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Actuellement, ce n'est pas tant face aux changements climatiques que les habitants des várzeas se sentent démunis mais plutôt face aux activités minières ou au développement de la pêche industrielle, qui menacent leur territoire, leurs conditions d'existence et renforcent leur précarité.

International audience

This report presents new stock assessments for the rock lobster (Jasus paulensis) fishery of the Saint Paul and Amsterdam islands with data up to the last fishing campaign of 2020/21. These new assessments are based on statistical catch at age models using all available data except tagging program data.Stock status trajectories for both stocks start from a period of unsustainable fishing in the 1980s and recovered in the 1990s. The assessment results indicate that exploitable biomass in 2020 is likely to be well above BMSY, biomass status (B/BMSY) are 1.09 (0.86 - 1.50) and 2.12 (1.66 – 2.92) for Saint Paul and Amsterdam stocks respectively, and that fishing mortality is well below FMSY. These estimates are consistent with the results of preliminary assessment from biomass dynamic models.The short-term projection scenarios that were tested show that current catch levels are compatible with the sustainability of the rock lobster stocks.

The widespread decline in fishery resources from the early 1980s prompted scientists and fisheries managers to develop quantitative assessment methods to improve their management. These methods have made it possible to justify policies of drastic reduction in fishing pressure which have had a positive impact on many resources. The development and use of these methods has been spearheaded in large-scale, commercial marine fisheries. They are based on long-term monitoring, complex analytical procedures and require frequent updating of assessments to adjust regulatory measures according to the state of the resource. These methods are rarely applied to small inland fisheries which are inherently very different from their marine counterparts. The diversity and complexity of these fisheries, dominated by artisanal or recreational practices, makes the application of such methods more challenging.The objective of this thesis is to develop a method for the quantitative evaluation of the performance of different regulatory scenarios for recreational fisheries of Brittany that target Atlantic salmon. The statistical modeling approach undertaken takes advantage of the very diverse set of data collected since the late 1980s on each of the 18 salmon populations targeted by these fisheries in order to simulate their specific dynamics under different regulatory scenarios. The Bayesian statistical framework used facilitated the integration of the main sources of uncertainty relating to these simulations. The conservation performance was assessed on the basis of a new, simple and clear definition of conservation proposed in the framework of this thesis and adopted by the stakeholders. The evaluation method developed aims to facilitate and fuel dialogue with and between management stakeholders to inform their decision-making. From this perspective, the chosen method is based on easily understandable decision rules and it makes it possible to obtain a sub-set of “best performing” scenarios, which leaves the stakeholders a latitude in the final choice they will make. The results obtained show that conservation is not respected, even in the absence of harvesting by fishing from at least one river, but that in the majority of cases, the current regulatory system is compatible with conservation. This thesis work, carried out at the level of a regional group such as Brittany, is a world first for Atlantic salmon. It could be extended to other spatial entities as the methodology can easily be applied and adjusted to different contexts. This work has shown that the current intensity of recreational fisheries does not constitute a substantial threat to salmon in Brittany. To better understand the different threats and their impacts on salmon populations of Brittany, we should move towards more ecosystem-based management of the resource., Le déclin généralisé des ressources halieutiques à partir du début des années 80 a incité les scientifiques et les gestionnaires des pêcheries à développer des méthodes quantitatives d’évaluation pour améliorer leur gestion. Ces méthodes ont permis de justifier des politiques de diminution drastiques de la pression de pêche qui ont été bénéfiques a beaucoup de ressources. Le développement et l’utilisation de ces méthodes a été amorcé par les grandes pêcheries commerciales océaniques. Elles reposent sur des suivis à long terme, des procédures analytiques complexes et nécessitent des mises à jour fréquentes pour ajuster les mesures de régulation en fonction de l’état de la ressource. Ces méthodes sont rarement appliquées aux petites pêcheries continentales qui sont par nature très différentes de leurs pendants océaniques. La diversité et la complexité de ces pêcheries, dominées par des pratiques artisanales ou récréatives, rend l’application de telles méthodes plus délicates.L’objectif de ce projet de thèse est d’élaborer une méthode d’évaluation quantitative des performances de différents scénarios de régulation des pêcheries récréatives bretonnes de saumon atlantique. La démarche de modélisation statistique entreprise valorise l’ensemble de données très diverses collectées depuis la fin des années 80 sur chacune des 18 populations de saumon ciblées par ces pêcheries afin de simuler leur dynamique spécifique sous différents scénarios de régulation. Le cadre statistique bayésien utilisé a facilité l’intégration des principales sources d’incertitude relatives à ces simulations. Les performances en matière de conservation ont été évaluées à partir d’une nouvelle définition simple et claire de la conservation proposée dans le cadre de cette thèse et adoptée par les gestionnaires bretons. La méthode d’évaluation élaborée vise à faciliter et alimenter le dialogue avec et entre les acteurs de la gestion pour éclairer leur prise de décision in fine. Dans cette optique, la méthode choisie se base sur des règles de décision aisément compréhensibles et elle permet d’obtenir un sous-ensemble de scénarios « les plus performants », qui laisse une latitude aux acteurs de la gestion dans le choix final qu’ils auront à opérer. Les résultats obtenus montre que la conservation n’est pas respectée, même en l’absence de prélèvement par la pêche sur au moins une rivière mais que dans la majorité des cas, le système de régulation actuelle est compatible avec la conservation. Ce travail de thèse, mené à l’échelle d’un ensemble régional tel que la Bretagne, constitue une première pour le saumon atlantique au travers de son aire de répartition. Il pourrait être étendue à d’autres entités spatiales car la méthodologie peut s’appliquer et s’ajuster facilement à différents contextes. Ce travail a permis de mettre en évidence que l’intensité actuelle des pêcheries récréatives ne constituait pas une menace substantielle pour le saumon en Bretagne. Pour mieux comprendre les différentes menaces et leurs impacts sur les populations bretonnes, il faudrait s’orienter vers une gestion plus écosystémique de la ressource.

International audience

This document presents an updated summary of the French purse seine fleet targeting tropical tunas in the Indian Ocean. The statistics cover the period 1981-2020 and specifically focus on the activity of the last year of the fishery. In 2020, a total of 13 French vessels operated in the western Indian Ocean including 10 purse seiners and 3 support vessels. The total capacity weighted by the months of activity for each vessel is 10626t. The total nominal effort in 2020 was of 1805 fishing days and 2414 sets with 1898 sets on floating objects and 516 on free schools. The total catch of the French component of the EU purse seine fleet of the Indian Ocean was 58149t, being composed of 42.2%, 52.6%, 4.5% and 0.8% of yellowfin tuna, skipjack tuna, bigeye tuna and other species respectively. The most noticeable change in 2020 was the decrease of 17.7% for the total of catches in comparison to 2019, respectively 58149t and 70622t. Remarkably, yellowfin tuna and skipjack tuna proportion of catches in 2020 for free swimming school returned to the proportion prevailing before 2018, after 2 years of a different fishing strategy targeting skipjack tuna on free swimming school.

In Martinique, some coastal species bivalves are harvested in mangrove swamps and beaches for consumption. Due to their habitat distribution and their life habits, these species are highly bio-accumulators of pollutants. Thus, these fisheries considered a priori, as localized by some authors, provide food resources potentially contaminated by pollutants. However, there is little data on the importance and characteristics of these fisheries; the quantitative assessment of the stock and the health status of the bivalves being unknown. In addition, since 2011, floating clumps of sargassum are more frequent and therefore lead to increased mortality in coastal biocenosis. These Sargassum algae are known for their ability to accumulate a large amount of metals in their tissues. The released of these substances and in particular arsenic by desorption or by decomposing algal biomass constitute a risk of contamination for coastal biocenoses but also for consumers of bivalves.In this thesis, the importance and characteristics of fisheries as well as of the main species caught were described. The impact of strandings on a bivalve population has been outlined and the state of contamination of the bivalves has highlighted the presence of significant contamination by some metals but especially by arsenic. The exposure of bivalve consumers to these metals has been estimated. These results reveal consumer exposure as the daily intake ranged from 1.6 mg.day-1 to 6 mg. day-1 for a meal of 240 g of bivalves. As arsenic has very toxic chemical species, the proportions of which in the flesh of bivalves could increase in the context of sargassum strandings, the consumption of these bivalves must be limited and away from periods of sargassum stranding. In order to preserve the health of consumers, toxicologic reference doses for all arsenic species present in the flesh of these bivalves are proposed and discussed, En Martinique, certaines espèces de bivalves, faciles à prélever, sont pêchées pour la consommation dans les mangroves et sur les plages. De part leur distribution et leur mode de vie, ces espèces sont hautement bio-accumulatrices de polluants. Ainsi, ces pêcheries considérées à priori, comme localisées par certains auteurs, fournissent des ressources alimentaires potentiellement contaminées par les xénobiotiques. Pourtant, il n’existe que peu de données sur leur importance et leurs caractéristiques et les stocks de bivalves n'ont pas fait l'objet de nombreuses évaluations et bilans sanitaires. De plus, depuis 2011, des radeaux de sargasses flottantes s’échouent de plus de plus fréquemment sur les rivages et provoquent lors de leur décomposition, une forte mortalité au sein des biocénoses. Ces algues sargasses sont connues pour leur capacité à accumuler une grande quantité de métaux dans leurs tissus. Le relargeage de ces substances et en particulier de l’arsenic par désorption ou lors de leur décomposition constitue un risque de contamination pour les biocénoses côtières mais aussi pour les consommateurs de bivalves. Dans le cadre de cette thèse, l’importance et les caractéristiques des pêcheries ainsi que des principales espèces péchées ont été décrites. L’impact des échouages sur une population de bivalves a été esquissé et l’état de contamination des bivalves a mis en évidence la présence d’une contamination importante par quelques métaux mais surtout par l’arsenic. L’exposition des consommateurs de bivalves à ces métaux a été estimée. Ces résultats révèlent une exposition des consommateurs car l’apport quotidien variait de 1,6 mg.jour-1 à 6 mg. jour-1 pour un repas de 240 g de bivalves. L’arsenic ayant des espèces chimiques très toxiques, dont les proportions dans la chair des bivalves pourraient augmenter dans le contexte des échouages de sargasses, la consommation de ces bivalves doit être limitée et éloignée des périodes d’échouages de sargasses. Dans le but de préserver la santé des consommateurs, des doses de référence pour toutes les espèces d’arsenic présentes dans la chair de ces bivalves sont proposées et discutées.

