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Auteur Lezama-Ochoa, N.; Murua, H.; Chust, G.; Ruiz, J.; Chavance, P.; Molina, A.D. de; Caballero, A.; Sancristobal, I.
Titre Biodiversity in the by-catch communities of the pelagic ecosystem in the Western Indian Ocean Type Article scientifique
Année 2015 Publication Revue Abrégée Biodivers Conserv
Volume 24 Numéro 11 Pages (down) 2647-2671
Mots-Clés By-catch; Diversity; Ecosystem Approach to Fisheries Management; Evolutionary Biology; Plant Sciences; Purse seine fishery; Tree Biology; Western Indian Ocean
Résumé Diversity in the by-catch communities from the pelagic ecosystem in the tropical tuna purse seine fishery has been poorly studied. This study uses different biodiversity measures to compare drifting fish aggregating devices (FADs) and Free School sets (sets made on schools of tuna) of the Western Indian Ocean. Data was collected from observer programs carried out by the European Union between 2003 and 2010 on board Spanish and French fleets. Alpha (species diversity of a particular area) and Beta diversity (difference in species composition between different areas) was analyzed to assess differences in the number of species, abundances and the species composition between areas and fishing modes. Generalized additive models were undertaken to explore which geographical/environmental variables explain the distribution of species richness index and Shannon diversity index in both fishing modes. Results showed that by-catch species in FAD communities may be used as observatories of surface pelagic biodiversity in combination with Free School communities. FAD communities were more diverse with higher number of species (74 species) and evenly distributed than Free School communities (56 species). However, environmental variables played a more important role in Free School communities. Somalia area and Mozambique Channel were the areas with highest biodiversity rates in both fishing modes. This work contributed for the future implementation of the EAFM to manage the pelagic ecosystem in a holistic and more integrated way.
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ISSN 0960-3115, 1572-9710 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1422
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Auteur Filmalter, J.D.; Cowley, P.D.; Potier, M.; Menard, F.; Smale, M.J.; Cherel, Y.; Dagorn, L.
Titre Feeding ecology of silky sharks Carcharhinus falciformis associated with floating objects in the western Indian Ocean Type Article scientifique
Année 2017 Publication Revue Abrégée J. Fish Biol.
Volume 90 Numéro 4 Pages (down) 1321-1337
Mots-Clés atlantic; By-catch; diet; ecosystem; fad; fish aggregating devices; fish aggregation device; food-consumption; isurus-oxyrinchus; pacific-ocean; pelagic fishes; Pelagic shark; Purse-seine fishery; shortfin mako; Yellowfin tuna
Résumé The silky shark Carcharhinus falciformis is commonly associated with floating objects, including fish aggregating devices (FADs), in the Indian Ocean. While the motives for this associative behaviour are unclear, it does make them vulnerable to capture in the tuna purse seine fishery that makes extensive use of FADs. Here, the diet of 323 C. falciformis, caught at FADs in the Indian Ocean, was investigated to test the hypothesis that trophic benefits explain the associative behaviour. A high proportion of stomachs with fresh contents (57%) suggested that extensive feeding activity occurred while associated with FADs. Multiple dietary indices showed that typical non-associative prey types dominated, but were supplemented with fishes typically found at FADs. While the trophic benefits of FAD association may be substantial, our results suggest that associative behaviour is not driven solely by feeding. (C) 2016 The Fisheries Society of the British Isles
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ISSN 0022-1112 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2142
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Auteur Ellis, J.R.; McCully Phillips, S. R.; Poisson, F.
Titre A review of capture and post-release mortality of elasmobranchs Type Article scientifique
Année 2017 Publication Revue Abrégée J. Fish Biol.
