Changes in the total amino acid (TAA) and the free amino acid (FAA) contents during embryonic development, through newly spawned eggs, to pre-settled larvae of blacklip abalone (Haliotis rubra) are described. The TAA (protein bound + free) and the FAA contents increased prior to hatching but decreased towards settlement, but the changes were not always significant between different stages of development. Threonine, arginine, lysine and leucine accounted for nearly 50 % of the total essential amino acids (TEAA) in all developmental stages. The mean FAA content of newly spawned eggs was 262.8 ± 28.2 pmol·ind–1 and accounted for 11.5 ± 8.3 % of the TAA. Free essential amino acid (FEAA) content increased significantly as development progressed (P < 0.05), in which threonine, arginine and lysine accounted for over 63 % of this pool. In all developmental stages, the FAA pool was dominated by the non-essential amino acids taurine + proline which accounted for 79.5 % of the total. Generally, the FAA accounted for between 10 to 15 % of the TAA in the different developmental stages of blacklip abalone. All evidence appears to indicate that in blacklip abalone the energy requirements during early ontogeny are mostly met with from the lipid reserves, and that there is a tendency to conserve amino acids until pre-settlement.

The uptake and release of material by oysters (Crassostrea gigas) and mussels (Mytilus edulis) in Marennes-Oléron Bay (SW France) were measured in situ using benthic ecosystem tunnels (BEST). There was a large variation in seston concentrations, owing to high sedimentation/erosion dynamics. Organic matter was diluted by resuspended sediment, but had a low C/N ratio, i.e. a high quality, owing to resuspension of microphytobenthos. In many cases a significant decrease of chlorophyll concentrations was observed in tunnels with oysters and mussels. Average clearance rates per tidal cycle ranged from 4 to 7, and from 0.9 to 2.7 1.g−1AFDW.h−1 throughout the season, for oysters and mussels respectively. Calculation of the filtration pressure (the fraction of the primary production filtered per day), indicated that bivalves in the bay were able to filter much more than the daily pelagic primary production. It seemed obvious that the bivalve stocks depended not only on phytoplankton but also on microphytobenthos. Significant regeneration of nitrogen could be demonstrated from musselbeds on the sediment, at higher rates than direct excretion of ammonium. No significant release of nutrients was observed for the oysters or mussels, when they were put on tables, as practised by the oyster farmers. lt seemed likely that biodeposits were flushed away from the tunnels in this case, and mineralization occurred elsewhere. It was concluded that the carrying capacity of the bay for herbivores is extensively exploited by the shellfish. Mineralization of bivalve biodeposits represent a large potential for nitrogen regeneration.

Fisheries management in the future will require that biological assessments be combined appropriately with operational, social, and economic considerations toward effective management of complex fisheries systems. This is not currently being done in fisheries management because of: (i) the lack of a conceptual and organizational framework for integrated and participatory decision making, and (ii) the lack of more appropriate methodologies for dealing with diverse sources of information, interdisciplinary objectives, and the inherent uncertainty of these systems. An integration of traditional "fisheries science" with other aspects of "fisheries management" and the field of "management science" in a new discipline of "Fisheries Management Science" is proposed. FMS is defined as "the rigorous application of the scientific method of problem solving in the development of strategic alternatives and their evaluation on the basis of objectives that integrate biological, economic, social, and operational factors into management decision making". Management science or operational research provides guidance in methodologies for complex decision making and problem resolution. A multidisciplinary decision framework is proposed involving the following key steps: (1) specification of quantifiable objectives and constraints; (2) modelling of the expected multicriteria performance of a range of proposed management decisions; (3) risk assessment through descriptions of the expected variability in performance measures; (4) risk management through analytical evaluation of risk and ranking of alternate solutions; and (5) continuous monitoring and improvement of past decisions including deviations from expected performance and corresponding adjustment of future alternatives toward achieving strategic objectives.

In recent decades, marine reserves have been established either to protect ecosystem structure and biological diversity or to serve as management tools to counter the overexploitation of fish stocks. The Cape Roux marine protected area (MPA), in the Mediterranean Sea, was established in December 2003 for the management of artisanal fisheries and enhancement target fish stocks.

