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Auteur Zudaire, I.; Murua, H.; Grande, M.; Pernet, F.; Bodin, N.
Titre Accumulation and mobilization of lipids in relation to reproduction of yellowfin tuna (Thunnus albacares) in the Western Indian Ocean Type Article scientifique
Année 2014 Publication Revue Abrégée Fisheries Research
Volume Numéro Pages 50-59
Mots-Clés FADs; Fecundity; Income-capital breeder; Lipid class composition; Reproductive allocation strategy; Tropical tuna
Résumé Total lipid content and lipid class composition were analyzed in gonads, liver and white muscle of yellowfin tuna (Thunnus albacares) throughout ovary development to understand its reproductive allocation strategy and to assess the relation between female condition and reproduction. A total of 112 females were collected onboard purse-seiner in the Western Indian Ocean from January to March 2009, from June to July 2009, and from April to May 2010. Gonads were characterized by highly variable total lipid contents ranging from 5 to 27 μg mg−1 of wet weight (ww) with a predominance of neutral lipids, mainly triacylglycerols (TAG) and sterol- and wax-esters. The different lipid classes in gonads described an accumulative pattern through the maturity process from immature to hydration phase. Total lipid content in liver varied from 10 to 21 μg mg−1 ww, and serves as fuel for yellowfin tuna reproduction. TAG and phospholipid deposits became depleted as the ovary developed, suggesting a transfer of lipids directly from liver to the oocytes during vitellogenesis. In contrast, muscle total lipid content was low and constant throughout ovarian development (2.5–6 μg mg−1 ww). Hence, yellowfin tuna can be defined as an income-capital breeder species for which the cost of reproduction depends mainly on concurrent energy income from feeding and only little on stored lipids. Besides, no significant relationship between gonad lipid composition and fecundity was found in females able to spawn. Finally, the influence of yellowfin tuna aggregation behaviour on reproductive female condition has been investigated: gonad total lipid contents were higher in females caught in free-swimming schools than in females caught under fish aggregating devices (FADs). However, these results did not clarify whether the influence of FADs on associated yellowfin tuna affects their reproductive capacity.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Advances in Fisheries Research in Ibero-America Titre de collection Abrégé
Volume de collection (down) 160 Numéro de collection Edition
ISSN 0165-7836 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1209
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Auteur Olson, R.J.; Young, J.W.; Menard, F.; Potier, M.; Allain, V.; Goni, N.; Logan, J.M.; Galvan-Magana, F.
Titre Bioenergetics, Trophic Ecology, and Niche Separation of Tunas Type Chapitre de livre
Année 2016 Publication Revue Abrégée
Volume Numéro Pages 199-344
Mots-Clés albacore thunnus-alalunga; atlantic bluefin tuna; eastern tropical pacific; fish aggregation devices; gulf-of-mexico; large pelagic fishes; oceanic top predators; predator-prey interactions; satellite archival tags; western indian-ocean
Résumé Tunas are highly specialized predators that have evolved numerous adaptations for a lifestyle that requires large amounts of energy consumption. Here we review our understanding of the bioenergetics and feeding dynamics of tunas on a global scale, with an emphasis on yellowfin, bigeye, skipjack, albacore, and Atlantic bluefin tunas. Food consumption balances bioenergetics expenditures for respiration, growth (including gonad production), specific dynamic action, egestion, and excretion. Tunas feed across the micronekton and some large zooplankton. Some tunas appear to time their life history to take advantage of ephemeral aggregations of crustacean, fish, and molluscan prey. Ontogenetic and spatial diet differences are substantial, and significant interdecadal changes in prey composition have been observed. Diet shifts from larger to smaller prey taxa highlight ecosystem-wide changes in prey availability and diversity and provide implications for changing bioenergetics requirements into the future. Where tunas overlap, we show evidence of niche separation between them; resources are divided largely by differences in diet percentages and size ranges of prey taxa. The lack of long-term data limits the ability to predict impacts of climate change on tuna feeding behaviour. We note the need for systematic collection of feeding data as part of routine monitoring of these species, and we highlight the advantages of using biochemical techniques for broad-scale analyses of trophic relations. We support the continued development of ecosystem models, which all too often lack the regional-specific trophic data needed to adequately investigate climate and fishing impacts.
