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Auteur Mazurais, D.; Covès, D.; Papandroulakis, N.; Ortega, A.; Desbruyeres, E.; Huelvan, C.; Le Gall, M.M.; de la Gándara, F.; Cahu, C.L.
Titre (up) Gene expression pattern of digestive and antioxidant enzymes during the larval development of reared Atlantic bluefin tuna (ABFT), Thunnus thynnus L Type Article scientifique
Année 2015 Publication Revue Abrégée Aquac Res
Volume 46 Numéro 10 Pages 2323-2331
Mots-Clés antioxidant; development; digestion; expression; gene; Tuna
Résumé The aim of this study was to determine whether mortality observed during the larval development of reared bluefin tuna (Thunnus thynnus) could be related to improper expression profiles of key genes involved in digestive or antioxidant response capabilities. Tuna larvae were sampled at hatching, 2, 5, 10, 15 and 20 dph (days post hatching) for the relative quantification of transcripts encoded by genes involved in digestive [trypsinogen 1 (TRYP1), alpha-amylase (AMY), aminopeptidase N (ANPEP)] and antioxidant [catalase (CAT)] functions. The levels of expression of ANPEP related to the development and maturation of intestinal function increased from 5 to 20 dph. Furthermore, AMY and TRYP1 genes, which are pancreatic enzymes implicated in carbohydrate and peptide digestions exhibit a typical peak of expression at 5 and 15 dph respectively. The antioxidant enzyme, CAT, exhibited higher mRNA levels during the first stage of larval development. In conclusion, our investigation indicates that the expression of genes involved in digestive and antioxidant physiological processes followed typical patterns which could not explain high mortality rate observed during the first stage of larval development.
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Volume de collection Numéro de collection Edition
ISSN 1365-2109 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1455
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Auteur Arrizabalaga, H.; Dufour, F.; Kell, L.; Merino, G.; Ibaibarriaga, L.; Chust, G.; Irigoien, X.; Santiago, J.; Murua, H.; Fraile, I.; Chifflet, M.; Goikoetxea, N.; Sagarminaga, Y.; Aumont, O.; Bopp, L.; Herrera, M.; FROMENTIN, J.-M.; Bonhomeau, S.
Titre (up) Global habitat preferences of commercially valuable tuna Type Article scientifique
Année 2015 Publication Deep Sea Research Part II: Topical Studies in Oceanography Revue Abrégée
Volume 113 Numéro Pages 102-112
Mots-Clés Habitat; Tuna fisheries; Catch/ effort; Environmental conditions; Quotient analysis; Generalized Additive Models; Ecosystem Approach to Fisheries Management
Résumé In spite of its pivotal role in future implementations of the Ecosystem Approach to Fisheries Management, current knowledge about tuna habitat preferences remains fragmented and heterogeneous, because it relies mainly on regional or local studies that have used a variety of approaches making them difficult to combine. Therefore in this study we analyse data from six tuna species in the Pacific, Atlantic and Indian Oceans in order to provide a global, comparative perspective of habitat preferences. These data are longline catch per unit effort from 1958 to2007 for albacore, Atlantic bluefin, southern bluefin, bigeye, yellowfin and skipjack tunas. Both quotient analysis and Generalized Additive Models were used to determine habitat preference with respect to eight biotic and abiotic variables. Results confirmed that, compared to temperate tunas, tropical tunas prefer warm, anoxic, stratified waters. Atlantic and southern bluefin tuna prefer higher concentrations of chlorophyll than the rest. The two species also tolerate most extreme sea surface height anomalies and highest mixed layer depths. In general, Atlantic bluefin tuna tolerates the widest range of environmental conditions. An assessment of the most important variables determining fish habitat is also provided.
Adresse Ifremer, UMR 212 EME, boulevard Jean Monnet, BP 171, Sete Cedex, 34203, France
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Editeur Elsevier BV Lieu de Publication Éditeur
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Volume de collection Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 31190 collection 981
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Auteur Nikolic, N.; Jérôme, M.; Fonteneau, A.; Evano, H.; Verrez-Bagnis, V.
Titre (up) Identification of skipjack tuna juveniles based on DNA control region sequences and potential spawning area around reunion island Type Article scientifique
Année 2016 Publication Revue Abrégée Environmental Biology of Fishes
Volume 99 Numéro 2 Pages 171-178
Mots-Clés Age; dna; juvenile; Reunion island; skipjack tuna
Résumé In this study, we confirmed that DNA control region can be used to identify potential spawning area from pelagic juveniles species. We used the mitochondrial DNA control region to identify tuna juveniles predated by common dolphinfish and sampled in surface waters around Reunion Island. These were skipjack juveniles at an early stage (small length and young age). The biological results confirmed the species identification based on DNA analysis. Catch data by longline reveal a higher number of skipjack from October to December around Reunion Island corresponding to the period of our skipjack juvenile sampling
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ISSN 0378-1909 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1518
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Auteur Sempo, G.; Dagorn, L.; Robert, M.; Deneubourg, J.-L.
