Vitellogenin (VTG) was isolated from the haemolymph of Penaeus vannamei by a three stepprocedure including ultracentrifugation, gel filtration and ion exchange chromatography. VTG wasused to raise polyclonal antibodies that were purified by ion exchange chromatography. A two stepcompetitive assay was developed in which VTG could be quantitated by its capacity to inhibit thebinding of antibody to the VTG previously adsorbed onto a solid phase. Sensitivity from equilibriumand from non-equilibrium assays was 41 and 2.3 ng/ml respectively. Estimates of within-assay andbetween-assay variabilities of standard curves were 4.2 and 9.6% respectively. The inhibition curves for dilutions of haemolymph from vitellogenic females, egg yolk extracts and purified vitellin (VTL) were parallel to the standard VTG curve, haemolymph from immature females and males showed no cross-reactivity. The antibodies directed against VTG recognize but partially VTL as shown by displacement curves. Recovery tests were near 100%. Thus the procedure was considered to be suitable for the measurement of haemolymphatic VTG. The VTG enzyme-linked immunosorbent assay (ELISA) developed in this study was validated by detecting physiological VTG changes in female shrimps after being fed squid extracts.

The nuclear DNA content in Dicentrarchus labrax, Sparus aurata, Liza ramada, and Anguilla anguilla, was measured by flow cytometric analysis. Male human leukocytes were used as internal reference cells. Nucleated fish erythrocytes were stained simultaneously to human leukocytes with a staining buffer containing propidium iodide (PI). Nuclear DNA contents of target species were estimated in relation to an assigned value of 7.0 pg DNA for male human leukocytes. The DNA content/nucleus (±CI) was 1.55 ± 0.02 pg for D. labrax, 1.90 ± 0.03 pg for S. aurata, 1.57 ± 0.02 pg for L. ramada, and 2.43 ± 0.04 pg for A. anguilla. Intraspecific DNA content variations ranged from 0-9% and averaged around 4% in all taxa. The results did not evidence significant differences in genome size between males and females in either D. labrax or L. ramada. / Anguilla anguilla

In the context of the European Water Framework Directive, the in- and outflow water quality from 13 German trout farms, rearing mainly rainbow trout (Oncorhynchus mykiss) and using inflow rates between 0.03–0.80 m3 s−1, were monitored for point-source pollution. The farms had a significant effect on the effluent quality and macro-invertebrate fauna in adjacent streams (saprobic index based on species assemblage and abundance was 1.56–2.10 upstream of the farms but increased to 2.06–2.37 downstream of the farms). Inflow water quality, type of rearing unit, feeding intensity (amount of feed input in relation to water resources) and effluent treatment method could be used to predict effluent quality by 50 to 88% for most water characteristics. Based on these results, different effluent treatment options were monitored for their treatment performance. Concrete sedimentation basins 11 m × 7 m × 1.2 m and 5.5 m ×  3.3 m × 1.5 m (L × W × H), respectively, used for total farm effluent had little or no treatment effects. The micro-screen examined was relatively effective on particulate water components, measured as total phosphorous (TP), biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), resulting in treatment efficiencies of 29–53%, which is less than expected from data in the literature. The constructed wetland examined showed the highest treatment efficiency: more than 35% for TP, COD, BOD5, TSS and total ammonia nitrogen (TAN). From these results and data from the literature, treatment strategies for trout farm effluents can be developed, depending on the rearing system and production intensity.

Quantitative real-time polymerase chain reaction (qPCR) is probably the most used method for gene expression quantification because of its high sensitivity and specificity. Nevertheless, this technology can undergo experimental errors and variations. Normalization of the results using a reference gene is therefore necessary to minimize these variations. As the study of immune genes in bivalve mollusks has increased in the last years, the establishment of adequate and stable reference genes for bivalves is strongly required. We analyzed the behavior of four putative reference genes: ribosomal RNA 18S, actin, elongation factor 1 − α and α-tubulin. The suitability of these four genes as internal control for qPCR was evaluated in mussel (Mytilus galloprovincialis) and clam (Ruditapes philippinarum) hemocytes after bacterial challenge. Four independent approaches (BestKeeper, GeNorm, NormFinder and DeltaCt ) were used to assess the suitable genes for stable expression. For these particular circumstances, the most stable gene in hemocytes was elongation factor 1 − α for mussels and α-tubulin for clams.