International audience

Overexploitation of fisheries resources leads to increasing competition between fisheries and marine biodiversity. This competition gives rise to depredation-type interactions (consumption of fish directly on the fishing gears by marine predators). Depredation has i) socio-economic consequences for fisheries (reduced yields); ii) ecological for marine predators (increased risk of bycatch or exposure to a lethal response) and iii) ecosystems (impacts on target and auxiliary resources). This thesis proposes to study, on one of the most lucrative fisheries, the most selective but also the most exposed to depredation, the decisional mechanisms (captains) and behavioural (marine predators) involved in the depredation exerted by the orcas (Orcinus orca) and sperm whales (Physeter macrocephalus) on the demersal longline fishery targeting Patagonian toothfish (Dissostichus eleginoides) in the French Exclusive Economic Zones of the Crozet and Kerguelen, Indian Ocean. By an original approach combining human and animal ethology against the backdrop of optimal foraging theory at two spatio-temporal scales, we show that i) this depredation is marked with a competition all the more important as the captains are experienced; (ii) odontocetes adjust their natural behaviour to benefit from the supply of food from the fisheries; (iii) no decision-making simultaneously allows high fishing yield and reduced depredation. These results highlight the importance of fisheries pressure on natural resources and the relevance of future bio economic and socio-ecosystem assessments to ensure the economic viability of fisheries and the sustainability of exploited and ancillary natural resources., La surexploitation des ressources halieutiques entraîne une compétition croissante entre les pêcheries et la biodiversité marine. Cette compétition donne lieu à des interactions de type déprédation (consommation des poissons directement sur le matériel de pêche par les prédateurs marins). La déprédation engendre des conséquences i) socio-économiques pour les pêcheries (diminution des rendements) ; ii) écologiques pour les prédateurs marins (risques accrus de capture accidentelle ou d’exposition à une réponse létale) et iii) écosystémiques (impacts sur les ressources cibles et auxiliaires). Cette thèse propose d’étudier, sur une des pêcheries des plus lucratives, des plus sélectives mais également des plus exposées à la déprédation, les mécanismes décisionnels (capitaines) et comportementaux (prédateurs marins) impliqués dans la déprédation exercée par les orques (Orcinus orca) et les cachalots (Physeter macrocephalus) sur la pêcherie à la palangre démersale ciblant la légine australe (Dissostichus eleginoides) dans les Zones Économiques Exclusives françaises des îles Crozet et Kerguelen, océan Indien. Par une approche originale combinant éthologie humaine et animale sur fond de théorie de l’approvisionnement optimal à deux échelles spatio-temporelles, nous montrons que i) cette déprédation est marquée avec une compétition d’autant plus importante que les capitaines sont expérimentés ; ii) les odontocètes ajustent leur comportement naturel pour bénéficier de l’apport de nourriture issue des pêcheries ; iii) aucune prise de décision ne permet simultanément un haut rendement de pêche et une déprédation réduite. Ces résultats soulignent l’importance de la pression exercée par les pêcheries sur les ressources naturelles et la pertinence de futures évaluations bioéconomiques et socio-écosystémiques pour assurer la viabilité économique des pêcheries et la durabilité des ressources naturelles exploitées et auxiliaires.

International audience

International audience; The introduction of ecosystem-based management measures for Baltic fisheries to achieve Good Environmental Status (GES) within the MSFD (Marine Strategy Framework Directive) and the HELCOM (Baltic Marine Environment Protection Commission) requires tools that can evaluate measures to reduce the spatial footprint on the seabed. We applied the DISPLACE modelling platform at the wide-scale Baltic Sea to evaluate the effect of different spatial fishery management measures such as area closures, both in terms of impact on benthic habitats and impacts on catch, revenue and profit for international fisheries. DISPLACE simulates individual fishing vessels (>12 m length using bottom-contact gears) and how they redistribute their fishing effort given spatial or temporal closures. A new module, informed from available science for projecting benthos dynamics in response to fishing pressure, provides quantification of depletion from fishing and recovery of specific benthic habitats and seabed types. This study evaluates different scenarios and trade-offs with the objective to identify effective measures to achieve GES by 2021 as stipulated by the Baltic Sea Action Plan. A suite of time and space mitigation scenarios are defined to compare the effects of a gradient of fishing restrictions and closures in different areas, habitat types, jurisdictions, breaking down to the impact from different type of gears and on several fisheries economics. The results obtained are intended to help the EU maritime policy in finding ways to improve the management of the Baltic Sea seafloor along reducing the human footprint induced by the fishing activities, while considering biological and economic impacts.

International audience

Antimicrobial resistance is a threat to global public health. Human can be contaminated by antibiotic resistant bacteria through food. However, data on antimicrobial resistant bacteria in seafood are scarce. The aim of this thesis was to study seafood bacterial flora and its antimicrobial resistance. First, mesophilic flora was obtained from 9 matrixes and MALDI-TOF and housekeeping genes sequencing technics were used to identify isolates. Antimicrobial resistance of most frequently bacteria were tested. In total, 1882 isolates were obtained and 150 bacterial species and 57 genera were identified. Enterococcus, Staphylococcus, Exiguobacterium, Pseudomonas, Vibrio and Proteus were most frequently isolated and their antimicrobial resistance was studied. Antibiotic resistant bacteria accounted for 46% of isolates and multidrug resistant bacteria accounted for 3% of isolates. Antimicrobial resistant bacteria were mostly isolated from shrimps. On a side study, antimicrobial resistance of a V.parahaemolyticus strain collection isolated from seafood was characterized. Antimicrobial resistant strains accounted for 15% and multi-drug resistant bacteria accounted for 3%. A NDM-1-producing multidrug resistant strain, 16-B3PA-006 was identified from shrimps imported from South-East Asia., La résistance aux antibiotiques est un enjeu de santé publique mondiale. L'alimentation est une des voies de contamination des bactéries résistantes aux antibiotiques entre l'environnement et l'Homme. Toutefois, les données concernant les bactéries résistantes aux antibiotiques dans les produits aquatiques sont rares. L'objectif de ces travaux a été d'étudier la flore bactérienne et sa résistance aux antibiotiques dans les produits de la pêche et de l'aquaculture. Dans un premier temps, la flore bactérienne mésophile cultivable a été isolée de 9 matrices différentes puis identifiée par la technique MALDI-TOF et/ou du séquençage de différents gènes de ménage. Au final, 1882 isolats bactériens ont été obtenus, et 150 espèces et 57 genres bactériens ont été identifiés. Dans un deuxième temps, nous avons étudié la résistance aux antibiotiques des genres bactériens les plus fréquemment isolés de ces produits. La résistance aux antibiotiques des genres Enterococcus, Staphylococcus, Exiguobacterium, Pseudomonas, Vibrio et Proteus a donc été étudiée. Au total, 46% des isolats étaient résistants aux antibiotiques et 3% étaient multi-résistants. Les crevettes étaient le produit dans lequel le plus de souches résistantes aux antibiotiques ont été identifiée. Et dans un troisième temps, la résistance aux antibiotiques d'une collection de souche de Vibrio parahaemolyticus, espèce bactérienne pathogène alimentaire pour l'homme, a été étudiée. Concernant V. parahaemolyticus, 15% des souches étaient résistantes et 3% des souches étaient multi-résistantes. Une souche, 16-B3PA-006, isolées de crevettes importées d'Asie du Sud-Est produisait une carbapénèmase NDM-1 et était résistante à 5 classes d'antibiotiques.

