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Auteur Benedetti, F.; Guilhaumon, F.; Adloff, F.; Ayata, S.-D.
Titre Investigating uncertainties in zooplankton composition shifts under climate change scenarios in the Mediterranean Sea Type Article scientifique
Année 2018 Publication Revue Abrégée Ecography
Volume (down) 41 Numéro 2 Pages 345-360
Mots-Clés marine biodiversity; species distribution models; north-atlantic; beta diversity; calanoid copepods; ecological-niche; envelope models; habitat-suitability; mass mortality; pseudo-absence data
Résumé Ensemble niche modelling has become a common framework to predict changes in assemblages composition under climate change scenarios. The amount of uncertainty generated by the different components of this framework has rarely been assessed. In the marine realm forecasts have usually focused on taxa representing the top of the marine food-web, thus overlooking their basal component: the plankton. Calibrating environmental niche models at the global scale, we modelled the habitat suitability of 106 copepod species and estimated the dissimilarity between present and future zooplanktonic assemblages in the surface Mediterranean Sea. We identified the patterns (species replacement versus nestedness) driving the predicted dissimilarity, and quantified the relative contributions of different uncertainty sources: environmental niche models, greenhouse gas emission scenarios, circulation model configurations and species prevalence. Our results confirm that the choice of the niche modelling method is the greatest source of uncertainty in habitat suitability projections. Presence-only and presence-absence methods provided different visions of the niches, which subsequently lead to different future scenarios of biodiversity changes. Nestedness with decline in species richness is the pattern driving dissimilarity between present and future copepod assemblages. Our projections contrast with those reported for higher trophic levels, suggesting that different components of the pelagic food-web may respond discordantly to future climatic changes.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0906-7590 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2282
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Auteur Kirkman, S.P.; Blamey, L.; Lamont, T.; Field, J.G.; Bianchi, G.; Huggett, J.A.; Hutchings, L.; Jackson-Veitch, J.; Jarre, A.; Lett, C.; Lipinski, M.R.; Mafwila, S.W.; Pfaff, M.C.; Samaai, T.; Shannon, L.J.; Shin, Y.-J.; van der Lingen, C.D.; Yemane, D.
Titre Spatial characterisation of the Benguela ecosystem for ecosystem-based management Type Article scientifique
Année 2016 Publication Revue Abrégée Afr. J. Mar. Sci.
Volume (down) 38 Numéro 1 Pages 7-22
Mots-Clés agulhas system; atlantic-ocean; biology; drivers; ecosystem approach to fisheries; large marine ecosystem; large marine ecosystem; marine spatial planning; models; monitoring; northern benguela; nursery areas; physical oceanography; regime shifts; sea use management; southern benguela; upwelling system; variability
Résumé The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibia and South Africa, have committed to implementing ecosystem-based management (EBM) including an ecosystem approach to fisheries (EAF) in the region, to put in practice the principles of sustainable development in ocean-related matters. There is also recognition of the need for marine spatial planning (MSP) as a process for informing EBM with regard to the allocation and siting of ocean uses so that ecosystem health is ensured and trade-offs between ecosystem services are appropriately dealt with. Marine spatial planning is both an integrated and an area-based process, and this paper produces a spatial characterisation of the BCLME for achieving a common basis for MSP in the region, focusing on the oceanography, biology and fisheries. Recognising spatial variation in physical driving forces, primary and secondary production, trophic structures and species richness, four different subsystems are characterised: (1) north of the Angola-Benguela Front, (2) from the Angola-Benguela Front to Luderitz, (3) from Luderitz to Cape Agulhas, and (4) from Cape Agulhas to Port Alfred on the south-east coast of South Africa. Research and monitoring requirements of relevance for MSP and EBM in the region are identified, focusing on understanding variability and change, including with regard to the boundary areas identified for the system. To this end, 14 cross-shelf monitoring transects are proposed (including seven that are already being monitored) to estimate fluxes of biota, energy and materials within and between the subsystems. The usefulness of models for understanding ecosystem variability and changes is recognised and the need for fine-scale resolution of both sampling and modelling for adequate MSP as input to EBM for the often-conflicting interests of conserving biodiversity, and managing fisheries, recreation, offshore oil and gas exploration and exploitation, offshore mining and shipping routes, is emphasised.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1814-232x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1658
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Auteur Nikolic, N.; Lauretta, M.; Patucca, A.; Morandeau, G.
Titre Characterization and standardization of the Atlantic albacore French pelagic trawl fishery Type Article scientifique
Année 2018 Publication Revue Abrégée Aquat. Living Resour.