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Editeur Elsevier Academic Press Inc Lieu de Publication San Diego Éditeur Curry, B.E.
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé Advances in Marine Biology, Vol 74
Volume de collection (down) 74 Numéro de collection Edition
ISSN ISBN 978-0-12-803607-5 Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 1661
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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 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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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 1467-2979 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 256
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Auteur Dueri, S.; Maury, O.
Titre Modelling the effect of marine protected areas on the population of skipjack tuna in the Indian Ocean Type Article scientifique
Année 2013 Publication Revue Abrégée Aquatic Living Resources
Volume 26 Numéro Pages 171-178
Mots-Clés Chagos MPA; fishery management; Fishery scenarios; marine reserves; null; Tropical tuna
Résumé The benefits of implementing no-take Marine Protected Areas (MPAs) for the conservation of highly migratory species are not easy to assess. They depend on several factors, such as the fish mobility, fisher behaviour and the area covered by the MPA with respect to the distribution area of the species to protect. In this study, we explore the simultaneous effects of MPAs and fishing scenarios on skipjack tuna population dynamics, using the spatially-explicit APECOSM-E model. The model represents the size-structured population dynamics of skipjack tuna in the Indian Ocean and their dependence on climatic variability and exploitation by fisheries. Numerical experiments were run from the beginning of industrial fisheries in the early 1980s to the year 2030, considering different scenarios for the future development of fisheries. These scenarios combined different trends in fishing effort and technological development, either assuming a continuous increase following historical trends or a stabilization of these factors at present values. The simulations were designed to explore the effects of two MPAs of different size and location: the recently established Chagos MPA, and a hypothetical MPA covering a large part of the Western Indian Ocean, where most of the skipjack catches are presently made. We modelled the redistribution of fishing effort around the MPAs assuming that the fishers had partial knowledge of the spatial distribution of the skipjack population. The effects of the two MPAs on the population dynamics, catch and fishing mortality are shown. Our results revealed a very minor effect of the Chagos MPA on the skipjack tuna population, while the Western Indian Ocean MPA had an important impact on the fishing mortality and succeeded in stabilizing the spawning population. The simulations also showed that the effect of an MPA depends on the evolution of fisheries and it is therefore important to explore different fishery scenarios to assess the future benefits of an MPA.
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Numéro d'Appel LL @ pixluser @ collection 257
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Auteur Pecoraro, C.; Babbucci, M.; Villamor, A.; Franch, R.; Papetti, C.; Leroy, B.; Ortega-Garcia, S.; Muir, J.; Rooker, J.; Arocha, F.; Murua, H.; Zudaire, I.; Chassot, E.; Bodin, N.; Tinti, F.; Bargelloni, L.; Cariani, A.
Titre Methodological assessment of 2b-RAD genotyping technique for population structure inferences in yellowfin tuna (Thunnus albacares) Type Article scientifique
Année 2016 Publication Revue Abrégée Marine Genomics
Volume 25 Numéro Pages 43-48
Mots-Clés Marine fish; Population genomics; RAD sequencing; Snp; Tropical tuna; Tuna fishery
Résumé Global population genetic structure of yellowfin tuna (Thunnus albacares) is still poorly understood despite its relevance for the tuna fishery industry. Low levels of genetic differentiation among oceans speak in favour of the existence of a single panmictic population worldwide of this highly migratory fish. However, recent studies indicated genetic structuring at a much smaller geographic scales than previously considered, pointing out that YFT population genetic structure has not been properly assessed so far. In this study, we demonstrated for the first time, the utility of 2b-RAD genotyping technique for investigating population genetic diversity and differentiation in high gene-flow species. Running de novo pipeline in Stacks, a total of 6772 high-quality genome-wide SNPs were identified across Atlantic, Indian and Pacific population samples representing all major distribution areas. Preliminary analyses showed shallow but significant population structure among oceans (FST = 0.0273; P-value < 0.01). Discriminant Analysis of Principal Components endorsed the presence of genetically discrete yellowfin tuna populations among three oceanic pools. Although such evidence needs to be corroborated by increasing sample size, these results showed the efficiency of this genotyping technique in assessing genetic divergence in a marine fish with high dispersal potential.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 1874-7787 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1539
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