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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 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
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ISSN (up) 0960-3115 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2482
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Auteur Gilman, E.; Chaloupka, M.; Bach, P.; Fennell, H.; Hall, M.; Musyl, M.; Piovano, S.; Poisson, F.; Song, L.
Titre Effect of pelagic longline bait type on species selectivity: a global synthesis of evidence Type Article scientifique
Année 2020 Publication Revue Abrégée Rev. Fish. Biol. Fish.
Volume 30 Numéro 3 Pages 535-551
Mots-Clés atlantic-ocean; Bait; by-catch; Bycatch; caretta-caretta; circle hooks; feeding-behavior; Longline; Mitigation; publication bias; sea-turtles; Selectivity; shark populations; size-selectivity; swordfish xiphias-gladius; Tuna
Résumé Fisheries can profoundly affect bycatch species with 'slow' life history traits. Managing bait type offers one tool to control species selectivity. Different species and sizes of marine predators have different prey, and hence bait, preferences. This preference is a function of a bait's chemical, visual, acoustic and textural characteristics and size, and for seabirds the effect on hook sink rate is also important. We conducted a global meta-analysis of existing estimates of the relative risk of capture on different pelagic longline baits. We applied a Bayesian random effects meta-analytic regression modelling approach to estimate overall expected bait-specific catch rates. For blue shark and marine turtles, there were 34% (95% HDI: 4-59%) and 60% (95% HDI: 44-76%) significantly lower relative risks of capture on forage fish bait than squid bait, respectively. Overall estimates of bait-specific relative risk were not significantly different for seven other assessed taxa. The lack of a significant overall estimate of relative capture risk for pelagic shark species combined but significant effect for blue sharks suggests there is species-specific variability in bait-specific catch risk within this group. A qualitative literature review suggests that tunas and istiophorid billfishes may have higher catch rates on squid than fish bait, which conflicts with reducing marine turtle and blue shark catch rates. The findings from this synthesis of quantitative and qualitative evidence support identifying economically viable bycatch management measures with acceptable tradeoffs when multispecies conflicts are unavoidable, and highlight research priorities for global pelagic longline fisheries.
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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 (up) 0960-3166 ISBN Médium
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Notes WOS:000555361400001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2843
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Auteur Nikolic, N.; Morandeau, G.; Hoarau, L.; West, W.; Arrizabalaga, H.; Hoyle, S.; Nicol, S.J.; Bourjea, J.; Puech, A.; Farley, J.H.; Williams, A.J.; Fonteneau, A.
Titre Review of albacore tuna, Thunnus alalunga, biology, fisheries and management Type Article scientifique
Année 2016 Publication Revue Abrégée Rev Fish Biol Fisheries
Volume Numéro Pages 1-36
Mots-Clés Albacore; Tuna; Thunnus alalunga; Biology; Fishery
Résumé Albacore is one of the most important commercially harvested species in the world’s oceans. Despite a long history of scientific research, there is no global review or synthesis of knowledge about the species across all oceanic regions. We analysed 613 published studies that report on albacore and summarize the current state of knowledge on biology, stock structure, fisheries and management. To describe the trends in albacore fisheries, we examined the catch and effort databases of Regional Fisheries Management Organisations. The stocks of albacore are generally largest in the Pacific Ocean and smallest in the Mediterranean Sea. The biology of Atlantic and Pacific Ocean stocks are well documented, while the Indian Ocean and the Mediterranean Sea stocks are more data deficient. These two latter areas should be considered as priorities for future research and data collection in order to better understand the state of global stocks of albacore tuna. Improved information would also assist with delineating stock boundaries needed for sustainable management of this species.
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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN (up) 0960-3166, 1573-5184 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1707
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Auteur Young, J.W.; Olson, R.J.; Ménard, F.; Kuhnert, P.M.; Duffy, L.M.; Allain, V.; Logan, J.M.; Lorrain, A.; Somes, C.J.; Graham, B.; Goñi, N.; Pethybridge, H.; Simier, M.; Potier, M.; Romanov, E.; Pagendam, D.; Hannides, C.; Choy, C.A.