Monitoring of littoral fish assemblages (0–30 m depth) in this zone began one year after the MPA was set up. The survey was conducted at 6 stations, located inside and outside the MPA, using three methods: underwater visual census (UVC) on transects, UVC using a new fish assemblage survey technique (FAST), and experimental net fishing performed by a fisherman. The FAST indices were derived from visual censuses, performed along a random pathway, scoring species on a presence/absence basis and size on a 2-class basis. Indices were calculated seasonally, by applying “weights” according to species and size. This study presents results obtained between October 2005 and June 2007. In the protected area, the experimental fishing yielded significantly higher abundance and species richness, and the FAST method highlighted a decrease in seasonal fluctuations. These two complementary methods (UVC and experimental fishing) revealed the early changes in fish assemblages in response to protection. The FAST method employed here seems to be relevant for the study of artisanal fishery target fishes, as a low-cost and sensitive UVC method.

Growing pressures from development activities, on aquatic environments in South American countries, have created an urgent need for tools to measure the quality of aquatic systems. The index of biotic integrity, based on fish assemblages, elaborated in North America, constitutes a basis for the development of these tools. However, its direct application is problematic in regions having a rich and diverse ichthyofauna and where the knowledge of fish species ecology is incomplete. The response of taxonomic or trophic groups is often unknown and the selection of fish assemblage metrics cannot be based on previous knowledge, as in intensely studied regions. This work proposes a method, similar to the approach recently pursued in Europe, based on comparing the variability of fish assemblages in reference situations with their variability influenced by human-induced perturbations. The method was developed from 53 samples of 27 reaches in 7 hydrographic basins of French Guiana. For each of 28 fish assemblage descriptors, stepwise multiple linear regressions with 28 habitat variables were carried out. The residuals of the models obtained were used as candidate metrics independent of natural environmental factors. Nine metrics showing significant differences between reference and disturbed samples were selected to constitute the index. The index was validated by analysing a temporal data series obtained from a reach disturbed by dam construction.

The Gambia Estuary is one of the last estuaries in West Africa not to have been affected by strong environmental changes and adverse human disturbances. In order to describe the spatio-temporal change in fish biomass in this estuary, and the seasonal changes in fish size classes, five research surveys have been conducted at characteristic periods in the river's water regime and meteorological seasons. The fish assemblages were sampled by two vertical echosounding protocols: mobile surveys (zigzag transects) in the estuary and moored stations. The two sampling methods produced a similar image of the fish assemblages in terms of the distribution of total biomass and target strength distributions. Large fish aggregations were detected in the most marine area at the end of the wet season, and fish biomass increased through the dry season in the upstream zone. Fish were smaller at the beginning of the wet season and they were always larger in downstream areas.

Cryopreservation is a valuable tool for genetic improvement programs. Several bivalvemollusc species have already been the subject of such programs and the Tahitian blackpearl oyster industry is now planning the development of selective breeding for desirabletraits in Pinctada margaritifera. The ability to cryopreserve spermatozoawould, therefore, offer significant benefits to the cultured black pearl industry.Spermatozoa were cryopreserved with cryoprotectant agent (CPA) 0.7 M trehalose in 0.8 MMe2SO and a two-step freezing process was used: straws were first maintainedin nitrogen vapour for 10 minutes, then directly plunged into liquid nitrogen and storedfor one week before use. The viability of thawed sperm was 23% lower than that of freshsperm. When using thawed sperm, therefore, a higher sperm/egg ratio of 100 000:1 wasrequired to reach 80% oocyte fertilization, compared with 100:1 for fresh sperm.Nevertheless, this first demonstration of cryopreserved sperm fertility in black pearloyster confirms the hatchery applicability of the cryopreservation technique defined here.Monitoring for larval viability during the first 23 days of life revealed no significantdifferences between the progeny produced with cryopreserved sperm and that produced usingfresh sperm.

