

This paper examines the extent to which the EKC inverted U relationship can be explained by trade and specifically the migration or displacement of ‘dirty’ industries from the developed regions to the developing regions (the pollution haven hypothesis (PHH)). Using detailed data on North-South trade flows for pollution intensive products the evidence for the PHH is assessed. Emissions of 10 air and water pollutants are then estimated, controlling for trade openness, structural change and ‘dirty’ North-South trade flows. Evidence of pollution haven effects is found, although such effects do not appear to be widespread and appear to be relatively small compared to the roles played other explanatory variables.; RefNo. [ 354 ]

2004

In light of concerns that structural changes to US production may not be accompanied by similar changes to US consumption, this paper provides a detailed examination of US environmental load displacement over the period 1974 2001. The forces that drive such displacement are also examined, with particular attention paid to the scale and composition of US consumption, the share of imports in consumption, the role of environmental regulations and the potential impact of NAFTA. It is found that the USA as a whole has experienced environmental load displacement over the period under consideration, with the extent of this displacement seeming to increase over the last decade. It would appear to be the increasing scale of US trade that is increasing environmental load displacement. Indeed, the composition of US imports and exports have become significantly cleaner over the period considered. However, although imports from Mexico have grown more rapidly than exports to Mexico, no evidence is found to suggest that NAFTA is increasing displacement to Mexico. With regard to US domestic consumption patterns, although they have become cleaner, a greater share than ever is now met via imports. Sectoral pollution abatement costs are found to be a determinant of this increasing share of imports in domestic consumption.; RefNo. [ 353 ]

2004

Equivalence tests evaluate whether a treatment effect lies within or outside a predetermined equivalence interval. The equivalence interval might be determined in relation to a precleanup value, reference values, or unimpacted controls. Such tests are little known in ecology, but offer advantages over the common tests of point-null hypotheses. They come in 2 forms. The first, testing the equivalence hypothesis, constitutes a proof of hazard approach by postulating that a difference lies within the interval. The second, testing the inequivalence hypothesis, also known as bioequivalence testing, constitutes a proof of safety approach by postulating that a difference lies beyond the interval. The proof of safety option provides a formal mechanism for the implementation of the precautionary approach. We demonstrate the usage of these tests for a subtidal rocky reef dataset evaluating the impact of dredge spoil disposal at New Plymouth, New Zealand. Sampling of conspicuous subtidal organisms was done once before, and twice after spoil disposal. Abundances of subtidal organisms were compared between 6 sites in the predicted path of the dredge spoil and 6 distant control sites. Comparison of mean numbers of species and of individuals on and off the dumpground before and after disposal demonstrated that greater effort was required for proof of safety, though there was no proof of hazard. The most important conclusion was that much greater sampling effort than is common in ecological study was required to demonstrate safety. Because equivalence tests are readily calculated, test a realistic hypothesis, and provide an outcome that is directly interpretable in terms of a biological endpoint, we suggest that they should be more widely adopted.; RefNo. [ 1711 ]

6

1998

It presents a study of the Mississippi River Delta most relevant characteristics.; RefNo. [ 2064 ]

2003

Reduced grazing on harmful algal bloom species has been attributed to both the feeding deterrence and toxicity of the algae. Both toxic and deterrent effects of dinoflagellates of the genus Alexandrium, which contain toxins that cause paralytic shellfish poisoning, have been reported on different copepod species. We examined how toxin-containing Alexandrium fundyense affected ingestion rates of 2 geographically distinct Acartia hudsonica (Copepoda: Calanoida) populations over short timescales. The copepod population from Great Bay, New Jersey, has never been exposed to blooms of toxic A. fundyense, whereas the population from Casco Bay, Maine, has experienced regular blooms of the highly toxic dinoflagellate for decades. Our goals were to examine the mechanisms by which toxin-containing Alexandrium reduced the ingestion rates of copepods and determine whether the mechanisms were related to the exposure history of copepod populations. Copepods were fed, for 48 h durations, sole diets of toxin-containing A. fundyense, non-toxin containing Alexandrium tamarense and the green flagellate Tetraselmis sp. (not known to have toxic effects) and different mixtures of each (70% Alexandrium/30% Tetraselmis sp., 40/60, 20/80). Changes in ingestion rates over time were determined by measuring ingestion at different time intervals (3, 6, 12, 24, 48 h) over the 48 h period using 3 h incubations. The naïve copepods from New Jersey initially ingested toxin-containing A. fundyense, in both sole and mixed diets, at high rates followed by decreases in ingestion over time. By 24 h, their total ingestion rates were near zero. The decreases in ingestion rates, which were not due to prey selection, were also accompanied by reduced respiration rates. In contrast, none of these effects were observed when the New Jersey copepods fed on non-toxic A. tamarense. Additionally, feeding rates of historically exposed copepods from Maine were not affected by the toxin-containing A. fundyense diets. These observations are consistent with the hypothesis that toxic A. fundyense physiologically incapacitated the copepods from New Jersey but not those from Maine. Such toxic effects, as opposed to deterrence effects, can have profound implications on the grazers’ ability to control harmful algal blooms.; RefNo. [ 355 ]

2003

The mode of development in marine invertebrates is believed to have consequences for dispersal, gene flow, geographic range, and speciation and extinction rates. The factors responsible for among-species differences in mode of development are not well understood and patterns of variation in mode of development have not been documented for many groups. I present a compiled data set of developmental characters for 78 species of calyptraeid gastropods: 53 Crepidula, 9 Calyptraea, 11 Crucibulum and 5 other species. Analysis of this data set shows that egg- and hatching-size distributions are strongly positively skewed. As expected, egg size correlates with hatching size and time to hatching in species without nurse eggs. Egg size is not significantly different between species with planktotrophic development and species with direct development with nurse eggs. Hatching size of direct developers with and without nurse eggs do not differ. Developmental characters do not vary with adult body size among species. There are strong latitudinal effects in mode of development, the frequency of planktotrophic species decreases with increasing latitude while the proportion of direct developers increases. There is also a striking latitudinal pattern in the occurrence of nurse eggs; almost all species with nurse eggs occur in the southern hemisphere. These latitudinal patterns do not appear to be explained by sea surface temperature. Comparisons with other gastropods for which similar compilations are available show a striking difference between heterobranchs (opisthobranchs and pulmonates) and caenogastropods in developmental characteristics.; RefNo. [ 356 ]

2001

; RefNo. [ 1874 ]

2003

To describe how decapod crustaceans are adapted to depth, the duration and timing of the reproductive periods of the 19 most abundant species were compared across the continental margin of the NW Mediterranean Sea. Reproductive activity centered on different seasons, depending on genus, but the deepest-dwelling species of this study, i.e. those living at depths from 600 to >1000 m, showed more seasonal reproductive activity than species dwelling in shallower waters, in which reproductive activity occurred year-round. Thus, in genera where 2 or more species were studied (Pasiphaea, Processa, Plesionika, Munida), the duration of the reproductive periods decreased with increasing depth distribution of congeneric species. This pattern was present in epi-mesopelagic, nektobenthic and benthic species. The only exception was the blind palinuran Polycheles typhlops. Suspended particulate matter concentration in the water column generally decreased from the shelf and upper-slope down to the deep-slope region along the 3 seasonal samplings. Furthermore, vertical fluxes collected near the bottom at ~1000 m depth showed a clear seasonal trend. We discuss how differential matter sinking to the benthic ecosystems versus species depth distribution may be the proximal cause of decapod crustacean reproductive seasonality, and how phylogenesis and light intensity should also be taken into account when describing how species are adapted to the transitional depths of the continental margin of the NW Mediterranean Sea.; RefNo. [ 357 ]

2002

Between March 1997 and May 1999, we studied the effect of solar UV-B (290 to 320 nm) and UV-A (320 to 400 nm) radiation on phytoplankton photosynthetic rates in a shallow coastal lagoon with periodic exchange with the Atlantic Ocean. In particular, we assessed whether the exchange with the ocean affected the severity of photosynthetic inhibition. During events of marine intrusion, the UV attenuation coefficient (Kd) in the brackish zone decreased up to 70% of the values observed under the influence of the freshwater discharge. The highest inhibition of the PARsaturated photosynthetic rates by UV radiation (up to 55%) was observed in summer at the brackish zone in association with marine intrusion events. In the freshwater zone, the highest inhibition was up to 3-fold lower than in the brackish area due to higher Kd values in the UV range. On average for the entire system, near-surface primary production was reduced by ca. 25%, and the contribution by UV-A and UV-B was close to 2:1. Our results provide a baseline for future comparisons at a latitude where predicted trends in reduction of stratospheric ozone are significant. However, hydrological changes affecting river discharge and communication frequency with the ocean appear to be more important for the UV underwater climate and primary production than the expected increase in incident UV-B fluxes.; RefNo. [ 358 ]

2000

Seasonal variations in above- and belowground biomass were examined over the 1994 growing season (May to October) in the 3 major plant zones of a saltmarsh located on the Bay of Fundy. Standing crop of aboveground biomass was measured over the growing season. Belowground samples were processed at depth intervals of 2 cm, providing high-resolution vertical profiles to a depth of 40 cm. Spartina alterniflora showed evidence of the translocation of belowground biomass to aboveground tissue in the early part of the growing season, when the rate of aboveground growth is at a maximum. Shifts in S. alterniflora organic matter storage were most dynamic in the surface 16 cm. Biomass translocation generally was not significant in the S. patens stands, where the rate of aboveground growth was consistent throughout the growing season. All seasonal changes associated with Plantago maritima biomass seem to occur before July, since no changes in above- and belowground biomass were observed between July and October. P. maritima contributes the least to marsh soil organic matter.; RefNo. [ 359 ]

2002

Fishery management plans ignore the potential for evolutionary change in harvestable biomass. We subjected populations of an exploited fish (Menidia menidia) to large, small, or random size-selective harvest of adults over four generations. Harvested biomass evolved rapidly in directions counter to the size-dependent force of fishing mortality. Large-harvested populations initially produced the highest catch but quickly evolved a lower yield than controls. Small-harvested populations did the reverse. These shifts were caused by selection of genotypes with slower or faster rates of growth. Management tools that preserve natural genetic variation are necessary for long-term sustainable yield.; RefNo. [ 360 ]

2003

; RefNo. [ 1878 ]

2003

The microdistribution and dynamics of deep-sea hydrothermal vent communities often reflect the extreme heterogeneity of their environment. Here we present an assessment of spatial variation in the reproductive development of the alvinellid polychaete Paralvinella palmiformis at the High Rise vent field (Endeavour Segment, Juan de Fuca Ridge, NE Pacific). Samples collected from different locations across the vent field suggest patchy reproductive evelopment for this species. Males and females from several locations contained few or no developing gametes, while gametes were abundant in samples collected at the same time from other locations. Samples lacking gametes were distinguished by body size-frequency distributions with peaks at smaller sizes and the presence or absence of other fauna consistent with early stage assemblages in a successional mosaic model previously proposed for Endeavour Segment communities. Where gametes were present, synchrony of reproductive development between females within samples and between samples was evident. Reproductive synchrony between pairs of samples initially declined over a 7 d interval between samples, suggesting a rapid rate of reproductive development for P. palmiformis. Samples collected 1 mo apart, however, displayed similar frequency distributions of developing gametes. A peak of mature male and female gametes appeared to develop and disappear within the limited temporal resolution of the samples, consistent with possible simultaneous maturation of gametes despite pseudocopulation and sperm storage in this species.; RefNo. [ 361 ]

2001

In comparison with the effects of the collection of marine intertidal organisms by humans, the effects of human recreational activities on assemblages of marine birds have received scarce attention. We evaluated whether in central Chile the spatial and temporal variation in the composition and abundance of the avian assemblage is affected by the presence of humans on the coast. We studied a 1.5km stretch of rocky coast, in the center of which is a small marine reserve where no fishing or recreational activities take place. At 15 observation points, we conducted 12 monthly surveys of birds that roost in the supralittoral zone, between the high-tide mark and the terrestial vegetation, and/or that forage in the intertidal zone. In addition, within the reserve we conducted daily bird surveys over 2 years to evaluate whether abundance or composition changed according to the activity of people outside the reserve. We recorded 19 species of coastal marine birds. Eleven species used the supralittoral zone only for roosting (roosting assemblage), whereas the others foraged on intertidal organisms and roosted in the supralittoral zone (foraging assemblage). Although the largest negative effect of human activity on bird abundance occurred in summer, the period of greatest recreational intensity, the presence of humans negatively affected birds year round, changing both the spatial and temporal distribution of birds along the shore. Bird abundance was higher at observation points inside the marine reserve, although the pattern was stronger for birds roosting on the supralittoral zone than for birds actively foraging in the intertidal zone. Similarly, the number of birds recorded during weekends inside the reserve was higher than during week days. Our results illustrate the important role played by this marine reserve, which offers marine birds safe roosting sites without human interference. Larger marine reserves than the one we studied are needed because the dynamics of birds inside the reserve were strongly influenced by human activities in immediately adjacent areas. Our results emphasize the need to consider human recreational activities along the coast when establishing conservation programs because harvesting refugia "no take" zones will not provide protection to coastal bird assemblages unless human access is restricted.; RefNo. [ 362 ]

2003

We studied seasonal and inter-annual variations in the diet, amount of food delivered to chicks, and body condition of chicks and adult red-tailed tropicbird at Europa Island (Mozambique Channel, Indian Ocean), during 3 consecutive seasons. The diet consisted of epipelagic fishes (13 families) and squid (3 families) totalling 32 taxa. Three families, the squid Ommastrephidae (mainly Sthenoteuthis oualaniensis) and the fishes Exocoetidae (flying-fish) and Coryphaenidae (dolphinfish), accounted for 68% of the number of prey and 83% of the ingested biomass. There were considerable differences in size and mass of the prey items, dolphin fish being the largest and squid the smallest. There were important seasonal variations in diet. During chick-rearing, 41% of the mass of food delivered to chicks consisted of dolphin fish, whereas these fish represented only 2% of the mass of food during incubation. The squid were caught in similar proportion throughout the breeding season but were larger during chick rearing. We did not find any inter-annual variation in the diet of chicks, nor in the body condition of either fledglings or adults, suggesting that no major inter-annual changes in food availability occurred during the course of our study. However, there was some interannual variation in feeding frequency and body condition of chicks of less than 60 d. There were also significant day-to-day variations in the feeding frequency in one of the 3 seasons studied. This suggests that day-to-day variation in the marine environment or in foraging conditions may have shortterm consequences in the food provisioning and body condition of growing chicks, but that these variations do not necessarily result in long-term (inter-annual) variations in diet and body condition of fledgling or adult red-tailed tropicbirds at Europa island. These results suggest that between 1995 and 1997, red-tailed tropicbirds of Europa relied on predictable and seasonal food resources when breeding.; RefNo. [ 363 ]

2003

Ghost shrimp, Lepidophthalmus louisianensis (Schmitt 1935) and Sergio trilobata (Biffar 1970) are 2 common burrowing decapod crustaceans in Tampa Bay, Florida, which affect the benthic community through bioturbation. The burrow also plays a crucial role in determining benthic community structure, since it may house several symbionts, one of which is the copepod Clausidium dissimile Wilson, 1921. This study was conducted to investigate factors that affect the density of C. dissimile on ghost shrimp specimens both in the field and in the laboratory. Collections of L. louisianensis and S. trilobata were made over a 15 mo period to determine the prevalence of C. dissimile in the field. Analysis of monthly field data showed that host shrimp (p = 0.0001), and sampling month (p = 0.0310) were significantly correlated with the host-size adjusted density of the symbiont C. dissimile, with more copepods preferring specimens of S. trilobata over L. louisianensis. Although host sex did not have a significant effect on host-size adjusted copepod density, percentage prevalence of copepods was significantly higher for females than males in S. trilobata (p < 0.0001). Aboratory experiments supported observations from the field in that C. dissimile significantly preferred S. trilobata over L. louisianensis (p < 0.001). However, unlike the field data, copepods did not appear to prefer female over male hosts when size was held constant. Higher colonization of females than males in the field may instead be attributed to differences in size and behavior between the sexes.; RefNo. [ 365 ]

