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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. url  doi
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  Titre 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 (up) 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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  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 1365-2109 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1455  
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Auteur Dueri, S.; Maury, O. doi  openurl
  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 (up) 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 Ruiz, J.; Batty, A.; Chavance, P.; McElderry, H.; Restrepo, V.; Sharples, P.; Santos, J.; Urtizberea, A. url  doi
openurl 
  Titre Electronic monitoring trials on in the tropical tuna purse-seine fishery Type Article scientifique
  Année 2015 Publication Revue Abrégée ICES J. Mar. Sci.  
  Volume 72 Numéro 4 Pages 1201-1213  
  Mots-Clés Bycatch; catch composition; data collection; electronic monitoring system; observers; Purse seining; Tropical tuna  
  Résumé (up) The difficulty of ensuring adequate statistical coverage of whole fleets is a challenge for the implementation of observer programmes and may reduce the usefulness of the data they obtain for management purposes. This makes it necessary to find cost-effective alternatives. Electronic monitoring (EM) systems are being used in some fisheries as an alternative or a complement to human observers. The objective of this study was to test the use and reliability of EM on the tropical tuna purse-seine fishery. To achieve this objective, seven trips of tuna purse seiners operating in the three Oceans were closely monitored to compare the information provided by EM and on-board observers to determine if EM can reliably document fishing effort, set type, tuna catch, and bycatch. Total tuna catch per set was not significantly different between EM and observer datasets; however, regarding species composition, only main species matched between EM and observers. Success on set-type identification using EM varied between 98.3 and 56.3%, depending on the camera placement. Overall, bycatch species were underestimated by EM, but large bodied species, such as billfishes, were well documented. The analyses in this study showed that EM can be used to determine the fishing effort (number of sets) and total tuna catch as reliably as observers can. Set-type identification also had very promising results, but indicated that refinement of the methods is still needed. To be fully comparable with observer data, improvements for accurately estimating the bycatch will need to be developed in the application and use of the EM system. Operational aspects that need to be improved for an EM programme to be implemented include standardizing installation and on-board catch handling methodology as well as improvements in video technology deployment.  
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  ISSN 1054-3139, 1095-9289 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1335  
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Auteur Torres-Irineo, E.; Dreyfus-Leon, M.; Gaertner, D.; Salas, S.; Marchal, P. doi  openurl
  Titre Adaptive responses of tropical tuna purse-seiners under temporal regulations Type Article scientifique
  Année 2017 Publication Revue Abrégée Ambio  
  Volume 46 Numéro 1 Pages 88-97  
  Mots-Clés atlantic; behavior; Closed season; eastern pacific-ocean; eastern tropical pacific; Fisher behaviour; Fisheries management; fishing strategies; fleet dynamics; mixed fisheries; model; Purse-seine fishing; state; trawlers; Tropical tuna  
  Résumé (up) The failure to achieve fisheries management objectives has been broadly discussed in international meetings. Measuring the effects of fishery regulations is difficult due to the lack of detailed information. The yellowfin tuna fishery in the eastern Pacific Ocean offers an opportunity to evaluate the fishers' responses to temporal regulations. We used data from observers on-board Mexican purse-seine fleet, which is the main fleet fishing on dolphin-associated tuna schools. In 2002, the Inter-American Tropical Tuna Commission implemented a closed season to reduce fishing effort for this fishery. For the period 1992-2008, we analysed three fishery indicators using generalized estimating equations to evaluate the fishers' response to the closure. We found that purse-seiners decreased their time spent in port, increased their fishing sets, and maintained their proportion of successful fishing sets. Our results highlight the relevance of accounting for the fisher behaviour to understand fisheries dynamics when establishing management regulations.  
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  ISSN 0044-7447 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2072  
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Auteur Zupa, R.; Fauvel, C.; Mylonas, C.C.; Pousis, C.; Santamaria, N.; Papadaki, M.; Fakriadis, I.; Cicirelli, V.; Mangano, S.; Passantino, L.; Lacalandra, G.M.; Corriero, A. doi  openurl
  Titre Rearing in captivity affects spermatogenesis and sperm quality in greater amberjack, Seriola dumerili (Risso, 1810) Type Article scientifique
  Année 2017 Publication Revue Abrégée J. Anim. Sci.  
  Volume 95 Numéro 9 Pages 4085-4100  
  Mots-Clés acute stress; apoptosis; atlantic bluefin tuna; cultured fish; germ cell apoptosis; germ cell proliferation; germ-cell proliferation; greater amberjack; Marine fish; Motility; ovarian-steroid production; rearing in captivity; reproductive-biology; Seriola dumerili; Sperm quality; thunnus-thynnus l.  
  Résumé (up) The greater amberjack, Seriola dumerili (Risso, 1810), is a promising candidate for the diversification of European aquaculture production, but inconsistent reproduction in captivity prevents commercial production. Recent studies showed that greater amberjack confined in sea cages exhibited scarce gonad development and early interruption of gametogenic activity during the reproductive season. The aim of the present study was to improve our understanding of the observed impairment of spermatogenesis. Adult wild and captive-reared males were sampled during 3 different phases of the reproductive cycle: early gametogenesis (EARLY; late April to early May), advanced gametogenesis (ADVANCED; late May to early June), and spawning (SPAWNING; late June to July). Spermatogonial stem cells and proliferating germ cells were identified through the immunohistochemical localization of Pou5f1 and proliferating cell nuclear antigen, respectively. Apoptotic germ cells were identified throughout the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling method. Sperm quality of captive-reared fish was evaluated using computer-assisted sperm analysis. Captive-reared males exhibited seminiferous lobules of a smaller diameter, a precocious and progressive decrease of spermatogonial mitosis, and a high level of apoptosis at the beginning of the reproductive season, concomitant with a many-fold higher 17 beta-estradiol plasma concentration. The motile spermatozoa percentage of captive greater amberjack was lower than in other teleosts, and a drastic decrease of spermatozoa motility duration, velocity, and ATP content occurred along the reproductive season. An abnormal increase of sperm concentration as well as an increase of dead spermatozoa occurred during the SPAWNING phase, probably because of lack of sperm hydration and ejaculation and consequent sperm ageing. The present study demonstrates the extreme susceptibility of greater amberjack to rearing stress and underscores the need for improvement of the rearing and handling procedures to ameliorate gametogenesis dysfunctions in commercial aquaculture production.  
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  Langue English Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 0021-8812 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2210  
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