We conducted displacement experiments using acoustic tags to study the orientation abilities of dolphinfish (Coryphaena hippurus) around FADs. Eleven fish were passively monitored using coded transmitters and acoustic receivers attached to FADs, while seven others were actively tracked with a vessel using continuous acoustic tags equipped with pressure sensors. All these 18 dolphinfish were captured close to a FAD and released between 70 and 1720 m from it. Five fish out of the 14 that were displaced at more than 360 m from a FAD (estimated detection range of our acoustic receivers, defining the target area during our experiment) returned to the target area. With one individual successfully returning to the target area after having been released at 1600 m from the FAD, the rate of return of fish released up to this distance was significantly higher than expected if they were moving at random, but many fish released at intermediate distances moved in other directions. Based on detailed statistical analysis of the return score, we estimated that dolphinfish are able to orientate towards a FAD area from at least 820 m. The connection between our definition of the target area and the association area of dolphinfish around a FAD is discussed, as well as the impact of stress and motivation in the rates of return observed. More experiments should be conducted to improve this first estimate. Specific experiments should also be designed to more accurately determine the association range of fish around FADs and their motivation to orientate towards FADs.

The effect of short-time Artemia spp. feeding on growth performance and cumulative survival rate of barbel (Barbus barbus) larvae were studied under controlled aquaria conditions during the 21-day larval period. Three different diets (presenting reduced Artemia feeding) were tested for first exogenous nutrition of larvae (since 13 days post hatch): (1) artificial feed (Asta); (2) Artemia nauplii for 7 days followed by artificial feed; (3) Artemia nauplii for 14 days followed by artificial feed. The longer period of live food statistically improved growth of larvae (W = 174 ± 20 mg and SGR = 14.5 ± 0.5% d−1). The artificial dry food Asta without the addition of Artemia nauplii caused statistically decreased growth (W= 135 ± 22 mg and SGR= 13.1 ± 0.7% d−1). However, the growth of larvae with the short period of Artemia nauplii (W = 153 ± 25 mg and SGR = 13.8 ± 0.7% d−1) did not differ compared to either group. All used feeding diets did not have a significant effect on the cumulative survival rate of larvae ranging from 73 ± 1% to 74 ± 1% at the end of the larval rearing period.

The effects of the rearing environment on growth performance and survival rate of juveniles were tested under intensive controlled conditions in aquaria and troughs for 84 days following the larval period (from 34 to 118 dph). The environment of the troughs caused significantly decreased growth (W = 2079 ± 433 mg and SGR = 3.1 ± 0.05% d−1) of juveniles compared to ones reared in aquaria (W = 3236 ± 264 mg and SGR = 3.6 ± 0.1% d−1) at the end of the juvenile rearing period. Nevertheless, rearing environment did not have a significant influence on the cumulative survival rate of barbels (S C = 90 ± 4% and 81 ± 3% in aquaria and troughs, respectively).

Two 12-week feeding experiments were conducted in aquaria with juvenile blue catfish, Ictalurusfurcatus. In experiment 1, juvenile (6 g) blue catfish were fed one of four isonitrogenous (34% protein) and isocaloric (10.0 kJ of digestible energy/g of diet) diets containing 13, 9, 4, and 0% menhaden fish meal. Soybean meal was added in increasing percentages (48, 55, 62, and 69%) to the respective diets. Fish were fed all they would consume in 40 minutes twice daily (08:00 and 16:00). After 12 weeks, fish fed a diet with 13% fish meal had a significantly higher individual body weight than fish fed any of the other diets. There was no significant difference (P > 0.05) in body weights of fish fed the other four diets. No significant differences were found in percentage survival, feed conversion ratio, and protein efficiency ratio among treatments. In experiment 2, blue catfish (9 g) were fed one of five isonitrogenous (35% protein) and isocaloric (10.5 kJ of digestible energy/g of fiet) diets. Diet 1 contained 15% menhaden fish meal and 42% soybean meal. Diets 2-5 contained 0% fish meal and 69% soybean meal with various (0.0, 0.3, 0.6, and 0.9%) percentages of added L-methionine. Fish were fed as in experiment 1. After 12 weeks, individual weight, weight gain, survival, specific growth rate, and feed conversion ratio were not significantly different (P > 0.05) among treatments and averaged 36 g, 302%, 100%, l.6%/day, and 2.4, respectively. Whole-body compositions of fish were not significantly different (P > 0.05) among treatments and averaged 61% and 27% for percentage protein and fat, respectively. These data indicate that soybean meal can totally replace fish meal in a diet for blue catfish without supplemental L-methionine. This may allow producers to feed more economical diets without adverse effects on growth and survival.

