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Auteur (up) Colléter, M.; Gascuel, D.; Albouy, C.; Francour, P.; Tito de Morais, L.; Valls, A.; Le Loc'h, F.
Titre Fishing inside or outside? A case studies analysis of potential spillover effect from marine protected areas, using food web models Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Marine Systems
Volume 139 Numéro Pages 383-395
Mots-Clés Biomass exports; Ecopath; EcoTroph; Fishing impact; food web model; Marine protected area (MPA)
Résumé Marine protected areas (MPAs) are implemented worldwide as an efficient tool to preserve biodiversity and protect ecosystems. We used food web models (Ecopath and EcoTroph) to assess the ability of MPAs to reduce fishing impacts on targeted resources and to provide biomass exports for adjacent fisheries. Three coastal MPAs: Bonifacio and Port-Cros (Mediterranean Sea), and Bamboung (Senegalese coast), were used as case studies. Pre-existing related Ecopath models were homogenized and ecosystem characteristics were compared based on network indices and trophic spectra analyses. Using the EcoTroph model, we simulated different fishing mortality scenarios and assessed fishing impacts on the three ecosystems. Lastly, the potential biomass that could be exported from each MPA was estimated. Despite structural and functional trophic differences, the three MPAs showed similar patterns of resistance to simulated fishing mortalities, with the Bonifacio case study exhibiting the highest potential catches and a slightly inferior resistance to fishing. We also show that the potential exports from our small size MPAs are limited and thus may only benefit local fishing activities. Based on simulations, their potential exports were estimated to be at the same order of magnitude as the amount of catch that could have been obtained inside the reserve. In Port Cros, the ban of fishing inside MPA could actually allow for improved catch yields outside the MPA due to biomass exports. This was not the case for the Bonifacio site, as its potential exports were too low to offset catch losses. This insight suggests the need for MPA networks and/or sufficiently large MPAs to effectively protect juveniles and adults and provide important exports. Finally, we discuss the effects of MPAs on fisheries that were not considered in food web models, and conclude by suggesting possible improvements in the analysis of MPA efficiency.
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ISSN 0924-7963 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1197
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Auteur (up) Corrales, X.; Coll, M.; Tecchio, S.; Bellido, J.M.; Fernández, Á.M.; Palomera, I.
Titre Ecosystem structure and fishing impacts in the northwestern Mediterranean Sea using a food web model within a comparative approach Type Article scientifique
Année 2015 Publication Revue Abrégée Journal of Marine Systems
Volume 148 Numéro Pages 183-199
Mots-Clés comparative approach; Ecopath model; ecosystem approach to fisheries; fishing impacts; Mass-balance model; Northwestern Mediterranean Sea
Résumé We developed an ecological model to characterize the structure and functioning of the marine continental shelf and slope area of the northwestern Mediterranean Sea, from Toulon to Cape La Nao (NWM model), in the early 2000s. The model included previously modeled areas in the NW Mediterranean (the Gulf of Lions and the Southern Catalan Sea) and expanded their ranges, covering 45,547 km2, with depths from 0 to 1000 m. The study area was chosen to specifically account for the connectivity between the areas and shared fish stocks and fleets. Input data were based on local scientific surveys and fishing statistics, published data on stomach content analyses, and the application of empirical equations to estimate consumption and production rates. The model was composed of 54 functional groups, from primary producers to top predators, and Spanish and French fishing fleets were considered. Results were analyzed using ecological indicators and compared with outputs from ecosystem models developed in the Mediterranean Sea and the Gulf of Cadiz prior to this study. Results showed that the main trophic flows were associated with detritus, phytoplankton, zooplankton and benthic invertebrates. Several high trophic level organisms (such as dolphins, benthopelagic cephalopods, large demersal fishes from the continental shelf, and other large pelagic fishes), and the herbivorous salema fish, were identified as keystone groups within the ecosystem. Results confirmed that fishing impact was high and widespread throughout the food web. The comparative approach highlighted that, despite productivity differences, the ecosystems shared common features in structure and functioning traits such as the important role of detritus, the dominance of the pelagic fraction in terms of flows and the importance of benthic–pelagic coupling.
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ISSN 0924-7963 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1327
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Auteur (up) Diankha, O.; Demarcq, H.; Fall, M.; Thiao, D.; Thiaw, M.; Sow, B.A.; Gaye, A.T.; Brehmer, P.
Titre Studying the contribution of different fishing gears to the Sardinella small-scale fishery in Senegalese waters Type Article scientifique
Année 2017 Publication Revue Abrégée Aquat. Living Resour.