Titre Setting the stage for a global-scale trophic analysis of marine top predators: a multi-workshop review Type Article scientifique
Année 2015 Publication Revue Abrégée Rev Fish Biol Fisheries
Volume 25 Numéro 1 Pages 261-272
Mots-Clés climate change; Freshwater & Marine Ecology; Global diet data; Global nitrogen model; Global stable isotope data; Predictive analyses; top predators; Tuna trophic ecology; Zoology
Résumé Global-scale studies of marine food webs are rare, despite their necessity for examining and understanding ecosystem level effects of climate variability. Here we review the progress of an international collaboration that compiled regional diet datasets of multiple top predator fishes from the Indian, Pacific and Atlantic Oceans and developed new statistical methods that can be used to obtain a comprehensive ocean-scale understanding of food webs and climate impacts on marine top predators. We loosely define top predators not as species at the apex of the food web, but rather a guild of large predators near the top of the food web. Specifically, we present a framework for world-wide compilation and analysis of global stomach-contents and stable-isotope data of tunas and other large pelagic predatory fishes. To illustrate the utility of the statistical methods, we show an example using yellowfin tuna in a “test” area in the Pacific Ocean. Stomach-contents data were analyzed using a modified (bagged) classification tree approach, which is being prepared as an R statistical software package. Bulk δ15N values of yellowfin tuna muscle tissue were examined using a Generalized Additive Model, after adjusting for spatial differences in the δ15N values of the baseline primary producers predicted by a global coupled ocean circulation-biogeochemical-isotope model. Both techniques in tandem demonstrated the capacity of this approach to elucidate spatial patterns of variations in both forage species and predator trophic positions and have the potential to predict responses to climate change. We believe this methodology could be extended to all marine top predators. Our results emphasize the necessity for quantitative investigations of global-scale datasets when evaluating changes to the food webs underpinning top ocean predators under long-term climatic variability.
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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
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ISSN (up) 0960-3166, 1573-5184 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1263
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Auteur Annasawmy, P.; Cherel, Y.; Romanov, E.; Le Loc'h, F.; Menard, F.; Ternon, J.-F.; Marsac, F.
Titre Stable isotope patterns of mesopelagic communities over two shallow seamounts of the south-western Indian Ocean Type Article scientifique
Année 2020 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.
Volume 176 Numéro Pages 104804
Mots-Clés biogeochemical provinces; Crustaceans; delta C-13; delta N-15; discrimination factors; feeding ecology; Fish; food-web structure; Micronekton; mozambique channel; particulate organic-matter; Squid; Trophic level; trophic structure; vertical-distribution; water column; yellowfin tuna
Résumé The stable carbon (delta C-13) and nitrogen (delta N-15) isotope values of soft tissues of micronekton (crustaceans, squid, mesopelagic fish) and zooplankton were measured from organisms collected on the RV Antea at two seamounts located in the south-western Indian Ocean: La Perouse (summit depth similar to 60 m) and “MAD-Ridge” (thus named in this study; summit depth similar to 240 m). Surface particulate organic matter (POM-Surf) showed higher delta C-13 at the more productive MAD-Ridge than at the oligotrophic La Perouse seamount. Particulate organic matter and zooplankton were depleted in N-15 at La Pemuse pinnacle compared with MAD-Ridge. Gelatinous organisms and crustaceans occupied the lowest and intermediate tmphic levels (TL similar to 2 and 3 respectively) at both seamounts. Mesopelagic fish and smaller-sized squid sampled at both seamounts occupied TL similar to 3 to 4, whereas the large nektonic squid, Ommastrephes bartramii, collected at MAD-Ridge only, exhibited a TL of similar to 5. The delta N-15 values of common open-water mesopelagic taxa were strongly influenced by specimen size and feeding habits at both seamounts, with an increase in delta N-15 values with increasing size. Carnivorous fish species sampled exclusively over the seamounts' flanks and summits exhibited TL values of similar to 4, irrespective of their wide size ranges. The work could not demonstrate any differences in delta C-13 values of mesopelagic fish between the seamounts and the surrounding oceanic areas. The study segregated clusters of mesopelagic organisms according to their delta C-13 and delta N-15 values, with variations in stable isotope values reflecting a complex range of processes possibly linked to productivity as well as biological and ecological traits of the species (size and feeding mode).
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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 (up) 0967-0645 ISBN Médium
Région Expédition Conférence
Notes WOS:000556810400002 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2835
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