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Many marine predator species feed on fish caught by fishers directly from the fishing gear. Known as depredation this interaction issue has substantial socio-economic consequences for fishermen and conservation implications for the wildlife. Costs for fishers include damages to the fishing gear and increased fishing effort to complete quotas. For marine predators, depredation increases risks of mortality (lethal retaliation from fishers or bycatch on the gear). Longline fisheries are the most impacted worldwide, primarily by odontocetes (toothed whales) depredation, urging the need for mitigation solutions to be developed. Most of studies assessing depredation have primarily relied on surface observation data, thus the way odontocetes interact with longlines underwater remains unclear. Besides, the way fishermen respond to depredation during fishing operations, or can influence their detectability to odontocetes, have been poorly investigated. This thesis therefore aimed at investigating these aspects through a passive acoustic monitoring, bio-logging and human ecology approaches, focusing on the French Patagonian toothfish (Dissostichus eleginoides) longline fisheries impacted by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). Firstly, this thesis reveals that captains behave as optimal foragers but with different personal perception of competition and fishing fulfilment. Some captains would thus be more likely to stay within a patch or to haul closest longline even in presence of competition, suggesting these captains would show higher interaction rates. Additionally, the propagation of vessels’ acoustics varied depending on the type of manoeuvre (e.g. going backward vs. forward). The way captains use their vessels to navigate may therefore influence their detectability and so their depredation level. Secondly, loggers deployed on both the longlines (accelerometers) and odontocetes (GPS-TDR) revealed that killer whales and sperm whales are able to depredate on longlines while soaking on the seafloor. These observations suggest, therefore, that odontocetes can localise fishing activity before the hauling, which could be partially explained by specific acoustic signatures recorded during the setting process. Altogether, the results of the thesis suggest that depredation rates on demersal longlines are most likely underestimated. The thesis also brings some important insights for mitigation measures, suggesting that countermeasures should start from setting to hauling., De nombreux prédateurs marins se nourrissent directement des prises des pêcheurs. Ces interactions, définies comme de la déprédation, engendrent des conséquences socio-économiques considérables pour les pêcheurs ainsi que des implications de conservation pour la faune sauvage. D’un côté, la déprédation endommage le matériel et augmente l’effort de pêche pour atteindre les quotas. D’un autre côté, la déprédation augmente le risque de mortalité des prédateurs marins (prise accidentelle ou rétorsion létale par les pécheurs). La pêcherie à la palangre est la plus impactée par la déprédation, principalement par les odontocètes, ce qui incite à trouver des solutions. La majorité des études se concentrant sur la déprédation s’est principalement basée sur des observations en surface, de ce fait la manière dont les prédateurs retirent les poissons sur les lignes reste confuse. Par ailleurs, l’impact de la déprédation sur le comportement des pêcheurs ainsi que les facteurs expliquant leur détectabilité n’ont reçu que peu d’intérêt. L’objectif de cette thèse est donc d’étudier ces problématiques par un suivi acoustique, une utilisation de balises et une approche en écologie comportementale humaine, en se concentrant sur la pêcherie palangrière française ciblant la légine australe (Dissostichus eleginoides) impactée par la déprédation des orques (Orcinus orca) et des cachalots (Physeter macrocephalus). Les capitaines ont été décrits comme recherchant leur ressource selon la théorie de « l’optimal foraging », mais avec des perceptions de la compétition et du succès de pêche qui divergent. Certains capitaines seraient ainsi plus enclins à remonter les palangres au plus proche et à rester sur une zone, même en présence de compétition, augmentant alors le risque d’interaction. L’acoustique des navires a révélé que certaines manoeuvres (marche arrière par exemple) propagent différemment sous l’eau. La manière dont les capitaines manoeuvrent leur palangrier influencerait ainsi leur détectabilité et donc leur risque d’interaction avec les prédateurs. D’autre part, l’utilisation de capteurs sur les palangres et les animaux a révélé que les orques et les cachalots sont capables de déprédater sur les palangres posées sur le fond marin. Ces observations laissent à penser que les odontocètes sont en mesure de localiser l’activité de pêche bien avant la remontée de la ligne, ce qui pourrait être expliqué par une signature acoustique spécifique du déploiement de la ligne. L’ensemble des résultats de cette thèse suggère que la déprédation sur les palangres démersales est très probablement sous-estimée. Cette thèse apporte également des éléments importants pour la lutte contre la déprédation, en montrant la nécessité de protéger les palangres dans l’intégralité du processus de pêche.

To understand the genetic basis of coping style in European seabass, fish from a full factorial mating (10 females x 50 males) were reared in common garden and individually tagged. Individuals coping style was characterized through behavior tests at four different ages, categorizing fish into proactive or reactive: a hypoxia avoidance test (at 255 days post hatching, dph) and 3 risk-taking tests (at 276, 286 and 304 dph). We observed significant heritability of the coping style, higher for the average of risk-taking scores (h2 = 0.45 ± 0.14) than for the hypoxia avoidance test (h2 = 0.19 ± 0.10). The genetic correlations between the three risk-taking scores were very high (rA = 0.96-0.99) showing that although their repeatability was moderately high (rP = 0.64-0.72), successive risk-taking tests evaluated the same genetic variation. A mild genetic correlation between the results of the hypoxia avoidance test and the average of risk-taking scores (0.45 ± 0.27) suggested that hypoxia avoidance and risk-taking tests do not address exactly the same behavioral and physiological responses. Genetic correlations between weight and risk taking traits showed negative values whatever the test used in our population i.e. reactive individual weights were larger. The results of this quantitative genetic analysis suggest a potential for the development of selection programs based on coping styles that could increase seabass welfare without altering growth performances. Overall, it also contributes to a better understanding of the origin and the significance of individual behavioral differences.

The national marine turtles recovery plan in FWI was adopted in 2006 by the National council for the nature conservancy. The bottom nets bycatch, i.e. the trammel, folle and gill nets, on the continental shelf are the main threat. Experimental nets with different heights, meshing and incline was compared to professional ones during 226 experimental trials. Trammel net is non selective. Low profile nets maintain a similar productivity and reduce the turtle bycatch. Trammel and folle nets cause more bycatch. The long soak times lead to more than 90 % of turtles mortality and more discards. Each year, about two thousands of turtles would be captured in FWI, with a mortality rate closed to 60 %. The mature turtles were captured during the nesting season and the resident ones are mostly juveniles or sub-adults, because of the local past overexploitation and indicator of non stable populations. The “fishery” threat is particularly important it affect nesting females, best stocks recovery hope. Closely to the marine professionals, the marine turtle and resources protection would be effective thanks to the reduction of the height and soak times nets and the total or partial ban of large meshing size nets., Le plan de restauration des tortues marines aux Antilles françaises a été validé par le Conseil National pour la Conservation de la Nature en 2006. Les captures accidentelles dans les filets de fond, i.e. les trémail, folle et filet droit, sur le plateau continental constituent la principale menace. Des filets faisant varier la hauteur, le maillage et l’inclinaison ont été comparés à des filets professionnels au cours de 226 pêches expérimentales. Le trémail est peu sélectif. Des filets à profil bas permettent d’obtenir des rendements comparables et réduiraient les captures de tortues. Les captures accidentelles sont plus abondantes dans les trémails et les folles. Les pêches à longs temps de calée provoquent plus de 90% de taux de mortalité de tortues et augmentent les quantités de rejets. Près de deux milliers de tortues seraient capturées chaque année aux Antilles françaises, avec une mortalité avoisinant les 60%. Les tortues adultes pêchées l’ont été en période de nidification et les tortues dites résidentes sont dans la grande majorité des juvéniles ou sub-adultes, cause de la surexploitation locale passée et signe de populations non stables. La menace « pêche » est d’autant plus importante qu’elle touche les femelles nidifiantes, meilleurs espoirs de rétablissement des stocks. En étroite collaboration participative avec les professionnels de la mer, la protection des tortues et des ressources marines passerait par une réduction de la hauteur des filets et de leurs temps de calée et l’interdiction totale ou partielle de ceux à mailles larges.

Coastal fisheries in Pacific island countries are characterised by a strong predominance of catches for subsistence purposes which involves mainly finfish and is difficult to quantify. In 1997–1998, a consumer survey conducted in the Northern Province of New Caledonia (Southwest Pacific Ocean) made it possible to indirectly estimate subsistence fishing production. Catch from subsistence fishing did not result in a significant change of the exploitation potential. The catch composition of subsistence fishing differed significantly from commercial fishing, with a higher proportion of species less vulnerable to exploitation. Interpretation of the consumer typology highlighted the importance of factors such as ethnic group and geographical location in explaining eating habits and therefore, indirectly, fishing behaviours. These results suggest that this fish consumption survey could assist in the design of subsistence fisheries monitoring programmes.