The change in catches and mean size of one-year-old perch (Perca fluviatilis) in Lake Geneva was studied between 1957 and 2005, and related to trophic changes and average temperature. The status of Lake Geneva, assessed on the basis of total phosphorus concentrations, switched from being oligotrophic before 1960 to eutrophic, with total phosphorus concentration reaching nearly 90 µg L−1 in 1976-1979. In response to management measures, the trophic status then returned to mesotrophy in the early 2000s. Zooplankton is the main food consumed by young perch, and quantities present (annual biovolumes of zooplankton) were recorded throughout the study period. The lake water temperature was also recorded. Data obtained from perch catches and perch spawns enabled eleven strong cohorts of perch to be identified. Strong cohorts dominated the stock for three years, until they were massively caught by fishermen. Yields have fluctuated widely, increasing rapidly until 1975, and subsequently decreasing, with an exceptional decline between 1976 and 1981. During the period 1977-1981, unfavourable climatic conditions in spring were probably the main cause of this fall in perch yields. For the other periods, perch yields and the mean size of one-year-old perch were significantly correlated with trophic parameters, total phosphorus concentration and zooplankton biovolume. Correlations are higher if only strong cohorts are taken into account. As a result of the re-oligotrophication process, perch growth has been progressively reduced, age at first maturity delayed and strong cohorts become less frequent; the mean size of 0+ individuals in strong cohorts is significantly smaller than in the other cohorts, suggesting a population density effect in the context of a limited supply of zooplankton. During the study period, trophic changes in Lake Geneva have had more impact on perch growth and yield than has temperature, since no significant correlation could be detected between water temperature and perch growth.

The sequencing of the human genome represented a watershed in the biological sciences. Post-genomic biology will be marked not only by vastly greater knowledge about the human genome and those of other species but will see an increasing application of novel and highly sophisticated technologies. Genomic strategies, together with those that look at the proteome of cells and tissues, are likely to revolutionize scientific research over the coming years. The ease with which novel and homologous genes can be isolated using the new databases and technologies, and the ability to study the expression of thousands of genes simultaneously at a global cellular level will be the major factors in this revolution. Genomic information is already being used to further our understanding of physiology and gene evolution in fish. Furthermore, the highly compact pufferfish (Takifugu rubripes) genome is being used extensively as a model to interpret those of tetrapods. Currently, studies of the fish genome are limited to gene evolution and to a much lesser extent, environmental toxicology. However, as interpretation of fish genomes gathers pace, we are likely to see the increasing involvement of other key areas such as reproduction, growth, pathology of disease, and flesh development/quality. Here, we present some of the advanced genomic technologies currently available and discuss how these might influence our knowledge of fish biology.

The aggregate backscattering cross-section, σag is the sum of backscattering cross-sections of all fish in a shoal. It is a basic acoustical parameter used for shoal description and biomass estimation. Simulations were undertaken for evaluating the impact of horizontal dimension, density, depth and beam width on measurements of σag for shoals with constant abundance. The important factor determining measurement bias is the ratio of shoal size expressed as along cross-section length relative to along ship beam width at mean shoal depth. The results show that 10 log10(σag) is underestimated by about 8 dB for a 5 m long shoal located at 200 m depth if detected by a 7° beam. A formula for correcting σag estimates for shoal sizes bigger than 1.3 times the beam width is proposed. The negative measurement bias can also be reduced by using transducers with narrower beam widths.

Tetraploidy was induced in embryos of Ruditapes philippinarum by treating the eggs with cytochalasin B (CB). Two treatment times were found to be effective in inducing tetraploidy: 0 to 10 minutes after insemination (before formation of the first polar body) and 45 minutes after insemination (just before the first cleavage). Treatments, started 5 and 45 minutes after insemination, produced $64.4\pm7.8{\%}$ and $28.3\pm2.3{\%}$ tetraploid embryos, respectively, after 6 hours (on the average over 3 experiments). However, no tetraploids were detected in 4-month-old spat. Sperm entry delayed by the CB could be involved in induction of tetraploidy by early treatment.