Mediterranean demersal fisheries have experienced an ongoing decline in catches over the past 20 years as a result of excessive increases in effort caused both by growth in trawler engine power and by rapid technological advances in fish finding and fishing technology. This has led to an overexploitation of these resources. An increasing share of the catches consists of immature individuals. This study was undertaken to test a sorting grid with a bar spacing of 20 mm as a means of excluding juveniles in the commercial hake (Merluccius merluccius) fishery in the Catalan Sea, western Mediterranean. The grid was placed in the extension section of the gear 5 m in front of a cod-end. Divided cod-end design was used to collect the escapees and target species. The mean selection length (L50) of the ten hauls was 14.2 ± 0.7 cm SE, with a selection range of 7.3 cm ± 0.4 SE. The biomass of hake under L50 that escaped through the grid represented 50.1% ± 6.7 SE of the total hake biomass. These results are promising and indicate that a sorting grid can be used in excluding young hake. This was a first step toward implementation of sorting grids in commercial trawl gears as means of avoiding unwanted catches of small individuals in the hake fisheries in the Mediterranean Sea. Further trials are required to improve the sorting efficiency of the grid.

Fish assemblage structure of 29 Brittany streams is examined. Catchment area, stream gradient, and distance from sources are significantly correlated with species richness. Addition of species with increasing stream size occurs for all streams with no evident longitudinal replacement, suggesting little discontinuity in the stream geomorphology or temperature. Total density of fishes decreases significantly with an increase in stream size but no relation was found between total biomass and catchment area. Headwaters are characterized by short-lived, solitary, and nocturnal feeding species, whereas downstream sites are characterized by long-lived, schooling, diurnal feeding species. Presence of solitary and nocturnal feeding species upstream could be related to predation and/or competition factors. Temporal variation of individual species density varies from an upstream-downstream gradient with the highest variation upstream. Species responsible for this variation were mostly small benthic ones relatively difficult to sample, therefore, the greater temporal variation in upstream areas could be attributed to a deficiency of the sampling methodology.

Marine protected areas (MPAs) have been depicted as a useful tool for improving fisherymanagement and protecting biodiversity. For example, by acting as source populations, MPAsmay provide a spillover of adults/propagules, enhancing recruitment to surrounding,non-protected waters. However, such positive effect will depend on how a MPAs designmatches population biology and dispersal abilities of the target species. High levels ofintraspecific genetic diversity without pronounced structure have been found in manymarine organisms over large spatial scales (from hundreds to thousands kilometres) but donot hold for other ecologically and economically important species such as coral reeffishes, seagrasses and kelps. In particular, the limited potential for dispersal of manymacroalgae suggests the occurrence of self-sustaining, “closed” populations that contrastwith the “open” populations of many fishes and invertebrates. Consequently, the highresilience of fish/invertebrate populations cannot be generalized to the whole marinerealm. In the present work, we use genetic tools to explore the role of the MPAParc naturel marin d’Iroise in the management of the emblematic kelpLaminaria digitata. While kelps have received much more scientificattention than any other seaweed group, there is still critical baseline knowledge whichneeds to be addressed for their effective management. Our genetic survey of 12 L.digitata populations along the Brittany coast, four of them located within theboundaries of the Parc naturel marin d’Iroise, allowed us to assess theconservation value of these kelp populations. In particular, classical genetic metrics aswell as more recent clustering approaches were used to identify and characterizeManagement Units. Moreover, assignment tests were employed to determine contemporarymigration events and source/sink populations. Our results show that populations withinthis MPA have high conservation value. However, we also identify other populations ofconservation interest.

