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Auteur Guillotreau, P.; Salladarre, F.; Dewals, P.; Dagorn, L. url  doi
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  Titre Fishing tuna around Fish Aggregating Devices (FADs) vs free swimming schools : skipper decision and other determining factors Type Article scientifique
  Année 2011 Publication Revue Abrégée Fisheries Research  
  Volume 109 Numéro 2-3 Pages 234-242  
  Mots-Clés Fish Aggregating Devices; Purse-seine; Skipper effect; tuna  
  Résumé Fish Aggregating Devices (FADs) are increasingly used by tuna purse-seine fleets all around the world, modifying the species catch composition. We analyse the determinants of FAD vs free school (FS) fishing, including the skipper effect, and environmental and economic factors. A multivariate and econometric analysis of a panel dataset for the French purse-seine fleet in the Indian Ocean (1980-2007), complemented by a survey of fishers, demonstrates the influential role of climate and prey on FAD fishing and also emphasises individual skipper preference. However, we found that the major determinant of FAD fishing remains the growing fishing capacity (use of bigger vessels, satellite buoys, echo-sounders, supply vessels), thus modifying the species catch composition towards smaller tuna. Other things being equal, raising the proportion of FAD sets by 1% would increase the catches of skipjack by 1.3% and decrease those of large yellowfin tuna by 1.7%. This result shows that the control of effort and investment could be adapted through management measures to encourage one fishing method.  
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  Editeur (up) Lieu de Publication Éditeur  
  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0165-7836 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 143  
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Auteur Capello, M.; Deneubourg, J.L.; Robert, M.; Holland, K.N.; Schaefer, K.M.; Dagorn, L. doi  openurl
  Titre Population assessment of tropical tuna based on their associative behavior around floating objects Type Article scientifique
  Année 2016 Publication Revue Abrégée Sci Rep  
  Volume 6 Numéro Pages 36415  
  Mots-Clés abundance; aerial surveys; archival tag data; bluefin tuna; continental-shelf; fish aggregating devices; katsuwonus-pelamis; pacific-ocean; tagging data; thunnus-albacares  
  Résumé Estimating the abundance of pelagic fish species is a challenging task, due to their vast and remote habitat. Despite the development of satellite, archival and acoustic tagging techniques that allow the tracking of marine animals in their natural environments, these technologies have so far been underutilized in developing abundance estimations. We developed a new method for estimating the abundance of tropical tuna that employs these technologies and exploits the aggregative behavior of tuna around floating objects (FADs). We provided estimates of abundance indices based on a simulated set of tagged fish and studied the sensitivity of our method to different association dynamics, FAD numbers, population sizes and heterogeneities of the FAD-array. Taking the case study of yellowfin tuna (Thunnus albacares) acoustically-tagged in Hawaii, we implemented our approach on field data and derived for the first time the ratio between the associated and the total population. With more extensive and long-term monitoring of FAD-associated tunas and good estimates of the numbers of fish at FADs, our method could provide fisheries-independent estimates of populations of tropical tuna. The same approach can be applied to obtain population assessments for any marine and terrestrial species that display associative behavior and from which behavioral data have been acquired using acoustic, archival or satellite tags.  
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  Auteur institutionnel Thèse  
  Editeur (up) 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 2045-2322 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1682  
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Auteur Van Beveren, E.; Fromentin, J.-M.; Bonhommeau, S.; Nieblas, A.-E.; Metral, L.; Brisset, B.; Jusup, M.; Bauer, R.K.; Brosset, P.; Saraux, C. doi  openurl
  Titre Predator-prey interactions in the face of management regulations: changes in Mediterranean small pelagic species are not due to increased tuna predation Type Article scientifique
  Année 2017 Publication Revue Abrégée Can. J. Fish. Aquat. Sci.  
  Volume 74 Numéro 9 Pages 1422-1430  
  Mots-Clés anchovy engraulis-encrasicolus; atlantic bluefin tuna; Energy density; fish condition; fisheries; food-consumption; Proximate composition; sea; thunnus-thynnus; Yellowfin tuna  
  Résumé Recently, the abundance of young Atlantic bluefin tuna (Thunnus thynnus) tripled in the northwestern Mediterranean following effective management measures. We investigated whether its predation on sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) could explain their concurrent size and biomass decline, which caused a fishery crisis. Combining the observed diet composition of bluefin tuna, their modelled daily energy requirements, their population size, and the abundance of prey species in the area, we calculated the proportion of the prey populations that were consumed by bluefin tuna annually over 2011-2013. To assess whether tuna could alter the size structure of the three small pelagic fish populations (anchovy, sardine, and sprat (Sprattus sprattus)), the size distributions of the consumed prey species were compared with those of the wild populations. We estimated that the annual consumption of small pelagic fish by bluefin tuna is less than 2% of the abundance of these populations. Furthermore, size selectivity patterns were not observed. We thus concluded that tuna predation is unlikely to be the main cause of major changes in the small pelagic fish populations from this area.  
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  Auteur institutionnel Thèse  
  Editeur (up) 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 0706-652x ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2195  
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Auteur Grande, M.; Murua, H.; Zudaire, I.; Arsenault-Pernet, E.J.; Pernet, F.; Bodin, N. doi  openurl
  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 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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  Auteur institutionnel Thèse  
  Editeur (up) 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 0022-1112 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1685  
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Auteur Guyader, O.; Robert, B.; Lionel, R. doi  openurl
  Titre Assessing the number of moored fishing aggregating devices through aerial surveys: A case study from Guadeloupe Type Article scientifique
  Année 2017 Publication Revue Abrégée Fish Res.  
  Volume 185 Numéro Pages 73-82  
  Mots-Clés abundance; Aerial survey; behavior; Dolphinfish; fads; Fish aggregating devices (FAD); fisheries; floating objects; islands; knowledge; management; Small-scale fisheries management; transect surveys; yellowfin; Yellowfin tuna  
  Résumé Moored fish aggregating devices (MFADs) are increasingly being used in small-scale tropical fisheries to access pelagic fish species that are otherwise difficult to harvest in large numbers. Little attention has yet been paid to monitoring MFADs in coastal areas, however. This is most likely due to the small-scale nature of most fisheries that utilize them and the presumed lower impact of those fisheries on fish stocks and their ecosystems. In this paper, we examined the abundance and density of MFADs around Guadeloupe, using aerial line transect surveys. Estimated MFAD densities were found to be high compared with previously reported densities in this area, especially within the 22-45 km range offshore. We examine and discuss possible reasons for these high densities. The main drivers appear to be the target species dolphinfish (Coryphaena hippurus) and yellowfin tuna (Thunnus albacares) and related fishing behaviour. We present different approaches for reducing and monitoring MFADs densities, including the co-management of MFAD territorial use rights by fishing communities. (C) 2016 Elsevier B.V. All rights reserved.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur (up) 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 0165-7836 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1696  
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