We investigated the patterns of occurrence of FAD-associated fish off the coast of Sardinia, Sicily and Majorca (Western Mediterranean). Two working hypotheses are presented to test whether or not “differences exist in fish assemblages at i) the spatial and ii) the temporal level”. Quantitative and qualitative experimental data were obtained from a total of 521 censuses at 17 fish aggregation devices (FAD) using underwater visual observations carried out in Sardinia and Sicily in May-October 2001 and 2002 and a purse seine data set on 3 FADs obtained from a previous investigation carried out in Majorca. The results from the multivariate analysis rejected both hypotheses. In all locations, patterns of fish assemblages were dominated by Coryphaena hippurus, Naucrates ductor, Seriola dumerili, Balistes carolinensis and Trachurus spp., a pattern evident from examining data at bi-monthly intervals. When the most dominant species highlighted with similarity percentage (SIMPER) analysis were analysed with an analysis of variance (ANOVA), a time effect was clearly apparent and subsequently confirmed for four of these five species (B. carolinensis being the exception); the location factor was also found to be relevant (except for the genus Trachurus). We concluded that differences noted were principally due to the “time shift” in the occurrence of these species in the three locations, leading to the assumption that a relationship did exist between the gradual but significant shift in seasonal temperature and colonization at the study locations. Defining selected community structure indices was also important because no reference points are actually available for the pelagic environment in the Mediterranean Sea.

Le modèle composite, communément admis pour décrire les deux stances de croissance de l'albacore dans l'Atlantique Est, est ré-examiné. La valeur du paramètre t0 est corrigée. L'équation de croissance est exprimée en fonction d'un âge conventionnel. Les limites de ce modèle sont soulignées. Différents modèles continus sont ensuite ajustés sur les données de Capisano et Fonteneau (1991), qui estiment l'âge par décomposition polymodale des fréquences de tailles des captures réalisées par les senneurs, durant la période 1983–1988. On montre que l'ajustement des modèles à 3 ou 4 paramètres (Gompertz, Richards et Von Bertalanffy généralisé) est peu satisfaisant. On propose un modèle à 5 paramètres, combinant une fonction linéaire et une loi de Von Bertalanffy généralisée. La validité et l'ajustement de ce modèle sont analysés. Il permet de décrire correctement la croissance dans l'intervalle 40 à 150 cm de longueur à la fourche et 0,25 à 4,25 ans. Afin de disposer d'une équation unique, couvrant l'ensemble de la phase exploitée jusqu'à 170 cm de longueur et 6,0 ans, le modèle est ré-ajusté à des données simulées à partir des modèles précédents. La croissance au sein de la phase exploitée s'exprime alors comme suit :

L(t) = 37,8 + 8,93×t + (137,0 - 8,93×t) × [l - exp(-0,808×t)]7,49

La fiabilité de cette équation est discutée, en relation notamment avec l'existence probable d'un dimorphisme sexuel de croissance. Des hypothèses sont développées pour expliquer l'existence d'une stance de croissance juvénile lente, suivie d'une accélération de croissance au voisinage de 47 cm, puis d'un point d'inflexion au voisinage 90 cm. En particulier, la succession des 2 stances de croissance semble liée aux migrations de l'espèce, à l'intérieur de l'Atlantique Est et vers l'Atlantique Ouest.