The Cyprinidae is the largest freshwater fish family in Vietnam, with over 220 recognised species, many of which play an important role in aquaculture or are harvested from the wild. Despite numerous studies on the taxonomy of this family based on traditional morphological data, the relationships between major cyprinid groups is poorly understood and the taxonomic validity of a number of these groups is under debate. While an increasing number of molecular studies on cyprinid relationships have been conducted many have used restricted sampling and none have incorporated Vietnamese species. In this study, mitochondrial 16S rRNA, D-loop and cytochrome b gene sequences from 25 species of cyprinids collected from Vietnam were obtained and combined with sequences of cyprinids available in GenBank, in order to investigate the taxonomic validity of subfamilies within Cyprinidae and their phylogenetic relationships. The molecular data supported traditional division of the Cyprinidae into two major lineages: Cyprinines and Leuciscines. The placement of the Danioninae as the sister lineage to this grouping was not supported. Many of the subfamily boundaries were questioned and doubt was raised on some of the generic level classifications. The validity of species designation in Cyprinus, Tor and Cyclocheilichthys was also questioned. This study will need to be extended with greater taxon and gene sampling to further consolidate our understanding of cyprinid relationships and classification.

Fish schools are aggregative structures encountered in all types of aquatic environments but have as yet been little studied in freshwaters except at small spatial scales. This study represents the three dimensional description of juvenile fish schools (Perca fluviatilis and Rutilus rutilus) in a lake environment using high resolution multibeam sonar system operating at a frequency of 455 kHz, composed of 60 beams of 1.5° allowing a 90° observation plane. The in situ diurnal schooling behaviour of young-of-the-year fish of both species is confirmed. The morphological, energetic and spatial variables of these schools are described and related to one another. The structures described are of the same order of magnitude as those described in the marine environment. The school shape is elliptical, they are shallow and they display a temporal and spatial stability over the course of a day but a highly variable morphology. The number of vacuoles, a descriptor of the internal morphology of the schools, was found to be significantly (p < 0.01) correlated with the volume of the school, and showed two distinct relationships, with proportions similar to the percentage occurrence of both species sampled by a pelagic trawl. The relation may be efficient for fish species discrimination by 3-D acoustics methods in this lake with two main aggregative fish species.

The feeding behaviour of small tuna on the mesopelagic fish Vinciguerria nimbaria was studied in an equatorial area of the Atlantic Ocean (10–20° W, 0–5° N). Acoustic data (from a scientific cruise) and tuna stomach content data (from the tuna purse-seine fishery) were combined. V. nimbaria formed loose schools that occurred in clusters during daytime, and large aggregations during the night. The characteristics of the schools and clusters were analysed. The average length, size and packing density of the day-school were estimated at 48.5 m, 24400 individuals, and 5.8 fish m–3, respectively. The average length of clusters was close to 10 km. The packing density of night-school was estimated at 1.6 fish m–3. The preying of tuna on V. nimbaria was modelled as a stochastic process based on two Poisson processes. Daily rations of tuna were estimated at 3.5% and 7% of the body weight. Taking into account the swimming performance of the prey and the predator, we showed that tuna were able to feed on day-schools in a very short time, whereas feeding during the night by filtering was not competitive. Furthermore, a cluster is able to feed a single tuna school during 2 months, proving the sustainability of the biomass of small tuna in the area by V. nimbaria.

