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Auteur Fonteneau, A.; Pereira, J.G.
Titre Analysis of the Daily Catch and Effort Data of the Bluefin (Thunnus Thynnus) Algarve Trap Fishery During the Years 1898–1900 Type Article scientifique
Année 2012 Publication Revue Abrégée Aquatic Living Resources
Volume FirstView Numéro Pages
Mots-Clés (up) Bluefin tuna; Daily catches; East Atlantic; Fish behaviour; Fish trap; Historical survey; Portugal; Spawning migration pattern
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Numéro d'Appel LL @ pixluser @ collection 187
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Auteur Mariani, P.; Křivan, V.; MacKenzie, B.R.; Mullon, C.
Titre The migration game in habitat network: the case of tuna Type Article scientifique
Année 2016 Publication Revue Abrégée Theor Ecol
Volume 9 Numéro 2 Pages 219-232
Mots-Clés (up) Bluefin tuna; Game theory; Habitat selection; Ideal free distribution; Plant Sciences; Structured population; Theoretical Ecology/Statistics; Zoology
Résumé Long-distance migration is a widespread process evolved independently in several animal groups in terrestrial and marine ecosystems. Many factors contribute to the migration process and of primary importance are intra-specific competition and seasonality in the resource distribution. Adaptive migration in direction of increasing fitness should lead to the ideal free distribution (IFD) which is the evolutionary stable strategy of the habitat selection game. We introduce a migration game which focuses on migrating dynamics leading to the IFD for age-structured populations and in time varying habitats, where dispersal is costly. The model predicts migration dynamics between these habitats and the corresponding population distribution. When applied to Atlantic bluefin tunas, it predicts their migration routes and their seasonal distribution. The largest biomass is located in the spawning areas which have also the largest diversity in the age-structure. Distant feeding areas are occupied on a seasonal base and often by larger individuals, in agreement with empirical observations. Moreover, we show that only a selected number of migratory routes emerge as those effectively used by tunas.
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ISSN 1874-1738, 1874-1746 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1465
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Auteur Sardenne, F.; Chassot, E.; Fouche, E.; Menard, F.; Lucas, V.; Bodin, N.
Titre Are condition factors powerful proxies of energy content in wild tropical tunas? Type Article scientifique
Année 2016 Publication Revue Abrégée Ecol. Indic.
Volume 71 Numéro Pages 467-476
Mots-Clés (up) body condition; cod gadus-morhua; condition indexes; ecosystem; Energy variability; fish; Fish health; katsuwonus-pelamis; Large pelagic species; Proximate composition; thunnus-albacares; western indian-ocean; Yellowfin tuna
Résumé The “condition” is used as an indicator of fish health and is generally equated with the quantity of energy reserves. Biometric condition factors have been widely used and preferred over costly and time-consuming biochemical condition. Here, we investigated the relevance of four common condition factors based on biometric measurements (Le Cren's index, girth -length index, gonado-somatic index and hepato-somatic index) and of size- and weight -based empirical models to describe the physiological condition of tropical tunas. Biometric condition factors of bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares) tunas sampled throughout 2013 in the western Indian Ocean region were assessed against benchmark biochemical indices (lipid content, protein content, triacylglycerol:sterol ratio and energy density) estimated in tissues with different physiological functions, i.e. red muscle, white muscle, liver, and gonads. Our findings suggest that tropical tunas do not store lipids in white muscle and that protein content is less variable than lipid content, which largely varies with ontogeny and the seasons according to tissue and species. This variability induced inconsistency between biometric factors, including the empirically adjusted ones, and biochemical indices, with the exception of the gonado-somatic index that fitted well to the composition of the gonads in the three species, and especially in females. (C) 2016 Elsevier Ltd. All rights reserved.
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Volume de collection Numéro de collection Edition
ISSN 1470-160x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1697
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Auteur Grande, M.; Murua, H.; Zudaire, I.; Arsenault-Pernet, E.J.; Pernet, F.; Bodin, N.
Titre Energy allocation strategy of skipjack tuna Katsuwonus pelamis during their reproductive cycle Type Article scientifique
Année 2016 Publication Revue Abrégée J. Fish Biol.
Volume 89 Numéro 5 Pages 2434-2448
Mots-Clés (up) bonito euthynnus-pelamis; cod gadus-morhua; fatty-acid-composition; highly migratory fish; Income breeder; Indian Ocean; lipid classes; oocyte growth; reproduction; sarda-sarda; teleost fish; thunnus-albacares; Tropical tuna; western indian-ocean
Résumé The lipid composition of somatic and reproductive tissues was determined for female skipjack tuna Katsuwonus pelamis caught in the western Indian Ocean between latitude 10 degrees N and 20 degrees S and longitude 40 degrees and 70 degrees E. The highest total lipid (TL) contents were in the liver and gonads, with white muscle levels approximately three-fold lower. Three lipid classes dominated: triacylglycerols (TAG), sterol esters and wax esters (SE-WE) and phospholipids (PL). Collectively, these accounted for between 70 and 80% of TLs. Changes in lipid concentrations were evaluated over the maturation cycle. Immature fish had the lowest gonad and liver TL levels; concentrations of TL, TAG, SE-WE and PL accumulated from immature to mature (spawning-capable) phase, reflecting sustained vitellogenic activity of the liver and a transfer of lipids to developing oocytes from the onset of vitellogenesis. Gonado-somatic and hepato-somatic indices were positively correlated with each other and positively related to TL in the gonads and liver. Fulton's condition index and lipid concentrations in muscle did not vary significantly over the maturation cycle; fat content in the main storage tissues was undepleted as the ovary developed. Hence, K. pelamis apparently supports reproduction directly from food intake over the breeding season. In the gonads, reserve lipids (SE-WE and TAG) and sterols were related to batch fecundity but this was not the case for somatic and hepatic tissues. These results suggest that K. pelamis utilizes an income breeding strategy.
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ISSN 0022-1112 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1685
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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 (up) 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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