Partial or total replacement of fish meal by a mixture of plant protein (PP) sources (corn gluten, wheat gluten, extruded peas, rapeseed meal and sweet white lupin) balanced with indispensable amino acids was examined in juvenile gilthead sea bream over the course of a 6-month growth trial. A diet with fish meal (FM) as the sole protein source was compared to diets with 50%, 75% and 100% of replacement (PP50, PP75, and PP100). The possible influence of diets on growth performance, plasma metabolites, gut integrity, liver structure, anti-oxidant and immune status was evaluated. Final body weight was progressively decreased with PP inclusion, but in PP50 and PP75-fed fish, feed efficiency (FE) was significantly improved and specific growth rates remained unchanged or slightly reduced in comparison to fish fed the FM diet. In fish fed PP100 diet, FE remained unchanged and feed intake and growth decreased dramatically. In this group of fish, liver fat deposition was also largely increased, enterocytes showed an increased number of lipidic vacuoles and/or deposition of protein droplets, and the submucosa of intestine was dilated/hypertrophied and infiltrated with eosinophilic granular cells. Plasma glucose levels did not differ among the four groups, but a significant and progressive decrease of plasma cholesterol and plasma protein levels was found with FM replacement. The glutathione redox status in blood and liver increased with the increase of PP content and this increment was statistically significant in the liver of the three PP-fed groups. Glutathione reductase and gamma-glutainyl transferase were also enhanced by PP inclusion. Plasma lysozyme levels were not altered by the dietary treatment, but respiratory burst of head kidney leucocytes and plasma myeloperoxidase values were significantly increased in PP75 and PP100 fish, respectively. Complement (ACH(50)) was significantly increased in PP50 fed fish and decreased in PP75 and PP100 groups. As a general conclusion, substitution of FM by a mixture of PP sources exerted an anti-oxidative effect, compromised growth performance only at the 100% level, and decreased one of the immune defence mechanisms at above 75% level. (c) 2005 Elsevier B.V All rights reserved.

Related sib-groups of rainbow trout × brown trout and rainbow trout × brook charr triploid hybrids and monospecific diploid and triploid rainbow trout controls were obtained from a common set of rainbow trout dams. On the basis of hybrid juvenile performances, 10 sib-groups were selected and the corresponding diploid rainbow trouts were raised up to adult stage. Females from each group of rainbow trout were used to produce a second generation of hybrid progeny, the performances of which were analysed for grandmaternal variation and relation with first-generation relatives. Results showed that hybrid traits (alevin yield and weight, survival and growth of fingerlings) were strongly influenced by maternal origin, and could be correlated to those of rainbow trout controls, but that maternal abilities had a low rate of inheritance. It was concluded that little improvement can be expected through selective breeding within parental populations.

Two diets based oil fish meal (FM) or oil a mixture of plant protein sources supplemented with free amino acids (PP) were fed to rainbow trout having a mean initial body weight of 162.5 g reared at 17 +/- 1 degreesC for 24 weeks to evaluate the effect of plant protein sources oil fish growth, morphological and body quality traits. At the end of the growth study, samples were withdrawn for chemical analyses as well as measurements of different parameters of quality. Compared to the FM group, the trout fed diet PP had lower growth rates (mean final body weight 663 vs. 800 g), feed efficiency (0.95 vs. 1.07) and protein efficiency ratio (1.96 vs. 2.13). Trout fed diet PP were also characterised by a lower dressed weight (89.45% vs. 91.07%), hepato-somatic index (0.92% vs. 1.01%) and fillet lipid content (5.50% vs. 6.98%), but had a higher mesenteric fat (5.65% vs. 4.08%), viscero-somatic index (10.55% vs. 8.93%) and fillet crude protein content (20.53% vs. 19.93%). The muscle fatty acid composition reflected that of the diet with a higher level of polyunsaturated (n-6) fatty acids in trout fed diet PP and a higher content in polyunsaturated n-3 fatty acids and n-3/n-6 ratio in trout fed diet FM. Sensory analysis was carried out at 5 days post-mortem on microwave-cooked dorsal portions of fillets stored at 1 degreesC with ice covering. The results of the triangular test showed differences between groups (P

The present work aimed at evaluating whether solubility and peptide profile of dietary protein can affect survival and growth performance of common carp during early stages of life. Water-insoluble casein and two forms of soluble casein (non-hydrolysed and hydrolysed) were used as protein sources at different proportions in the experimental diets for first-feeding carp larvae. When provided as the only protein source water-insoluble casein led to high mortality and depressed growth after 21 days. The partial or total substitution of water-insoluble casein by soluble non-hydrolysed casein effectively improved survival and enhanced growth of larvae. An optimum level of soluble non-hydrolysed protein was found at 25% of total protein. The addition of some hydrolysed casein (25% of soluble protein) further improved results. However, high dietary levels of hydrolysed casein led to negative effects on larval performance, which would be related with a surplus of di-/tripeptides or/and amino acids. Protein solubility appears to have only a temporary effect on larval performance, probably related with the ontogeny of the digestive tract, since about 2 weeks after the onset of exogenous feeding larvae became able to use efficiently water-insoluble protein. Results also suggest the need for a balance in the peptide profile to optimise the utilization of dietary protein by fish larvae.

Five practical diets in which the supply of protein from fish meal was decreased gradually from 100% to about 2% and replaced by plant protein sources were formulated. European seabass weighing about 190 g were fed these diets for 12 weeks at a water temperature of 22 °C. Feed was dispensed using automatic self-feeders and voluntary feed intake (VFI) was closely monitored. We did not find any significant difference among diets in the apparent digestibility coefficients (ADC) of dry matter (80–82%), protein (94–96%), energy (88–92%) or phosphorus (49–58%). Replacement of fish meal by plant protein ingredients did not influence VFI. All groups had very good growth rates (DGI above 1.3%/day) and there were no significant differences in growth rate, feed efficiency or in daily nitrogen gains among groups. There was, however, a slight increase in fat deposition in fish fed diets with plant protein sources. Ammonia nitrogen and soluble phosphorus excretion rates were measured. Nitrogen and phosphorus balance studies indicated that fish meal replacement by plant ingredients led to a slight increase in nitrogen losses (from 83 to 103 g N/kg weight gain) but led to a significant reduction in total phosphorus losses (from 13 to 5 g P/kg weight gain). These results combined with the remarkable acceptability of diets containing high levels of plant protein ingredients with identical growth performances of European seabass show clearly that dietary fish meal levels can be considerably reduced without any adverse consequence in terms of somatic growth or nitrogen utilisation.

The model used by the early Internet, with public folders and repositories, to develop new content and transmit them, is almost exhausted. This is a book that might help us remember that if nobody comes to your webpage, that if you restrict yourself to talk about yourself without asking questions; conversely, if one facilitates a range of responses and promotes them building an exciting thing, if quarterly objectives are established, if there is always a long time horizon. Then access is provided to the new and easy-to-use tools known as Web 2.0, which people use to be connected giving rise to web-based social networks, working together with others and promoting many other personal interactions. Web 2.0 means that we can build bridges between the online world and those who are off line. The book provides readers with a resource list of basic readings (which they want to consider using), and the practical exercises that will help feel the essential energy of Web 2.0 and social media for development in fisheries and aquaculture. The challenge embodies many elements that must work together to make sure that a high profile on social networks means as many people as possible with which we share a range of common interests., El modelo usado por la antigua red, en base a carpetas compartidas y repositorios, para desarrollar nuevos contenidos y transmitirlos se agota. En éste libro se propone recordar que si nadie visita tu página, que si uno se limita a hablar de si mismo sin formular preguntas, que si por el contrario facilita respuestas y las promociona construyendo algo excitante, si establece objetivos trimestrales, y si siempre tiene un horizonte a largo término. Entonces accede a las nuevas y fáciles de usar herramientas que se conocen como Web 2.0, las cuales conectan gente dando lugar a redes sociales, colaborando y promocionando muchas otras formas de interacción personal. Web 2.0 significa que podemos lanzar puentes entre los que están en línea y los que están fuera de línea. El libro proporciona a sus lectores tanto las lecturas básicas, que abarcan los principales temas, como los ejercicios prácticos con los que explorar elementos esenciales de la Web 2.0 y los medios sociales para el desarrollo en pesca y acuicultura. El desafío es el de los muchos elementos que tienen que trabajar juntos para que presencia en redes sociales signifique un máximo de personas con intereses comunes a nosotros., Le ancien modèle utilisé par Internet, avec les dossiers ouverts et les dépôts publics, pour développer des contenus innovants et permetre leur transmission, est presque épuisé. Ce livre est écrit pour avertir que si personne ne vient jamais visiter votre page Internet, si vous vous limitez à parler de vos problèmes sans poser des questions; à l'inverse, si on facilite des réponses et on assure leur promotion pour élaborer une nouvelle chose passionnante, si des objectifs trimestriels sont établis, si l'on compte toujours sur un horizon disposant d'une longue période. Alors l'accès est franchi aux nouveaux outils simples à utiliser que l'on connaît aujourd'hui sous le nom "Web 2.0", que les gens utilisent pour être connectés et provoquer des réseaux sociaux sur le Web, en travaillant ensemble avec d'autres, et en promouvant de nombreuses autres interactions personnelles. Web 2.0 implique que nous pouvons construire de ponts entre le monde en ligne sur Internet et ceux et celles qui sont hors ligne. Le livre présent aux lecteurs une liste des lectures fondamentales (qui pourrait leur intéresser), et les exercices pratiques qui leur aidera à mieux maîtriser l'énergie essentielle du web 2.0 et des médias sociaux, pour le développement dans les secteurs de la pêche et de l'aquaculture. La difficulté incarne de nombreux éléments qui doivent travailler ensemble pour assurer qu'une haute visbilité sur les réseaux sociaux signifie qu'un nombre aussi élevé que possible de personnes partagent un éventail de questions qui nous intéressent.