The potential of carp pituitary powder (CPP) at one dose, or the luteinizing hormone-releasing hormone (LH-RH) analogue, des–Gly10,(D–Ala6)–LH-RH–ethylamide, at three different doses to stimulate spermiation in paddlefish (Polyodon spathula) was tested. Single injections of the LH-RH analogue at 0.2, 0.1, or 0.05 mg·kg–1 increased the number of spermatozoa per kilogram of body weight (kg–1 b.w.) by 4.7, 3.4, and 3.4 times respectively compared to control, but the number of spermatozoa per kilogram of body weight decreased with CPP (4 mg·kg–1) by 1.7 times compared to the control. The LH-RH analogue prolonged active spermiation, with numbers of spermatozoa ranging from 7.69 to 1.19 × 109 kg–1 b.w. up to 96 h after treatment. Analysis of variance showed significant influence of experimental groups on volume of sperm per male and per kilogram of body weight, and the total number of spermatozoa per kilogram of body weight, but insignificant influence on the total number of spermatozoa per male. The percentage of motile spermatozoa was not different between experimental groups for sperm collection at different times after injection. A very high positive correlation (r = 0.93) was obtained between sperm concentration and sperm transmittance measured with a spectrophotometer. This relationship was described with the following linear regression: sperm concentration (× 109 mL–1) = 1.3244 X–0.9969, where X is the percentage of sperm transmittance.

Using examples, we discuss some aspects of surplus production models. Although the precision of some parameter estimators may appear to be good, the strong asymmetry of confidence intervals and the large impact of the choice of a given formula on those estimators go against this feeling. Models are often formulated with inference to the biological background, but giving a biological meaning to (the estimates of) the parameters may be very dangerous. Fishing effort standardization does not lead necessarily to useful results for management. The fleet dynamics, per se, may not allow equilibrium States. In the context, of general frameworks, where the evaluation of the resource is not the unique objective, surplus production models may be however very flexible tools for fishery analysis, with low parameter requirements.

The common whelk Buccinum undatum (Neogastropoda, Buccinidae) iswidespread along the north Atlantic coasts of France. In west Cotentin (Normandy), animportant local fishery exists that depends exclusively on this marine resource andrepresents about 90% of French whelk production. Despite successive restrictive measures,fishing yields have decreased since 2000. Shell length frequency distributions ofBuccinum undatum caught in west Cotentin were studied in 2005(N = 2910), in 2007 (N = 2032) and in 2009(N = 4145) ranging from 7 to 85 mm. In order to preserve this fisheryand to characterise the whelk stock at this site, the reproductive biology of this specieswas studied in relation to age, sex and size, for whelks of commercial size (45 to 61 mm)over the complete annual cycle in 2008. Age was determined by reading the number ofoperculum striae: animals between 45 and 59 mm had 2 to 4 striae. Four reproductive stageswere defined for males and females on the basis of histological analysis. The time courseof reproductive events was described according to size and sex: the highest percentages ofripe stages were found in October for both sexes. Spawning events occurred between Octoberand December. The shell length that corresponded to 50% of animals having mature gonads(49 mm and 52 mm for males and females, respectively, corresponding to 3 and 4 years oldanimals) exceeded the minimal landing size (45 mm). Fifty percent maturity was reached formales in their third year and for females in their fourth year. Reproductive investmentwas evaluated by quantitative analysis of the gonadal thickness or surface and was foundto be proportional to shell size. We found that less than 20% of females under 49 mm inlength were sexually mature and that these produced only a few eggs. This information,collected in a major fishing area, should assist fishery management decisions.

Parameters of hemocyte populations have been considered as relevant indicators of bivalve health and are currently used in immunotoxicological studies. Hemocytes in hemolymph can be collected by puncturing either the pericardial cavity or the adductor muscle sinus with a syringe. Flow cytometry is a methodological approach that is increasingly being used in laboratories for the study of hemocyte parameters in aquatic invertebrates. However, various protocols for hemocyte processing in laboratories equipped with different types of cytometers have been published. In this context, two flow cytometers (EPICS XL4®, Beckman Coulter and FacsCalibur®, Becton Dickinson) and two sites of hemocyte collection (pericardial cavity and adductor muscle sinus) were compared for the analysis of hemocyte parameters in the Pacific oyster, Crassostrea gigas. Hemolymph cells were analyzed in terms of their number and organelle contents. Cell mortality, phagocytosis, non specific esterase, extension of the lysosomal compartment and production of reactive oxygen species were quantified. The results showed that the phagocytic index was higher for hemocytes obtained in the muscle sinus hemolymph. The results are discussed with respect to the potential use of flow cytometry as a tool for hemocyte studies in bivalves.