2002

I explored the effect of uncertainty in dempgraphic traits on demographic analyses of sharks, an approach not used before this taxon. I used age-structured life tables and Leslie matrices based on a prebreeding survey and a yearly time step applied only to females to model the demography of 41 populations from 38 species of shraks representing four orders and nine families. I used Monte Carlo simulation to reflect uncertainty in the estimate of demographic traits and to calculate population statistics and elasticities for these populations; I used correlation analyses to identify the demographic traits that explained most of the variation in population growth rates. The populations I examined fell along a continuum of life-history characteristics that can be linked to elasticity patterns. Sharks characterized by early age at maturity, short lifespan, and large litter size had high growth rates values and short generation times, whereas sharks that mature late and have long lifespans and small litters have low growth rate values and long generation times. Sharks at the "fast" end of the spectrum tended to have comparable adult and juvenile survival elasticities. Whereas sharks at the "slow" end of the continuum had high juvenile elasticity and low-age zero survival (or fertility) elasticity. Ratios of adult survival to fertility elasticities and juvenile surivival to fertility elasticites suggest that many of the populations studies do not possess the biological attributes necessary to restore growth rates to its original level after moderate levels of expoitation. Elasticity analysis suggests that changes in juvenile survival would have the greatest effect on growth rates, and correlation anlaysis indicates that variation in juvenile survival, age at maturity, and reproduction account for the most variation in growth rates. In general, combined results from elasticity and correlation analyses suggest that research, conservation, and management efforts should focus on these demographic traits.; RefNo. [ 366 ]

2001

A new, inexpensive, and time-saving method for the estimation of the net production of leaves and reproductive structures of mangroves was applied to 2 Vietnamese stands of Kandelia candel. The method combines the allometric relationship between the number of meristems in trees and their diameter with knowledge of the number of leaf pairs and reproductive structures each meristem develops annually to calculate the net leaf and inflorescence roduction of each tree in the stand. Each apical meristem of K. candel produced about 6 leaf pairs and 1.3 to 1.9 inflorescences annually, with the number of meristems in each tree increasing to the square of their girth. The size distribution of K. candel was highly skewed at all sites, with an exponential decline in the number of plants as the size increased. The net leaf production (dry wt), calculated by scaling the production per meristem to that of individual trees and then to the entire stand, ranged from 176.5 to 1338.7 g m 2 yr 1 among stands, with an estimated total inflorescence production ranging from 0.91 to 101 g m 2 yr 1. The largest individuals, comprising 10% of the population, contributed the majority of the stand production. The approach demonstrated overcomes serious deficiencies in the traditional litter-fall method, particularly when applied to developing mangrove stands, and should be applicable to other mangrove species as long as they display clear nodes, leaf, flower and fruit scars, as do other members of the Rhizophoraceae family.; RefNo. [ 367 ]

2001

The spawning biology of the tropical abalone Haliotis asinina on Heron Reef, Australia, was investigated to identify putative environmental and endogenous factors controlling spawning. Spawnings by H. asinina were highly regular and, in comparison to most other haliotids and marine invertebrates, frequent and extremely synchronous. These events appeared to be regulated by more than 1 environmental cue. The spawning season of H. asinina extends from October to April and is associated with an increase in water temperature. During the spawning season, recently captured abalone, housed in flow-through aquaria, released gametes for 2 nights every 2 wk during the new and full moons. However, the exact date of spawning did not correlate precisely with the lunar cycle. Occasionally the spawning events between 2 populations of H. asinina on Heron Reef that were 1.5 km apart differed by 1 d, suggesting that differential tidal regimes might influence the date of spawning. The population that was exposed to slightly longer spring low tides occasionally spawned 1 d earlier. In the aquaria, the onset of male spawnings was earlier than the onset of female spawnings by an average of 31 min. The time of spawning of either sex was highly correlated with the evening high tide; males spawned an average of 19 min prior to the high tide, and females spawned 11 min after the high tide. Spawnings were highly synchronous amongst individuals, with 90% commencing spawning within 89 min of the first individual that spawned. A greater percentage of individuals spawned when in the presence of the opposite sex and the frequency of male ejaculation was greater when in the presence of females. Synchronous spawning patterns persisted for 6 wk in H. asinina maintained in aquaria; after this period, spawnings continued but were irregular and asynchronous. We propose that low tide exposure and time of high tide indirectly regulate the date and time of spawning respectively, and that these tidal elements influence the spawning biology of H. asinina by maintaining endogenous rhythms that persist in non-tidal environments for at least 6 wk.; RefNo. [ 368 ]

2000

; RefNo. [ 1881 ]

2000

; RefNo. [ 1882 ]

2000

Most marine populations are thought to be well connected via long-distance dispersal of larval stages. Eulerian and Lagrangian flow models, coupled with linear mortality estimates, were used to examine this assumption. The findings show that when simple advection models are used, larval exchange rates may be overestimated; such simplistic models fail to account for a decrease of up to nine orders of magnitude in larval concentrations resulting from diffusion and mortality. The alternative process of larval retention near local populations is shown to exist and may be of great importance in the maintenance of marine population structure and management of coastal marine resources.; RefNo. [ 369 ]

2000

The response of an estuarine macrobenthic community to different intensities of physical disturbance was examined using comparable field and mesocosm experiments. In the ®eld study, areas of sediment 2500 cm2) were disturbed by surface-raking at a range of disturbance intensities: no disturbance, once every 2 mo, once every month, once every 2 wk, once or three times every week. These disturbance regimes were also imposed on buckets of sediment (855 cm2) collected from the field study site and maintained within a me- ocosm system. In the univariate data analysis, neither field nor mesocosm communities displayed any trends in relation to the frequency of disturbance. Diversity indices were generally reduced in the mesocosm commu- nities compared with the field communities. Multivariate analysis indicated significant differences between the field communities subjected to the most intense disturbance and those communities disturbed every 2 wk or less. These differences were attributed to reductions in the five numerically dominant species in the high-disturbance treatments. More statistically significant differences were observed between the different disturbance intensities in the mesocosm experiment than in the field study. The implications of differences between field and mesocosm experiments results are discussed.; RefNo. [ 370 ]

2002

; RefNo. [ 1219 ]

2000

; RefNo. [ 1883 ]

2002

; RefNo. [ 1885 ]

2002

; RefNo. [ 1884 ]

2003

Benthic infauna communities were characterized along a chronosequence (1 to 28 yr old) of 7 constructed Spartina alterniflora Loisel marshes and 7 natural (reference) marshes to identify patterns of succession following salt marsh creation. Infauna density and species richness (per 7.07 cm2 core) achieved equivalence to comparable reference marshes within 8 yr following marsh creation. Taxa with dispersing larval stages (e.g. Streblospio benedicti, apitella sp.) achieved equivalence within 3 yr following marsh creation. Taxa that lack a planktonic dispersal stage, such as tubificid oligochaetes and Manayunkia aesturina, were slower to develop. Densities of Manayunkia did not achieve equivalence to natural marshes until 8 yr after marsh creation. Twenty-five yr elapsed before oligochaete densities of constructed marshes were similar to natural marshes. In constructed marshes, densities of surface-deposit feeders, dominated by Streblospio and Manayunkia, achieved equivalence to natural marshes within 8 yr following marsh creation. Subsurface-deposit feeders, consisting mostly of oligochaetes, did not become equivalent to natural marshes for 25 yr. Predictable trajectories, described by an asymptotic increase over time, existed for total species, species richness, and surface- and subsurface-deposit feeders. Oligochaetes and Manayunkia, which produce nondispersing larvae, exhibited linear trajectories over time. In constructed marshes, total density and density of dominant taxa and trophic groups were strongly correlated with soil characteristics, especially organic C, N, bulk density and macro-organic matter (MOM, the living and dead root and rhizome mat). Non-linear regressions using soil organic C and MOM explained 38 to 40% of the variation in constructed marsh infauna density. The regressions suggest that a threshold of 0.5% soil organic C (500 g m 2, 0 to 10 cm) and 500 g MOM m 2 (0 to 10 cm) is needed to support infauna densities comparable to densities found in natural marshes. Taxon richness of constructed marshes was more strongly related to vegetation characteristics, especially macro-organic matter quality (e.g. lignin) than soil characteristics. Development of benthic infauna ommunities following marsh construction requires longer than the 5 yr monitoring period required by many wetland mitigation plans, and as much as 25 yr are needed for some attributes (e.g. oligochaetes) to achieve equivalence.; RefNo. [ 371 ]

2000

; RefNo. [ 1886 ]

1996

; RefNo. [ 1887 ]

2000

; RefNo. [ 1898 ]

1997

; RefNo. [ 1888 ]

1987

; RefNo. [ 1889 ]

1998

; RefNo. [ 1890 ]

2000

The cerith Cerithium atratum (Born 1778) is an abundant gastropod in the seagrass beds at Cabo Frio, Brazil. In order to estimate the ecological importance of cerith shells as a rare hard substratum in the seagrass bed, the abundance of C. atratum and of cerith shells occupied by hermit crabe were quantified. The mean densities of C. atratum and hermit crabs were 1887 and 100 individuals m-2, respectively, and these provided o.5 m2 shell area m-2 available for epizoite colonization. The tube-forming polychaete Hydroides plateni (Kinberg 1867) and oyster Ostrea puelchana Orbigny, 1841 were the dominant visible epizoites on inhabited cerith shells. These epizoite populations were compared in order to investigate whether the temporal and spatial patterns in the epibiotic community were related to ecological and behavioral aspects of the occupant species (cerith or hermit crabs). Larger cerith shells had a greater abundance of epizoites. Each epizoite showed a preference for a different occupant of the shells (the oyster for C. atratum and the polychaete for the cerith shells occupied by hermit crabs). The oyster showed a seasonal pattern in abundance on C. atratum, being more common in fall (March-April). The distribution of the epizoites on the shells depended on the shell occupant species and was probably related to their different foraging activity - C. atratum ploughs half buried through the sediment surface. In both cases, the activity of the shell occupant was considered to be beneficial to the epizoites, as empty shells and shell fragments did not support a macroepifauna.; RefNo. [ 373 ]

2001

This paper examines the optimal management strategy for a forested catchment that yields timber, water and carbon sequestration benefits. The Faustmann multiple rotation model is extended to allow for the maximisation of the net present value of these timber and non-timber benefits. The model is applied to the Thomson Catchment in Central Gippsland, Victoria. Carbon sequestration benefits are modelled via total stand biomass accumulation. The cost of carbon release back into the atmosphere upon logging is estimated as a function of rotation age using an adjusted pulpwood/sawlog ratio. The allowance for both non-timber benefits is found to lengthen the optimal rotation, in a large range of cases to infinity.; RefNo. [ 374 ]

2001

; RefNo. [ 1891 ]

1999

This study quantifies the schooling behavior of a coral reef fish and, in particular, examines the stimuli that may motivate school formation. The focus of the study was the parrotfish Chlorurus sordidus (famliy Scaridae) which, in the juvenile phase, is able to undergo rapid physiological colour pattern ('PCP') changes. Juvenile C. sordidus frequently schools with other juvenile parrotfish species that share some PCPs. Solitary juveniles were followed in the field before and after joining a school to investigate whether their behavior correlated with characteristics of the school joined. The variable recorded were size and PCP of focal juveniles, size and composition of schools and the feeding behavior and PCPs displayed by the school members. Data were systematically collected and analysed using log-linear modelling to quantitatively examine the relationship between all possible combinations of the variables measured. The results of the study provide correlational evidence that juvenile C. sordidus display assortative schooling based on PCP and size characteristic of schools. In addition, the foraging behavior of schools was influential in determining an individual's schooling behavior. These data serve to highlight the complex and dynamic nature of schooling behavior in this species.; RefNo. [ 955 ]

6

2002

It describes a framework to define and weight priorities and strategies for addressing natural and anthropogenic threats to coral reefs in Pacific Island Nations.; RefNo. [ 2065 ]

2001

Expenditures on threatened-species programs are increasing in many countries. Evaluation of the effectiveness and cost efficiency of these programs rarely occurs. An obstacle to evaluation of these programs is the need for a versatile unit of output. This paper reports how an output measure, COPY, and Cost-Utility Analysis methodology, are applied to evaluate New Zealand threatened-species programs. Program effectiveness, cost, and cost-utility ratios are presented, and the results show wide divergences occur between the programs studied. Cost-utility analysis provides a practical means to evaluate the productive efficiency of many threatened-species programs.; RefNo. [ 375 ]

2002

Tissue injury, in which the skeleton is stripped of living tissue, is common in reef-building corals and has potentially important demographic consequences. To examine the significance of tissue injury for natural populations, I monitored 1627 colonies in 30 taxa of Indo-Pacific branching corals at 3 to 5 mo intervals over a 2 yr period. Recent injury (inflicted within the few days prior to censusing) was a highly significant predictor of colony fate within 3 to 5 mo, for acroporid corals with small, compact branches (hispidose and corymbose growth forms). In contrast, colony size was not a significant predictor of fate for these corals after recent injury was included in the models. Both recent injury and colony size were significant predictors of fate for pocilloporids (small bushy growth form). Neither were good predictors of fate for arborescent acroporids (large, widely-spaced branches), even though recent injury was up to 3 times more common in these corals. Old injury (inflicted several weeks or more prior to censusing) covering >5% of the colony was a highly significant predictor of colony death within 3 to 5 mo for corymbose species. Colonies with both old and recent injuries were highly likely to die: 33 and 54% of colonies in separate censuses died within 3 mo. The predictive power of recent injury implies chronic or repetitive tissue loss and prolonged decline, since most recent injuries were small (<30 cm2) and did not account for the colony decline per se. Since colony size was not as good a predictor of colony fate as recent injury for small-branched acroporids, sizebased population models for these corals may be improved by incorporating tissue injury as an indicator of colony condition.; RefNo. [ 376 ]

2004

In soft-sediment systems, terrestrial sediment deposits may result in a marked change in habitat and benthic community composition. We conducted a series of experiments to investigate the behavioural response of juveniles of 2 bivalve species common on New Zealand intertidal sandflats (Paphies australis and Macomona liliana) to terrestrial sediments. Both species are able to actively disperse as juveniles and do so in response to 'unfavourable' conditions. In the laboratory, we investigated the ability of these potential colonists to burrow into thin (0.5, 1.0 cm) surface and submerged terrestrial sediment layers, and their subsequent ability to burrow into natural sediments. Field experiments assessed their response to terrestrial sediments that had been 'aged' in the natural estuarine environment for different lengths of time (up to 1 mo). Exposure to terrestrial sediment treatments negatively affected both species, with fewer individuals burrowing into the terrestrial sediment treatments. In the laboratory, burrowing was slower in the 1 cm-thick surface layers than in the 0.5 cm-thick and submerged layers, and the subsequent burrowing rate in natural sand of individuals recovered from these treatments was similarly affected. This latter effect is important as it suggests that settlement by juvenile bivalves on terrestrial sediment deposits can have a lasting effect even if an individual is able to find a more suitable habitat at a later date. In the field, dispersal of M. liliana away from the terrestrial sediment treatments was reduced, even after the sediment had been ‘aged’ on the sandflat. Depending upon the extent and frequency of disturbance, terrestrial sediments are likely to have important effects on the population and community dynamics of mobile bivalve species, and at a wider scale than that of their immediate impact.; RefNo. [ 1708 ]