A 21-day feeding trial was carried out to investigate the ability of first feeding European sea bass larvae to utilize medium-chain triacylglycerols as an alternative source of energy. Three compound diets based on soluble fish protein concentrate and yeast were supplemented with either 3% tricaproin (TC6), tricaprylin (TC8) or tricaprin (TC10). A diet containing triolein (TOL) was used as a reference diet. Diets were tested on four replicate groups of first feeding European sea bass larvae at 20°C, i.e. 6 days after hatching. At the end of the 21-day trial, TC8 yielded significantly higher survival (57±8% vs. 28±11% for the three other groups). Considered together, larvae fed TC8 and TC6 displayed better growth rates than larvae fed TOL and TC10 (final mean wet weights: 1.5±0.3 mg vs. 1.2±0.2 mg, respectively). The fatty acid composition of larval total lipid revealed a low deposit of medium-chain fatty acids (between 1 and 3% of total fatty acids) suggesting that medium-chain fatty acids were oxidized for energetic purposes. Tricaprylin and to a lesser extent tricaproin, appear to be potential energy sources for first feeding European sea bass larvae reared on compound diets.

This study was performed to assess growth rate, feed efficiency, and N and P loss of sea bass (initial body weight 3.5 g), held in 500-l tanks under ambient temperature and natural light, and fed according to the following methods: by automatic feeders that released feed continually in daylight according to feed manufacturers' recommendations (AF100%); half of the above continually in daylight (AF50%); half of the above again but in two meals only (AF50%M); and by self-feeders that supplied feed at low (SFL), medium (SFM) and high (SFH) reward. None of the feeding conditions affected the survival rate of fish. SFL fish had the highest specific growth rate, while AF50% and AF50%M the lowest. Population weight distribution in the restricted automatic-fed fish (AF50% and AF50%M) was more homogenous compared to the other feeding conditions. These two practices produced high feed efficiency ratios (0.93 and 0.95, respectively), compared to the AF100% (0.57) and self-fed ones (SFL: 0.60; SFM: 0.37; SFH: 0.21). Self-feeding at low reward of 0.6 g trigger −1 could be considered as the optimum feeding practice, combining higher weight gain, lower N and P loss, and intermediate feed supply compared to the other treatments. In the SFH method, fish did not adjust their manipulation of the self-feeders according to their feed needs. Daily feeding activity in all self-fed fish groups was independent of feeding reward.

A 21-day feeding trial was carried out to investigate the ability of first-feeding carp larvae to utilize medium-chain fatty acids (MCFA). Six semi-purified diets, with a common casein and soluble fish protein concentrate basis, were tested on triplicate groups of 400 larvae. The diets were isolipidic (23–24% of dry matter). They differed only by triacylglycerol supplementation (10% of diet) which consisted of either triolein (TO), coconut oil (CO) or tricaprylin (TC) alone or in combination of two of these (TO+CO, CO+TC, TO+TC). Survival and growth rates of larvae fed with CO or TO were high (survival 95–97%, mean wet weight 60–67 mg after 21 days). Addition of TC (5 or 10% of diet) induced a significant mortality as early as 11 days of feeding and resulted in a final survival of less than 6%. TC also led to reduced growth rates (final mean larval weight 6–13 mg). The fatty acid (FA) composition of larvae fed with TO or CO reflected that of the diets with high levels of oleic acid (42% of total FA) in larvae fed with TO and lauric and myristic acids (17 and 10% of total FA, respectively) in larvae fed with CO. In contrast, larvae fed with TC contained only traces (0.3% of total FA) of caprylic acid but had higher levels of capric acid than other larvae (6% vs. 1–2%). Present results indicate an important difference in the utilization between MCFA supplied as CO (12:0) and TC (8:0).

Gilthead seabream were fed a fish meal based diet, supplemented with graded amounts of ascorbyl polyphosphate equivalent to 0, 25, 50, 100 and 200 mg of l -ascorbate (AA)/kg, for 12 weeks. Although there were no significant differences between growth rates of each group, the feed gain ratio and voluntary feed intake were significantly lower, and the protein efficiency ratio was significantly higher for the fish fed 200 mg AA/kg, when compared with the group fed 0 mg AA/kg. An increase of the ascorbate concentration within the liver and spleen occurred with the increasing vitamin supplementation. After 12 weeks, the fish were subjected to hypoxia for 24 h to determine the influence of AA supplementation on the physiological response to this stressor. A significant hyperglycaemia occurred in fish fed all the diets 3 h after the onset of stress, although a significantly higher resting plasma glucose was observed in fish fed the AA free diet. No significant difference was found in plasma cortisol concentration with stress, with the exception of fish fed the 100 mg of AA/kg diet, where a significantly lower cortisol level was found after 9 h of hypoxia. Fish fed the non-supplemented diet showed wider variation and a tendency to increase this variable, having significantly higher levels at 9 h and 24 h of stress then all the other groups and than fish fed the 200 mg AA/kg diet, respectively. Stress had no detectable effect on liver AA concentration in all groups. However, spleen AA showed significantly increased levels between 3–6 h of hypoxic stress in fish fed 25 and 200 mg AA/kg diet and a further increase after 9 h in fish fed the 200 mg of AA/kg diet. These results suggest that the ascorbic acid requirements for seabream is less than 25 mg/kg diet based on a 12-week growth study and that it requires about a four-field increase in weight before signs of deficiency can be observed. Also, the fact that no variation in liver vitamin C concentration was be detected as a response to stress, suggests that this kind of stress does not significantly increase the utilization of this vitamin. However, a possible relation between dietary ascorbate and the physiological response to hypoxia was found, since the fish receiving the non-supplemented diet showed increased plasma glucose and a tendency to have wider plasma cortisol variations than the fish fed the supplemented diets.

Histological observations were made in common carp larvae in order to understand the origin of the phospholipid (PL) requirement of fish during their young stages. Larvae were fed for 6 or 8 days after start-feeding on semi-purified diets containing peanut oil and supplemented with or without different PL fractions enriched in phosphatidylcholine (PC) or phosphatidylinositol (PI). A group of larvae was also fed Artemia nauplii. Dietary PL deficiency was associated with an accumulation of fat droplets in the enterocytes of the anterior intestine, an increase in height of mucosal epithelium, a reduced total liver volume and mean hepatocyte volume. In contrast, diet supplementation with PC from hen egg yolk or from soybean prevented the intestinal steatosis and resulted in larger liver volume and larger hepatocyte volume. Larvae fed Artemia showed the same features as larvae fed PC-enriched diets. Hydrogenated PC also prevented the intestinal steatosis but resulted in small liver and hepatocyte size. Larvae fed PI-enriched diets exhibited intestinal steatosis, although less systematically than larvae fed PL-deficient diets, and reduced liver and hepatocyte size. Results support previous opinions that PL are needed for the absorption of neutral lipids although their beneficial effect appears to be independent of their emulsifying properties. The limiting stage seems to be the synthesis and exportation of chylomicrons or very low density lipoprotein (VLDL) by the enterocytes and not the intraluminal formation of micelles. PC appears to have a specific role for chylomicrons and VLDL synthesis and secretion, as in mammals. The reduced liver and hepatocyte size in the absence of PC could result from a decreased energy supply due to poor lipid absorption.