Volume 30 Numéro Pages 27
Mots-Clés abundance; africa; aurita; catch; dynamics; Effects of fishing; environmental-factors; Generalized additive model; generalized additive-models; patterns; Pelagic fish; Purse seine; retention; Sardinella aurita; Sardinella maderensis; Senegal; Surrounding gillnet
Résumé This study investigated variations of landings of two key species, Sardinella aurita and Sardinella maderensis, in Senegalese waters over a ten-year period (2004-2013). Using generalized additive models, it was found that fishing gear played a major role in explaining differences in monthly landings for both species (51-71% deviance explained). Its effect was more significant in the southern part of Senegal. Fishing effort (number of trips) accounted only for 4-18% of variability in landings. Purse seine (PS) fishing was the most important contributor to the landings of both species. In addition, in the southern area, surrounding gillnet fishing was also important for S. maderensis. Modeling results showed that the relationship between monthly effort and landings was generally positive and leveling off, while it was dome shaped for PSs and surrounding gillnets. Thus, when estimating fishing effort indices for management in Senegal, it is necessary to account for differences in fishing gears and the non-linear relationship between fishing effort and landings.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0990-7440 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2168
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Auteur (up) Diaz, E.; Heymans, J.J.; Hill, L.; Johannesen, E.; Jouffre, D.; Kifani, S.; Labrosse, P.; Link, J.S.; Mackinson, S.; Masski, H.; Shin, Y.-J.; Mollmann, C.; Neira, S.; Ojaveer, H.; Abdallahi, K.O.M.; Perry, I.; Thiao, D.; Yemane, D.; Cury, P.; Shannon, L.J.; Bundy, A.; Coll, M.; Aydin, K.; Bez, N.; Blanchard, J.L.; Borges, M.D.; Diallo, I.
Titre Using indicators for evaluating, comparing, and communicating the ecological status of exploited marine ecosystems. 2. Setting the scene Type Article scientifique
Année 2010 Publication Revue Abrégée Ices Journal of Marine Science
Volume 67 Numéro Pages 692-716
Mots-Clés approach; comparative; ecological; ecosystem; ecosystems; effects; exploited; Fishing; indicators; IndiSeas; marine; of
Résumé Background is provided to the selection of ecological indicators by the IndiSeas Working Group, and the methodology adopted for analysis and comparison of indicators across exploited marine ecosystems is documented. The selected indicators are presented, how they are calculated is explained, and the philosophy behind the comparative approach is given. The combination of selected indicators is intended to reflect different dynamics, tracking processes that display differential responses to fishing, and is meant to provide a complementary means of assessing marine ecosystem trends and states. IndiSeas relied on inputs and insights provided by the local experts from participating ecosystems, helping to understand state and trend indicators and to disentangle the effect of other potential ecosystem drivers, such as climate variability. This project showed that the use of simple and available indicators under an ecosystem approach can achieve a real, wide-reaching evaluation of marine ecosystem status caused by fishing. This is important because the socio-economics of areas where fishing activities develop differs significantly around the globe, and in many countries, insufficient data are available for complex and exhaustive analyses.
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Volume de collection Numéro de collection Edition
ISSN 1054-3139 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 67
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Auteur (up) Fernandez-Arcaya, U.; Bitetto, I.; Esteban, A.; Teresa Farriols, M.; Garcia-Ruiz, C.; Gil de Sola, L.; Guijarro, B.; Jadaud, A.; Kavadas, S.; Lembo, G.; Milisenda, G.; Maina, I.; Petovic, S.; Sion, L.; Vaz, S.; Massuti, E.
Titre Large-scale distribution of a deep-sea megafauna community along Mediterranean trawlable grounds Type Article scientifique
Année 2019 Publication Revue Abrégée Sci. Mar.
Volume 83 Numéro Pages 175-187
Mots-Clés aristeus-antennatus risso; biodiversity; biomass; community; continental slope; decapod crustaceans; deep sea; demersal fish diversity; distribution pattern; fishing impact; impacts; megafauna; red shrimp; relative roles; size; spatial-distribution; western
Résumé The large-scale distribution pattern of megafauna communities along the Mediterranean middle slope was explored. The study was conducted between 500 and 800 m depth where deep-water fishery occurs. Although community studies carried out deeper than 500 m are partly available for some geographic areas, few large-scale comparative studies have been carried out. Within the framework of the MEDITS survey programme, we compared the megafauna community structure in ten geographical sub-areas (GSAs) along the Mediterranean coasts. Additionally, the spatial distribution of fishing was analysed using vessel monitoring by satellite information. Overall, the community showed a significant difference between sub-areas, with a decreasing eastward pattern in abundance and biomass. Longitude was the main factor explaining variation among sub-areas (by generalized additive models). However, we found a region which did not follow the general pattern. GSA 6 (northern Spain) showed significantly lower abundance and a different composition structure to the adjacent areas. The decrease in community descriptors (i.e. abundance and biomass) in this area is probably a symptom of population changes induced by intense fishery exploitation. Overall, a combination of environmental variables and human-induced impacts appears to influence the bentho-pelagic communities along the slope areas of the Mediterranean.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0214-8358 ISBN Médium
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Notes WOS:000504829900014 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2699
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