217 results on '"Gascuel, D."'
Search Results
2. Food for thought from French scientists for a revised EU Common Fisheries Policy to protect marine ecosystems and enhance fisheries performance
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Drouineau, H., Moullec, F., Gascuel, D., Laloë, F., Lucas, S., Bez, N., Guillotreau, P., Guitton, J., Hernvann, P.-Y., Huret, M., Lehuta, S., Léopold, M., Mahévas, S., Robert, M., Woillez, M., Vermard, Y., Drouineau, H., Moullec, F., Gascuel, D., Laloë, F., Lucas, S., Bez, N., Guillotreau, P., Guitton, J., Hernvann, P.-Y., Huret, M., Lehuta, S., Léopold, M., Mahévas, S., Robert, M., Woillez, M., and Vermard, Y.
- Abstract
Since the 1980s, the Common Fisheries Policy (CFP) has shaped European fisheries. It has often been criticised for being too prescriptive and, above all, for failing to protect either fishermen or ecosystems. The last reform dates back to the early 2010 s and has led to a slight but slow improvement in the state of ecosystems. Given that the CFP is in the process of evaluation, a group of French fishery scientists set up an initiative to add to the debate on what should be retained, reinforced or added to a possible new reform. This initiative came 10 years after a previous manifesto that presented their vision for fisheries in Europe. Four major issues emerged from the current initiative: (1) a need for transparency and simplification in fisheries management, (2) a need for more consultation and dialogue between stakeholders, (3) the urgency of the situation in the Mediterranean Sea, and (4) the necessity of putting into practice all research developments for an ecosystem approach to fisheries. Compared to 10 years ago, the response of scientists shows that the focus is no longer on achieving the maximum sustainable yield, but rather on the following steps to protect ecosystems and fisheries. An ecosystem approach to fisheries remains indispensable for both ecosystems and fishing activities. To this end, scientists put forward numerous proposals to improve the CFP, acknowledging that the final solutions should emerge from consultation with stakeholders. Climate change, an issue raised much more than in the manifest, reinforces the need to act.
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- 2023
3. Climate-induced changes in ocean productivity and food-web functioning are projected to markedly affect European fisheries catch
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Du Pontavice, H, Gascuel, D, Kay, S, Cheung, Wwl, Du Pontavice, H, Gascuel, D, Kay, S, and Cheung, Wwl
- Abstract
In European waters, climate-induced changes in ocean conditions will alter marine ecosystems, leading to potential repercussions for the European fisheries and the status of exploited species. Here, we used a new version of the EcoTroph model, forced by a regional high-resolution coupled hydrodynamic-ecosystem model, to investigate the effects of climate change on biomass and catch in 15 areas (ICES divisions) of the European Atlantic shelf ecosystems. Based on the projected changes in temperature, zooplankton and benthic secondary producers, we modeled the changes in biomass and catch at each trophic level by the end of the 21st century. We projected that total biomass and catch for the whole Atlantic European seas would decrease by 11.5 and 10.0%, respectively, by 2090-2099 relative to 2013-2017 under a ‘no mitigation’ greenhouse gases emissions scenario (RCP8.5). The projected decrease in catch is 310000 or 240000 t by 2090-2099 under a high (RCP8.5) or a moderate (RCP4.5) emissions scenario, respectively. Some areas, such as the Celtic Sea, would be more affected than others, while the climate impact on the bentho-demersal biomass and catches would be more pronounced, especially toward the higher trophic levels. Our study suggests that climate change may strongly impact European fisheries, with ecological consequences and potential socio-economic repercussions. Future studies using alternative climate and ecosystem models would allow the exploration of uncertainties in projected biomass and catch. While fisheries management is required to adapt to these changes, the projected impacts on catch cannot be avoided without aggressive mitigation of greenhouse gas emissions.
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- 2023
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4. Stock Assessment Coastal shrimp (P. notialis) in West Africa by length frequency analysis
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Thiaw, Modou, Bâ, K., García-Isarch, Eva, Quinzán, Marta, Sidibeh, M., Quemper, F., Gascuel, D, Guitton, J., Thiaw, Modou, Bâ, K., García-Isarch, Eva, Quinzán, Marta, Sidibeh, M., Quemper, F., Gascuel, D, and Guitton, J.
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- 2023
5. SEAwise Report on consistency of existing targets and limits for indicators in an ecosystem context
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Kempf, A., Taylor, M., Kuhn, B., Brown, E., Trijoulet, V., Vinther, M., Girardin, Raphael, Savina-rolland, Marie, Lehuta, Sigrid, Halouani, Ghassen, Robert, Marianne, Woillez, Mathieu, Mahevas, Stephanie, Travers-trolet, Morgane, Andres, M., Garcia, D., Ibaibarriaga, L., Sanchez-marono, S., Astarloa Diaz,, A., Batts, L., Reid, D., Bitetto, I., Spedicato, M.-t., Romagnoni, G., Giannoulaki, M., Sgardeli, V., Tsoukali, S., Liontakis, A., Vassilopoulou,, C., Miller, S., Depestele, L., Van Hoey, G., Piet, G., Hamon, K., Kraan, M., Smout, S., Ransijn, J., Thorpe, R., Lynam, C., Bluemel, J., Voss, R., Ojaveer, H., Hommik, K., Melia, P., Gascuel, D., Potier, M., Ustups, D., Plikss, M., Heath, M., Poos, J.-j., Blinch, L., Rindorf, A., Kempf, A., Taylor, M., Kuhn, B., Brown, E., Trijoulet, V., Vinther, M., Girardin, Raphael, Savina-rolland, Marie, Lehuta, Sigrid, Halouani, Ghassen, Robert, Marianne, Woillez, Mathieu, Mahevas, Stephanie, Travers-trolet, Morgane, Andres, M., Garcia, D., Ibaibarriaga, L., Sanchez-marono, S., Astarloa Diaz,, A., Batts, L., Reid, D., Bitetto, I., Spedicato, M.-t., Romagnoni, G., Giannoulaki, M., Sgardeli, V., Tsoukali, S., Liontakis, A., Vassilopoulou,, C., Miller, S., Depestele, L., Van Hoey, G., Piet, G., Hamon, K., Kraan, M., Smout, S., Ransijn, J., Thorpe, R., Lynam, C., Bluemel, J., Voss, R., Ojaveer, H., Hommik, K., Melia, P., Gascuel, D., Potier, M., Ustups, D., Plikss, M., Heath, M., Poos, J.-j., Blinch, L., and Rindorf, A.
- Abstract
SEAwise deliverable 6.7 is the first of two deliverables in task 6.4. It investigates the consistency of existing targets and limits from the Common Fisheries Policy (CFP) and the Marine Strategy Framework Directive (MSFD). Trade-offs between different objectives (ecological, economic, social), targets and limits are highlighted. A wide range of model types (from bio-economic to full ecosystem models) has been applied to various case study areas across the North East Atlantic and Mediterranean. Although model predictions are by nature uncertain, this study provides important information on likely inconsistencies between existing targets and limits and trade-offs expected under ecosystem- based fisheries management (EBFM). The scenarios investigated include the current range of management applied in terms of the Maximum Sustainable Yield (MSY) concept (i.e. strict MSY approach vs. Pretty Good Yield (PGY) approach allowing sustainable deviations from single species FMSY point estimates). The landing obligation is a key aspect of current fisheries management and was fully considered, in particular for mixed demersal fisheries. Maintaining current fishing effort without further management measures was the least sustainable option in nearly all cases studies. This approach led to increased risk of stocks falling below critical biomass limits. Although the fishing effort adaptions needed is highly case specific, this indicates that further management measures are likely to be needed to ensure a sustainable exploitation of all stocks. Scenarios applying a strict MSY approach in combination with the landing obligation (i.e. FMSY as upper limit with fisheries ending when the first stock reaches FMSY) in most case studies led to the lowest fishing effort. This had positive effects on MSFD related indicators such as bycatch of Protected, Endangered and Threatened (PET) species, benthic impact and the Large Fish Indicator as well as global indicators such as CO2 emission or eco
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- 2023
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6. Including foraging arena and top-down controls improves the modeling of trophic flows and fishing impacts in aquatic food webs
- Author
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Colléter, M., Walters, C. J., Gatti, P., and Gascuel, D.