The aim of this thesis was to study the feeding habits of coastal fish species of commercial interest andto use stable isotopes of carbon (δ13C) and nitrogen (δ15N) to investigate the trophic niches of fish and their use of coastal habitats in the south-west Indian Ocean. In the Bay of La Possession, the species among the most abundant around the artificial reefs immersed in 2003 (Luljanus kasmira, Priacanthus hamrur and Selar crumenophthalmus) feed essentially on pelagic prey and partition their trophic niche to limit interspecific competition. There was also a positive correlation between fish size and muscle δ15N values due to fish larvae contributing more to the diet of fish with age. The stable isotopie composition of the particulate organic matter (POM) was measured at the microscale (< 10 km) in the Bay of La Possession, the mesoscale (10's of km) around Reunion Island and, for the fish muscles, at the macroscale 100’s of km) along the Mascarene plateau and the Mozambique channel. At microscale, POM δ15N values do not show any spatial variability; at mesoscale, POM is 15N-enriched in the south-west of Reunion Island; at macroscale, fish muscles are gradually 15N-enriched towards the north. At microscale, POM shows a 13C-enrichment on the shallowest station; at mesoscale, stations on the east coast of the island are 13C-enriched compared to the west; at macroscale, POMδ13C values are not significantly correlated with latitude. Thus, the stable isotopes of carbon do not seem to be appropriate for the study of fish coastal habitat use at the meso- and macroscale, and the stable isotopes of nitrogen represent a better indicator of fish habitat use at the macroscale., L'objectif de cette thèse est l'étude du régime alimentaire de poissons côtiers commerciaux et la compréhension de l'utilité des isotopes stables du carbone (δ13C) et de l'azote (δ15N) dans l'étude des niches trophiques et de l'occupation des habitats côtiers par les poissons dans le sud-ouest de l'océan Indien. Dans la Baie de La Possession, les espèces représentatives des récifs artificiels immergés en 2003 (Luljanus kasmira, Priacanthus hamrur et Selar crumenophthalmus) ingèrent surtout des proies pélagiques et partitionnent leurs niches trophiques afin de limiter la compétition. Les valeurs de δ15N sont positivement corrélées avec la taille des poissons, traduisant une contribution croissante des larves de poissons au régime alimentaire. Les isotopes stables de la matière organique particulaire (MOP) ont été analysés à microéchelle (< 10 km) dans la Baie de La Possession, à mésoéchelle (10aines de km) autour de La Réunion et, pour les muscles de poissons à macroéchelle (l00aines de km) le long,du plateau .des Mascareignes.et du cana1 du Mozambique. À microéchelle, le δ15N de la MOP ne varie pas; à mésoechelle, Il existe un enrichissement significatif en 15N dans le sud-ouest de l'île; à macroéchelle, les muscles des poissons s'enrichissent progressivement en 15N vers le nord. À microéchelle, la MOP est enrichie en 13C à faible profondeur; à mésoéchelle, les stations de l'est sont enrichies en 13C ; à macroéchelle, aucune tendance n'est observée. Ainsi, l'utilité des isotopes stables du carbone pour l'étude de l'utilisation des habitats côtiers est limitée à méso- et macroéchelle et les isotopes stables de l'azote constituent un outil plus pertinent à macroéchelle

La méconnaissance des stratégies de pêches développées par les pêcheurs thoniers à la senne (utilisation de nouvelles technologies, changement d’espèces cibles, choix des zones de pêche) rend incertaine la quantification de l’effort de pêche effectif utilisable dans l’évaluation des stocks et ne permet pas d’anticiper l’efficacité des mesures spatio-temporelles de gestion des stocks. Nos travaux ont montré que le concept de capture par unité d’effort rend compte de plusieurs activités de pêche successives (recherche des zones de concentrations des bancs, détection visuelle d’un banc de thons, réalisation et succès de la calée, etc.) au cours desquelles interagissent les décisions prises par les pêcheurs et les progrès technologiques introduits à bord. En l’absence d’estimation directe de l’abondance due à la nature de la pêche thonière, nous avons utilisé des données de marquage-recapture comme source additionnelle d’information pour mieux évaluer, dans une approche plurispécifique, les interactions entre ressource et exploitation. Nos travaux s’effectuent en coopération avec les partenaires du Sud (affectations, encadrements, missions de soutien) et dans un contexte de restitution des connaissances sous forme d’expertise auprès des Commissions thonières internationales et des administrations des pêches nationales ou européennes.

Awareness of natural resource limitation was raised since the first fish stock collapse, promoting the need of efficient management tools for sustainable exploitation of resources. In contrast with other, more widely used management tools, artificial reefs (AR) try to keep the equilibrium of sustainable exploitation trough the physical alteration of natural habitats in order to enhance local fish production. The alteration of natural seascapes by AR implantations impacts reef fish populations and communities. We investigated some of the potential effects of the AR from Leucate – Le Barcarès (LB; NW Mediterranean) using underwater visual counts, landing surveys and acoustic tagging on white sea bream (Diplodus sargus). The ARs of LB were used as essential habitat by white sea breams, particularly for refuge and foraging. Furthermore, functional diversity on these ARs was higher than on a natural reef location, which could convey an increased carrying capacity and fish production on the French Catalan sandy coast. These effects are nevertheless not directly visible on fish landings and production, due to lower fish catchability on ARs. Moreover, habitat alteration by ARs arises new movement patterns of the white sea bream suggesting individual specialization within the realized niche of white sea breams from the French Catalan sandy coast. Individual specialization can have implications on functioning of food webs and ecosystem resilience, but also more long term consequences as speciation by mating isolation. These potential effects of ARs on coastal fish communities and populations should be taken into account for future AR projects., Depuis les premiers effondrements de stocks de poissons, l’Homme a pris conscience que les ressources naturelles étaient limitées et que pour les exploiter de manière durable, il était important de trouver des outils de gestion. Contrairement aux autres outils de gestion des ressources halieutique existants, les RA sont les seuls dont l’objectif est de maintenir l’équilibre de l’exploitation durable des ressources en cherchant à augmenter localement la production des ressources par l’action directe sur le milieu physique. En modifiant les paysages sous-marins, les RA impactent les communautés et les populations de poissons inféodées aux récifs rocheux. Le suivi des communautés de poissons par le comptage visuel en plongée, le suivi des débarquements de pêche et plus particulièrement du sar commun (Diplodus sargus) par le marquage acoustique ont permis d’apporter des réponses sur certains effets des récifs artificiel de Leucate – Le Barcarès (Golfe du Lion, NO Méditerranée) sur l’écologie des poissons. L’utilisation des récifs artificiel (RA) de Leucate – Le Barcarès (LB) par le sar commun comme habitat essentiel de refuge et de nutrition, ainsi que la grande diversité fonctionnelle des RA de LB mènent à penser que ces nouveaux habitats plus complexes augmentent la capacité écologique et ainsi la production de la côte catalane française sableuse. En revanche ces effets ne se retranscrivent pas dans les débarquements des pêcheurs artisanaux de la zone en raison d’une plus faible capturabilité sur les RA. De plus la modification de l’habitat par l’implantation des RA fait émerger de nouveaux patrons de déplacements chez le sar commun, traduisant la spécialisation individuelle au sein de la niche réalisée de la population de sars commun de la côte catalane française sableuse. La spécialisation individuelle peut avoir des conséquences écologiques sur le fonctionnement des réseaux trophiques et la résilience des écosystèmes, mais également évolutives à plus long terme comme la spéciation par l’isolation reproductive. Ces effets potentiels des RA sur les communautés et populations de poissons sont à prendre en considération dans les futurs projets d’implantation de RA.

The spatial distribution of human activities and decision-making support for the sustainable management of coral reef ecosystems: Recreational boat fishing in the south west lagoon of New-Caledonia. The coral reef resources in the New Caledonian lagoon are under growing pressure due to fishing activities. This is especially true in the south west where two thirds of the population and of private boats, whose owners are mainly recreational fishers, are located. In order to limit the pressure, it is necessary to manage the resources as well as the users in a sustainable manner, by developing knowledge on their fishing behaviours and their spatial dynamic. An historical approach exposes the evolution of the human communities’ fishing practices. The analysis of questionnaires targeting fishers from oct. 2004 to oct. 2005, enabled the study of their fishing behaviours influenced by social, economical, cultural or external factors and to determine a typology of the fishers and their fishing trips. Moreover, aerial flights were carried out throughout 2006 to assess the annual activity. These two methods were used to realize a spatial analysis in order to understand the way fishers create their own fishing territories, the spatial dynamic of the fishing activity in response to different criteria, and to assess the fishing pressures and impacts of boating and boat fishing activities. Fishers still consider that some areas in the lagoon are under threat in spite of the management of the lagoon environment. However, the way environmental management has been conceived has changed with the enlistment of the Caledonian coral reefs on the UNESCO world heritage list in 2008. The social acceptability of the management measures as well as the notion of heritage have been considered in order to propose a set of perspectives related to the management policies for resources and ecosystems., Les écosystèmes récifo-lagonaires de la Nouvelle-Calédonie subissent une pression de pêche croissante surtout dans le sud-ouest, où se concentrent les deux tiers de la population et des bateaux de plaisance dont la majorité des propriétaires pratique la pêche. Pour limiter les pressions,il est nécessaire de gérer durablement la ressource et les usagers en développant la connaissance de leurs comportements de pêche et de leur dynamique spatiale. A travers une étude historique est exposée l’évolution des pêches pratiquées par les groupes humains. L’analyse de questionnaires proposés aux pêcheurs entre oct. 2004 et oct. 2005 a permis de réaliser une étude des comportements de pêche, influencés par des facteurs sociaux, économiques, culturels ou externes et de déterminer des typologies des pêcheurs et des sorties de pêche. Aux questionnaires s’ajoute une série de survols aériens réalisés en 2006 pour estimer l’activité annuelle. L’analyse spatiale réalisée à partir de ces méthodes a permis de comprendre les processus de territorialisation, de connaître la dynamique spatiale de l’activité de pêche selon différents critères, et d’estimer les pressions et impacts de la plaisance et de la pêche plaisancière. Les pêcheurs estiment qu’il existe des zones en danger dans le lagon, bien que la gestion de l’environnement ne soit pas récente. La conception de la réglementation a fortement évolué depuis l’inscription des récifs coralliens au patrimoine mondial de l’UNESCO en 2008. Enfin, une réflexion sur l’acceptabilité sociale des mesures de gestion et sur la notion de patrimoine conduit à proposer des perspectives pour aider la politique de gestion des ressources et des écosystèmes.