The impact of toxic outbreaks of Gymnodinium catenatum, producer of paralytic shellfish poisoning toxins (PSP toxins) and Pseudonitzschia spp., producer of amnesic shellfish poisoning toxins (ASP toxins), was studied throughout the culture cycle of the king scallop Pecten maximus (length from 40 to 100 mm). Toxin concentration, in plankton and in the digestive gland of the scallops, other variables that describe the state of the cultured scallops (mortality, growth, length/weight ratio, gonadosomatic index) and the main environmental conditions (temperature and in vivo fluorescence) were determined from December 2001 to April 2003. Temperature ranged from 14 °C during the winter to 22 °C at the end of July. In vivo fluorescence ranged from not detectable to 25 relative units, with a maximum also recorded at the end of July. ASP toxin levels, in both plankton and organisms, were high during the first half of the sampling period (maximum 450 ng domoic acid L−1, in plankton, and 175 µg·g−1 of scallop digestive gland) when the scallops were juvenile. PSP toxins attained larger concentrations in the second half of the sampling period (maximum of 1.8 nmol L−1 in plankton and 550 nmol g−1 of digestive gland, of gonyautoxins after hydrolysis). Several mortality events took place during the period studied, but none of them coincided neither with an ASP or PSP outbreak nor with long exposure of the scallops to these toxins. One of the recorded mortalities occurred simultaneously with a high concentration of PSP in the scallops, but also with an important spawning. Additionally, it was not coincidental with the bloom of toxic plankton, thus, post-spawning stress seemed to be the main responsible for the mortality. No appreciable effect of ASP or PSP toxinson growth or reproductive state of the cultured scallops was found. Therefore, neither ASP nor PSP toxins appeared to represent a direct threat to the culture of Pecten maximus in that case.

The smooth hammerhead shark Sphyrna zygaena (Sphyrnidae) is regularlycaught as bycatch in pelagic longline fisheries, but is one of the least studied of allpelagic sharks. Recently, ICCAT (International Commission for the Conservation of AtlanticTunas) issued recommendations underlining the need for more studies on the life historyparameters of this and other pelagic shark species. To this end, the age and growth ofS. zygaena were studied in the Eastern Equatorial Atlantic Ocean, in anarea where growth parameters were not yet available for this species. Data from 139specimens, caught between June and September 2009, ranging in size from 136 to 233 cm forklength (FL), were analysed. Preliminary trials were carried out to assess the mostefficient growth band enhancement technique. These indicated that sectioning the vertebraeinto 500 μm sections followed by staining with crystal violet producedthe best results. Growth models were fitted using the traditional von Bertalanffy growthequation and a modification of this equation using a known size at birth. Growth modelswere compared using the Akaike information criterion (AIC). The von Bertalanffy growthequation seemed to be the most adequate model to describe growth in this species, withresulting growth parameters of Linf = 272 cmFL, k = 0.06 year for males andLinf = 285 cm FL,k = 0.07 year for females. In the first four years of life, S.zygaena grows 25 cm per year on average, but its growth slows down in laterlife. Future stock assessment models should incorporate these age and growth parametersfor species management and conservation.

The potential yields of demersal reefal and lagoonal finfish, which are valuable for trade or consumption in the Northern Province of New Caledonia, are unknown. Fishing pressure was estimated from tally-sheets of professional fishermen to assess trade fishing and a household consumption survey to assess subsistence fishing. Total yield was estimated to be 1326 tonnes in 1995, 94 % of which correspond to subsistence fishing. Most of the catches were taken from the east and west coasts; in the north zone (Bélep Archipelago) catches were very low. From this fishing pressure and the total stock values, the maximum sustainable yield (MSY) was estimated to be 12600 t, which was about 10 % of the total stocks assessed in the Northern Province (138300 t). This MSY was dominated by five families, namely Lethrinidae, Acanthuridae, Scaridae, Serranidae and Lutjanidae. The results suggest that fishing effort in the Northern Province of New Caledonia could increase without endangering the stock. However, on a smaller geographical scale, some locations (Koné and Népoui on the west coast), reef habitats (near-reef areas) or species groups (fish caught by line) were already being intensively fished. Fishing techniques should be diversified so that part of the fishing effort be redirected toward the least heavily exploited groups of species and biotopes.

Entre marzo de 1986 y junio de 1987 se estudió et contenido de hierro, zinc y manganeso en partes duras y hierro, cobre, zinc y mercurio en gónadas del erizo de mar Echinometra lucunter, collectado en sitios del litoral rocoso habanero son diferente grado de contaminación metálica. Se obtuvieron variaciones estacionales y los resultados procesados mediante el análisis de varianza y el de clasificación automática, mostraron diferencias entre los sitios estudiados, que permiten considerar a este organismo como capaz de reflejar la contaminación por hierro y mercurio en sus gónadas y por los tres meules estudiados en sus partes duras.