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- 2015
7. Structure and functioning of the Bay of Biscay ecosystem: A trophic modelling approach
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Corrales, X., Preciado, I., Gascuel, D., Lopez De Gamiz-zearra, A., Hernvann, P.-y., Mugerza, E., Louzao, M., Velasco, F., Doray, Mathieu, López-lópez, L., Carrera, P., Cotano, U., Andonegi, E., Corrales, X., Preciado, I., Gascuel, D., Lopez De Gamiz-zearra, A., Hernvann, P.-y., Mugerza, E., Louzao, M., Velasco, F., Doray, Mathieu, López-lópez, L., Carrera, P., Cotano, U., and Andonegi, E.
- Abstract
Characterizing the structure and functioning of marine ecosystems requires a deep understanding of the dynamics of its populations and the biotic interactions among them. To this end, we developed a mass-balanced food-web model of a regional sea in the Northeast Atlantic, the Bay of Biscay (BoB), considering one of the most important anthropogenic disturbance in the area, the fishing pressure. The food-web model was performed for the whole BoB region for the first time. The model represents the ecosystems in the early 2000s, encompassing 120433 km2 between 0 and 1000 m depth. The model was composed of 52 functional groups, ranging from primary producers to top predators, and considering both Spanish and French fishing fleets. Input data included biomass obtained locally from bottom trawl and acoustic surveys, data from stock assessment, official fishery statistics, published and unpublished data on stomach content analyses and the use of empirical equations to estimate consumption and production rates. Our results highlight the importance of the pelagic domain, since the main trophic flows are determined by the interaction between phytoplankton, zooplankton and forage fishes. The role of the detritivore pathway was also relevant due to the relatively high abundance of detritivores organisms and the large percentage of primary production flowing to the detritus. Forage fish have resulted to be a key compartment fostering the connectivity between the benthic and pelagic domains. Pelagic sharks, dolphins, anglerfish, large hake and large demersal fishes were identified as potential keystone functional groups in the BoB model. The results also showed an intense exploitation by fisheries in early 2000s. Different strategies between Spanish and French fleets were also found. French fleets were mainly focussed on low trophic level forage fish (e.g., sardine and anchovy) and had larger impacts on higher trophic levels, while Spanish fleets mostly focussed on higher trophic
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- 2022
- Full Text
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8. Potential impacts of climate change on agriculture and fisheries production in 72 tropical coastal communities
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Cinner, J., Caldwell, I., Thiault, L., Ben, J., Blanchard, J., Coll, M., Diedrich, A., Eddy, T., Everett, J., Folberth, C., Gascuel, D., Guiet, J., Gurney, G., Heneghan, R., Jägermeyr, J., Jiddawi, N., Lahari, R., Kuange, J., Liu, W., Maury, O., Müller, C., Novaglio, C., Palacios-Abrantes, J., Petrik, C., Rabearisoa, A., Tittensor, D., Wamukota, A., Pollnac, R., Cinner, J., Caldwell, I., Thiault, L., Ben, J., Blanchard, J., Coll, M., Diedrich, A., Eddy, T., Everett, J., Folberth, C., Gascuel, D., Guiet, J., Gurney, G., Heneghan, R., Jägermeyr, J., Jiddawi, N., Lahari, R., Kuange, J., Liu, W., Maury, O., Müller, C., Novaglio, C., Palacios-Abrantes, J., Petrik, C., Rabearisoa, A., Tittensor, D., Wamukota, A., and Pollnac, R.
- Abstract
Climate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations (> 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status.
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- 2022
9. Structure and functioning of the Bay of Biscay ecosystem: A trophic modelling approach
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Ministerio de Ciencia e Innovación (España), Eusko Jaurlaritza, Corrales, X., Preciado, Izaskun, Gascuel, D., Lopez de Gamiz-Zearra, A., Hernvann, P. Y., Mugerza, E., Louzao, M., Velasco, Francisco, Doray, M., López-López, Lucía, Carrera, Pabl, Cotano, U., Andonegi, E., Ministerio de Ciencia e Innovación (España), Eusko Jaurlaritza, Corrales, X., Preciado, Izaskun, Gascuel, D., Lopez de Gamiz-Zearra, A., Hernvann, P. Y., Mugerza, E., Louzao, M., Velasco, Francisco, Doray, M., López-López, Lucía, Carrera, Pabl, Cotano, U., and Andonegi, E.
- Abstract
Characterizing the structure and functioning of marine ecosystems requires a deep understanding of the dynamics of its populations and the biotic interactions among them. To this end, we developed a mass-balanced food-web model of a regional sea in the Northeast Atlantic, the Bay of Biscay (BoB), considering one of the most important anthropogenic disturbance in the area, the fishing pressure. The food-web model was performed for the whole BoB region for the first time. The model represents the ecosystems in the early 2000s, encompassing 120433 km2 between 0 and 1000 m depth. The model was composed of 52 functional groups, ranging from primary producers to top predators, and considering both Spanish and French fishing fleets. Input data included biomass obtained locally from bottom trawl and acoustic surveys, data from stock assessment, official fishery statistics, published and unpublished data on stomach content analyses and the use of empirical equations to estimate consumption and production rates. Our results highlight the importance of the pelagic domain, since the main trophic flows are determined by the interaction between phytoplankton, zooplankton and forage fishes. The role of the detritivore pathway was also relevant due to the relatively high abundance of detritivores organisms and the large percentage of primary production flowing to the detritus. Forage fish have resulted to be a key compartment fostering the connectivity between the benthic and pelagic domains. Pelagic sharks, dolphins, anglerfish, large hake and large demersal fishes were identified as potential keystone functional groups in the BoB model. The results also showed an intense exploitation by fisheries in early 2000s. Different strategies between Spanish and French fleets were also found. French fleets were mainly focussed on low trophic level forage fish (e.g., sardine and anchovy) and had larger impacts on higher trophic levels, while Spanish fleets mostly focussed on higher trophic
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- 2022
10. Modelling dynamic ecosystems: venturing beyond boundaries with the Ecopath approach
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Coll, M., Akoglu, E., Arreguín-Sánchez, F., Fulton, E. A., Gascuel, D., Heymans, J. J., Libralato, S., Mackinson, S., Palomera, I., Piroddi, C., Shannon, L. J., Steenbeek, J., Villasante, S., and Christensen, V.
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- 2015
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11. Global assessment of the fishing impacts on the Southern Benguela ecosystem using an EcoTroph modelling approach
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Gasche, L., Gascuel, D., Shannon, L., and Shin, Y.-J.