2003

Elevated rates of sedimentation as a result of human activities is a recognised problem in many marine environments. Thus, it is important to develop a mechanistic understanding of the impact and subsequent recovery of terrestrial sediment deposits in these areas. This paper describes an experiment to investigate possible reasons for the slow recovery of intertidal soft-sediment macrofaunal communities following smothering by storm-associated terrestrial sediment deposits. We measured, and monitored changes in, a large number of physical and biogeochemical properties of terrestrially derived sediments, in order to identify those characteristics that were most important to potential colonists. Properties of the terrestrial sediments were remarkably different to those of the surrounding sandflat and showed little signs of change over the duration (4.5 mo) of the experiment. Despite this, we were able to identify that temporal changes in macrofaunal community composition were strongly correlated with the levels of chl a, total carbohydrate, phosphorus (P), nitrogen (N) and coarse sand in the sediments. We recommend that future studies of macrofaunal recolonisation following deposition of terrestrial sediment should include measurement of these sediment properties. In addition, analyses which isolate the biologically available portions of carbohydrate, P and N may provide even more insight as to the importance of these properties as settlement cues and indicators of recovery. We also assessed the influence on macrofaunal communities of the conditioning the sediment receives prior to being deposited on the sandflat (i.e. mixing with seawater or freshwater), and found no effect of this on the impact on existing macrofaunal communities or on the subsequent recovery of sediments or macrofauna.; RefNo. [ 377 ]

2004

A common symptom of eutrophication in temperate estuaries is the proliferation of ephemeral, floating macroalgae. Information on the effects of blooms on underlying assemblages mostly originates from non-vegetated intertidal and subtidal habitats. Blooms also often settle in large aggregations over seagrasses, where they decompose. To test hypotheses concerning the effect of dense mats on underlying assemblages of benthic invertebrates within a seagrass meadow, biomass of the green macroalga Enteromorpha intestinalis was experimentally manipulated in the Tuggerah Lakes estuary, New South Wales, Australia. Algae, equivalent to a naturally occurring bloom (~4.5 kg wet wt m 2), were added to caged plots (1 m2) at 2 sites in the seagrass meadow. After 3 mo, the E. intestinalis population began to decompose in the treatment plots and in shallow habitats adjacent to the foreshore. Dramatic declines in the biomass of seagrass and components of the infauna were detected in plots containing decomposing macroalgae. The results have implications for managing estuaries, since assemblages of seagrasses and macrobenthic organisms are considered to be important in nutrient-cycling and food-webs.; RefNo. [ 378 ]

2001

Registered voters of Barnstable County, Massachusetts, voted on November 3, 1998 to establish the Cape Cod Open Space Land Acquisition Program for this coastal region of 15 towns. Known locally as the Cape Cod Land Bank, the legislation is intended "to protect public drinking water supplies, acquire open space and conservation land, provide bicycling and walking trails, and enhance opportunities for recreation" on Cape Cod. The idea of a Cape Cod land bank grew from the experience of neighboring Nantucket Island. Despite the existence of numerous planning tools, such as building restrictions, zoning bylaws, subdivision regulations, and historic district designations, rapid development threatened the island. In the early 1980s, other management tools were explored. Nantucket integrated two ideas — a tax on real estate sales and land-banking (buying land while its affordable and saving it for future use) — into the country's first land bank. Revenues collected are used to purchase land, which is preserved as open space rather than developed. The Cape Cod Land Bank includes an excise tax on real estate bills, matched by $15 million in state funds (Gerwin, Saving Cape Cod, Commonwealth, Summer 1999). This case study chronicles the land bank process and implementation issues and challenges readers to assess its potential to preserve Cape Cod's quality of life.; RefNo. [ 1892 ]

10

2005

A guide to improving fisheries management. It draws on successful management experiences to identify the fundamentals of good practice. ; RefNo. [ 1983 ]

2002

; RefNo. [ 1893 ]

2002

; RefNo. [ 1894 ]

2002

Ranchers, conservationists, and researchers in the Mexico-United States borderlands have implemented a community-based conservation program that relies on monitoring and peer-reviewed science. Their collaboration with the Malpai Borderlands Group supports large-scale, long-term studies, but- perhaps more importantly - it helps assure that science effectively addresses local concerns. Conservation programs are organized around understanding and maintaining the processes that sustain arid landscapes, including fire and herbivory (by both cattle and native species), and understanding how they interact with climate. Sustaining ecosystem processes in the face of climatic variability requires a sound foundation of monitoring and research and a good working relationship between people and organizations with diverse goals and interests. This collaboration between ranching, research and conservation communities demonstrates that these groups, working together for mutual benefit, can reach scientific and conservation goals unobtainable by any one group on its own.; RefNo. [ 379 ]

2003

Economic sustainability is best secured by the creation of local or regional self-reliant, community economies. This is the central argument of eco-local economic theory. Drawing on the experience of local currencies, community corporations, regional food economies and other locally oriented efforts, eco-local theory presents a new analysis of the ‘‘economy of place’’. It focuses on locally symbiotic capital, positive externalities of self-reliance and negative externalities of long-distance trade, and its specific concepts and analyses of the economy, efficiency and economies of scale, and consumption and welfare. Given its specific values and assumptions, it is an economic theory of the social economy that is compatible with, but distinct from, ecological economics.; RefNo. [ 380 ]

7

2005

As part of research aimed at furthering the ecosystem approach to fisheries, six trophodynamic indicators (catch or biomass ratios, primary production required to support catch, production or consumption ratios and predation mortality, trophic level of the catch, fishing-in-balance, and mixed trophic impact) were selected for trial application to the northern and southern Benguela ecosystems. These indicators were selected because of their ability to reveal ecosystem-level patterns, and because they match published criteria. Results show that trends in indicators are sensitive to the choice of trophic level made for certain species and that trophodynamic indicators appear to be conservative because they respond slowly to large structural changes in an ecosystem.; RefNo. [ 2023 ]

1

1983

; RefNo. [ 2127 ]

1999

We investigated avian use of the Pantan habitats, a Mediterranean wetland on the Croatian coast of the Adriatic Sea, by comparing censuses from two periods. The Pantan was surveyed for breeding, resident, wintering, and passage birds in the periods from 1968-1972 and 1986-1991. Species richness declined from 67 to 54. Wintering/passage bird species was the most important group of birds but they also declined from 55 in the period 1968-1972 to 42 in the period 1986–1991. The value of the Pantan coastal area to birds was determined by 25 threatened species and 15 Species of European Special Concern (SPEC; Tucker & Heath, 1994). The Pantan wetland ecosystem has a floristical, ornithological, and aesthetic value at both the regional and international levels. The wetland ecosystem has been destroyed in part by the construction of artificial fishponds and by the regulation of the water course, and it is threatened by the dumping of garbage and rubble, the sedimentation of lead and nitrogen compounds, and the planned construction of housing and a slaughterhouse. There are impacts from fishing and bunting on waterbirds. The degradation of wetlands is reflected in the reduction of the frequency and/or abundance of 87% of the bird species. We discuss the socioeconomic context for conservation management and sustainable development of coastal wetlands in Croatia. Management measures for conservation of the wetland as a whole are suggested.; RefNo. [ 381 ]

2004

Ecosystems of Hawaii and other Pacific Islands have been greatly affected by invasive pest plants and ongoing, deliberate plant introductions make it likely that additional pest plants will become established. We tested the ability of a modified version of the Autralian and New Zealand weed risk-assessment system to identify pest plants in Hawaii and other Pacific Islands. We used information taken from outside Hawaii to predict the behavior - "pest" or "not a pest" - of almost 200 plant species introduced to Hawaii and other Pacific Islands. The screening system initially recommended further evaluation of 24% of these species, but an additional secondary screening was applied to this group, thereby reducing the rate of indecision to only 8%. To independently test the accuracy of the screening system, we compared its decisions - pest or not a pest - to opinions of 25 expert botanists and weed scientists who had substantial field experience in Hawaii or other Pacific Islands. We asked the experts to rate each species as "major pest", "minor pest", or "not a pest" in native or managed ecosystems. The screening system correctly identified 95% of major pests and 85% of nonpests. Among minor pests identified by the experts, 33% were classified as nonpests by the screening system. Use of the screening system to assess proposed plant introductions to Hawaii or other Pacific Islands and to identify high-risk species used in horticulture and forestry would greatly reduce future pest-plant problems and allow entry of most nonpests. The screening process is objective, rapid, and cost-efficient. With minor modifications, it is likely to be useful in many parts of the world.; RefNo. [ 382 ]

2001

In this article, we use sibling correlations in schooling to measure differences in integrational mobility for 16 latin american countries. The results show that there are substantial differences in mobility within latin america. Social mobility increases with mean schooling and income per capita but is only mildly associated with public xpenditures on education.; RefNo. [ 1895 ]

2004

Gazi Bay, Kenya, covers an area of 18 km2, and its mangroves are degraded. We present a quantitative and qualitative evaluation of the degradation of vegetation structure and dynamics of mangrove communities over a period of 25 yr, using aerial photography in a geographical information system (GIS), combined with ground-truth data for different vegetation layers, and with faunal and environmental factors. Retrospective analysis and understanding of current practices were aided by interviews with Gazi village elders and by field observations of mangrove tree stumps. GIS-based vegetation maps were combined with data obtained using the point-centred quarter method (PCQM), an accuracy analysis was performed, and forestry parameters were derived from the resultant PCQM data. In addition to general human-induced degradation of vegetation structure and floristic composition of the seaward mangrove zone, a particular sandy beach is expanding at the expense of mangrove, whereas the back mangrove zone has undergone minor changes. Aerial photographs of 1992 and current field data show an apparent zonation of 6 different monospecific or mixed mangrove communities, with a high importance of Rhizophora mucronata in each community and each vegetation layer. Retrospective vegetation structure was combined with correspondence analyses on the PCQM data derived for adult, young and juvenile trees in order to make predictions. Present dynamics initiated by anthropogenic degradation of mangroves continues, even though human impact has diminished. We predict that under a ‘no impact scenario’, the sandy ridge will continue to expand, that this will speed up under a ‘mangrove cutting scenario’, and that a scenario altering the complex topography will lead to a major re-organisation of the mangrove and terrestrial vegetation structure.; RefNo. [ 383 ]

1984

; RefNo. [ 1896 ]

1992

; RefNo. [ 1777 ]

1994

; RefNo. [ 1897 ]

2001

Nassau grouper Epinephelus striatus is a reef fish that settles in off-reef nursery habitats before emigrating to coral reefs. Because little is known of its habitat use and population dynamics before moving onto reefs, we conducted monthly visual censuses from May to December (3 to 10 mo post-settlement) to quantify spatio-temporal variability in density, microhabitat use, and size-structure in a cohort of early juvenile Nassau grouper residing in an off-reef nursery system in the central Bahamas. Juvenile Nassau grouper density decreased significantly from August to September, but this decrease was small compared to a decrease of over 90% during the first 3 to 4 mo post-settlement, a pattern consistent with Type III survivorship. Throughout the study, Nassau grouper had a disproportionately high association with the macroalgae Laurencia sp., while other microhabitats (e.g. seagrass, corals) were usually used in proportion to their availability. Percent cover of Laurencia sp. significantly influenced spatial variability in fish density during May and June (4 to 5 mo post-settlement), but not later in the year. Spatial differences in juvenile Nassau grouper density later in the year were correlated with spatial variability in the size distribution of fish. Sites harboring disproportionately high numbers of large juveniles also had greater juvenile densities. Thus, microhabitat characteristics were determined to influence the spatial distribution of Nassau grouper up to 5 mo post-settlement, but the population appears to be influenced by size-dependent processes (e.g. predation or ontogenetic habitat shifts) after that time. Microhabitat characteristics, as well as spatially variable growth rates or size-dependent mortality may cause nursery areas to vary in their contribution to the local population at subsequent life history stages.; RefNo. [ 384 ]

2000

Sexual reproduction and genetic variation of the scleractinian coral Mycedium elephantotus at Maoao (MO), Yenliao Bay, northern Taiwan, and at Tiaoshi (TS), Nanwan Bay, southern Taiwan, were studied from 1990 to 1996. M. elephantotus is a hermaphroditic broadcast spawner with an annual reproductive cycle. Gametogenesis of the MO population began in January, and spawning occurred in July-August. In the TS populations, there were 2 reproductive groups with different timing of gametogenesis and spawning. Gametogenesis of the first group started in November, and spawning occurred in April or May, while gametogenesis of the second group started in March and spawning occurred in August or September. The temporal reproductive isolation of the 2 groups was possibly the byproduct of adaptation. Allozyme electrophoresis was applied to study the genetic variations among regional coral populations and the 2 reproductive groups. Significant genetic variations were detected among the MO and TS populations and between the 2 reproductive groups at TS, but no fixed differences were found. The MO population demonstrated larger genetic distances with TS populations (Nei’s unbiased D = 0.229 and 0.165, for the first and second reproductive groups respectively) reflecting the effect of isolation by distance. Significant genetic variation and moderate genetic distance (D = 0.045) between the 2 reproductive groups at TS indicate the effect of genetic differentiation due to reproductive isolation in sympatric populations. The lack of morphological differences and the moderate genetic distance between the 2 reproductive groups suggest recent diversification within the taxon. The presence of 2 reproductive groups of M. elephantotus in Nanwan Bay may represent the initial stage of sympatric speciation in marine environment or a secondary contact of allopatric populations.; RefNo. [ 385 ]

2002

Sediment incubation microcosms, multitrap apparatus and water column variables have been employed to describe the dynamic changes in benthic-pelagic coupling between nutrient pools in the Pontevedra ria, NW Spain, during spring and summer 1998. A comparison of the chemical characteristics of suspended and bed sediment together with sediment nutrient effluxes revealed that particulate organic nitrogen and carbon were progressively depleted upon transit through the nutrient pools. The main fate of particulate organic nitrogen reaching the bed sediment is denitrification, although resuspension is also important. An estimate of net denitrification (Dnet) was made at 2 muddy sites in the ria with a mass balance at the benthic boundary layer. First-order approximations calculate Dnet to be 178 and 182 µmolN m 2 h 1 at the 2 stations, and agree well with previous modelling estimates. Denitrification is highest when upwelling relaxes and the flux of organic matter to the sediment increases. Regular inputs of offshore water ensure water renewal and re-oxygenation of bottom waters, thus preventing anoxia, particularly in the summer. With upwelling, large quantities of ammonium are effluxed to the water column (250 µmolNH4 + m 2 h 1), probably as a result of the bed sediment resuspension engendered by upwelling and stirring of phytodetrital fluff held in suspension as neutrally buoyant material above the sediment surface. We hypothesise that hydrodynamical processes play an important role in determining the quantity of nutrients remineralised in the Pontevedra ria and, in the case of nitrogen, the rate of denitrification at the benthic boundary layer.; RefNo. [ 386 ]

2000

; RefNo. [ 1899 ]

1995

; RefNo. [ 1900 ]

2000

; RefNo. [ 1901 ]

2000

; RefNo. [ 1902 ]