International audience; The assessment of socio-economic effects of marine protected areas on fishing activity points out some methodological difficulties. As a methodology we propose a selection of two components : the fishing unit profitability and the fishery household income distribution and a comparison between a marine protected area versus an “unprotected zone”. The methodology has been applied on a case study: the Chumphon National Park versus the Chumphon Province (Gulf of Thailand). Three phases have been implemented: a bibliographical analysis, the carrying out of village monographs, the carrying out of a sample-based survey. The sample-based survey results are presented as follows : the characterization of categories of the variable “marine protected area” by quantitative variables, a multivariate analysis, the performance of Chi-square tests on the relationship between a “profit per fishing day” variable divided into two categories (“in or around MPA” and “remote from the MPA”, the measurement of the concentration of income or operating profit per fishery household and the Lorenz curves.

The macro-benthic communities of Mont-Saint-Michel Bay, located in the Norman-Breton Gulf (English Channel) along the French coast, are mainly dominated by filter-feeders which include cultivated species (oysters and mussels). The decline in shellfish farms production and the significant spreading of the invasive slipper-limpet Crepidula fornicata have conducted scientists and stakeholders to undertake a reflexion on the trophic balance between cultivated and wild (native or invasive non-native) filterfeeders. An ecological model of the bay was developed, coupling a 2D hydro-sedimentary model along with biological models for primary production and filter-feeder growth. The objectives of the project were first to provide indicators to stakeholders on the future evolution of the trophic resource taking in account environmental modifications and human pressure, and establish with them the scenarios to be developed by the model. To accomplish these objectives different focus groups were organised between scientists and stakeholders. Based on these exchanges scenarios on shellfish practices, watershed runoffs and Crepidula fornicata spreading, were investigated through numerical modeling tools. Then results of the models were presented to 6 stakeholders' focus groups and a social scientist has analysed first the interaction between scientists and stakeholders, second the perception of the models by the stakeholders and the ideas of stakeholders concerning the environmental problems face within the Bay.

International audience; We consider a stage structured model of a harvested fish population. The model is a discrete-time system involving a nonlinear recruitment function. Using Control Theory tools we show how to act on the fishing effort in order to prevent the extinction of the population. More precisely, we show how to compute the fishing effort as a feedback control (i.e., a function of the state) in order to maintain the fish population state around a desired steady state.

The scientific journal and scientific paper reconfiguration inside the new prices model transition, emphasizes a change that opens up the open access environment. With the opening of new managerial chronologies. In the open space authority editors, librarians and authors explain, by their disparity, the responsibility and the models of the information sources. A sustainable and profitable industry search for the kind of interaction that is necessary to the full understanding of the problem. The uneasy relationship between the oceanographic and fisheries problems, its insularity, is a case of variation of the degree of integration that is well exemplified by the "closeness" between the free of charge electronic publications and the costs of the paper publications., La reconfiguración de la revista y el artículo científico en el nuevo modelo de precios en transición pone el énfasis en el cambio hacia el entorno en acceso abierto. Abriendo así nuevas cronologías gestionarias. En el espacio de la autoridad editores, bibliotecarios y autores explican, dispares, la responsabilidad y los modelos de las fuentes de información. Una industria sostenible y productora de beneficios persigue la clase de interacción que le es necesaria para comprender por completo el problema. La relación no fácil entre los problemas oceanográficos y los pesqueros, su insularidad, es un caso de variación de grado en la integración que en el acceso a las publicaciones ejemplifica bien la "solicitud" entre las publicaciones electrónicas gratuitas y los costes de las publicaciones en papel., La reconfiguration en cours de la revue et de l'article scientifique à l'intérieur de la transition vers un nouveau modèle des prix, souligne un changement en tant que renvoi dans l'environnement de l'accès ouvert. Confronté à la perspective de l'ouverture de nouvelles chronologies directoriales. Dans l'espace ouvert, les rédacteurs en chef, les bibliothécaires et les auteurs expliquent, en raison de leur disparité, les responsabilités et les modèles des sources d'information. Un secteur viable et rentable est arrivé à considérer la forme d'interaction dont on a besoin pour comprendre pleinement le problème.Les relations difficiles entre les problèmes océanographiques et halieutiques, leur insularité, font etat de leur variable degré d'intégration, ce qu'illustre bien la "proximité" entre les versions électroniques des publications disponibles gratuitement en ligne et les frais des publications sur support papier.

[EN] Marine botany appears to contribute to the marine ecological publication system early on the XXth Century. But a pattern of continuance in bibliographical occurrence can be discerned only from 1946. The original aim of this contribution is to determine the significance of the collection 1946-2006 (61 years) of the published material in marine botany, by analysing: (i) the rates of publication, from a cumulative point of view, and after the coverage of sources in the databases scrutinized; (ii) the number of contributions on each ecosystem type and the geographic location of study sites; (iii) the authors scientific community by ranking their countries and institutions after the number of publications produced and citations received and by discriminating low, middle and high incomes; (iv) the aging of the literature throughout indicating its utility and fitting the data to the Weibull distribution; (v) the number and imbalances of the journals employed. The US contribution was below its mean for the complete set of disciplines in marine sciences. The EU affords with 36% of the publication area. The obsolescence is visible in particular in the European case by the explicit visualization of the half-life of this literature.[ES] La botánica marina contribuye al sistema de publicaciones de la ecología marina desde principios del siglo XX. Aunque sólo cabe discernir desde 1946 una pauta de continuidad en la ocurrencia bibliográfica. El objetivo original de ésta contribución es el de determinar el significado de la colección 1946-2006 (61 años) del material publicado en la botánica marina, analizando: (i) las tasas de publicación, desde un punto de vista acumulativo y según la cobertura de las fuentes en las bases de datos estudiadas; (ii) la cantidad de contribuciones de cada tipo de ecosistema y la localización geográfica de los sitos de estudio; (iii) los autores de la comunidad científica, disponiendo de forma escalonada sus países e instituciones según el número de publicaciones producidas y de citas recibidas, y discriminando en razón de los ingresos bajos, medios y altos; (iv) el envejecimiento de la literatura en base a indicar su utilidad y ajustando los datos a la distribución de Weibull; (v) la cantidad y la falta de equilibrio de las revistas empleadas. La contribución de los EEUU estuvo en ciencias marinas por debajo de su media para el conjunto total de las disciplinas. La UE responde al 36% del área de publicación. La obsolescencia en particular es visible en el caso europeo por la visualización explícita de la vida media de esta literatura., Skretting; Deputación de Pontevedra; Consellería de Pesca e Asuntos Marítimos; WAS; FOESA; SEA; Praxair; Cortiplas; Okana-21, S.L.; Acquavisión/Galicia; Acuarium Finisterrae; Ipac; misPeces; Colexio Oficial de Biólogos de Galicia; Hotel Louxo A Toxa

[ES] La reconfiguración de la revista y el artículo científico en el nuevo modelo de precios en transición pone el énfasis en el cambio hacia el entorno en acceso abierto. Abriendo así nuevas cronologías gestionarias. En el espacio de la autoridad editores, bibliotecarios y autores explican, dispares, la responsabilidad y los modelos de las fuentes de información. Una industria sostenible y productora de beneficios persigue la clase de interacción que le es necesaria para comprender por completo el problema. La relación no fácil entre los problemas oceanográficos y los pesqueros, su insularidad, es un caso de variación de grado en la integración que en el acceso a las publicaciones ejemplifica bien la >solicitud> entre las publicaciones electrónicas gratuitas y los costes de las publicaciones en papel., [EN] The scientific journal and scientific paper reconfiguration inside the new prices model transition emphasize a change that opens up the open access environment. With the opening of new managerial chronologies. In the open space authority editors, librarians and authors explain, in the disparity, the responsibility and the models of the information sources. A sustainable and profitable industry search for the kind of interaction that is necessary to the full understanding of the problem. The uneasy relationship between the oceanographic and fisheries problems, its insularity, is a case of variation of the degree of integration that is well exemplified by the >closeness> between the free of charge electronic publications and the costs of the paper publications., Éste artículo está elaborado a partir del texto de la conferencia virtual organizada por Oceanógrafos sin Fronteras (Kiel, Al emania) y Aqua Center (Nuevo Chimbo- te, Perú), el día 13 de diciembre del 2007 a las 16:00 h (hora europea).