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- 2012
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12. Structure and functioning of the Bay of Biscay ecosystem: A trophic modelling approach
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Corrales, X., primary, Preciado, I., additional, Gascuel, D., additional, Lopez de Gamiz-Zearra, A., additional, Hernvann, P.-Y., additional, Mugerza, E., additional, Louzao, M., additional, Velasco, F., additional, Doray, M., additional, López-López, L., additional, Carrera, P., additional, Cotano, U., additional, and Andonegi, E., additional
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- 2022
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13. Overfishing of marine resources: some lessons from the assessment of demersal stocks off Mauritania
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Meissa, B. and Gascuel, D.
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- 2015
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14. The Celtic Sea Through Time and Space: Ecosystem Modeling to Unravel Fishing and Climate Change Impacts on Food-Web Structure and Dynamics
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Hernvann, P. Y., Gascuel, D., Gruss, A., Druon, J. N., Kopp, D., Perez, Ilan, Piroddi, C., Robert, M., Écologie et santé des écosystèmes (ESE), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Sciences et Technologies Halieutiques (STH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), National Institute of Water and Atmospheric Research [Wellington] (NIWA), University of Washington [Seattle], European Commission - Joint Research Centre [Ispra] (JRC), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Unité de recherche Sciences et Technologies Halieutiques (STH), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-AGROCAMPUS OUEST
- Subjects
Ecopath with Ecosim and Ecospace ,ecosystem modeling ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,[SDE.MCG]Environmental Sciences/Global Changes ,Celtic Sea ,fishing impact ,Ecopath with ,Ecosim and Ecospace ,habitat model ,environment ,primary production - Abstract
International audience; Both trophic structure and biomass flow within marine food webs are influenced by the abiotic environment and anthropogenic stressors such as fishing. The abiotic environment has a large effect on species spatial distribution patterns and productivity and, consequently, spatial co-occurrence between predators and prey, while fishing alters species abundances and food-web structure. In order to disentangle the impacts of the abiotic environment and fishing in the Celtic Sea ecosystem, we developed a spatio-temporal trophic model, specifically an Ecopath with Ecosim with Ecospace model, for the period 1985-2016. In this model, particular attention was paid to the parameterization of the responses of all trophic levels to abiotic environmental changes. Satellite remote sensing data were employed to determine the spatial distribution and annual fluctuations of primary production (PP). Spatial and temporal changes in the habitat favorable for zooplankton were predicted with a novel ecological-niche approach using daily detection of productivity fronts from satellite ocean color. Finally, functional responses characterizing the effect of several abiotic environmental variables (including, among others, temperature, salinity and dissolved oxygen concentration, both at the surface and at the bottom) on fish species groups' habitat suitability were produced from the predictions of statistical habitat models fitted to presence-absence data collected by multiple fisheries-independent surveys. The dynamic component of our model (Ecosim) was driven by time-series of fishing effort, PP, zooplankton habitat suitability and abiotic environmental variables, and was fitted to abundance and fisheries catch data. The spatial component of our model (Ecospace) was constructed, for specific years of the period 1985-2016 with contrasted abiotic environmental conditions, to predict the variable distribution of the biomass of all functional groups. We found that fishing was the main driver of observed ecosystem changes in the Celtic Sea over the period 1985-2016. However, the integration of the environmental variability into the model and the subsequent improvement of the fit of the dynamic Ecosim component highlighted (i) the control of the overall pelagic production by PP and (ii) the influence of temperature on the productivity of several trophic levels in the Celtic Sea, especially on trophic groups with warm and cold water affinities. In addition, Ecospace predictions indicated that the spatial distributions of commercial fish species may have substantially changed over the studied period. These spatial changes mainly appeared to be driven by temperature and may, therefore, largely impact future fisheries given the continuity of climatic changes.
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- 2020
15. Approche conceptuelle de la modélisation de la dynamique du stock d'anguilles dans un bassin versant : intérêt et adaptation du modèle de rendement par recrue
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GASCUEL D. and FONTENELLE G.
- Subjects
population dynamics ,anguilla anguilla ,watershed ,stock management ,Aquaculture. Fisheries. Angling ,SH1-691 - Abstract
A partir de l'approche structurale utilisée en halieutique pour des stocks exploités de poissons, une adaptation à l'Anguille au sein d'un bassin versant est présentée. Cette approche conceptuelle essaie de considérer toutes les particularités de cette espèce amphihaline exploitée à tous ses stades biologiques pour estimer les paramètres conduisant à l'élaboration d'un modèle. Les résultats que l'on peut attendre d'un tel modèle sont mis en évidence.
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- 1994
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16. Consistency of Stock Assessment and Evaluation of Fisheries Management for European Fish Stocks, 1983-1995
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Gascuel, D, primary, Fontenelle, G, additional, Maguer, C, additional, and Biseau, A, additional
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- 1998
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17. The Ocean revealed
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Cury, Philippe, Gascuel, D., Euzen, A. (ed.), Gaill, F. (ed.), Lacroix, D. (ed.), and Cury, Philippe (ed.)
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- 2017
18. Ecological indicators to capture the effects of fishing on biodiversity and conservation status of marine ecosystems
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Coll, M., Shannon, L. J., Kleisner, K. M., Juan-jorda, M. J., Bundy, A., Akoglu, A. G., Banaru, Daniela, Boldt, J. L., Borges, M. F., Cook, A., Diallo, I., Fu, C., Fox, C., Gascuel, D., Gurney, L. J., Hattab, Tarek, Heymans, J. J., Jouffre, D., Knight, B. R., Kucukavsar, S., Large, S. I., Lynam, C., Machias, A., Marshall, K. N., Masski, H., Ojaveer, H., Piroddi, C., Tam, J., Thiao, D., Thiaw, M., Torres, M. A., Travers-trolet, Morgane, Tsagarakis, K., Tuck, I., Van Der Meeren, G. I., Yemane, D., Zador, S. G., Shin, Y. -j., Coll, M., Shannon, L. J., Kleisner, K. M., Juan-jorda, M. J., Bundy, A., Akoglu, A. G., Banaru, Daniela, Boldt, J. L., Borges, M. F., Cook, A., Diallo, I., Fu, C., Fox, C., Gascuel, D., Gurney, L. J., Hattab, Tarek, Heymans, J. J., Jouffre, D., Knight, B. R., Kucukavsar, S., Large, S. I., Lynam, C., Machias, A., Marshall, K. N., Masski, H., Ojaveer, H., Piroddi, C., Tam, J., Thiao, D., Thiaw, M., Torres, M. A., Travers-trolet, Morgane, Tsagarakis, K., Tuck, I., Van Der Meeren, G. I., Yemane, D., Zador, S. G., and Shin, Y. -j.