2002

Measurements of secondary production of meiofaunal assemblages are limited, and for most seagrass systems no information is available yet. In the present study meiofaunal production was estimated in a Posidonia oceanica bed in the NW Mediterranean Sea using the summation of biomass increments and different equations based on the production:biomass ratio (i.e. biomass turnover). Total meiofaunal production ranged from 7.5 to 13.2 gC m 2 yr 1, according to the approach utilised (mean value 10.0 ± 1.9 gC m 2 yr 1, median value 9.6 gC m 2 yr 1). These values are among the highest reported worldwide, indicating that seagrass systems are hot spots of meiofaunal production. Despite the numerical dominance of nematodes, harpacticoid copepods were responsible for about 50% of total meiofaunal production, followed by polychaetes and nematodes (34 and 12%, respectively). Daily meiofaunal production rates were highest in February-March (21.3 mgC m 2 d 1), late May-June (31.4 mgC m 2 d 1) and October-December (44.6 to 52.0 mgC m 2 d 1). Analysis of daily secondary production of the dominant taxa suggested that different meiofaunal components dominated in different periods. During February-March, May-June and September-October harpacticoid copepods displayed highest production rates, but in November and December daily meiofaunal production was largely accounted for by polychaetes and nematodes. Temporal analysis of total meiofaunal production also revealed that, conversely to what is expected for temperate environments, only ca. 15% of the meiofaunal carbon was produced in summer, whereas 23% was observed in spring and 45% in autumn. Temporal changes in total meiofaunal daily production were apparently not dependent upon temperature, but rather reflected changes in the content and bio-availability of sediment organic matter in the seagrass bed. The seagrass P. oceanica was responsible, together with microphytobenthos, for high primary production values (169 to 300 gC m 2 yr 1). The fraction of total benthic primary production potentially consumed by meiofauna (as a measure of seagrass trophic efficiency) ranged from 10 to >50%. These estimates provide evidence of the relevance of meiofauna in benthic energy flows. At the same time, the production efficiency in the Posidonia bed (calculated by the ratio of total meiofaunal production to total primary production) was only 3.0 to 5.3%. These values, comparable to those observed in estuarine/organic-rich systems, are 2 to 10 times lower than those estimated in Cymodocea nodosa or Zostera noltii seagrass meadows, indicating that the Posidonia system is less efficient than other seagrass systems in channelling primary production to higher trophic levels.; RefNo. [ 387 ]

2003

The harbour porpoise Phocoena phocoena, grey seal Halichoerus grypus, harbour seal Phoca vitulina and white-beaked dolphin Lagenorhynchus albirostris are regularly found stranded along southern North Sea coasts. Occasionally, offshore species such as the fin whale Balaenoptera physalus, the white-sided dolphin L. acutus and the sperm whale Physeter macrocephalus are also found stranded. In order to trace their diet, we measured 13C and 15N in their muscles as well as in 49 invertebrate and fish species collected from the southern North Sea. The 15N data indicate that the harbour seal, grey seal and white-beaked dolphin occupy the highest trophic position, along with ichtyophageous fishes such as the cod Gadus morhua (mean muscle values of 18.7, 17.9, 18.8 and 19.2 respectively). The harbour porpoise occupies a slightly lower trophic position (mean 15N value of 16.2), reflecting a higher amount of zooplanktivorous fishes in its diet (mean 15N of 14.7); 2 suckling harbour porpoises displayed a significant 15N enrichment of 2.2 compared to adult females. Adult females are 15N-enriched compared to adult male harbour porpoises. Fin whales, sperm whales and white-sided dolphins are 13C-depleted compared to southern North Sea particulate organic matter and species, suggesting that despite regular sightings, they do not feed within the southern North Sea area.; RefNo. [ 388 ]

2002

During recent decades, environmental conditions have deteriorated in the Black Sea. Population explosions of phytoplankton and jellyfish have become frequent and several fish stocks have collapsed. In this study, literature sources and long-term data are explored in order to find empirical evidence for ecosystem effects of fishing. Inverse trends of decreasing predators, increasing planktivorous fish, decreasing zooplankton and increasing phytoplankton biomass are revealed. Increased phytoplankton biomass provoked decreasing transparency and nutrient content in surface water. A massive development of jellyfish during the 1970s and 1980s had a great impact on consumption and consequent decrease in zooplankton. The turning point for these changes occurred in the early 1970s, when industrial fishing started and stocks of pelagic predators (bonito, mackerel, bluefish, dolphins) became severely depleted. A ‘trophic cascade’ is invoked as a mechanism to explain observed changes. According to this hypothesis, reduction in apex predators decreases consumer control and leads to higher abundance of planktivorous fish. The increased consumption by planktivorous fish causes a consequent decline in zooplankton biomass, which reduces grazing pressure on phytoplankton and allows its standing crop to increase. The effects of fishing and eutrophication are explored using a dynamic mass-balance model. A balanced model is built using 15 ecological groups including bacteria, phytoplankton, zooplankton, protozoa, ctenophores, medusae, chaetognaths, fishes and dolphins. Ecosystem dynamics are simulated over 30 yr, assuming alternative scenarios of increasing fishing pressure and eutrophication. The changes in simulated biomass are similar in direction and magnitude to observed data from long-term monitoring. The cascade pattern is explained by the removal of predators and its effect on trophic interactions, while the inclusion of eutrophication effects leads to biomass increase in all groups. The present study demonstrates that the combination of uncontrolled fisheries and eutrophication can cause important alterations in the structure and dynamics of a large marine ecosystem. These findings may provide insights for ecosystem management, suggesting that conserving and restoring natural stocks of fish and marine mammals can contribute greatly to sustaining viable marine ecosystems.; RefNo. [ 389 ]

2003

Hydroclimatic, biological and anthropogenic data-series (1915-1993) were analysed to determine and compare main trends and fish stock-environment relationships in the Black Sea. Long-term patterns were studied on different temporal scales: interdecadal, decadal and interannual variation. The results showed evidence of coherent patterns across different indices. Temperature, atmospheric pressure, wind and river run-off series were significantly correlated with most of the biological, anthropogenic and fish stock indices. Anthropogenic factors such as eutrophication and hypoxia were responsible for degradation of the coastal ecosystems, but they can also have negative impacts on open-sea populations. The correlations established allow formulation of hypotheses on the causal links between the abiotic environment, productive processes and population dynamics. The physical environment was recognised as being the main factor driving the biological productivity and essentially influencing all processes in the sea. Other factors responsible for a great part of the observed variability in marine data were biological interactions and anthropogenic impact. The rise in overall productivity after 1970 might be explained by several factors acting simultaneously: a favourable climatic regime, increased eutrophication, and the effect of trophic cascades attributable to overfishing of predators. The indices and relationships studied can be useful for integrating environmental information in fisheries and ecosystem management.; RefNo. [ 390 ]

2003

In the marine environment, the distribution of primary producers and higher trophic levels is strongly dictated by the physical characteristics of the water column. Typically, life concentrates in regions where there are strong horizontal or vertical gradients in temperature or density (‘frontal regions’). Top predators, such as diving mammals and birds, target fronts and their associated high biomass of prey. Until now, the study of the interaction between diving predators and the physical environment has been hindered by the lack of adequate instrumentation. The response times of the available animal-borne temperature-depth recorders have been too slow to accurately measure the external environment where the animals are foraging. This limitation has been overcome by the development of a lightweight, rapidly responding temperature-depth logger. The instrument was successfully deployed on 2 diving seabird species (the common guillemot Uria aalge and the European shag Phalacrocorax [Stictocarbo] aristotelis) in the North Sea. A method for correcting temperature data for the time lag in the response of the temperature sensor is presented. The findings show the potential of this technology in 2 important ways: in providing unparalleled information on the interaction between predators and the marine environment, and as a low-cost method of obtaining high-quality oceanographic data.; RefNo. [ 391 ]

2001

Access to and use of natural resources as a cornerstone in sustaining indigenous cultures has recently obtained considerable international attention. Access to marine resources has become a key issue for many aboriginal peoples struggling to move from dependency on the nation state to self-determining agency. This essay describes and compares recent developments respecting Eastern Canadian Mi’kmaq and North Norwegian Saami initiatives to achieve recognition and realization of their aboriginal entitlements. Core characteristics of the Canadian and Norwegian nation state responses to these initiatives are outlined and discussed, with an emphasis on the implications of aboriginal entitlements for the present ‘privilege allocation’ premise and paternalistic character of fisheries management systems. The essay concludes with a discussion of the potentials for an alliance between coastal zone non-indigenous peoples and indigenous peoples for the purpose of developing an alternative approach to fisheries management that will enhance local agency in and the ecological sustainability of fisheries livelihoods.; RefNo. [ 393 ]

2001

The federal consistency provision of the Coastal Zone Management Act (1972) created a new form of interaction between federal and state governments. The implementation of this provision has significant ramifications for coastal management and intergovernmental cooperation in the United States. Past studies have focused on the provision’s implementation patterns among U.S. coastal states and federalstate disputes mediated by the Secretary of Commerce. This supplemental article examines judicial interpretations of the federal consistency provision over the past two decades in relation to major issues deliberated by Congress at the time of enactment. Recent changes in the provision, as well as those unresolved issues likely to resurface in future litigation, are also discussed. Seemingly, coastal land use authority and offshore energy exploration remain the most contentious issues surrounding the federal consistency provision.; RefNo. [ 392 ]

2001

The sustainable management of marine natural resources presents particular challenges to the managers of those resources. While such management has typically been based on biological considerations, it is argued that this has resulted in overexploitation and destruction of important marine assets in industries such as fishing and tourism. Consequently, it is concluded that other approaches are needed, with the use of economic concepts and management tools particularly relevant. At the same time, the human welfare outcomes of the application of various policy instruments must be carefully considered. While biological information is critical to the formulation and implementation of successful management regimes, it is concluded that the application of economic instruments will become more attractive to resource managers, with these instruments underpinned by consideration of property rights and an appropriate allocation of economic rents. A greater focus on these economic matters will take resource managers further in the direction of sustainable management of increasingly scarce marine resources. The conclusions in the paper are supported by various case studies from fisheries and tourism.; RefNo. [ 394 ]

1999

Thalassia testudinum (Banks ex Konig) is an important primary producer in nearshore tropical marine ecosystems. In the past several years, mass mortality of T. testudinum populations within the Florida Bay estuary has highlighted the need to know more about levels of clonal variation and the spatial arrangement of genets within population of this species. Historically, most of the reproduction within this species was thought to be through clonal growth, and populations have been assumed to exhibit little genetic diversity. We used DNA fingerprinting techniques and spatially hierarichal sampling to search for genetically distinct plants within T. testudinum meadows in Rabbit Key Basin, Florida Bay, USA. We detected 22 genetically distinct individuals out of 74 samples. Multiple genetic individuals were detected over small spatial scales (<0.25 m). Analysis of molecular variance (AMOVA) detected significant levels of variation of both the largest and smallest spatial scales studied. This result suggested that genets of this species genetically do not grow in discreet monoclonal patches and that most genets are not large enough to span the entire basin (~5 km). Further, analysis of genetic distances between phenotypes suggests a pattern of isolation by distance, with individuals that were nearer in space being more genetically similar. GIS analysis of seagrass density over the period from 1985 to 1994, combined with the clonal diversity data presented here, suggest seedlings may play a significant role in colonization of bare patches. These results imply that the role of sexual reproduction in population structure within this species is greater than previously thought.; RefNo. [ 956 ]

2003

Concentrations and fluxes of C, N, and P were measured in dwarf and fringe mangrove wetlands along the Taylor River, Florida, USA from 1996 to 1998. Data from these studies revealed considerable spatial and temporal variability. Concentrations of C, N, and P in the dwarf wetland showed seasonal trends, while water source was better at explaining concentrations in the fringe wetland. The total and dissolved organic carbon (TOC and DOC), total nitrogen (TN), and total phosphorus (TP) content of both wetlands was higher during the wet season or when water was flowing to the south (Everglades source). Concentrations of nitrate plus nitrite (Nox ), ammonium (NH4 +), and soluble reactive phosphorus (SRP) in the fringe wetland were all highest during the dry season or northerly flow (bay source). Nutrient concentrations most effectively explained patterns of flux in both wetlands. Increased wetland uptake of a given constituent was usually a function of its availability in the water column. However, the release of Nox from the dwarf wetland was related to the NH4 + concentration, suggesting a nitrification signal. Nitrogen flux in the dwarf wetland was also related to surface water salinity and temperature. Our findings indicate that freshwater Everglades marshes are an important source of dissolved organic matter to these wetlands, while Florida Bay may be a source of dissolved inorganic nutrients. Our data also suggest that temperature, salinity, and nutrient concentrations (as driven by season and water source) influence patterns of materials flux in this mangrove wetland. Applying long-term water quality data to the relationships we extracted from these flux data, we estimated that TN and TP were imported by the dwarf wetland 87 ± 10 and 48 ± 17% of the year, respectively. With Everglades restoration, modifications in freshwater delivery may have considerable effects on the exchanges of nutrients and organic matter in these transitional mangrove wetlands.; RefNo. [ 395 ]

2003

Key forage species lie at the core of complex marine food webs, providing essential linkages among trophic levels. We examined the interactions of an important forage and commercial fish, capelin Mallotus villosus, and its primary avian predator, the common murre Uria aalge, in the NW Atlantic. Murres are capelin specialists and robust samplers of capelin biology. During the 1990s, the coldest surface-water event in the past 50 to 100 yr occurred in the NW Atlantic (1991), and the eastern Canadian ground-fishery was closed (1992). Concordantly, the biology and behaviour of capelin has undergone very substantial changes. We examined parental food deliveries and production at the world’s largest common murre colony on Funk Island off the northeast coast of Newfoundland throughout the 1990s. Murres delayed breeding and delivered smaller and lower quality capelin to their chicks. These changes, corroborated with independent fisheries data, resulted in poor condition of murre chicks, indicating significant effects of changing capelin demographics at higher trophic levels. The diets of the murre chicks indicate that the composition of the capelin population has shifted from high size diversity to mainly smaller capelin. We hypothesize that this change resulted from the elimination of the larger-sized and earlier-spawning genotype and that the NW Atlantic capelin population is exhibiting signs of reduced reproductive potential that likely reflects lower spawning biomass.; RefNo. [ 397 ]

2003

We examined distributional patterns of a pursuit-diving seabird, the common murre Uria aalge, and its fish prey, capelin Mallotus villosus, within the avian foraging range of the largest murre colony in eastern North America: Funk Island, Newfoundland. During chick-rearing, the foraging habitat was previously partitioned into: (1) a high-quality area, 45 km from the colony where energyrich capelin schools were found, which were spatially and temporally persistent and (2) a low-quality area, 60 km from the colony where schools were composed of lower-energy capelin that were ephemeral. At the scale of the foraging range (meso-scale: 1 to 100 km), murres were highly clustered into 25% of the surveyed area, with fewer murres in the low-quality relative to the high-quality area. There were tighter associations among murre and capelin aggregations in the low-quality (1.2 ± 0.2 km) relative to the high-quality area (2.6 ± 0.4 km). This likely resulted from the divergent capelin behaviour and, thus, different foraging strategies used by murres to search for (e.g. memory vs local enhancement) and capture prey. At fine spatial scales (250 m2) within foraging areas, murres were found at lower densities (mode: 2 murres), revealing that interference competition among individuals may be important during prey capture. Modeling revealed that at >50 murres per 250 m2 in the highquality area, a murre would have a >90% chance of increasing its foraging efficiency by switching to forage in the low-quality area. Overall, this scale-dependent aggregative behaviour of murres suggests that cooperative foraging among conspecifics may be important in locating prey at the scale of a foraging range, or murres may simply aggregate in areas of high prey abundance, but competitive interactions among conspecifics become important at the scale of prey capture.; RefNo. [ 398 ]

2002

Recruits of the South African abalone Haliotis midae are more abundant on irregularly textured than on smooth encrusting corallines, and experimental removal of the urchin Parechinus angulosus leads to the virtual disappearance of H. midae recruits. Explanations include the following; (1) In the absence of larger grazers, prostrate diatoms that are preferentially consumed by abalone recruits become displaced by less suitable overstorey diatoms, filamentous algae or blue-green algae; (2) textured corallines protect pockets of suitable diatoms, whereas large grazers eliminate these from smooth corallines. We tested these possibilities in aquarium experiments in which microalgal communities were grown on artificial coralline mimics with different textures and then exposed to different grazers at densities simulating those in the field. Microalgal standing stocks (measured as chlorophyll a) increased in the absence of grazers, but this was reflected only in the amounts of filamentous and blue-green algae. Diatoms remained unchanged in quantity and community composition between different grazing treatments and substratum textures. Changes in diatom communities following urchin removal are thus unlikely to explain the ensuing disappearance of abalone recruits, although changes in filamentous and blue-green algae may do so. Textured surfaces did, however, consistently support higher stocks of microalgae than smooth surfaces (in either the presence or the absence of grazers), which may account for the preference of abalone recruits for irregular encrusting corallines in the field.; RefNo. [ 399 ]