Une méthode d'ajustement de l'analyse des cohortes, combinant calcul en mode inverse et calcul en mode direct, est présentée ; elle permet d'analyser l'évolution des puissances de pêche par flottille et par âge, à partir de la matrice des capturabilités nominales. La méthode est appliquée aux deux principales flottilles exploitant l'albacore dans l'Atlantique Est, entre 1980 et 1990 : les senneurs franco-ivoiro-sénégalais (FIS) et les senneurs espagnols. A l'aide d'un modèle linéaire généralisé, les puissances de pêche globales sont décomposées en deux termes : puissances locales et efficiences globales. Les évolutions tendancielles des trois grandeurs, puissances globales, puissances locales et efficiences globales, par catégorie d'âge ou en moyennes, sont analysées en calculant des taux d'accroissement inter-annuels sur des intervalles pluriannuels. Les changements de tactiques de pêche sont étudiés au travers des corrélations entre puissances de pêche résiduelles appliquées à des groupes d'âge différents.

Les résultats obtenus sont peu sensibles aux paramètres introduits lors de l'ajustement de l'analyse des cohortes. Sur l'ensemble de la décennie, un accroissement des puissances de pêche globales moyennes est mis en évidence, avec un taux estimé à 17 et 9 % par an pour chacune des flottilles FIS et espagnole respectivement. Cet accroissement est lié à une forte augmentation des puissances de pêche globales appliquées aux adultes, alors que celles appliquées aux juvéniles semblent en diminution. Les changements de l'efficience de pêche globale jouent un rôle essentiel dans le cas de la flottille FIS. Trois schémas type d'évolution, traduisant des stratégies de pêche différentes entre flottilles et entre périodes, sont définis ; l'impact des changements de tactique de pêche est souligné. Les raisons susceptibles d'expliquer les variations des puissances de pêche sont discutées, ainsi, plus généralement, que les potentialités et limites de la méthode d'analyse utilisée.

Variations in fish communities of shallow lakes in the Yangtze basins were investigated from September 2007 to September 2009. Six lakes were chosen for comparative study of species composition and diversity in relation to environmental variations. Lake heterogeneity was described with environmental physico-chemical variables, using principal component analysis. Sixteen families, composed of 75 species of fish were found in the studied lakes, Cyprinidae being the dominant group. Fish species were divided by habitat preference and trophic guild: benthopelagic and herbivorous fish were the most common guilds in all lakes. Species diversity and richness were significantly higher in spring, while the evenness, expressed by equitability of Simpson’s index, was not significantly different among seasons. Species richness and diversity were significantly higher in vegetated lakes (e.g. Liangzihu Lake) than in non-vegetated lakes (e.g. Biandantang Lake), with the largest area (Liangzihu Lake) harbouring the largest species richness and the greatest diversity. The relationship between environmental variables and fish assemblage were analysed using canonical correspondence analysis (CCA). The dominant gradients describing species composition and abundance among the sampling sites were: total phosphorus, total nitrogen, chlorophyll a, transparency and water depth. Our study led to the following conclusions: 1) the water quality was better - i.e. high transparency, low total phosphorus (TP) and total nitrogen (TN) and chlorophyll a- in vegetated lakes than in unvegetated lakes; 2) vegetated lakes had higher fish diversity than unvegetated lakes; 3) fish relative abundance (CPUE: number of fish per fishing pass) was significantly related to water chemical parameters. Consequently, the details of the findings are useful and relevant for developing suitable conservation strategies to sustain the integrity of fish communities in these lakes.

Cold shocks and hydrostatic pressure shocks, respectively, were applied for the induction of bothtriploidy and tetraploidy in the common carp. Cold shocks of 0-2 °C, lasting 40 minutes and starting 2–5 minutes after the activation of gametes and hydrostatic pressure shocks with 1-3-5 minute exposures at 49.03–56.88 MPa (i. e. 7 116-8 225 psi – pounds per square inch), starting 5 minutes after the activation of gametes gave the best results. The tetraploidy induction by cold shocks or hydrostatic pressure shocks resulted either in negligible (1.54%), or in zero yields, respectively. The applicability of particular types of ploidy manipulation and the standardization of shock initiation were discussed.