- Abstract
IndiSeas (“Indicators for the Seas”) is a collaborative international working group that was established in 2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem using several criteria (i.e., ecological meaning, sensitivity to fishing, data availability, management objectives and public awareness). The suite comprised: (i) the inverse coefficient of variation of total biomass of surveyed species, (ii) mean fish length in the surveyed community, (iii) mean maximum life span of surveyed fish species, (iv) proportion of predatory fish in the surveyed community, (v) proportion of under and moderately exploited stocks, (vi) total biomass of surveyed species, and (vii) mean trophic level of the landed catch. In line with the Nagoya Strategic Plan of the Convention on Biological Diversity (2011–2020), we extended this suite to emphasize the broader biodiversity and conservation risks in exploited marine ecosystems. We selected a subset of indicators from a list of empirically based candidate biodiversity indicators initially established based on ecological significance to complement the original IndiSeas indicators. The additional selected indicators were: (viii) mean intrinsic vulnerability index of the fish landed catch, (ix) proportion of non-declining exploited species in the surveyed community, (x) catch-based marine trophic index, and (xi) mean trophic level of the surveyed community. Despite the lack of data in some ecosystems, we also selected (xii) mean trophic level of the modelled community, and (xiii) proportion of discards in the fishery as extra indicators. These additional indicators were examined, along with the initial set of IndiSeas ecological indicators, to evaluate whether adding new biodiversity indicators provided useful additional information to refine our understand
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- 2016
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19. Ecological indicators to capture the effects of fishing on biodiversity and conservation status of marine ecosystems
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Coll, M., primary, Shannon, L.J., additional, Kleisner, K.M., additional, Juan-Jordá, M.J., additional, Bundy, A., additional, Akoglu, A.G., additional, Banaru, D., additional, Boldt, J.L., additional, Borges, M.F., additional, Cook, A., additional, Diallo, I., additional, Fu, C., additional, Fox, C., additional, Gascuel, D., additional, Gurney, L.J., additional, Hattab, T., additional, Heymans, J.J., additional, Jouffre, D., additional, Knight, B.R., additional, Kucukavsar, S., additional, Large, S.I., additional, Lynam, C., additional, Machias, A., additional, Marshall, K.N., additional, Masski, H., additional, Ojaveer, H., additional, Piroddi, C., additional, Tam, J., additional, Thiao, D., additional, Thiaw, M., additional, Torres, M.A., additional, Travers-Trolet, M., additional, Tsagarakis, K., additional, Tuck, I., additional, van der Meeren, G.I., additional, Yemane, D., additional, Zador, S.G., additional, and Shin, Y.-J., additional
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- 2016
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20. Evaluation of integrated ecological-economic models – Review and challenges for implementation
- Author
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Nielsen, J. Rasmus, Thunberg, E., Schmidt, J.O., Holland, Dan, Bastardie, Francois, Andersen, J. L., Bartelings, Heleen, Bertignac, M., Bethke, E., Buckworth, R., Carpenter, G., Da-Rocha, J.M., Deng, R., Dichmont, C., Döring, R., Esteban, A., Frost, Hans, Fulton, E. A., Garcia, D., Gasche, L., Gascuel, D., Gourguet, S., Groeneveld, R.A., Guillen, J., Guyader, O., Hamon, Katell, Hoff, Ayoe, Horbowy, J., Kaplan, I.C., Lehuta, Sigrid, Little, R., Lleonart J., Lleonart J., Macher, C., Mackinson, S., Mahevas, S., Mato-Amboage, R., Mapstone, B., Maynou F., Maynou F., Merzéréaud M., Merzéréaud M., Palacz, Artur, Pascoe, S., Paulrud, Anton, Prellezo, R., Punt, A., Quaas, M., Ravn-Jonsen, Lars, Sanchez , S., Simons, S., Thébaud, O., Tomczak, M.T., Ulrich, Clara, Van Dijk, D., Vermard, Youen, Voss, R., Waldo, Staffan, Nielsen, J. Rasmus, Thunberg, E., Schmidt, J.O., Holland, Dan, Bastardie, Francois, Andersen, J. L., Bartelings, Heleen, Bertignac, M., Bethke, E., Buckworth, R., Carpenter, G., Da-Rocha, J.M., Deng, R., Dichmont, C., Döring, R., Esteban, A., Frost, Hans, Fulton, E. A., Garcia, D., Gasche, L., Gascuel, D., Gourguet, S., Groeneveld, R.A., Guillen, J., Guyader, O., Hamon, Katell, Hoff, Ayoe, Horbowy, J., Kaplan, I.C., Lehuta, Sigrid, Little, R., Lleonart J., Lleonart J., Macher, C., Mackinson, S., Mahevas, S., Mato-Amboage, R., Mapstone, B., Maynou F., Maynou F., Merzéréaud M., Merzéréaud M., Palacz, Artur, Pascoe, S., Paulrud, Anton, Prellezo, R., Punt, A., Quaas, M., Ravn-Jonsen, Lars, Sanchez , S., Simons, S., Thébaud, O., Tomczak, M.T., Ulrich, Clara, Van Dijk, D., Vermard, Youen, Voss, R., and Waldo, Staffan
- Published
- 2015
21. Evolution comparative de l'abondance des ressources halieutiques démersales en Guinée entre 1985 et 1998 = Comparative evolution of demersal fisheries resources abundance in Guinea between 1985 and 1998
- Author
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Sidibé, A., Laurans, M., Gascuel, D., Domain, François, Chavance, Pierre (ed.), Ba, M. (ed.), Gascuel, D. (ed.), Vakily, J.M. (ed.), and Pauly, D. (ed.)
- Subjects
PECHE EXPERIMENTALE ,RESSOURCES HALIEUTIQUES ,ANALYSE DE VARIANCE ,MODELE LINEAIRE ,CHALUTAGE ,ABONDANCE ,ESPECE DEMERSALE - Published
- 2004
22. Assessing stocks in data-poor African fisheries: a case study on the white grouper Epinephelus aeneus of Mauritania
- Author
-
Meissa, B, Gascuel, D, and Rivot, E
- Abstract
The lack of reliable stock assessment for numerous exploited stocks in West Africa often results from poor-quality data, high multi-specificity of captures, and the heterogeneity of exploitation methods. However, many signs of overexploitation exist, particularly for demersal resources, highlighting the urgent need for a more quantitative and comprehensive evaluation of these resources. This study aims to show how, in such a context of poor-quality data and high uncertainty, a multi-method approach for stock assessment can generate a consistent diagnosis of the condition of a resource. As a case study, several methods were combined to assess the stock status of the white grouper Epinephelus aeneus, a flagship species in West Africa that is exploited by industrial and small-scale fisheries in Mauritania. These were estimation of abundance indices using delta generalised linear models; a biomass production model using a pseudo-equilibrium method and including an environmental effect of upwelling intensity; a dynamic biomass production model fitted in a Bayesian framework also including an environmental effect; and an age-structured model based on a modified pseudo-cohort analysis. Sensitivity analyses were performed for most of these assessment methods. Results show that the white grouper stock is highly overexploited due to an excess in the fishing effort estimated at between 30% and 50%, depending on the model used to estimate the effort at maximum sustainable yield.Keywords: age-structured model, Bayesian approaches, diagnosis, production model, stock assessmentAfrican Journal of Marine Science 2013, 35(2): 253–267
- Published
- 2013
23. 43rd Plenary Meeting Report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-13-01)
- Author
-
Casey, J., Abella, J. A., Andersen, J., Bailey, N., Bertignac, M., Cardinale, M., Curtis, H., Daskalov, G., Delaney, Alyne, Döring, R., Garcia Rodriguez, M., Gascuel, D., Graham, N., Gustavsson, T., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Malvarosa, L., Martin, P., Murua, H., Nord, J., Nowakowski, P., Prellezo, R., Sala, A., Scarcella, G., Simmonds, J., Somarakis, S., Stransky, C., Theret, F., Ulrich, C., Vanhee, W., and Van Oostenbrugge, H.