2002

This paper examines the effect of oxygen on nitrous oxide (N2O) concentrations in estuarine waters. N2O has been measured year-round in the Schelde estuary, a high-nitrogen, lowoxygen macrotidal system. N2O concentrations were above atmospheric equilibrium levels indicating that this estuary represents a source to the atmosphere. The distribution of N2O showed consistent and systematic relationships with distribution patterns of ammonium, oxygen, nitrite and nitrification activities. A controlled laboratory experiment with a natural bacterial community from the Schelde estuary revealed maximum N2O production to occur at oxygen concentrations of about 5 µM. This production was inhibited by acetylene, a nitrification inhibitor. Maximum N2O concentration in the field occurred at oxygen concentrations below 35 µM. The difference in the oxygen concentration that results in maximum N2O may have arisen because low-oxygen environments present in the estuary were destroyed by stirring in our laboratory experiment. It appears that low oxygen concentrations in estuarine water trigger enhanced N2O production if ammonium is present in sufficient amounts. This conclusion is further illustrated by data from the Thames, Loire and Gironde estuaries.; RefNo. [ 401 ]

2001

; RefNo. [ 1904 ]

2003

Juveniles of a number of reef fish species develop in shallow-water ‘nursery’ habitats such as mangroves and seagrass beds, and then migrate to the coral reef. This implies that some reef fish species are distributed over the mangrove-seagrass-reef continuum in subpopulations with different size distributions that are spatially separated for considerable periods of time. To test this assumption, and to determine ontogenetic dietary changes (which may drive fish migrations from nursery habitats to the coral reef), we selected 9 herbivorous and carnivorous reef fish species whose juveniles are highly abundant in nearby nursery habitats. 13C:12C and 15N:14N ratios were measured in fish muscle tissues and in potential food items collected from each of the 3 habitats, and fish gut contents were identified. All 13C signatures of fishes sampled from the coral reef were close to the carbon isotope signatures of food items on the reef, and were significantly depleted compared to those of fishes from the nursery habitats (with the exception of Scarus iserti). Gut-content analysis of herbivorous fishes entailed problems with identification of the ingested food items, but there was no change in the 13C or 15N signatures of the muscle tissue as a function of fish size. Regression analysis showed significant positive relationships between 15N content and fish size in all carnivorous fish species; this was correlated to the decreasing dietary importance of small crustaceans and the increasing consumption of decapod crabs or prey fishes with increasing size. The combined study of stomach contents and stable isotopes showed that the juveniles and adults of these reef fish species are separated ecologically and spatially for a considerable period of time, and that herbivorous fishes do not change their trophic status with increasing size, whereas carnivorous fishes feed on increasingly larger prey at increasingly higher trophic levels prior to their migration from the nursery habitat to the coral reef.; RefNo. [ 882 ]

2004

The objective of this study is to investigate the cost of the use of fire in the Amazon. Burnings are commonplace in the Amazon production process and contribute towards the region’s agricultural expansion. Fire is used by farmers in the land preparation process and in clearing forest areas. It also helps combat plants that overrun pastures. However, fire also generates losses for farmers and landowners when it gets out of control. Since the use of fire from a private perspective obeys an economic rationale, the measurement of losses associated to the use of fire must consider the difference between intentional and accidental fires. This study introduces these important concepts which are fundamental to measure the cost of fire. Losses also reach social proportions. To address this issue, we estimated losses related to the release of carbon into the atmosphere, as well as losses due to respiratory ailments provoked by smoke from fires. Our study covered costs related to accidental pasture fires, fence losses, forest losses, carbon emissions, and impacts on human health. Our most conservative estimates indicate an average cost of around 0.2% of the region’s GDP during the 1996-1999 period.; RefNo. [ 402 ]

1986

; RefNo. [ 1912 ]

2001

; RefNo. [ 1914 ]

2003

Several harpacticoid copepod species are adapted to an epiphytic lifestyle. Previous studies on tropical seagrass meiofauna mainly focussed on the epiphytic communities and neglected the benthic component. The present study aims to document the benthic harpacticoid copepod communities sampled from different sediment depth horizons adjacent to five seagrass species in the intertidal and subtidal zone of a tropical seagrass bed (Gazi Bay, Kenya). Two benthic copepod communities could be identified mainly based on the tidal position of the samples: a first community was collected near the intertidal seagrasses Halophila ovalis and Halodule wrightii; a second community occurred near the subtidal seagrasses Thalassia hemprichii, Syringodium isoetifolium and Halophila stipulacea. The first community was mainly determined by sediment characteristics (e.g. skewness), while the second community was split of based on organic matter content (% TOM), nutrient and pigment values. A subtle combination of horizontal and vertical niche segregation was reported for the dominant copepod families. Species of the families Thalestridae, Laophontidae and Diosaccidae were structured by tidal position and showed a strong preference for the subtidal zone. The opposite strategy, i.e. a clear preference for the intertidal zone, was found for copepods belonging to the families Paramesochridae and Canuellidae. In addition, Apodopsyllus africanus Paramesochridae) was well-adapted to stress and was concentrated in the deeper sediment layers near thesubtidal seagrasses. On the other hand, Canuellidae, as filter feeders, were concentrated in the upper centimetres of the sediment. The families Ectinosomatidae and Cletodidae did not show any vertical or horizontal segregation. On the species level, however, clear horizontal niche segregation was detected for the family Cletodidae. In addition to the reported ecological results, the study material was used to evaluate different niche definitions. We found tidal position to be the most important factor forcing harpacticoids to specialise. Sediment depth horizon was less powerful in dividing the families into different guilds (from specialists to generalists) based on standardised niche breadth. The present study documents the subtle habitat partitioning of co-existing species in a limited area and its role in sustaining high biodiversity in the community.; RefNo. [ 404 ]

2000

In a comparative study of 4 bivalve species we show that the apparent widely different tolerances in survival time observed in a closed system filled with N2-gassed seawater is mainly due to the experimental conditions. Both a high dose of cadmium and the antibiotic chloramphenicol increase survival time 2- to 4-fold. Without precautions for bacterial growth, the survival time of the most tolerant species, Scapharca inaequivalvis, is about 4 times longer than that of the most sensitive species, Venus gallina. The other bivalves Tapes philippinarum and Mytilus galloprovincialis, have intermediate survival times. When proliferation of bacteria is prevented by chloramphenicol, the survival time of S. inaequivalvis remains the highest; however under these conditions the other 3 species show similar survival times. Bacteria cause a drop in pH of the incubation medium and the accumulation of sulphide. S. inaequivalvis exhibits a significant decrease in survival time in the presence of exogenous sulphide. The antibiotic postpones the accumulation of sulphide, but a significant population of sulphate-reducing bacteria is able to survive in its presence. In the case of V. gallina and M. galloprovincialis, exogenous sulphide (up to 400 µM) does not affect the improved survival time due to the antibiotic. This holds also for a decrease in pH. Bacterial toxins other than sulphide or direct action on the integrity of the organism must be responsible for the adverse effects on survival. The responsible micro-organisms are associated with the bivalves, and anoxia induces their proliferation. For this reason, accumulation of bacterial noxious products cannot be avoided by frequent renewal of the medium.; RefNo. [ 1920 ]

2002

We examined the potential role of food limitation in constraining the recovery of sea otters Enhydra lutris in Prince William Sound, Alaska, following the ‘Exxon Valdez’ oil spill. The spill resulted in the removal of a large number of sea otters in 1989, and as of 1998, the portion of the population in the heavily oiled northern Knight Island region had not fully recovered. Between 1996 and 1998, prey consumption rate was higher and the condition of sea otters was better at northern Knight Island than in an unoiled area of the sound (Montague Island). Estimates of prey energy available per unit mass of sea otter were about 4 times higher at Knight than Montague Island, albeit not significantly different between the 2 areas. Over this same period, the number of sea otters remained constant at northern Knight Island but increased at Montague Island. These data suggest that food was at least as abundant at Knight than at Montague Island, and that recovery of sea otters via intrinsic population growth was limited by factors other than food. However, the availability of food, the prey consumption rate, and the condition of sea otters were all much lower at both Knight and Montague Islands than in areas newly occupied by sea otters where the population growth rate was near the theoretical maximum. It is possible that the relatively short supply of food (compared to areas where sea otter population growth rate was high) may have inhibited immigration or interacted with other factors (e.g. oil-induced mortality or predation) to restrict sea otter population growth. Nonetheless, these data suggest that impacts of anthropogenic disturbances on large, often food-limited vertebrate predators can persist in spite of the availability of food resources that are sufficient for intrinsic population growth.; RefNo. [ 405 ]

2000

Interactions between sea otters Enhydra lutris, sea urchins Strongylocentrotus droebachiensis, and kelp were investigated following the reduction in sea otter density in Prince William Sound, Alaska, after the Exxon Valdez oil spill in 1989. At northern Knight Island, a heavily oiled portion of the sound, sea otter abundance was reduced to a minimum of 50% by the oil spill, and from 1995 through 1998 remained at an estimated 66% lower than in 1973. Where sea otter densities were reduced, there were proportionally more large sea urchins. However, except in some widely scattered aggregations, both density and biomass of sea urchins were similar in an area of reduced sea otter density compared with an area where sea otters remained about 10 times more abundant. Furthermore, there was no change in kelp abundance in the area of reduced sea otter density. This is in contrast to greatly increased biomass of sea urchins and greatly reduced kelp density observed following an approximate 90% decline in sea otter abundance in the western Aleutian Islands. The variation in community response to a reduction in sea otters may be related to the magnitude of the reduction and the non-linear response by sea urchins to changes in predator abundance. The number of sruviving sea otters may have been high enough to suppress sea urchin populations in Prince William Sound, but not in the Aleutians. Alternatively, differences in response may have been due to differences in frequency or magnitude of sea urchin recruitment. Densities of small sea urchins were much higher in the Aleutian system even prior to the reduction in sea otters, suggesting a higher rate of recruitment.; RefNo. [ 957 ]

2003

Marine mesocosm experiments were conducted using a natural phytoplankton assemblage from the Tromsheim fjord, Norway, in June 2000. Replicate experiments were conducted at 2 inorganic nitrogen:silicon (N:Si) molar ratios, 4:1 and 1:1. Time course changes in the different groups that comprised the microplanktonic community and inorganic nutrient concentrations were recorded. We sought to simulate these data using 3 alternative mathematical models based on a common framework of functional groups and inter-group interactions following an earlier model. The functional groups incorporated within the model were bacteria, diatoms, dinoflagellates, phytoflagellates, picophytoplankton, heteroflagellates and larger microzooplankton along with inorganic nutrients, dissolved organic matter and detritus. We modified the autotroph functional group submodels to achieve different levels of model sophistication in terms of utilisation of nutrients (single [N] or dual [N:Si] inorganic nutrient models) and organism structure (biomass growth made a function or extracellular or intracellular nutrient concentration). We tested the influence of different model formulations on simulations of particulate carbon (C) biomass and its partitioning amongst the microbial groups in the 2 different experimental nutrient regimes. To achieve satisfactory global simulations (both nutrient regimes) with a single-parameter set, it was found necessary to include a dual currency of both inorganic N and Si in the model, and to relate C biomass growth to the intracellular rather than extracellular concentration of the nutrient in the least relative supply. Models lacking these 2 features were unable to simulate N and Si and C biomass dynamics of the microbial assemblage in alternative conditions of high and low N:Si ratio.; RefNo. [ 406 ]

2001

The invertebrate assemblages in sediments bordering exposed fringing reefs at Hanalei Bay, Kauai, Hawaii, were examined during July to September 1994. Densities of invertebrate animals larger than 0.5 mm in sediments of the bay ranged from counts of 10 260 m 2 in the fine carbonate sands of the central bay to 870 m 2 in the habitat dominated by terrigenous silt near the reef edge close to the Hanalei river mouth. Similar sediment types supported broadly similar infaunal communities. Within the primarily carbonate sediments, mean grain size and wave exposure appear to have an important influence on the community. Taxonomic richness, number of individuals, and diversity showed significant negative relationships with exposure to wave energy (as estimated by sand ripple wavelength). The number of individuals was also significantly correlated with mean grain size. Overall, polychaetes and small crustaceans were numerically dominant among the major taxonomic groups investigated. Macrophagous and microphagous polychaetes had significant, but opposite, associations with grain size. In addition, microphagous polychaetes were significantly negatively correlated with wave exposure. No habitat variable measured could explain the variation in percent composition of crustaceans or echinoderms in the sedimentary habitats. The percentage of gastropods in the community was significantly negatively correlated with grain size, grain-size standard deviation and exposure, and positively with percent organic carbon. Bivalves were significantly positively associated with depth and grain size. These strong relationships imply that, in Hanalei Bay, physical processes are especially important in influencing assemblage structure, and that community structure and composition vary continuously along environmental gradients.; RefNo. [ 407 ]

2003

; RefNo. [ 1905 ]

2003

The chthamalid barnacles Chthamalus montagui and C. stellatus occupy distinctive distributional patterns on European rocky shores. To explore whether these patterns are determined primarily by larval settlement or by post-settlement mortality, we examined the abundance of each species from cyprid attachment through successive stages in its intertidal life history and thus attempted to determine the critical stage for the establishment of adult patterns of dominance. Sampling was carried out on 4 shores in Cork, SW Ireland. On 2 of the shores, sampling sites were in zones in the upper shore dominated by C. montagui, and on the other 2 shores, sites were in zones in the midshore dominated by C. stellatus. The patterns of cyprid settlement and recruitment of early metamorphs in these zones did not reflect that of adult abundances. Patterns of mortality of the 2 species were determined from photographs. Mortality of recruits between 6 and 12 mo after settlement differed between the 2 zones. Mortality of C. montagui was higher than that of C. stellatus in the midshore zone, while the reverse trend was observed in the upper C. montagui-dominated zone, with C. stellatus recruits suffering higher rates of mortality than those of C. montagui. Post-settlement mortality, rather than larval supply, was therefore deemed to be the more significant factor in determining the characteristic patterns of these chthamalid species on SW Ireland shores.; RefNo. [ 409 ]

2003

We conducted a displacement experiment to determine the influence of sensory cues on homing of pelagic fish to fish aggregation devices (FADs). If pelagic fish use chemical cues to home to a FAD, and cues such as odours from fouling organisms and fish associated with the FAD only occur down-current, we hypothesised that fish released down-current from a FAD would return in higher proportions than fish released across-current. Coryphaena hippurus (n = 161) and Seriola lalandi (n = 31) were caught from January to May in 2000, 2001 and 2002 within 50 m of a FAD and displaced to release sites 20, 75, 275 or 500 m across- or down-current. Overall proportions of return of C. hippurus to FADs varied among the 3 yr, with returns highest in 2000 (48.3%), lowest in 2001 (7.6%) and intermediate in 2002 (33%). There was a strong relationship between abundance of C. hippurus around FADs and current speeds, possibly due to a behavioural shift towards closer association with FADs during strong currents. This may have affected the proportions of return in different years, as currents were strongest in 2000 (0.46 m s 1 ± 0.06), weakest in 2001 (0.13 m s 1 ± 0.02) and intermediate in 2002 (0.30 m s 1 ± 0.09). Both C. hippurus and S. lalandi returned in proportions significantly higher than could be expected if fish swam in a random direction from the point of release, indicating a directed homing behaviour. Returns from down- and across-current release sites were similar at all distances for C. hippurus and S. lalandi, providing no evidence to suggest that these species used only chemical cues to home to FADs. As fish returned from up to 275 m away, sensory processes other than vision and olfaction must operate. Sound or vibrations from associated fish and the FAD are possible cues for homing.; RefNo. [ 412 ]