This article deals with a performant parallel solution for a host-macroparasite model, both deterministic and stochastic, in a marine environment. Detailed biological phenomena are reproduced, such as spatial and temporal heterogeneities in these populations. A new version of the simulator and a new parallel algorithmic solution are presented. The interdisciplinary work presented here is at the interface of ecology, mathematics and computer science.

Marine botany appears to contribute to the marine ecological publication system early on the XXth Century. But a pattern of continuance in bibliographical occurrence can be discerned only from 1946. The original aim of this contribution is to determine the significance of the collection 1946-2006 (61 years) of the published material in marine botany, by analysing: (i) the rates of publication, from a cumulative point of view, and after the coverage of sources in the databases scrutinized; (ii) the number of contributions on each ecosystem type and the geographic location of study sites; (iii) the authors scientific community by ranking their countries and institutions after the number of publications produced and citations received and by discriminating low, middle and high incomes; (iv) the aging of the literature throughout indicating its utility and fitting the data to the Weibull distribution; (v) the number and imbalances of the journals employed. The US contribution was below its mean for the complete set of disciplines in marine sciences. The EU affords with 36% of the publication area. The obsolescence is visible in particular in the European case by the explicit visualization of the half-life of this literature., La botánica marina contribuye al sistema de publicaciones de la ecología marina desde principios del siglo XX. Aunque sólo cabe discernir desde 1946 una pauta de continuidad en la ocurrencia bibliográfica. El objetivo original de esta contribución es el de determinar el significado de la colección 1946-2006 (61 años) del material publicado en la botánica marina, analizando: (i) las tasas de publicación, desde un punto de vista acumulativo y según la cobertura de las fuentes en las bases de datos estudiadas; (ii) la cantidad de contribuciones de cada tipo de ecosistema y la localización geográfica de los sitos de estudio; (iii) los autores de la comunidad científica, disponiendo de forma escalonada sus países e instituciones según el número de publicaciones producidas y de citas recibidas, y discriminando en razón de los ingresos bajos, medios y altos; (iv) el envejecimiento de la literatura en base a indicar su utilidad y ajustando los datos a la distribución de Weibull; (v) la cantidad y la falta de equilibrio de las revistas empleadas. La contribución de los EEUU estuvo en ciencias marinas por debajo de su media para el conjunto total de las disciplinas. La UE responde al 36% del área de publicación. La obsolescencia en particular es visible en el caso europeo por la visualización explícita de la vida media de esta literatura., La botanique marine contribue, de manière active, au système des publications sur le milieu marin du début du 20ème siècle. Mais une pratique de publication permanente ne peut se dégager qu'à partir de 1946. L'objectif initial de cette contribution est de déterminer l'importance de la collection 1946-2006 (61 ans) des documents publiés en botanique marine, en analysant: (i) les taux de publication, considérés au point de vue cumulatif, et selon la portée des sources d'informations dans les bases de données évaluées; (ii) le nombre de contributions pour chaque type d'écosystème et la localisation géographique des sites de recherche; (iii) la communauté d'auteurs scientifiques par le classement de leur pays et des institutions où ils travaillent, en termes de publications produites et des citations reçues, et comportant un élément distinctif en vue de représenter les revenus faibles, moyens et élevés; (iv) l'obsolescence de la littérature en indiquant son utilité et par l'ajustement des données à la distribution de Weibull; (v) le nombre et les déséquilibres des journaux employés. La contribution des États-Unis en botanique marine a été inférieure à sa moyenne pour l'ensemble complet des disciplines des sciences marines. L'UE offre un 30% des publications. En particulier, l'obsolescence figure visiblement sur la carte européenne par l'estimation de la durée de vie moyenne de cette littérature.

Although the North-East Atlantic stock of European hake has been widely studied, certain characteristics of its biology are still relatively poorly known. This is particularly true of its seasonal migrations and growth, which a recent tagging campaign shows was probably largely underestimated. These uncertainties have several consequences both for the quality of the stock assessment using the usual population dynamics models and for management, particularly by limiting the possibilities of evaluating spatial management measures. To improve the estimation of the parameters of these processes, we have developed an integrated spatialized and length-structured population dynamics model based on a state model describing the dynamics of the population and the fishing activity, and on a model describing the observation processes, allowing the writing of a model of the population dynamics, allowing the writing of a likelihood function.A literature review of existing length-structured models highlighted the key role of growth process modelling in this type of model. To ensure the robustness of the model assumptions related to the discretisation of this continuous process and to individual growth variability, we performed a sensitivity analysis of the growth model. This method of numerical exploration of the model is based on (i) the development of experimental designs and (ii) the fitting of statistical models to the model outputs to quantify the impact of these assumptions. This generic approach is transposable to any sensitivity analysis of a discrete model describing a continuous process. In our case, it showed that for North-East Atlantic hake it was preferable to choose a quarterly time step, 1 cm classes, a gamma distribution of growth increments and a uniform distribution of individuals within the classes. During the development of the model, particular attention was paid to writing the likelihood function so that it would be robust and consistent with the observation processes. Different algorithms were also tested to carry out the numerical optimisation of this function. The choice was finally made for a quasi-Newton type algorithm. The fitting of the population dynamics model to the available observations allowed the estimation of migration rates and the growth rate, which is lower than that estimated from the tagging data. tagging data. It also made it possible to establish a diagnosis in terms of the evolution of the spawning biomass that was consistent with the diagnoses previously established using the current assessment model. However, due to its complexity and certainly to the poor quality of some observations, the adjustment of the model However, due to its complexity and certainly to the poor quality of some observations, the adjustment of the model is difficult. The model suffers from some identifiability problems even though the migration and growth parameters do not seem to be affected., Bien que le merlu de l'Atlantique Nord-Est ait été largement étudié, certaines caractéristiques de sa biologie sont encore assez mal connues. C'est en particulier le cas de ses migrations saisonnières et de sa croissance, dont une campagne récente de marquage montre qu'elle était probablement largement sous-estimée. Ces incertitudes ont plusieurs conséquences tant sur la qualité des diagnostics établis à l'aide des modèles de dynamique des populations usuels, que sur la gestion en limitant notamment les possibilités d'évaluation de mesures de gestions spatialisées. Pour améliorer l'estimation des paramètres de ces processus, nous avons développé un modèle de dynamique de population intégré spatialisé et structuré en longueur reposant sur un modèle d'états décrivant la dynamique de la population et de l'activité de pêche, et sur un modèle décrivant les processus d'observation, permettant l'écriture d'une fonction de vraisemblance.Une revue bibliographique des modèles structurés en longueur existants a mis en évidence le rôle clé de la modélisation du processus de croissance dans ce type de modèles. Pour s'assurer de la robustesse des hypothèses du modèle liées à la discrétisation de ce processus continu et à la variabilité individuelle de croissance, nous avons réalisé une analyse de sensibilité du modèle de croissance. Cette méthode d'exploration numérique du modèle repose sur (i) le développement de plans d'expériences et (ii) l'ajustement de modèles statistiques aux sorties du modèle pour quantifier l'impact de ces hypothèses. Cette démarche générique est transposable à toute analyse de sensibilité d'un modèle discret décrivant un processus continu. Dans notre cas, elle a permis de mettre en évidence que pour le merlu de l'Atlantique Nord-Est il était préférable de choisir un pas de temps trimestriel, des classes de 1 cm, une distribution gamma des incréments de croissance et une distribution uniforme des individus au sein des classes. Au cours du développement du modèle, une attention particulière a été portée à l'écriture de la fonction de vraisemblance afin qu'elle soit robuste et cohérente avec les processus d'observation. Différents algorithmes ont également été testés pour réaliser l'optimisation numérique de cette fonction, le choix se portant finalement vers un algorithme de type quasi-Newton. L'ajustement du modèle de dynamique de population aux observations disponibles a permis l'estimation des taux de migration et du taux de croissance, plus faible que celui estimé à partir des données de marquage. Il a permis également d'établir un diagnostic en terme d'évolution de la biomasse féconde cohérent avec les diagnostics préalablement établis à l'aide du modèle actuel d'évaluation. Cependant, du fait de sa complexité et très certainement de la mauvaise qualité de certaines observations, l'ajustement du modèle est difficile. Le modèle souffre de certains problèmes d'identifiabilité même si les paramètres de migration et de croissance ne semblent pas concernés.