- Abstract
The Scientific, Technical and Economic Committee for Fisheries hold its 43rd plenary on 8-12 July 2013 in Brussels (Belgium). The terms of referenceincluded both issues assessments of STECF Expert Working Group reports and additional requests submitted to the STECF by the Commission. Topicsdealt were inter alia assessments of the economic performance of the EU fishing fleet, fishing effort regime evaluations, future EU data collection, andreview of stock advice.
- Published
- 2013
24. 41th Plenary Meeting Report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-12-03)
- Author
-
Abella, J. A., Andersen, J., Bailey, N., Bertignac, M., Cardinale, M., Casey, J., Curtis, H., Delaney, Alyne, Daskalov, G., Döring, R., Gascuel, D., Graham, N., Garcia Rodriguez, M., Gustavsson, T., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Martin, P., Malvarosa, L., Murua, H., Nord, J., Nowakowski, P., Prellezo, R., Sala, A., Scarcella, G., Simmonds, J., Somarakis, S., Stransky, C., Theret, F., Ulrich, C., Vanhee, W., and Van Oostenbrugge, H.
- Abstract
The Scientific, Technical and Economic Committee for Fisheries hold its 41st plenary on 5-9 November 2012 in Brussels (Belgium). The terms ofreference included both issues assessments of STECF Expert Working Group reports and additional requests submitted to the STECF by the Commission.Topics dealt were inter alia assessments of Mediterranean and Black Sea stocks, evaluations of fishing effort regimes, technical measures, review ofscientific advice on stocks and fisheries of EU interest, fisheries management plans evaluation issues.
- Published
- 2012
25. 39th Plenary Meeting Report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-12-01)
- Author
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Abella, J. A., Andersen, J., Bailey, N., Bertignac, M., Cardinale, M., Casey, J., Curtis, H., Delaney, Alyne, Daskalov, G., Döring, R., Gascuel, D., Graham, N., Garcia Rodriguez, M., Gustavsson, T., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Martin, P., Malvarosa, L., Motova, A., Murua, H., Nord, J., Nowakowski, P., Prellezo, R., Sala, A., Scarcella, G., Simmonds, J., Somarakis, S., Stransky, C., Theret, F., Ulrich, C., Vanhee, W., and Van Oostenbrugge, H.
- Abstract
The Scientific, Technical and Economic Committee for Fisheries hold its 39th plenary on 16-20 April 2012 in Brussels (Belgium). The terms of referenceincluded both issues assessments of STECF Expert Working Group reports and additional requests submitted to the STECF by the Commission. Topicsdealt with ranged from fisheries economics to management plan evaluation issues.
- Published
- 2012
26. Les espaces de l'halieutique
- Author
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Millischer, L., Gascuel, D., Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
MODELE MATHEMATIQUE ,CAPTURE ,EFFORT DE PECHE ,LANGAGE ORIENTE OBJET ,TECHNIQUE DE PECHE ,SIMULATION ,SYSTEME MULTI AGENTS ,DISTRIBUTION SPATIALE ,EFFICACITE ,MODELISATION ,LOGICIEL D'APPLICATION - Abstract
Les tactiques de pêches développées par les pêcheurs peuvent être interprétées comme des adaptations à l'hétérogénéité spatiale de la distribution d'une ressource. Elles visent en effet à réduire l'incertitude relative aux probabilités de captures que peut attendre le pêcheur, incertitude induite par la répartition spatiale de la ressource. Les facteurs intervenants dans la constitution d'une tactique donnée sont a priori nombreux, mais surtout difficiles à quantifier car issus pour une grande part de choix subjectifs et qualitatifs. On se propose ici de les aborder de manière théorique à partir d'un travail de simulations. Les comportements individuels des pêcheurs sont ainsi modélisés en fonction de trois types de facteurs : facteurs informatifs, concernant les échanges d'informations entre pêcheurs au sein d'une flotille ; facteurs "cognitifs", liés à la connaissance partielle du milieu et la faculté d'apprentissage des pêcheurs ; facteurs directifs, liés au comportement du pêcheurs ; facteurs directifs, liés au comportement du pêcheur : interactions pêcheur-pêcheur, pêcheur-ressource, pêcheur-structure d'autorité. Plus précisément, la présente étude se concentre sur les déterminants des tactiques de pêche relevant des deux premières composantes. On définit ainsi un modèle d'échange d'informations individuelles entre navires d'une part, et de savoir-faire individuel d'autre part. Ces modèles définissent des tactiques de recherche de la ressource. Ils sont mis en oeuvre au sein d'un simulateur de type système multi-agent, où sont représentées explicitement l'activité de pêche des navires d'une flotille et la ressource sur laquelle elle se développe... (D'après résumé d'auteur)
- Published
- 2000
27. Les espaces de l'halieutique
- Author
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Maury, Olivier, Gascuel, D., Fonteneau, Alain, Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
MODELE MATHEMATIQUE ,BIOMASSE ,THON ,MORTALITE PAR PECHE ,MODELISATION ,ABONDANCE ,CAPTURE ,BIOTOPE ,MORTALITE ,SIMULATION ,THERMOCLINE ,DYNAMIQUE DE POPULATION ,PECHE THONIERE ,REPARTITION GEOGRAPHIQUE ,SURPECHE - Abstract
L'objet de l'article est la présentation d'un modèle spatialisé forcé par l'environnement de la population de thons albacore de l'Atlantique. Le modèle s'appuie sur des relations non linéaires estimées par modélisation additive généralisée (GAM) caractérisant, d'une part les préférences environnementales des albacores et d'autre part leur capturabilité à différents engins. Formulées analytiquement, les relations caratéristiques des préférences environnementales des albacores sont utilisées pour forcer un modèle d'advection-diffusion-réaction des albacores. Egalement formulées analytiquement, les relations caractérisant la capturabilité à différents engins permettent d'envisager l'ajustement du modèle aux captures observées. Le modèle permet de simuler la répartition des animaux en fonction de l'environnement océanique et des captures réelles. A travers différentes simulations, on s'intéresse au phénomène de surexploitation locale des thons adultes dans le Golfe de Guinée. La très grande ampleur du phénomène observée dans les simulations est discutée. (Résumé d'auteur)
- Published
- 2000
28. Les espaces de l'halieutique
- Author
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Rougeron, N., Gascuel, D., Morize, Eric, Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
BIOTOPE ,BATHYMETRIE ,DYNAMIQUE DE POPULATION ,HABITAT ,DISTRIBUTION SPATIALE ,ABONDANCE ,FAUNE ICHTYOLOGIQUE - Published
- 2000
29. Les espaces de l'halieutique
- Author
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Ulrich, C., Gascuel, D., Bellail, R., Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
POISSON MARIN ,MODELE MATHEMATIQUE ,CAPTURE ,RESSOURCES HALIEUTIQUES ,ESTIMATION DE STOCK ,GESTION DES PECHES ,ANALYSE DE COHORTES ,PRODUCTION HALIEUTIQUE ,REPARTITION GEOGRAPHIQUE ,MODELISATION ,ANALYSE STATISTIQUE - Abstract