Titre (up) Impact of increasing deployment of artificial floating objects on the spatial distribution of social fish species Type Article scientifique
Année 2013 Publication Revue Abrégée Journal of Applied Ecology
Volume 50 Numéro 5 Pages 1081-1092
Mots-Clés behaviour-based modelling; Bycatch; Fad; Fob; sustainable fishery; tuna
Résumé * Approximately 300 pelagic fish species naturally aggregate around floating objects (FOBs) at the surface of the oceans. Currently, more than 50% of the world catch of tropical tuna comes from the industrial tuna fisheries around drifting FOBs. Greater understanding of the complex decision-making processes leading to this aggregation pattern and the impact of the massive release of artificial FOBs by fishermen on the spatial distribution and management of tuna is needed. * We analyse how the interplay between social (relationships between individuals) and non-social (responses to the environment) behaviours may affect the spatial distribution of a population in a multi-FOB environment. Taking the example of tropical tunas associating with FOBs and using differential equations and stochastic simulations, we examine how, when increasing the number of FOBs, fish aggregation dynamics and the distribution of the population among patches are affected by the population size, level of sociality and the natural retentive and/or attractive forces of FOBs on individual tuna. * Our model predicts that, depending on the species' level of sociality, fish will be scattered among FOBs or aggregated around a single FOB based on the number of FOBs deployed in a homogeneous oceanic region. * For social species, we demonstrated that the total fish catch is reduced with increasing FOBs number. Indeed, for each size of population, there are a number of FOBs minimizing the total population of fish associated with FOBs and another number of FOBs maximizing the total population of associated fish. * Synthesis and applications. In terms of fisheries management, the total catch volume is directly linked to the total number of floating objects (FOBs) for non-social species, and any limit on the number of sets would then result in a limit on the total catch. For social species (e.g. tuna), however, increasing the number of FOBs does not necessarily lead to an increase in the total catch, which is a non-intuitive result. Indeed, our model shows that, for specific values of the parameters, deploying a greater number of FOBs in the water (all other parameters being constant) does not necessarily help fishermen to catch more tuna, but does increase the level of fishing effort and bycatch.
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Volume de collection Numéro de collection Edition
ISSN 1365-2664 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 265
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Auteur Robinson, J.; Guillotreau, P.; Jimenez-Toribio, R.; Lantz, F.; Nadzon, L.; Dorizo, J.; Gerry, C.; Marsac, F.
Titre (up) Impacts of climate variability on the tuna economy of Seychelles Type Article scientifique
Année 2010 Publication Revue Abrégée Climate Research
Volume 43 Numéro Pages 149-162
Mots-Clés climate; economy; Enso; fisheries; Seychelles; tuna; variability
Résumé Many small island states have developed economies that are strongly dependent on tuna fisheries. Consequently, they are vulnerable to the socio-economic effects of climate change and variability, processes that are known to impact tuna fisheries distribution and productivity. The aim of this study was to assess the impacts of climate oscillations on the tuna-dependent economy of Seychelles. Using a multiplier approach, the direct, indirect and induced economic effects of the tuna industry expenditure benefiting the Seychelles' economy declined in 1998 by 58, 26 and 35%, respectively (mean decline: 42%), a year of strong climate oscillation in the western Indian Ocean. Multivariate patterns in tuna purse-seine vessel expenditures in port were substantially modified by strong climate oscillations, particularly in 1998. A cointegration time-series model predicted that a 40% decline in tuna landings and transhipment in Port Victoria, a value commensurate with that observed in 1998, would result in a 34% loss for the local economy solely through reductions in cargo handling expenditures. Of several indices tested, the Indian Oscillation Index was best at predicting the probability of switching between low and high regimes of landings and transhipment, which translate into impacts for the economy. It is hypothesised that a late 2006/early 2007 climate oscillation was compounded by prior overfishing to produce a stronger impact on the fishery and economy of Seychelles. The effects of fishing and climate variability on tuna fisheries are complex and pose significant challenges for fisheries management and the economic development of countries in the Indian Ocean.
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Volume de collection Numéro de collection Edition
ISSN 0936-577x ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 101
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