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Auteur Nikolic, N.; Jérôme, M.; Fonteneau, A.; Evano, H.; Verrez-Bagnis, V. url  doi
openurl 
  Titre 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 (down) 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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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0378-1909 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1518  
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Auteur Eveson, J.P.; Million, J.; Sardenne, F.; Le Croizier, G. url  doi
openurl 
  Titre Estimating growth of tropical tunas in the Indian Ocean using tag-recapture data and otolith-based age estimates Type Article scientifique
  Année 2015 Publication Revue Abrégée Fisheries Research  
  Volume Numéro Pages (down) 58-68  
  Mots-Clés Bigeye (Thunnus obesus); maximum likelihood; Otolith; Skipjack (Katsuwonus pelamis); Tag-recapture; Two-stanza growth; Yellowfin (Thunnus albacares)  
  Résumé A growth model from which the expected age of a fish can be estimated based on its length is a key component to most stock assessments. For the three tropical tuna species in the Indian Ocean – yellowfin (YFT; Thunnus albacares), bigeye (BET; T. obesus) and skipjack (SKJ; Katsuwonus pelamis) – information about growth has been very limited until recently, when data from a large-scale Indian Ocean tuna tagging program became available. In this paper, parametric growth models were fit to tag-recapture data for all three species using a maximum likelihood method that models the joint density of release and recapture lengths as a function of age by treating age at tagging as a random variable. The method allows for individual variability in growth by modelling the asymptotic length parameter as a random effect. Direct age and length data from otolith readings were also included in the analysis for YFT and BET. The results support two-stanza growth models for all three species; however, the growth patterns for YFT and BET differ from SKJ. YFT and BET exhibit a transition in growth between age 2 and 3, with faster growth in the second stanza than the first, whereas SKJ exhibit a transition in growth around age 1, with much faster growth in the first stanza than the second. Most likely, YFT and BET also experience a phase of rapid growth directly following hatching, but lack of data for fish less than 50 cm for these species precludes its estimation. Differences in growth between sexes were found for YFT and BET, with males growing to a larger size; information on sex was not available for SKJ.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection IO Tuna tagging Titre de collection Abrégé  
  Volume de collection 163 Numéro de collection Edition  
  ISSN 0165-7836 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1264  
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Auteur Gaertner, D. url  doi
openurl 
  Titre Estimates of historic changes in total mortality and selectivity for Eastern Atlantic skipjack (Katsuwonus pelamis) from length composition data Type Article scientifique
  Année 2010 Publication Revue Abrégée Aquatic Living Resources  
  Volume 23 Numéro Pages (down) 3-11  
  Mots-Clés analysis; Bayesian; change-point; Fad; Fishing; Mortality; rate; Skipjack; strategies; tuna  
  Résumé Catch-at-size data of the eastern Atlantic skipjack were used to estimate changes in total mortality from 1969 to 2007. We used a transitional model of mean length that generalized the Beverton-Holt mortality estimator to allow change in mortality rate under nonequilibrium conditions. Then, from homogeneous periods of time, length-converted catch curves were used to access qualitative changes in selectivity patterns for two surface fisheries (the baitboat fishery operating from Dakar, Senegal, and the European and associated purse seine fisheries). To explore the impact of catch on the mortality rate, a Bayesian change-point analysis was conducted on the catch time series to detect concomitant variation between mortality rates and catch. Finally, potential causes of these changes are discussed in relation to the implementation of new fishing technology, such fish aggregating devices (FAD). The general pattern depicted by total mortality is in agreement with previous knowledge on this fishery: a state of complete or practically complete exploitation during the nineties followed by the decrease in nominal purse seine fishing effort in the last decade, combined with the effect of a seasonal moratorium on FAD fishing operations. There was no evidence of a change in selectivity between the two contrasted periods of time considered: 1969-1979 and 1986-1999; the second period being characterized by the introduction of new technology onboard vessels. In contrast, the covariation over time between total catch and mortality rate three years later highlights the effect of the fishing pressure on the stock of eastern Atlantic skipjack.  
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  Langue Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 0990-7440 ISBN Médium  
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  Numéro d'Appel LL @ pixluser @ collection 74  
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Auteur Dueri, S.; Guillotreau, P.; Jiménez-Toribio, R.; Oliveros-Ramos, R.; Bopp, L.; Maury, O. url  doi
openurl 
  Titre Food security or economic profitability? Projecting the effects of climate and socioeconomic changes on global skipjack tuna fisheries under three management strategies Type Article scientifique
  Année 2016 Publication Revue Abrégée Global Environmental Change  
  Volume 41 Numéro Pages (down) 1-12  
  Mots-Clés Bioeconomic model; climate change; fishery management; Mey; Msy; Skipjack tuna  
  Résumé We investigate the interactions between anthropogenic climate change, socioeconomic developments and tuna fishery management strategies. For this purpose, we use the APECOSM-E model to map the effects of climate change and commercial fishing on the distribution of skipjack tuna biomass in the three oceans, combined with a new bioeconomic module representing the rent or profit of skipjack fisheries. For forcing, we use Representative Concentration Pathway (RCP) 8.5, the highest emission scenario for greenhouse gas concentrations presented in the IPCC’s Fifth Assessment Report (AR5), and the IPCC Socioeconomic Shared Pathway (SSP) 3, which is characterized by low economic development and a strong increase in the world population. We first investigate the impact of climate change on regional skipjack abundance, catches and profits in three oceans (Atlantic, Indian and Pacific) in 2010, 2050 and 2095. We then study the effects of three management strategies (maximum sustainable yield or MSY, maximum economic yield or MEY, and zero rent or ZR) on the future distribution of fishing fleets between oceans and on global economic rent. Our model projections for 2050 and 2095 show an increase in global skipjack biomass compared to 2010 and major changes in its distribution, impacting local and regional fishing efforts. The Pacific Ocean will continue to dominate the skipjack market. In our modeling of management strategies, the currently predominant MSY strategy would have been unprofitable in 2010, due to a decreased catch per unit effort (CPUE). In the future, however, technological developments should increase fishing efficiency and make MSY profitable. In all the scenarios, a MEY strategy is more profitable than MSY but leads to the lowest catches and the highest prices. This raises ethical questions in a world where food security may become a top priority. In the scenarios where MSY generates an economic loss (e.g. 2010), a ZR strategy allows global stocks to be exploited at high but still profitable levels. Conversely, in the scenarios where MSY is profitable, (e.g. 2095) ZR leads to overfishing and smaller global catches. We conclude that the most appropriate management strategy at any time is likely to change as environmental and socioeconomic conditions evolve. The decision to follow one or other strategy is a complex one that must be regularly reviewed and updated.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0959-3780 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1601  
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Auteur Govinden, R.; Jauhary, R.; Filmalter, J.; Forget, F.; Soria, M.; Adam, S.; Dagorn, L. url  doi
openurl 
  Titre Movement Behaviour of Skipjack (Katsuwonus Pelamis) and Yellowfin (Thunnus Albacares) Tuna at Anchored Fish Aggregating Devices (FADs) in the Maldives, Investigated by Acoustic Telemetry Type Article scientifique
  Année 2012 Publication Revue Abrégée Aquatic Living Resources  
  Volume FirstView Numéro Pages (down)  
  Mots-Clés Behaviour; Fish Aggregating Devices; Indian Ocean; Passive acoustic telemetry; skipjack tuna; Yellowfin tuna  
  Résumé  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel LL @ pixluser @ collection 193  
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