The pout, Trisopterus luscus, is one of the most important gadoid fishcaptured by northern Portuguese traditional fisheries. In spite of a substantial decreasein fish catches, little data are available either on the population structure or on themanagement of the species. In this study, chemical analysis with inductively coupledplasma mass spectrometry of whole otoliths of 90 pouts (age group 2, total length:17.9–25.0 cm) provided location-specific elemental signatures. Sampling took place inshallow waters along the coastline in three fishing grounds off the Portuguese north coast(Viana do Castelo, Matosinhos and Aveiro) between February and March 2010. Otolithfingerprint analysis detected the presence of several informative trace elements. Molarconcentrations for each site were analysed through uni- and multivariate statisticaltests. Strontium, barium, magnesium and lithium (Sr, Ba, Mg and Li) differed significantlyamong locations, while no significant differences were found for manganese (Mn) and nickel(Ni). Canonical analysis allowed us to discriminate the tested individuals with respect totheir sampling origin with a mean classification accuracy of 69%. The observedsite-specific elemental differences in pout otoliths suggest a high level of site-fidelityin relation to their growing/feeding areas. Pouts from these locations can be regarded asa single, although not necessary homogenous, stock. Furthermore, this study also suggeststhat the populations of juvenile fish mix partially and, therefore, cannot be assumed tobe separate units for fisheries management purposes.

This review aims at comparing the fisheries management systems existing in New Zealand and in the European Union. The involvement of stakeholders at all stages of the management process is generally more transparent and better established in New Zealand than in the EU. Both systems aim at achieving an adequate balance between sustainability and utilisation and consider the precautionary approach as a founding principle. The socialobjectives are probably more explicit in the EU management system. In New Zealand, B MSY is a legal management target for all stocks in the quota management system (QMS), but management strategies were poorly explicituntil most recently. In the EU, there have not been any legal management targets or strategies until 1999. Since 1999, a number of multi-annual recovery and management plans have been established, including bothmanagement targets and strategies. Both management systems include conservation and access regulation measures. The EU management measures aim at regulating fisheries outputs and inputs, and discarding is tolerated. New Zealand management is almost exclusively output-based, and discarding practices are banned. In the EU, while individual quotas (IQs) are implicit in several countries, there is no consistent pattern across Member States for allocating TACs. In New Zealand, individual transferable quotas (ITQs) are implemented, and some flexibility in catch-quota balancing is provided by a carry-over allowance and the payment of a landing tax, the deemed value, for every fish landed above quota. If rights-based management were introduced in the EU based on, e.g., the New Zealand model, we suggest that concentration rules be set in accordance with the social objectives of the Common Fisheries Policy, and also that the deemed value should be set based on science and economics.

A fish aggregating device (FAD) called a payao is conventionally installed to catch pelagic species in the Philippines. The waters around the Philippines are important regions for yellowfin tuna stocks because they include spawning grounds and nurseries. To understand the schooling behavior of juvenile yellowfin tuna Thunnus albacares around a payao, 13 juveniles (20.5−24.0 cm fork length) double tagged with ultrasonic transmitters (V7-2L-R256; Vemco Ltd.) and data loggers (DST-micro; Star-Oddi Ltd.) were released around a payao. A self-recording receiver (VR2-DEL; Vemco Ltd.) was attached on the mooring rope of the payao to follow the horizontal movements and data loggers recorded the vertical movements of tagged juveniles. Nine juveniles were recaptured simultaneously by ring net at the same payao after 4-7 days. One juvenile was recaptured by hand line at another payao 12 km away from the tagging site after 6 days. Recaptured juveniles showed a diurnal schooling pattern suggesting different school shape and foraging strategy between daytime and nighttime. Juveniles showed a diurnal horizontal moving pattern, concentrated near the payao during daytime, while they were distributed around the payao at nighttime. The fluctuations of swimming depth were synchronized among fish. Juveniles also showed a diurnal vertical movement pattern in surface mixed layer. They concentrated in a shallow and narrow range (11.2±8.2 m, mean ± SD) at nighttime, while they were distributed to a deep and wide range (20.0 ± 11.8 m) during daytime. The maximum vertical neighbor distance indicated the vertical thickness of the school and showed a peak around noon. Higher vertical movement speed during daytime indicated vertical foraging in a water column, while at nighttime the juveniles might forage horizontally following the diurnal migration patterns of prey in the surface layer.