Un stock est considéré comme une unité de gestion fonctionnelle couvrant une étendue géographiquement délimitée. Cependant, une politique de gestion peut souvent être envisagée dans une zone à une échelle différente de l'aire de répartition du stock. Dans le cadre d'un projet européen de modélisation bioéconomique des pêcheries de la Manche, on cherche ainsi à estimer les courbes de production locale (c'est-à-dire production Manche vs. effort Manche) des principaux stocks, dont certains sont évalués à une échelle spatiale beaucoup large que le seul bassin Manche ; un changement de l'effort en Manche aura donc souvent un effet mineur sur le stock global. Or l'homogénéité complète du stock n'est pas toujours vérifiée, et la fraction présente en Manche peut être, au moins pour partie, indépendante de la fraction hors Manche. Afin d'estimer l'impact d'un changement d'effort local, on propose un modèle appélé In/Out. Les captures en Manche sont considérées comme résultant de deux composantes : une fraction b qui provient d'un stock local présent uniquement en Manche (composante IN), et une fraction 1b qui provient du stock global, stock qui comprend également la partie extérieure à la Manche (composante OUT). Chaque stock subit une mortalité par pêche estimée par analyse des cohortes (VPA). Le modèle permet d'explorer la sensibilité de la fonction de production locale à la valeur de b. Une méthode statistique d'estimation de b, basée sur l'utilisation d'un modèle global, est également proposée. La méthode est appliquée à 7 différents stocks de la Manche, évalués jusqu'à présent à plus large échelle par les groupes de travail du CIEM. On montre que la méthode s'applique bien pour le sole et la plie, qui peuvent être considérées comme des stocks "Manche". Les résultats concernant le merlan et la morue sont peu significatifs. (Résumé d'auteur)
- Published
- 2000
30. Estimation d'abondance et changement de répartition spatiale : le cas du bobo (Pseudotolithus elongatus) en Guinée
- Author
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Sidibé, A., Gascuel, D., Domain, François, Chavance, Pierre, Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
POISSON MARIN ,CAPTURE ,REPARTITION VERTICALE ,PECHE DEMERSALE ,BIOMASSE ,ESTIMATION DE STOCK ,ANALYSE SPATIALE ,REPARTITION HORIZONTALE ,ZONE COTIERE ,PECHE ARTISANALE ,ABONDANCE - Abstract
Les variations spatio-temporelles d'abondance du stock de bobo de Guinée sont analysées sur la période 1985/98 par trois catégories d'approches complémentaires. Premièrement, une évaluation du stock est conduite par les méthodes d'analyse de cohorte et de rendement par recrue, en s'appuyant sur les statistiques de captures disponsibles pour la période récente (96/98). Deuxièmement, des indices annuels de densité sont calculés par modélisation linéaire des données des campagnes de chalutages scientifiques, réalisées depuis 1985 dans les strates bathymétriques de 5 à 30 m. Enfin, l'estimation des surfaces des strates permet de mettre en cohérence ces deux types de résultats et d'estimer un modèle de répartition des biomasses en début et fin de période, dans l'ensemble des strates de 0 à 30 m. Dans la période récente, la biomasse du stock est estimée à environ 9000 tonnes ; l'exploitation, très majoritairement liée à la pêche artisanale, conduirait à une situation globale de pleine exploitation. Les indices de densité montrent une forte diminution de l'abondance du bobo, entre début et fin de période. Cette diminution est particulièrement marquée dans les strates de forte abondance, entre 5 et 10 M. Le modèle de répartition des biomasses, montre qu'une part essentielle du stock (probablement supérieure à 75%) se situe dans la strate la plus côtière (0 à 5m) qui échappe au navire océanographique. La biomasse de début de période, qui correspondait à une situation proche de l'état vierge, est estimée à environ 18 000 tonnes. Le développement de l'exploitation s'est ainsi traduit par une baisse d'abondance, avec un impact qui s'avère être différent selon les strates bathymétiques. On met ainsi en évidence une rétraction du stock sur la zone la plus côtière. (Résumé d'auteur)
- Published
- 2000
31. 38th plenary meeting report of the scientific, technical and economic committee for fisheries (PLEN-11-03). Corrigendum
- Author
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Casey, J., Abella, J.A., Andersen, J.L., Bailey, N., Bertignac, M., Cardinale, M., Curtis, H., Daskalov, G.M., Delaney, A.E., di Natale, A., Döring, R., García-Rodriguez, M., Gascuel, D., Graham, N., Gustavsson, T.K.-E., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Malvarosa, L., Martin, P., Motova, A., Murua, H., Nowakowski, P., Prelezzo, R., Sala, A., Somarakis, S., Stransky, C., Théret, F., Ulrich, C., Vanhee, W., and Van Oostenbrugge, H.
- Abstract
This corrigendum should replace the corresponding section 8.4 of the 38th Plenary meeting report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-11-03). Publications Office of the European Union, Luxembourg, EUR 25033 EN, JRC67714.
- Published
- 2011
32. Assessing the effects of fisheries on marine top-predators: the Bay of Biscay case study
- Author
-
Lassalle, G., Gascuel, D. (Didier), Le-Loc'h, F., Lobry, J., Peltier, H., Pierce, G.J. (Graham John), Ridoux, V. (Vincent), Santos, M.B. (María Begoña), Spitz, J. (Jérôme) (Jérôme), and Niquil, N. (Nathalie)
- Published
- 2011
33. 36th plenary meeting report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-11-01)
- Author
-
Casey, J., Abella, J.A., Andersen, J.L., Bailey, N., Bertignac, M., Cardinale, M., Curtis, H., Daskalov, G.M., Delaney, A.E., Di Natale, A., Döring, R., García-Rodriguez, M., Gascuel, D., Graham, N., Gustavsson, T.K.-E., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Malvarosa, L., Martin, P., Motova, A., Murua, H., Nowakowski, P., Prelezzo, R., Sala, A., Somarakis, S., Stransky, C., Théret, F., Ulrich, C., Vanhee, W., Van Oostenbrugge, H., Guillén, J., Rätz, H.-J., Simmonds, E.J., and Virtanen, J.
- Abstract
The Scientific, Technical and Economic Committee for Fisheries hold its 36th plenary on 11-15 April 2011 in Barza d’Ispra (Italy). The terms of reference included both issues assessments of STECF Expert Working Group reports and additional requests submitted to the STECF by the Commission. Topics dealt with ranged from fisheries economics to management plan evaluation issues.
- Published
- 2011
34. Scientific, Technical and Economic Committee for Fisheries. Evaluation of fishing effort regimes - Deep sea and Western waters (STECF-11-12)
- Author
-
Barrat, K., Bell, E., Carlshamre, S., Davie, S., Demaneche, S., Dolder, P., Holmes, S., Jardim, E., Kempf, A., Kovsars, M., Lövgren, J., O’Hea, B., Radtke, K., Raid, T., Silva, C., Van der Kamp, P., Vermand, Y., Mitrakis, N., Casey, J., Abella, J.A., Andersen, J.L., Bailey, N., Bertignac, M., Cardinale, M., Curtis, H., Daskalov, G.M., Delaney, A.E., Döring, R., García-Rodriguez, M., Gascuel, D., Graham, N., Gustavsson, T.K.-E., Jennings, S., Kenny, A., Kirkegaard, E., Kraak, S., Kuikka, S., Malvarosa, L., Martin, P., Motova, A., Murua, H., Nowakowski, P., Prellezo, R., Sala, A., Somarakis, S., Stransky, C., Théret, F., Ulrich, C., Vanhee, W., and Van Oostenbrugge, H.