Volume (down) 31 Numéro Pages 31
Mots-Clés Albacore; Atlantic; behavior; catch; catch rates; fisheries; habitat; migration; north pacific albacore; ocean; stock; thunnus-alalunga; trawl; tuna
Résumé We compiled and analysed logbook data from the French trawl albacore fishery covering the period 1991-2015. The dataset comprised catch and effort data for the French fleet operating in the Bay of Biscay and Celtic Sea, as well as spatiotemporal and gear characteristics. Generalized linear modelling was used to model spatial, seasonal, environmental, and gear covariates of fleet CPUE rates. A long-term index of relative abundance is provided that can be integrated into the stock assessment of North Atlantic albacore. The analysis revealed higher albacore CPUE associated with relatively low sea surface temperature and distinct seasonal effects. The derived abundance trend for the French trawl fishery agreed with the estimated time series of stock abundance from recent assessments.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0990-7440 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 2426
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Auteur Escalle, L.; Gaertner, D.; Chavance, P.; Murua, H.; Simier, M.; Jose Pascual-Alayon, P.; Menard, F.; Ruiz, J.; Abascal, F.; Mérigot, B.
Titre Catch and bycatch captured by tropical tuna purse-seine fishery in whale and whale shark associated sets: comparison with free school and FAD sets Type Article scientifique
Année 2019 Publication Revue Abrégée Biodivers. Conserv.
Volume (down) 28 Numéro 2 Pages 467-499
Mots-Clés diversity; mortality; atlantic; biology; Bycatch; strategies; Megafauna; behavior; dominance; yellowfin; Catch composition; Diversity; Ecosystem approach to fisheries management; swimming speeds; Tuna purse-seine fishery
Résumé In an ecosystem approach to fisheries management (EAFM) framework of the tuna purse-seine fishery, the assessment of target species, but also that of bycatch species, is essential. In the Atlantic and Indian oceans, purse-seine nets are sometimes set around tuna schools associated with whale sharks and baleen whales, although less frequently than around free-swimming tuna schools or those associated with fish aggregating devices (FAD). However, knowledge on the targeted catch and bycatch in these megafauna associated fishing sets is still relatively limited. Therefore, the aims of this study were to assess species and size composition of the target tuna species, as well as the diversity of bycatch species in whale and whale shark associated sets. Whale associated sets were found to be very similar to free school sets in terms of tuna catch (large yellowfin tuna), bycatch occurrence (presence in half the sets) and species assemblage (alpha and beta diversity). Whale shark associated sets were intermediate between FAD and free school sets, with tuna catch (skipjack and juvenile yellowfin) closer to FAD than to free school sets. However, the presence of large yellowfin, the bycatch composition (with almost no finfish, abundantly captured in FAD sets) and the species assemblage showed similarity with free school sets. This study highlights the need for an EAFM in the tuna purse-seine fishery by providing knowledge on pelagic multi-specific catches and bycatches.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0960-3115 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2482
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Auteur Escalle, L.; Pennino, M.G.; Gaertner, D.; Chavance, P.; Delgado de Molina, A.; Demarcq, H.; Romanov, E.; Mérigot, B.
Titre Environmental factors and megafauna spatio-temporal co-occurrence with purse-seine fisheries Type Article scientifique
Année 2016 Publication Revue Abrégée Fish. Oceanogr.
Volume (down) 25 Numéro 4 Pages 433-447
Mots-Clés cetaceans; Eastern Atlantic Ocean; generalized additive models-boosted regression trees; marine conservation; purse-seine fishery; residual autocovariate; Western Indian Ocean; whale sharks
Résumé Tropical tuna purse-seine fisheries spatially co-occur with various megafauna species, such as whale sharks, dolphins and baleen whales in all oceans of the world. Here, we analyzed a 10-year (2002–2011) dataset from logbooks of European tropical tuna purse-seine vessels operating in the tropical Eastern Atlantic and Western Indian Oceans, with the aim of identifying the principle environmental variables under which such co-occurrence appear. We applied a Delta-model approach using Generalized Additive Models (GAM) and Boosted Regression Trees (BRT) models, accounting for spatial autocorrelation using a contiguity matrix based on a residuals autocovariate (RAC) approach. The variables that contributed most in the models were chlorophyll-a concentration in the Atlantic Ocean, as well as depth and monsoon in the Indian Ocean. High co-occurrence between whale sharks, baleen whales and tuna purse-seine fisheries were mostly observed in productive areas during particular seasons. In light of the lack of a full coverage scientific observer on board program, the large, long-term dataset obtained from logbooks of tuna purse-seine vessels is highly important for identifying seasonal and spatial co-occurrence between the distribution of fisheries and megafauna, and the underlying environmental variables. This study can help to design conservation management measures for megafauna species within the framework of spatial fishery management strategies.
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Langue en Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1365-2419 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1587
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