2002

Aggregations of wild fish were counted around 9 floating sea-cage fish farms along a 300 km stretch of the Spanish coastline in the south-western Mediterranean Sea. Each fish farm cultivated Sparus aurata and Dicentrarchus labrax in 6 to 16 floating sea cages between 10 m and 7.4 km from the coast. During September and October 2001, assemblages of fish were counted on 3 separate days at each of 9 farms. Six 5 min rapid visual counts using SCUBA and covering 11 250 m3 were performed within each farm complex and at open water control sites 200 m distant from farms. Abundance (52 to 2837×), biomass (2.8 to 1126×) and number of species (1.6 to 14×) were greater in fish farm counts than control counts at all locations. Twenty-seven species were recorded at fish farms, with 2 families, Sparidae (12 species) and Carangidae (4 species), being particularly abundant. Over 85% of farm-associated fish were of adult size. Assemblages of wild fish differed greatly between farms separated by 10s to 100s of km, although there was some evidence to suggest that similar assemblages occur at farms separated by 100s of m to several km. abundance, biomass and number of species differed among fish farms, with all 3 variables negatively correlated with distance of farms from shore and positively correlated with size of farms. Limited variability of wild fish assemblages and abundance of the dominant taxa at each farm among times sampled indicated some degree of temporal stability on a scale of several weeks. Due to the strong aggregative effect of fish farms, possible residence of fishes for periods of weeks to months and the prohibition of fishing within farm leasehold areas, we suggest that coastal sea-cage fish farms may act as small (up to 160 000 m2), pelagic marine protected areas (MPAs). Furthermore, at farms where wild fish are abundant, ecological interactions that may influence both wild fish stocks and the impact of farms must be considered.; RefNo. [ 410 ]

2002

This article evaluates the environmental effectiveness and economic implications of the Kyoto Protocol (KP) after the Bonn agreement and the Marrakesh Accords. We will break it down into several components that correspond with major steps in the international process: pre-COP 6 version of the KP, with unrestricted international emissions trading but without sinks; withdrawal of the USA; and decisions on sinks in Bonn and Marrakesh. The Marrakesh Accords bring Annex-I emissions in 2010 without the USA at 0.5% under base-year levels; this corresponds to nearly 2% above the 1990-levels. The US withdrawal has by far the greatest impact in reducing the environmental effectiveness of the KP, whereas the impact of the decision on sinks is comparatively small. The US withdrawal also substantially reduces the permit demand and permit prices will drop dramatically. Hot air becomes increasingly dominant and may threaten the viability of the Kyoto Mechanisms (KM), especially in lower baseline (business-as-usual (BaU)) scenarios. Therefore, banking of hot air is of absolute importance to improve the environmental effectiveness of the protocol at moderately higher costs, while enhancing the development of a viable emission trading market. A strategy of curtailing and banking permit supply is also in the interest of the dominant seller, Russia.; RefNo. [ 414 ]

2003

Extensive investigations on macrozoobenthic communities of the Pechora Sea (SE Barents Sea), carried out between 1991 and 1995, indicate that it is rich in terms of diversity, with a total of 712 taxa observed (505 identified to species level). Biomass distribution of zoobenthos varied greatly (2.6 to 1200 g m 2 wet wt). Average values recorded for the offshore areas are high for an Arctic environment, implying that the influence of the large Pechora River may extend far into the offshore area. In addition, intensive sedimentation of organic matter during the retreat of the highly productive ice-edge zone in the summer may also contribute to the observed high biomass. A method combining the abundance and biomass values of species was used to calculate an index approximating the production of each species. This index was used to distinguish the different community types in the area. In the study area, 13 benthic community types were identified, of which 2 main types covered most of the offshore areas. The concentration of total organic carbon (TOC) in the sediment was shown to have a strong influence on the diversity of the benthic communities, while both TOC and water depth affected the distribution of communities and the feeding mode of the dominant species. A community type consisting of surface deposit-feeders is the most widely distributed type in the area. Suspension feeders, however, dominate an extensive shallow offshore area. Boreal-Arctic species show a marked predomination (68.9%) in the whole Pechora Sea. The share of Arctic species is greater in the northern part influenced by cold water currents, while boreal species predominate in areas affected by warmer coastal waters. These observations indicate that the Pechora Sea functions as a transitional zone between boreal and Arctic biogeographic regions.; RefNo. [ 415 ]

2004

This study reports the response of snapper Pagrus auratus to the establishment of notake status in a marine reserve around the Poor Knights Islands in northeastern New Zealand. The Poor Knights and 2 reference locations, Cape Brett and the Mokohinau Islands, were sampled biannually for 4 yr using baited underwater video (BUV). Following the implementation of full marine reserve status at the Poor Knights in October 1998, snapper showed significant increases in abundance and biomass relative to fished control locations. This was particularly apparent for large snapper (>270 mm), whose numbers increased rapidly to levels 7.4 times higher in the final survey compared to the initial pre-reserve survey, and total snapper biomass increased by 818%. There was no significant increase in the abundance, biomass or size of snapper at the reference locations over this time. There was a strong seasonal trend in snapper abundance, with higher numbers in autumn (March/April) compared to spring (September/October). The daily batch fecundity was 11 to 18 times higher at the Poor Knights compared to the reference locations. Once fishing ceased in previously partially protected areas, a rapid recovery of snapper ensued, suggesting that partial fishing regulations are ineffective for protecting targeted species. The speed of increase in snapper density resulted from the immigration of adult fish into the reserve, rather than from within-reserve recruitment.; RefNo. [ 417 ]

1991

; RefNo. [ 1907 ]

1993

; RefNo. [ 1911 ]

1995

; RefNo. [ 1908 ]

1996

; RefNo. [ 1909 ]

1997

; RefNo. [ 1910 ]

2003

An examination of the trophic status of a cryptobenthic reef fish community from the central Great Barrier Reef was carried out to evaluate the potential role of cryptobenthic fishes in coral reef ecosystems. Using frequency of occurrence data, dietary analyses revealed a diverse range of trophic groups, although detritivory (in 10 out of 16 species and 39.3% of individuals) and carnivory (5 of 16 species and 40.5% of individuals) clearly dominate as trophic modes. Herbivory (1 species; 2.4% of individuals) is only a minor component in the community trophic structure. Of the 18 dietary categories identified, detritus and copepods were the only constituents represented in all 16 species examined. Although the degree of dietary specialization varied among taxa, the 2 most abundant species, Eviota queenslandica and Istigobius goldmanni, utilised the broadest range of dietary items. Morphology reflected the trophic partitioning among fishes: carnivores were invariably <28 mm total length (TL) and had gut-length ratios (GLRs) of <0.5; detritivores were all >38 mm TL with GLRs generally exceeding >1.0. The trophic composition and numerical strength of the cryptobenthic fish fauna suggests that cryptobenthic reef fishes have the potential to make a significant contribution to reef trophodynamics along a number of trophic pathways. This prompts a re-evaluation of the roles of reef fishes in the functioning of coral reefs, particularly those related to the recycling of primary production through detrital pathways.; RefNo. [ 418 ]

2000

; RefNo. [ 1913 ]

6

2000

Multicriteria evaluation used to solve coastal and marine resource use conflicts used to support decision making in Tanzania. ; RefNo. [ 2066 ]

2003

The exchange of propagules or mobile adults between isolated habitat patches is of critical importance for some types of preserves, especially for species that cannot propagate locally. In the marine realm, the role of planktonic dispersal in maintaining viable local populations can be tested by examining life-history traits of species that colonize (or do not colonize) isolated habitat patches. We compared the abundances of benthic species on an exposed rocky jetty surrounded by dissimilar habitats on the coast of Washington (U.S.A.) with those of species at distant bedrock sites within potential source areas. Despite its isolation, the jetty lacked only a small proportion of the potential algal species; these absences could result from the 40- to 100-km distances to larger source areas or from subtle habitat differences at the jetty. Coralline algae are expected to be poor dispersers, both because propagules are short-lived and because adults are unlikely to float. These algae were absent on the study jetty, although they occur on other isolated jetties on this coast. Shortterm transplant experiments indicated that corallines can survive locally once they colonize. Few animals were absent; one was a chiton that settles and feeds on coralline algae. Animals with obligate dispersal of offspring were abundant on the jetty despite their inability to propagate locally and despite dilution of larvae dispersing in the plankton from distant sources. Conversely, some animal species with no planktonic phase were also present; thus, organisms with a wide range of life-history traits can persist at this distant and small patch of suitable habitat. Isolation along this shoreline did not eliminate either poor dispersers or obligate dispersers.; RefNo. [ 420 ]

2003

The relationship between tissue weights and haemolymph copper levels in field collected European lobsters Homarus gammarus was investigated to assess whether haemolymph copper concentration can be used to reliably determine nutritional condition in lobsters. During the moult cycle, the soft tissue weight (mostly muscle) increased concomitantly with a decrease in haemolymph weight while exoskeleton weight increased from postmoult to intermoult. Haemolymph copper concentration gradually increased from postmoult to premoult with a range of 29.7 (Stage B) to 163.5 µg g 1 wet weight (ww) (Stage D0). Our measurements suggest that the main processes that increase haemolymph copper concentration is a reduction in haemolymph space and an increase in haemolymph copper content, indicating synthesis of new haemocyanin for the oxygen supply of growing tissues. During the moult cycle, haemolymph copper content was proportional to soft tissue mass and amounted to 43.6 µg Cu g 1 of soft-tissue ww (95% confidence limits = 35.5 and 51.6 µg g 1). Models for estimating soft-tissue and haemolymph wet weights from the haemolymph copper concentration and moult stage are presented. The use of haemolymph copper concentration as an index of nutritional condition reflecting tissue growth and food quantity and quality is validated.; RefNo. [ 421 ]

2000

An assessment of the status of production and consumption of tilapia in five Asian countries was made to provide a baseline for the analysis of the potential benefits of the introduction of a new, improved strain of Nile tilapia. This paper provides a comparative analysis of the profile of tilapia farmers and their farming systems, costs, returns and productivity of tilapia production, and fish consumption patterns in Bangladesh, China, the Philippines, Thailand and Vietnam, using data from household surveys conducted by ICLARM and its partners in 1995-96. Farmers grow tilapia in varied farming environments depending on the nature of their farmland and on their investment capacity. Tilapia is cultured mainly in semi-intensive systems on small and medium farms. The average farm size (pond area) of the surveyed pond operators varies from 0.60 ha (0.05 ha) in Bangladesh to 4.91 ha (1.56 ha) in the Philippines. In Asia, tilapia farming is very profitable. The productivity, costs of production and profitability of tilapia farms vary considerably among countries and production environments. Tilapia farming is becoming increasingly commercial with a large proportion of production is marketed. Tilapia is consumed mainly by poor consumers because of its relatively low price compared to other fish species.; RefNo. [ 1917 ]

2000

The determination of efficient production levels for tilapia growout operations, given the existing technology, is necessary to examine alternative options to increase productivity. If farmers are not making efficient use of existing technologies, improving their efficiency is usually more costeffective than introducing new technology. This paper examines the technical efficiency of tilapia growout operations in ponds in the Philippines. A stochastic production frontier with technical inefficiency effects model is specified and estimated. The estimated mean technical efficiency of the 78 farmers in the sample is 83%. Total farm area, education and age of the farmers are some of the factors affecting technical efficiency. Those with a larger farm area, higher age and a higher educational level attain higher technical efficiency. As growers in the Philippines have attained a high level of technical efficiency under existing technology, the introduction of new technology is a key to raising the productivity of tilapia farming. The genetically improved farmed tilapia (GIFT) strain that has recently become available provides a promising new technology to raise the productivity and output of tilapia farming.; RefNo. [ 1916 ]

2000

An analysis of fish consumption patterns, and how they are likely to change as income and relative price changes, is required to assess the welfare impact of technological and policy changes in the fisheries and aquaculture sectors. This analysis is based on a matrix of price and income elasticities of demand for fish by type, as fish is a heterogeneous product and consumption patterns may differ by type of product. This paper presents estimates of fish demand elasticities by fish type for Bangladesh, using individual household expenditure data (5,667 households) collected by the Bangladesh Bureau of Statistics in 1988/89. It uses a multistage budgeting framework that estimates a demand function for food in the first stage, a demand function for fish (as a group) in the second stage and a set of demand functions for fish by type in the third stage. Estimated demand elasticities vary across fish type and across income class. Among the various types of fish, carp have the highest (in absolute terms) own-price elasticity. Income elasticities of all fish types consistently fall with the increase in per capita expenditure level of households, but none of the fish types become an inferior good at the highest income quartile. Dried fish has the lowest income elasticities for the richest quartile of the population.; RefNo. [ 1919 ]

2000

; RefNo. [ 1922 ]

2000

; RefNo. [ 1923 ]

2001

; RefNo. [ 1925 ]

2001

; RefNo. [ 1924 ]

2004

; RefNo. [ 1921 ]

2004

; RefNo. [ 1020 ]

2003

Although the global community has recognized the importance of environment, gender, and population linkages in the Rio, Cairo, and Beijing action plans during the last decade, there has not been enough collaborative work by integrated coastal management (ICM), gender, and population organizations. The costs of not making these linkages are steep and immediate action is needed. By understanding these linkages and forming new partnerships, coastal managers can improve governance and planning, support more sustainable resource use/management, build capacity for ICM, and attract new funding sources. A proposed action agenda makes recommendations for national governments, civil society, donors, projects/programs, and researchers.; RefNo. [ 422 ]

2002

The mass bleaching of corals that occurred on the Great Barrier Reef (GBR), Australia, in early 1998 was one of the most severe on record. There is surprisingly little known about the fate of bleached corals, which may either regain their zooxanthellae and recover, or may die, in which case they generally become overgrown by algae. The nature and dynamics of this algal overgrowth and its effects on the corals are not well understood. In this study we describe the composition and time-course of algal recruitment on bleached corals, and the possible roles of that recruitment on the fate of the corals, at 2 inshore reefs of the GBR. Massive Porites spp. corals were selected with different degrees of bleaching, and the cover of live coral tissue, and relative abundance and composition of algal recruitment were followed in small plots over 2.5 yr. The bleaching disturbance precipitated a major shift in abundance of corals and algae. All dead corals were colonised by a diverse community of epilithic and endolithic algae, the nature and composition of which was variable and related to the stage of the succession, the severity of bleaching and reef location. Quantitative data on species composition of colonising algae are given, and are apparently the first such data. The epilithic algal assemblage was initially dominated by diatoms and blue-green algae, but rapidly shifted to an assemblage dominated by upright and branched filamentous algae (e.g. Polysiphonia spp., Hincksia mitchelliae, Sphacelaria spp.) and, on 1 reef, fleshy macroalgae (e.g. Asparagopsis taxiformis, Sargassum spp.). Endolithic algal assemblages were largely dominated by the green algae Ostreobium spp. and cyanobacteria. Algal colonisation on clay settlement plates was distinctly different from that on dead coral skeleton. Algal colonisation was not the initial cause of coral tissue mortality, although it may have contributed to the failure of corals to recover after bleaching. The results thus emphasise the role of coral disturbances and substratum availability in controlling abundance of coral reef benthic algae, in contrast to ‘bottom-up’ and ‘top-down’ views that assume changes in algal abundance are the major cause of changes in coral abundance. The considerable variability in the outcome of bleaching damage and algal colonisation demonstrates the potential for major and variable effects on the recovery of coral populations, with implications for the future reef status.; RefNo. [ 423 ]