Volume 90 Numéro 3 Pages (down) 653-722
Mots-Clés algarve southern portugal; batoids; By-catch; bycatch reduction devices; california recreational fishery; discards; dogfish; dogfish squalus-acanthias; gulf-of-mexico; pelagic longline fishery; physiological stress-response; shark prionace-glauca; sharks; shrimp trawl fishery; survival; turtle excluder devices
Résumé There is a need to better understand the survivorship of discarded fishes, both for commercial stocks and species of conservation concern. Within European waters, the landing obligations that are currently being phased in as part of the European Union's reformed common fisheries policy means that an increasing number of fish stocks, with certain exceptions, should not be discarded unless it can be demonstrated that there is a high probability of survival. This study reviews the various approaches that have been used to examine the discard survival of elasmobranchs, both in terms of at-vessel mortality (AVM) and post-release mortality (PRM), with relevant findings summarized for both the main types of fishing gear used and by taxonomic group. Discard survival varies with a range of biological attributes (species, size, sex and mode of gill ventilation) as well as the range of factors associated with capture (e.g. gear type, soak time, catch mass and composition, handling practices and the degree of exposure to air and any associated change in ambient temperature). In general, demersal species with buccal-pump ventilation have a higher survival than obligate ram ventilators. Several studies have indicated that females may have a higher survival than males. Certain taxa (including hammerhead sharks Sphyrna spp. and thresher sharks Alopias spp.) may be particularly prone to higher rates of mortality when caught. (C) 2016 Crown copyright
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0022-1112 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2106
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Auteur Dagorn, L.; Holland, K.N.; Restrepo, V.; Moreno, G.
Titre Is it good or bad to fish with FADs? What are the real impacts of the use of drifting FADs on pelagic marine ecosystems? Type Article scientifique
Année 2013 Publication Revue Abrégée Fish And Fisheries
Volume 14 Numéro 3 Pages (down) 391-415
Mots-Clés by-catch; ecological trap; Fad; purse seine; tuna
Résumé The use of fish aggregating devices (FADs) by purse seine fisheries has come under increasing criticism for its potential deleterious impacts on tuna stocks, for high levels of by-catch and threats to the biodiversity of tropical pelagic ecosystems. Here, we review the current state of scientific knowledge of this fishing technique and current management strategies. Our intent is to encourage objective discussion of the topic and highlight areas worthy of future research. We show that catching juvenile tuna around FADs does not necessarily result in overfishing of stocks, although more selective fishing techniques would likely help obtain higher yield. Levels of non-tuna by-catch are comparable to or less than in other commercial tuna fisheries and are primarily comprised of species that are not considered threatened. Accordingly, to minimize impacts on ecosystem balance, there is merit in considering that all species captured in purse seine fisheries (excluding vulnerable species such as turtles and sharks) should be retained, but the consequences of such a measure should be carefully examined before implementation. The take of vulnerable species could be further reduced by introduction of additional mitigation measures, but their potential benefits would be limited without parallel efforts with other gears. Finally, there is no unequivocal empirical evidence that FADs represent an ‘ecological trap’ that inherently disrupts tuna biology although further research should focus on this issue. We encourage RFMOs to expand and improve their FAD management plans. Under appropriate management regimes, FAD fishing could be an ecologically and economically sensible fishing method.
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ISSN 1467-2979 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 256
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Auteur Follesa, M.C.; Marongiu, M.F.; Zupa, W.; Bellodi, A.; Cau, A.; Cannas, R.; Colloca, F.; Djurovic, M.; Isajlovic, I.; Jadaud, A.; Manfredi, C.; Mulas, A.; Peristeraki, P.; Porcu, C.; Ramirez-Amaro, S.; Salmeron Jimenez, F.; Serena, F.; Sion, L.; Thasitis, I.; Cau, A.; Carbonara, P.
Titre Spatial variability of Chondrichthyes in the northern Mediterranean Type Article scientifique
Année 2019 Publication Revue Abrégée Sci. Mar.
Volume 83 Numéro Pages (down) 81-100
Mots-Clés abundance; adriatic sea; balearic-islands; bottom trawl surveys; by-catch; Chondrichthyes; demersal assemblages; depth distribution; distribution; dynamics; elasmobranchs; fish; fisheries; Mediterranean; parameters; patterns
Résumé Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families). 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth). while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicida and the Torpediniformes Torpedo matmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavaia and then by R. miraleius, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canictda, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers.
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Langue English Langue du Résumé Titre Original
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ISSN 0214-8358 ISBN Médium
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Notes WOS:000504829900007 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2700
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