- Abstract
EWG-11-11 meeting was held on 26 – 30 September 2011 in Cadiz (Spain). This Section of the report covers the Deep Sea and Western Waters and provides fleet specific trends in catch (including discards), nominal effort and catch (landings) per unit of effort in order to advise on fleet specific impacts on stocks under multiannual management plans. STECF reviewed the report during its November 2011 plenary meeting.
- Published
- 2011
35. Eastern boundary upwelling ecosystems : integrative and comparative approaches
- Author
-
Thiaw, M., Gascuel, D., Jouffre, Didier, Thiom Thiaw, O., Fréon, Pierre (ed.), Barange, M. (ed.), Arístegui, J. (ed.), and McIntyre, A.D. (ed.)
- Subjects
CREVETTE ,VARIATION INTERANNUELLE ,EFFORT DE PECHE ,ANALYSE DE CORRESPONDANCE ,PECHE DE CRUSTACES ,ESTIMATION DE STOCK ,IMPACT DE L'ENVIRONNEMENT ,UPWELLING - Published
- 2009
36. Efforts et puissances de pêche : redéfinition des concepts et exemple d'application
- Author
-
Gascuel, D., Gascuel, D. (ed.), Durand, J.L. (ed.), and Fonteneau, Alain (ed.)
- Subjects
EFFORT DE PECHE ,DYNAMIQUE DES FLOTTILLES ,PUISSANCE DE PECHE ,ETUDE DE CAS ,EVOLUTION DES PECHERIES ,CAPTURABILITE ,GESTION DE STOCK ,ALBACORE ,PECHE THONIERE ,ANALYSE DE DONNEES - Abstract
Les caractéristiques actuelles de nombreuses flottilles, ainsi que l'évolution récente des méthodes d'évaluation et de gestion de stocks, justifient aujourd'hui une reformulation de la définition des concepts relatifs à l'effort de pêche. L'effort nominal (fn) doit être défini comme un paramètre de gestion, et l'effort effectif (fe) comme un paramètre d'évaluation, égal au coefficient de mortalité par pêche (F) à un facteur de disponibilité (d) près. Par suite, la capturabilité (q) correspond au produit d'une disponibilité et d'une puissance de pêche globale (Pg). Les différentes notions peuvent être reliées par la formulation suivante : F = q.fn = d.Pg.fn = d.fe. ... A titre d'illustration de ces définitions, on présente une analyse de l'évolution des puissances de pêche des flottilles de senneurs exploitant le thon albacore dans l'Atlantique Est. On montre qu'un effort de pêche standardisé ne constitue pas une mesure satisfaisante de l'effort effectif. Les puissances de pêche, estimées à partir de l'analyse des cohortes, croissent à un taux moyen de + 10% par an, au cours de la dernière décennie. (D'après résumé d'auteur)
- Published
- 1995
37. Les recherches françaises en évaluation quantitative et modélisation des ressources et des systèmes halieutiques : actes du colloque
- Author
-
Gascuel, D., Gascuel, D. (ed.), Durand, J.L. (ed.), and Fonteneau, Alain (ed.)
- Subjects
EFFORT DE PECHE ,EXPLOITATION ECONOMIQUE ,RESSOURCES HALIEUTIQUES ,ESTIMATION DE STOCK ,MODELISATION ,INDICE D'ABONDANCE ,METHODOLOGIE - Published
- 1995
38. Trophic signature of coral reef fish assemblages : towards a potential indicator of ecosystem disturbance
- Author
-
Bozec, Yves-Marie, Kulbicki, Michel, Chassot, E., and Gascuel, D.
- Subjects
anthropogenic disturbances ,fungi ,trophic structure ,technology, industry, and agriculture ,ecological indicator ,trophic level ,fish community - Abstract
Face to the increasing anthropogenic disturbances that affect coral reef ecosystems, it becomes urgent to define appropriate ecological indicators for monitoring purposes. One useful approach is to search for a simplified description of the structure of biological communities that are highly diverse and complex on coral reefs. To this end, we propose to represent the trophic structure of coral reef fish assemblages by using fractional trophic levels assigned to each fish species. Fish abundance trophic spectra (i.e., the distributions of fish abundance per trophic level) were established for the fringing reefs of two bays located in the city of Noumea (New Caledonia). The comparison of these trophic spectra revealed a similar trophic structure in the two bays, in spite of contrasted levels of fish abundance due to habitat damages. The embayment degree was characterized by changes in the fish trophic structure, reflecting a decreasing influence of urban and industrial wastes discharged in the bottom of the bays. This case of study shows the interest of using fractional trophic levels for the description of highly diverse biological communities. The trophic level-based approach offers new prospects in the search for ecological indicators, by characterizing the structure of biological communities by trophic signatures which testify to the disturbance level affecting their environment.
- Published
- 2005
39. Pêcheries maritimes, écosystèmes et sociétés en Afrique de l'Ouest : un demi-siècle de changement : actes du symposium international = Marine fisheries, ecosystems and societies in West Africa : half a century of change
- Author
-
Chavance, Pierre (ed.), Ba, M. (ed.), Gascuel, D. (ed.), Vakily, J.M. (ed.), and Pauly, D. (ed.)
- Subjects
PECHE MARITIME ,INFORMATIQUE SCIENTIFIQUE ,RESSOURCES HALIEUTIQUES ,ESTIMATION DE STOCK ,DEVELOPPEMENT DURABLE ,AMENAGEMENT DES PECHES ,ANALYSE DE DONNEES ,LOGICIEL D'APPLICATION - Published
- 2004
40. Balancing complexity and feasibility in Mediterranean coastal food-web models: uncertainty and constraints
- Author
-
Prato, G, primary, Gascuel, D, additional, Valls, A, additional, and Francour, P, additional
- Published
- 2014
- Full Text
- View/download PDF
41. Trophic level-based indicators to track fishing impacts across marine ecosystems
- Author
-
Shannon, L, primary, Coll, M, additional, Bundy, A, additional, Gascuel, D, additional, Heymans, JJ, additional, Kleisner, K, additional, Lynam, CP, additional, Piroddi, C, additional, Tam, J, additional, Travers-Trolet, M, additional, and Shin, Y, additional
- Published
- 2014
- Full Text
- View/download PDF
42. Overfishing of marine resources: some lessons from the assessment of demersal stocks off Mauritania
- Author
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Meissa, B., primary and Gascuel, D., additional
- Published
- 2014
- Full Text
- View/download PDF
43. Le poulpe Octopus vulgaris : Sénégal et côtes nord-ouest africaines
- Author
-
Laurans, M., Gascuel, D., and Caverivière, Alain
- Subjects
EFFORT DE PECHE ,CAPTURE ,BIOMASSE ,ESTIMATION DE STOCK ,DYNAMIQUE DE POPULATION ,FACTEUR ECOLOGIQUE ,ETUDE D'IMPACT ,PECHE DE MOLLUSQUES ,UPWELLING ,MODELISATION ,ABONDANCE - Published
- 2002
44. Le poulpe Octopus vulgaris : Sénégal et côtes nord-ouest africaines
- Author
-
Jouffre, Didier, Lanco, S., Gascuel, D., and Caverivière, Alain
- Subjects
CAPTURE ,VARIATION ANNUELLE ,GESTION DES PECHES ,SIMULATION ,ANALYSE DE COHORTES ,DYNAMIQUE DE POPULATION ,PECHE DE MOLLUSQUES ,STOCK ,AMENAGEMENT DES PECHES ,MODELISATION ,EXPLOITATION DES RESSOURCES NATURELLES - Published
- 2002
45. Les espaces de l'halieutique
- Author
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Gascuel, D. (ed.), Chavance, Pierre (ed.), Bez, N. (ed.), and Biseau, A. (ed.)