1999

Plankton smaples were collected from 4 container ships which took on ballast water in Manzanillo, Mexico, and discharged it 21 d later in Hong Kong, China. As expected, the lack of light during transport in ballast anks was inimical to the survival of many autotrophic (phytoplankton) species. After 21 d at sea, few of the dinoflagellate and diatom species taken on in Manzanillo Harbour were alive in the ballast water delivered to Hong Kong. In addition, 5 ships from Manzanillo which reballasted with open ocean water were sampled. To assess the effectiveness of mid-ocean exchange, the mean number of diatoms and dinoflagellates in the coastal ballast water (436 cells 1-1) delivered to Hong Kong. Open ocean exchange of ballast water (reballasting) was 48% effective in reducing diatom and dinoflagellate abundance. When we compared the Manzanillo study with our previous study of ships from Oakland, California, we concluded that the older container ships such as those coming from Manzanillo were not as effective in getting rid of diatom and dinoflagellate species as the newer container ships. This is probably because the reballasting design of the older ships is not as efficient in removing the water and sediments located near the bottom of the ballast tanks. This bottom water is associated with a large number if resting cysts and cells.; RefNo. [ 958 ]

1999

; RefNo. [ 1926 ]

2002

; RefNo. [ 424 ]

2002

Carapace length growth data were obtained from 197 hawksbill turtles Eretmochelys imbricata which were marked and recaptured from 1992 to 2000 at feeding grounds of Mona and Monito Islands, Puerto Rico. Straight-line carapace length (SCL) upon initial capture ranged from 20.0 to 84.5 cm. SCL growth rates ranged from 0.59 to 9.08 cm yr 1, were non-monotonic, and averaged highest in turtles measuring 34 to 35 cm. Somatic growth rates varied by site within the study area, with turtles from the aggregation at Monito Island growing on average 2.1 times faster than residents of Mona Island habitats. Aggregation density and body condition index (body mass SCL 3) were also highest at Monito Island. Hawksbills recruiting to Monito Island at 23 cm SCL are expected to reach maturity less than 14.7 yr later. Growth rates in the turtles studied are similar to those reported for other Caribbean localities, but faster than hawksbills of the southern Great Barrier Reef, Australia. Hawksbills appear capable of utilizing habitats of widely varying quality, with prey abundance exerting a strong effect on somatic growth rates.; RefNo. [ 425 ]

2001

This paper seeks to improve the practice of vulnerability assessment for food security purposes by addressing long-standing issues that have hampered the development of both theory and methods. In food security contexts, vulnerability is usually defined in relation to an outcome, such as hunger, food insecurity or famine. This precludes employing the concept for the more specific task of evaluating the susceptibility of a population to explicitly-identified exogenous events or shocks that could lead to these outcomes. This lack of specificity has clouded interpretation of causal factors of food insecurity and famine. Alternatively, in a widely-applied framework for disaster risk assessment, the concept of vulnerability serves the more specific purpose of identifying characteristics of population groups or other elements that make them more or less susceptible to experiencing damage when exposed to particular hazards or shocks. Risks of negative outcomes are created by the combination of hazards and vulnerability, and vulnerability is defined by its relation to hazards rather than directly in relation to the outcomes themselves. The result has been an easier and more transparent translation of concepts into practice. That this latter formulation can also be applied in the food security context is illustrated through an analysis of food security risks in Tanzania. The analysis identifies economic alternatives households can exercise to meet their minimum annual food requirements. Exogenous threats or shocks that can suppress or eliminate particular alternatives exercised by different groups are identified as a means of assessing households' vulnerability and consequently their risks of becoming food insecure, or falling below the minimum threshold.; RefNo. [ 1927 ]

2001

; RefNo. [ 1928 ]

2003

Early benthic stages of the snow crab Chionoecetes opilio are presumed to be very stenothermic; they may be sensitive to environmental changes and thus affect subsequent adult population abundance. Little quantitative information exists on the habitat preferences of juvenile snow crabs to verify this. We determined the distribution pattern of juveniles in the NW Gulf of St. Lawrence, Canada, in May 2001. Temperature and substratum preferences were evaluated through controlled laboratory experiments in aquaria that had a temperature gradient and offered a choice of 3 sediment types (mud, sand and gravel). In general, early benthic stages displayed sharp size-/agedependent distributions and habitat preferences. In the field, juveniles from Instars I to IV were scarce in the core of the cold intermediate layer (CIL) but present immediately above and below this layer, where temperatures were >0°C. Older juveniles (Instars VI to VIII) were concentrated at depths <27 m above the CIL. An analysis of historical data from 1989 to 2000 supported this depthdistribution pattern. Temperature preference in the laboratory shifted from a cold (0.0 to 1.5°C) to a warmer temperature range (1.0 to 4.5°C) between Instars III and V. Juveniles preferred mud in general. Early juvenile instars could represent the weakest link in the snow crab’s life cycle because of their narrow habitat requirements.; RefNo. [ 426 ]

2001

; RefNo. [ 1929 ]

2001

Mangroves play an important role in the biogeochemical cycles of coastal and marine ecosystems in the tropics. However, few studies have been carried out to clarify the extent to which mangroves represent a source of nutrients and organic matter for adjacent coastal waters or function, alternatively, as a sink. Here we present results of a long-term nutrient-flux study in one of the world's largest mangrove areas in North Brazil. These are up to now the only published nutrient flux data for Brazilian mangroves, and constitute one of the most comprehensive data sets in this field. Throughout 36 tidal cycles in the course of 1 yr, fluxes of organic carbon (DOC, POC), nitrogen (DON, PON) and dissolved inorganic nutrients (N, Si, P compounds) were determined in a tidal creek connecting a clearly defined area of mangroves (2.2 km2) with the Caeté Estuary. Additionally, a qualitative whole-estuary approach was applied (190 km2 of mangroves). Both methods revealed an outwelling of dissolved organic matter and nutrients from the mangroves, exceeding considerably that of mangroves in other regions of the world. This net export was (annual average, mmol [m2 mangrove] 1 d 1) DOC 10, DON 0.7, ammonium 0.2, silicate 6 and phosphate 0.02. Nitrate fluxes were comparatively low. Silicate and phosphate were exported mainly during the dry season and DON during the rainy season. DOC showed no seasonal trend. Especially ammonium fluxes presented strong asymmetries between day and night. Although only ~6% of the fluvial catchment area is covered by mangroves, their nutrient export exceeded that of the hinterland. The annual export from mangroves on a regional scale (6700 km2 from 0° S, 50°W to 3° S, 42° W) was estimated (mol yr 1) as DOC 30 ×109, DON 2 ×109, ammonium 0.4 ×109, silicate 15 ×109 and phosphate 0.04 ×109. Compared with the Amazon River discharge these fluxes are low (1 to 3% of the Amazon fluxes). The nutrient cycles of coastal marine environments are probably mangrove-dominated southeast of the Amazon Estuary, contrary to the river-dominated cycles to the northwest.; RefNo. [ 427 ]

2003

Phytoplankton pigments were measured using HPLC during non-ENSO conditions in mid-summer along a South Pacific transect from 67° S to the equator along 170°W. Highest concentrations of chlorophyll a (chl a) occurred in the Polar and the Subtropical Fronts (PF and STF, respectively) with concentrations exceeding 500 ng l 1. In the STF, there was a distinct subsurface chl a maximum (SCM) at 40 m, which gradually deepened northward to 120 m in the Subtropical Convergence Zone. Northwards, the SCM shoaled to about 30 m in the Equatorial Zone (EZ). Relatively high concentrations of fucoxanthin and 19’-butanoyloxyfucoxanthin occurred in the nutrient-rich waters south of the Subantarctic Front, and CHEMTAX analyses indicated that diatoms, chrysophytes, pelagophytes, and haptophytes dominated the phytoplankton assemblage. Northward of the PF to the STF, where silicate concentrations were <1 µM, pelagophytes and coccolithophorids dominated the water column; diatoms were virtually absent, and Phaeocystis, prasinophytes, cryptophytes, and chlorophytes contributed significantly to the total algal biomass. Phaeocystis populations were dominant at or below the 1% light level. In the South Pacific Gyre (SPG), Synechococcus (Syn) and Prochlorococcus (Pro) were major components of the phytoplankton assemblage with Pro dominant as indicated by both flow cytometry and by the ratio of divinyl chl a:total chl a (0.43 ± 0.07). Photoacclimation by Pro in the SPG was pronounced, with a higher average divinyl chl a per cell ratio in the SCM (1.1) relative to values (0.1) in the upper waters (0 to 100 m). Primary production rates exceeding 1 µg C l 1 h 1 occurred at the surface in the STF. Surface primary production rates were generally <0.4 µg C l 1 h 1 across the SPG, but exceeded 1.4 µg C l 1 h 1 at the equator. In the EZ, Pro dominated the phytoplankton assemblage, but Phaeocystis and prasinophytes were also major constituents of the assemblage.; RefNo. [ 428 ]

2003

Beach erosion presents a hazard to coastal tourism facilities, which provide the main economic thrust for most Caribbean small islands (CSIs). Ad hoc approaches to addressing this problem have given way to the integrated coastal zone management (ICZM) approach, which recommends data collection, analysis of coastal processes, and assessment of impacts. UNESCO's Coast and Beach Stability in the Caribbean (COSALC) project has provided most CSIs with an opportunity to monitor their beaches and collect over 10 years of data. Research has been directed at integrating these data with geographic information systems (GIS) and other information technologies to develop a prototype beach analysis and management system (BAMS) for CSIs. This article presents the results of phase I development of this effort, which includes the development of tools for integrating spatial and non-spatial coastal data, estimating long-term beach erosion/accretion and sand volume change trends at individual beaches, identifying erosion-sensitive beaches, and mapping beach erosion hazards. The Southeast Peninsula, St. Kitts, is used as a case study to develop these tools and demonstrate system functionality.; RefNo. [ 1903 ]

2001

The vertical distribution of veligers, pediveligers and post-larvae of the mussel Mytilus edulis L. was examined in Kandalakshsky Gulf (White Sea), Russia. Plankton samples showed that about 65% of all planktonic larvae were collected from a depth of 1.5 to 3 m. Maximum numbers of veligers were found at 3 m, immediately above the thermocline. The vertical distribution of veligers was stable throughout the study. The vertical distribution of pediveligers, however, varied over time. Pediveligers were mostly observed at 3 m before settlement peaked while they migrated closer to the water surface (1.5 m) during the settlement period. Pediveliger concentrations were correlated positively with small phytoplanktonic cell (<150 µm) and dissolved organic matter concentrations before settlement peaked. Both factors were correlated negatively with pediveliger concentrations during the settlement period. Newly settled post-larvae mainly colonized settlement panels situated at 1.5 m below the water surface (ca 70% of total post-larvae abundance). These results support the hypothesis that planktonic larvae of M. edulis change their vertical distribution in relation to larval stages, which in turn, increases settlement success.; RefNo. [ 429 ]

2004

In the last two decades there has been a broad literature within the field of fisheries economics and other social sciences about the usefulness of delegating management responsibilities to resource users (co-management). The line of argument of these proposals is that a greater user involvement in designing and implementing management policies will help to obtain the economic efficiency in exploiting fishing resources. In this article, we will analyse in depth the factors and requirements that make co-management structures promote efficient allocation of resources. Taking this analysis as a base, we will focus on the economic performance of the Spanish fleet in the Community waters at Grand Sole and the process of management decentralisation that this fishery has undergone in the last years.; RefNo. [ 430 ]

2004

Studies of competition in benthic marine organisms have focused on sessile filter-feeders and mobile grazers, to the neglect of mobile filter-feeders, including porcelain crabs. The present study demonstrates intraspecific competition in Petrolisthes cinctipes (Randall) (Porcellanidae: Anomura). P. cinctipes settles gregariously and lives in high-density, multi-size aggregations. Studies of gregarious species often identify the benefits of aggregation without quantifying the concomitant costs; this study quantifies these costs. In field and laboratory experiments, P. cinctipes growth rates declined with increasing conspecific density and this decline was more severe for smaller individuals. P. cinctipes also fed less frequently at high density, and this effect was more pronounced for smaller individuals. This indicates that size-dependent agonistic interactions in P. cinctipes have effects on feeding rate and, ultimately, on growth rate. Resource levels were manipulated in laboratory experiments by using filtered and unfiltered seawater. The effect of resource level also depended on size: smaller crabs were more sensitive to changes in food level. Thus, conspecific density and food availability both affected growth rate in a size-dependent manner. Therefore, the costs of aggregation are more extreme for recruits than for adult crabs; recruits suffer more from competition, but may also benefit more if conspecific cueing results in settlement to sites with higher food availability.; RefNo. [ 434 ]

1991

; RefNo. [ 1932 ]

2000

; RefNo. [ 1933 ]

2003

; RefNo. [ 435 ]

2003

A process-oriented modelling study is used to examine biophysical control of the distribution of particulate organic matter, or seston, in a tidal embayment with shellfish aquaculture. The focus is on the spatio-temporal dynamics of seston as influenced by the processes of water motion and mixing, internal primary production of seston, and the clearance of the water volume by the grazing activity of a large bivalve population. A fluid dynamical framework is used wherein seston is treated as a non-conservative tracer in an advection–diffusion equation with additional source and sink terms. An idealized one-dimensional (1D) tidal inlet is first used to examine the sensitivity of tidally averaged seston concentration and flux to variations in tidal transport, internal production, and shellfish grazing. This model is then applied to Tracadie Bay, a tidal inlet off Canada's east coast, to illustrate temporal variability in seston level and flux for a more complex tidal regime. The results of this study suggest that seston flux is mainly under physical control, with its spatial distribution set by tidal transport processes. Seston level, on the other hand, is affected by both grazing and production, with the magnitude of these effects being spatially dependent as dictated by the tidal currents. Grazing and production effects on seston are most pronounced near the head of the inlet, which depends on internal, or local, processes. More seaward areas are buffered against these changes due the advection of seston from the adjacent open ocean. Variation in the spatial distribution of grazing activity demonstrates how local processes have inlet-wide effects. The temporal response of the inlet to tidal changes in the incoming far-field seston flux resembles a low-pass filter with a phase lag; temporal changes in seston at the head of the inlet are highly dampened and occur later than the forcing flux at the mouth. The implications of these results for marine bivalve aquaculture in terms of growth potential (seston level) and carrying capacity (seston flux) are discussed.; RefNo. [ 1937 ]

6

2000

This paper makes an analysis of the state of the art of web-GIS tools and their application to environmental modelling and decision making process.; RefNo. [ 2067 ]

2002

The only procedure used frequently to reduce the risk of invasion by ballast-mediated biota is open-ocean exchange of ballast water, a procedure in which vessels release coastal water and replace it with oceanic water. Limited information exists concerning the effects of transport upon the aquatic microbial community throughout transit and following open-ocean exchange. A transoceanic voyage aboard a commercial bulk carrier afforded us the opportunity to sample the microbial community in exchanged and unexchanged ballast-water holds during the journey from Hadera, Israel to Baltimore, USA. Five days following the exchange process, all microbial metrics tested (i.e. bacteria concentration, virus-like particle density, chl a and phaeopigment concentration, and microbial biomass) had decreased 1.6- to 34-fold from initial values. With respect to microbial measures, no significant differences existed between exchanged and unexchanged holds on Day 15, the final day of sampling. We stress that we quantified differences in total microorganism abundance and biomass, not species composition, and more research is necessary to determine the changes that nonindigenous microorganisms, including potential pathogens, may effect in receiving waters.; RefNo. [ 436 ]

2000

Satellite images show large volumes of cold shelf water lying offshore of the Scotian Shelf in the spring of 1991. The seaward boundary of the shelf water was highly convoluted and indicated that shelf water was being entrained offshore into the slope water region by warm-core Gulf Stream eddies. An interdisciplinary field study of this region in late April and May found relatively high concentrations of redfish (Sebastes spp.) larvae in the entrained shelf waters, 100 km offshore of the shelf. Historical data indicate that these larvae were most likely spawned along the edge of the Scotian Shelf. Based on weight-at-length relationships, the larvae off the shelf were in poorer condition than those on the shelf. We suggest the larvae swept offshore eventually die, a result consistent with earlier studies that entrainment by Gulf Stream eddies negatively affects redfish recruitment.; RefNo. [ 1936 ]