- Subjects
SYSTEME D'EXPLOITATION ,PROTECTION DE L'ECOSYSTEME ,BIOMASSE ,RESSOURCES HALIEUTIQUES ,GESTION DES PECHES ,PECHEUR ,MODELISATION ,EXPLOITATION DES RESSOURCES NATURELLES ,EFFORT DE PECHE ,ECONOMIE DES PECHES ,ESTIMATION DE STOCK ,DYNAMIQUE DE POPULATION ,FONCIER COUTUMIER ,GEOPOLITIQUE ,DROIT D'USAGE ,DISTRIBUTION SPATIALE ,SURPECHE ,DROIT DE LA MER ,ECOLOGIE - Published
- 2000
46. A future for marine fisheries in Europe (Manifesto of the Association Francaise d'Halieumetrie)
- Author
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Gascuel, D., Bez, Nicolas, Forest, Andre, Guillotreau, P., Laloe, F., Lobry, Jeremy, Mahevas, Stephanie, Mesnil, Benoit, Rivot, Etienne, Rochette, S., Trenkel, Verena, Gascuel, D., Bez, Nicolas, Forest, Andre, Guillotreau, P., Laloe, F., Lobry, Jeremy, Mahevas, Stephanie, Mesnil, Benoit, Rivot, Etienne, Rochette, S., and Trenkel, Verena
- Abstract
We, members of the Association Francaise d'Halieumetrie, share the conviction that European fisheries have a future. It is time to get off the wrong track. Radical change is required to embark on the path of sustainable development and truly implement the ecosystem approach to fisheries. Today, high fishing pressure is deployed to catch a rare resource, which in return is responsible for the rarity. We must reverse the situation: an abundant resource that affords high catches applying moderate fishing pressure. All management tools and especially all actors must be mobilized. The transition is not simple, and European solidarity must accompany the changes. It is well worth the effort. By reducing fishing pressure, it will be possible in the medium term to restore fish stocks, to make ecosystems return to good ecological status, to stabilize and even increase catches and to considerably improve economic efficiency. This is obviously in the interest of fishers but it is also in the interest of future generations and all users of this common heritage that is the sea. (C) 2011 Elsevier B.V. All rights reserved.
- Published
- 2011
- Full Text
- View/download PDF
47. Estimates of the mortality and the duration of the trans-Atlantic migration of European eel Anguilla anguilla leptocephali using a particle tracking model
- Author
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Bonhommeau, Sylvain, Le Pape, O., Gascuel, D., Blanke, Bruno, Treguier, Anne-marie, Grima, Nicolas, Vermard, Youen, Castonguay, M., Rivot, E., Bonhommeau, Sylvain, Le Pape, O., Gascuel, D., Blanke, Bruno, Treguier, Anne-marie, Grima, Nicolas, Vermard, Youen, Castonguay, M., and Rivot, E.
- Abstract
Using Lagrangian simulations, based on circulation models over three different hydroclimatic periods in the last 45 years in the North Atlantic Ocean, the trans-Atlantic migration of the European eel Anguilla anguilla leptocephali was simulated via the passive drift of particles released in the spawning area. Three different behaviours were modelled: drifting at fixed depth, undergoing a vertical migration or choosing the fastest currents. Simulations included mortality hypotheses to estimate a realistic mean migration duration and relative survival of A. anguilla larvae. The mean migration duration was estimated as 21 months and the mortality rate as 3 center dot 8 per year, i.e. < 0 center dot 2% of A. anguilla larvae may typically survive the trans-Atlantic migration.
- Published
- 2009
- Full Text
- View/download PDF
48. Investigating trophic-level variability in Celtic Sea fish predators
- Author
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Chassot, E, Rouyer, Tristan, Trenkel, Verena, Gascuel, D, Chassot, E, Rouyer, Tristan, Trenkel, Verena, and Gascuel, D
- Abstract
The trophic level mean and variance, and the degree of omnivory for five Celtic Sea fish predators were estimated using a database of stomach content records characterized by a high level of taxonomic resolution. The predators occupied a high position in the food web, i.e. 4.75 for Atlantic cod Gadus morhua, 444 for haddock Melanogrammus aeglefinus, 4.88 for European hake Merluccius merluccius, 5.00 for megrim Lepidorhombus whiffiagonis and 5.27 for whiting Merlangius merlangus. The level of taxonomic resolution of the prey did not greatly affect mean T-L predator values; an effect on variance was evident, low resolution masking intra-population variability in T-L. Generalized additive models (GAM) were used to explain the variability of predator T-L caused by environmental variables (international Council for the Exploration of the Sea, ICES, division and season) and predator characteristics (total length, L-T). Significant year, location season and interaction effects were found for some species and with L-T, at the scale of ICES subdivision. The species-specific variability of T-L could be due to spatio-temporal variations in prey availability and in predator selectivity following ontogenetic changes. Omnivorous fish T-L. was less affected by spatio-temporal variations. In addition, results showed that the omnivory index and T-L variability provide dissimilar information on predator feeding strategy. Combining information on T-L. variability and omnivory allowed between within individual and between-individual components contributing to trophic niche width to be separated and the type of generalization of fish predators to be identified. (c) 2008 The Authors Journal compilation (c) 2008 The Fisheries Society of the British Isles.
- Published
- 2008
- Full Text
- View/download PDF
49. Size matters: How single-species management can contribute to ecosystem-based fisheries management
- Author
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Froese, Rainer, Stern-Pirlot, A., Winker, H., Gascuel, D., Froese, Rainer, Stern-Pirlot, A., Winker, H., and Gascuel, D.
- Abstract
In this study we show how substantial gains towards the goals of ecosystem-based fisheries management (EBFM) can be achieved by different single-species management. We show that fishing has much less impact on stocks if fish are caught after they have reached the size (Lopt) where growth rate and cohort biomass are maximum. To demonstrate our point we compare the impact of three fishing scenarios on 9 stocks from the North Sea and the Baltic. Scenario (1) is the current fishing regime, scenario (2) is a new management regime proposed by the European Commission, aiming for maximum sustainable yield obtained from all stocks, and scenario (3) is set so that it achieves the same yield as scenario (2), albeit with fishing on sizes beyond Lopt. Results show that scenarios (2) and (3) are significant improvements compared to current fishing practice. However, scenario (3) consistently shows least impact on the stocks, with seven-fold higher biomass of demersal fishes and an age structure similar to an unfished stock. This allows juveniles and adults to better fulfil their ecological roles, a major step towards the goals of ecosystem-based fisheries management. We give examples where scenario (3) is practiced in successful fisheries. We present a new interpretation of the relative yield per recruit isopleth diagram with indication of a new target area for fisheries operating within the context of EBFM. We present a new expression of the relative biomass per recruit isopleth diagram, which supports our analysis. We conclude that size matters for precautionary and ecosystem-based fisheries management and present a list of additional advantages associated with fishing at Lopt.
- Published
- 2008
- Full Text
- View/download PDF
50. Assessing stocks in data-poor African fisheries: a case study on the white grouperEpinephelus aeneusof Mauritania
- Author
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Meissa, B, primary, Gascuel, D, additional, and Rivot, E, additional
- Published
- 2013
- Full Text
- View/download PDF
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