2002

Previous studies have shown a genetic interface (MPI, GPI loci) between 2 populations of the barnacle Semibalanus balanoides in the vicinity of the Miramichi Estuary, New Brunswick, in the Gulf of St. Lawrence. We examined whether gene flow between these 2 adjacent populations was restricted by larval dispersal. We determined the distribution pattern of Semibalanus balanoides planktonic larvae. Current velocity and direction, larval settlement and genetic structure of recruits were measured. Physical results and genotype distribution for MPI support the larval exchange hypothesis (north to south). The presence of another allele, GPI*4, suggests a substantial contribution of another population, possibly from the subtidal zone, to the larval pool. In accordance with previous studies, our results suggest strong selection on newly settled spat in the intertidal zone.; RefNo. [ 437 ]

1999

Comaprison of the amount and nature of suspended material within Posidonia oceanica canopies, in 6 meadows in the Spanish Mediterranean coast differing in extent and depth, with those in the overlying waters showed the canopies to be significantly enriched in particulate organic carbon, nitrogen and phosphorous relative to the overlying waters (on average, 87, 34 and 54% more C, N and P, respectively). Biovolume of detritus (both angiosperm-derived and plankton-derived) was large, particularly within seagrass canopies, where it dominated the seston pool (about 5-fold greater biovolume than that of living particles), compared to a roughly equal biovolume of detrital and living particles in the particle pools in the overlying waters. The dominance of detrital particles was further reflected in the high C/N and C/P ratios of the suspended materials (median atomic C:N:P ratios = 492:40.9:1 and 596:45:1 of the materials suspended within the canopy and in the overlying waters, respectively), which were intermediate between those of living plankton and P. oceanica. The relative enrichment of P. oceanica canopies by particles tended to be greatest when particle loads in the overlying waters were small, suggesting that the effect of seagrasses as traps of particles is enhanced in particle-poor waters. The results obtained support the hypothesis that the water within seagrass canopies is enriched by (mostly detrital) particles, particularly particle-poor waters. This suggests that seagrasses not only contribute a substantial fraction of the particle themselves, but also act as sinks of particles.; RefNo. [ 959 ]

2000

The occurrence of competitive interactions among the seagrass species present in a multispecific SE Asian seagrass species meadow was tested by the cumulative removal of shoots of an increasing number of seagrass species from the meadow in order of decreasing and increasing resource requirements for plant growth. The removal of shoots of the dominant species Thalassia hemprichii had very few effects on shoot size, shoot density and leaf area index of the extant seagrass species. The shoot density of Enhalus acoroides decreased when T. hemprichii shoots were removed, but that of Syringodium isoetifolium increased when the shoots of all the species with higher resource requirements than itself were removed from the experimental plots. The size of Halophila ovalis shoots decreased by 30% when both T. hemprichii and E. acoroides shoots were removed from the plots. The shoot density of T. hemprichii increased only when the shoots of all the accompanying species were removed from the plots. The results show that species interactions in this multispecific seagrass meadow are asymmetric. The elucidation of the nature of the interactions among seagrass species provides a key to understanding the maintenance of the high biodiversity asnd production that characterizes pristine SE Asian coastal ecosystems.; RefNo. [ 966 ]

1998

The root and rhizome biomass of the seagrass species present in 3 mixed and 2 monospecific meadows representative of different floras (Spanish Mediterranean, Mexican Caribbean, Kenyan coast, and the South China Sea off the Philipines) was examined to test a simple approach based in age determinations to estimate root production. The thickness of roots was scaled to the thinckness of seagrass rhizomes, (r - 0.92, p<0.001). Root and rhizome biomass were high (>100 and >200 g DW m-2, respectively) for the mixed meadows examined; these belowground structures had a projected surface area often exceeding 1 m2 m-1 when roots and rhizomes were considered together, and they formed a dense web of root material comprising several hundred meters per square meter. Belowground biomass showed considerable vertical stratification within the sediments, with a tendency for the larger species to extend deeper into the sediments than smaller ones. This tendency for segregation should reduce the potential interspecific competition for sediment resources, which is likely to be greater in the uppermost layers, where the belowground biomass is more evenly distributed among species. The rate of adventitious root production on vertical shoots varied from species that produced a root on almost every node to species that produced 1 adventitous root for every 10 nodes. Root production - both on horizontal rhizomes and vertical shoots - was substantial, with the combined root production approaching, or exceeding, 1000 g DW m-2. The resulting root turnover was quite high, with most values ranging between 2 and 10 yr-1, indicative of characteristic turnover of months for the root compartment. The setimates of root production derived here often exceed those of rhizome production and reach values comparable to leaf production cl;early demonstrating that root production is an important component (up to 50%) of total seagrass production.; RefNo. [ 960 ]

2000

The hypothesis that increasing nutrient supply increases the biomass of autotrophs proportionately more than the biomass of heterotrophs was tested by increasing (0, 1-, 2-, 4-, 8-, and 16- fold over the background loading of 5 mmol N m 2 d 1, 1.6 mmol Si m 2 d 1, and 0.25 mmol P m 2 d 1) the addition of nutrients to large (33 000 l) mesocosm units enclosing an oligotrophic coastal Mediterranean planktonic community. Autotrophic plankton biomass increased 50-fold along the range of nutrient inputs, whereas heterotrophic biomass increased only 10-fold. Heterotrophic biomass increased as the 1 5 power of the increase in the biomass of autotrophs, implying that the ratio of heterotroph to autotroph biomass (HB/AB ratio) declined rapidly as the biomass of autotrophs increases with increasing nutrient inputs. The biomass distribution within the community shifted from an ‘inverted pyramid’ distribution, involving greater biomass of heterotrophs than that of autotrophs, at low nutrient inputs, to the conventional ‘upward’ pyramid pattern, where the biomass of autotrophs exceeds that of consumers, at the highest nutrient inputs. This shift stabilized after 4 d, and the pyramids remained quite constant for the rest of the experiment. The experimental test presented supports the hypothesis that the relative biomass distribution between heterotrophs and autotrophs is regulated by nutrient supply.; RefNo. [ 438 ]

2002

Despite the intense impact of diseases on tropical marine communities, little is known about mechanisms of resistance to disease or the role of disease as a selective factor in these communities. Spatial variation in chemical resistance of Gorgonia ventalina (sea fan coral) to the fungus Aspergillus sydowii was investigated by sampling G. ventalina populations in the Florida Keys, USA, and San Salvador, Bahamas. A. sydowii is the causative agent in aspergillosis, a fungal disease affecting G. ventalina throughout the Caribbean. Using field census and experimental inoculation, this study examines if sea fan chemical extracts provide resistance to disease caused by A. sydowii and the potential role of disease as a selective force in shaping the chemical defenses of sea fan populations. Chemical resistance against A. sydowii was assessed with a fungal growth assay. Higher anti-fungal activity of small versus large fans observed in field sampling and increased disease severity in mature versus young fans in inoculation studies support the hypothesis that resistance decreases with increasing fan age. This result is also consistent with patterns predicted by the optimal defense theory and growth-differentiation balance hypotheses in plant studies. Anti-fungal activity of large sea fans increased upon inoculation, consistent with the hypothesis of inducible resistance. Anti-fungal activity of sea fan extracts from the Florida Keys and Bahamas did vary significantly with site and was negatively correlated with fan height and extract concentration (mg extract per g dry coral weight). Anti-fungal activity did not correlate significantly with disease status in a multiple regression model. The mean anti-fungal activity of sea fans varied significantly among Florida Keys but not among San Salvador sites, nor between Florida Keys and San Salvador sites. Disease pressure was not correlated with anti-fungal activity across sites, as would be expected under a simple resistance-selection model. A simple mean resistance-selection model may not be appropriate in relatively open marine systems in which environmental induction may obscure natural selection. However, the coefficient of variation in anti-fungal activity among sites is negatively correlated with disease pressure, consistent with the hypothesis that A. sydowii imposes detectable directional selection and eliminates susceptible individuals from sites with high disease pressure.; RefNo. [ 439 ]

2004

; RefNo. [ 1018 ]

2001

Benthic vegetation plays an important role in determining the fate of nitrogen inputs to estuaries, thus influencing their degree of eutrophication. This study investigated the role of benthic vegetation as a sink for anthropogenic inputs of nitrate and ammonium into Wilson Inlet, a mesotrophic estuary in southwestern Australia. The dominant aquatic angiosperm in Wilson Inlet is Ruppia megacarpa Mason. We examined: (1) whether R. megacarpa leaves remove inorganic N (as nitrate and/or ammonium) from the water column, despite the presence of a layer of epiphytes; (2) whether the macrophyte and its epiphytes are equally important in the removal of inorganic N from the water column; and (3) whether inorganic N taken up by leaves is translocated to other plant parts. We added inorganic 15N nitrogen, as ammonium, nitrate, or both, to aquaria containing intact cores of sediment, R. megacarpa and attached epiphytes, and unfiltered estuary water. We measured depletion of nitrogen species from the water column and incorporation of 15N into components of the core. Epiphytes removed more nitrate and ammonium from the water column than R. megacarpa, despite having 25% of the biomass of the macrophyte. Maximum rates of nitrate uptake were 4.6 (for epiphytes) and 2.0 µmol h 1 g 1 DW (for R. megacarpa), and maximium rates of ammonium uptake were 35 (for epiphytes) and 23 µmol h 1 g 1 DW (for R. megacarpa). The presence of ammonium reduced rates of nitrate uptake, indicating that benthic vegetation prefers ammonium as a nitrogen source. Using mass spectrometry, we recovered between 37 and 45% of the added 15N nitrogen. The remainder was transformed to either organic nitrogen in the water column by algal epiphytes or nitrogen gas via coupled nitrification-denitrification in the sediment. This experiment indicates ecosystem-scale responses to dissolved inorganic nitrogen which would not have been observable from experiments conducted with isolated plants. Benthic vegetation in Wilson Inlet removes nitrate and ammonium quickly from the water column. Depending on water mixing, it may reduce transient increases in the concentration of these nutrients to background levels within 30 h. This process may be responsible for maintaining low water-column concentrations and reducing the likelihood of algal blooms.; RefNo. [ 440 ]

2001

Small, grazing invertebrates often benefit seagrasses by cropping their epiphytic algal competitors. Yet predictive relations between grazer abundance and seagrass performance are elusive, in significant part because of poorly understood diversity in mesograzer feeding biology. We conducted experiments in eelgrass Zostera marina microcosms to explore how differences in feeding between 2 common grazing amphipod taxa affected accumulation and species composition of epiphytes on eelgrass, as well as amphipod population growth, competition and production, over a 4-week period in summer. Gammarus mucronatus and ampithoids (a mixture of Cymadusa compta and Ampithoe longimana) were stocked, singly and in combination, along with a grazer-free control treatment. Amphipod population growth rates indicated that the 2 taxa competed for a common limiting resource, presumably periphyton, which was essentially eliminated in all grazer treatments. Final abundances of both amphipod taxa were 53 to 68% lower in treatments where the other grazer was present than in single-species grazer treatments. A common carrying capacity was also indicated by the nearly identical final biomass of amphipods across treatments, despite 2-fold variation in initial amphipod densities. These results support the hypothesis that the 2 amphipod taxa are roughly equivalent in terms of resource requirements and production rates. Despite this equivalence, subtle differences in diet breadth between amphipod taxa translated into substantial differences in biomass and composition of the fouling assemblage among treatments. Whereas grazer-free eelgrass became heavily fouled with periphyton and tunicates, eelgrass exposed to G. mucronatus alone was overgrown by the red alga Polysiphonia harveyi, which reached a biomass equal to the total fouling mass of grazer-free controls. P. harveyi was nearly absent from all other treatments. In contrast, eelgrass with ampithoids was virtually devoid of all fouling material. Thus, similar mesograzer species can have markedly different impacts on fouling assemblages, and these occur despite strong similarity in grazer energetics and primary food sources. Our results may help to reconcile evidence of diet overlap and diffuse competition among mesograzer species with the different feeding preferences and community impacts shown for several mesograzers in experimental studies.; RefNo. [ 442 ]

2003

Kelps (benthic algae in the order Laminariales) live in a highly dynamic fluid environment, and exhibit many adaptations to meet the challenges imposed by hydrodynamic forces. We examined flow effects (direct and indirect) on understory kelp population dynamics, morphology and biomechanics along gradients of current velocity and wave accelerations in the San Juan archipelago, Washington. Costaria costata, Agarum fimbriatum, and Laminaria complanata all exhibited significantly higher mortalities at wave-impacted sites, but no gradient was detectable in the effects of tidal currents on survival, despite the strong tidal signal in waters of the archipelago. This pattern stands in contrast to that reported earlier for the surface-canopy bull kelp Nereocystis luetkeana in these waters; N. luetkeana mortality was strongly correlated with current, but not wave energy. The higher wave-driven mortalities of the understory species occur, even though a suite of morphological and biomechanical attributes (thallus size and thickness, holdfast area and biomass, stipe crosssectional area, holdfast strength, blade toughness) indicate that kelps at sites characterized by high flow energy are better adapted to resist the forces imposed by waves and currents. While the forces imposed by strong currents have little effect on survival, they do have significant effects on morphology and biomechanical strength. We propose that morphological plasticity in A. fimbriatum and C. costata ameliorates the effects of both currents and waves on their survival.; RefNo. [ 443 ]

2050

; RefNo. [ 444 ]

2003

We present the results of a microcosm experiment in which benthic foraminifera had to re-establish microhabitat distributions under simulated anoxic and oxygenated bottom-water conditions after initial homogenization of the sediment (obtained from the northern Adriatic Sea at 32 m water depth). After 3 wk, the vertical distribution of the 12 most abundant species was assessed. These taxa could be divided into 2 distinct groups: (1) typical shallow-living species with maximum abundances in the top 2 cm of the sediment; and (2) deeper-dwelling taxa that were more homogeneously distributed throughout the sediment column. Compared to the oxygenated environment, the average living depth of all species was less under anoxic bottom-water conditions in which the group of shallow dwellers was almost restricted to the top 5 mm of the sediment. This distribution was most probably caused by negative geotaxis, induced by an external stimulus associated with anoxic conditions (e.g. high [H2S]). The deeper-living taxa apparently lack the ability for negative geotaxis or are less sensitive to the stimulus.; RefNo. [ 445 ]

2004

Movement is likely a major factor contributing to the marked size partitioning of populations in relation to depth and habitat, as observed for many coastal invertebrates. Here, 2 approaches were used to examine the relationship of movement to size for the green sea urchin Strongylocentrotus droebachiensis on persistent urchin barrens in the northern Gulf of St. Lawrence, eastern Canada. The first approach involved quantifying the dispersal of tagged urchins from release points. Experiments were started by tagging all urchins in 1.0 m2 plots with a fluorescent stain, then quantifying their abundance 9 or 40 d later in the release plots and at different distances from the release plots. The rate of dispersal of urchins from the plots varied greatly with size. In the initial plots, we recaptured 69% of <10 mm diameter urchins, compared to 2% for >15 mm diameter urchins, after 9 d, and 25 and 0%, respectively, after 40 d. In 5 of 6 trials executed, movement was directional, albeit in different directions in the different trials. The second approach evaluated urchin movement relative to size by quantifying the numbers of different-sized urchins moving into 1.0 m2 circular plots, from which the natural population of urchins had been removed 48 h earlier. Trials were made either with or without algae in the center of the plots. After 48 h most urchins which had moved into the plots were large (>15 mm diameter). The movement of urchins was size-dependent, as the presence of algal food affected the rates of movement of large urchins into the plots, but had no detectable effect on small (<15 mm diameter) urchins. Both approaches demonstrated that urchins measuring <15 mm diameter (juveniles) have a relatively sedentary and cryptic lifestyle. Those >15 mm diameter showed increased movement, probably related to the search for food. This ontogenetic change in movement likely affects growth rates and contributes to size partitioning of urchin populations in different subtidal habitats.; RefNo. [ 446 ]

2000

; RefNo. [ 1934 ]