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Auteur (up) 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 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
Auteur institutionnel Thèse
Editeur Elsevier BV 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 0967-0645 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 31190 collection 981
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Auteur (up) Ba, K.; Thiaw, M.; Fall, M.; Thiam, N.; Meissa, B.; Jouffre, D.; Thiaw, O.T.; Gascuel, D.
Titre Long-term fishing impact on the Senegalese coastal demersal resources: diagnosing from stock assessment models Type Article scientifique
Année 2018 Publication Revue Abrégée Aquat. Living Resour.
Volume 31 Numéro Pages 8
Mots-Clés west-africa; dynamics; management; West Africa; fisheries; overexploitation; marine ecosystems; populations; mauritania; lessons; Bayesian approach; Coastal demersal species; delta-GLM models; epinephelus-aeneus; experience; surplus production models
Résumé For the first time in Senegal, assessments based on both stochastic and deterministic production models were used to draw a global diagnosis of the fishing impact on coastal demersal stocks. Based one national fisheries databases and scientific trawl surveys data: (i) trends in landings since 1971 were examined, (ii) abundance indices of 10 stocks were estimated using linear models fitted to surveys data and commercial catch per unit efforts, and (iii) stock assessments were carried out using pseudo-equilibrium Fox and Pella-Tomlinson models and a Biomass dynamic production model fitted in a Bayesian framework to abundance indices. Most stocks have seen their abundance sharply declining over time. All stocks combined, results of stock assessments suggest a 63% reduction compared to virgin state. Three fifth of demersal stocks are overexploited and excess in fishing effort was estimated until 75% for the worst case. We conclude by suggesting that the fishing of such species must be regulated and an ecosystem approach to fisheries management should be implemented in order to monitor the whole ecosystem.
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Editeur 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 0990-7440 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2278
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Auteur (up) Brehmer, P.; Guillard, J.; Pinzon, P.I.C.; Bach, P.
Titre Exploratory and instantaneous swimming speeds of amphidromous fish school in shallow-water coastal lagoon channels Type Article scientifique
Année 2011 Publication Revue Abrégée Estuaries and Coasts
Volume 34 Numéro 4 Pages 739-744
Mots-Clés Direct approach; Gregarious fish; Horizontal beaming; indicator; Schooling; sonar
Résumé Fish school swimming speeds is essential for ecological and management studies. The multibeam sonar in horizontal beaming provided dynamic echo traces of mobile fish schools. We used two school swimming speed indicators: the average of a series of instantaneous speed values, and the exploratory speed. These swimming speeds were estimated for each fish school observed on the basis of their Euclidian position within the sonar beams. The average ISS values per school ranged from 0.15 m s(-1) to 4.46 m s(-1), while the ESS values per school were lower, ranging from 0.04 m s(-1) to 3.77 m s(-1). Multibeam sonar technology makes it possible to measure fish school swimming speeds in their natural habitat at small spatio-temporal scales. This methodology can therefore be used to analyse in situ their movements, and has a wide range of applications in behavioural studies and management purposes.
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Volume de collection Numéro de collection Edition
ISSN 1559-2723 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 123
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Auteur (up) Brophy, D.; Haynes, P.; Arrizabalaga, H.; Fraile, I.; Fromentin, J.-M.; Garibaldi, F.; Katavic, I.; Tinti, F.; Karakulak, F.S.; Macias, D.; Busawon, D.; Hanke, A.; Kimoto, A.; Sakai, O.; Deguara, S.; Abid, N.; Santos, M.N.
Titre Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus) Type Article scientifique
Année 2016 Publication Revue Abrégée Mar. Freshw. Res.
Volume 67 Numéro 7 Pages 1023-1036
Mots-Clés carrying-capacity; elliptical Fourier analysis; fish; holistic approach; identification; management; Mediterranean Sea; mitochondrial-dna; population structure; population-structure; spatial structure; stock mixture analysis; western atlantic
Résumé Two stocks of bluefin tuna (Thunnus thynnus) inhabit the north Atlantic; the western and eastern stocks spawn in the Gulf of Mexico and the Mediterranean Sea respectively. Trans-Atlantic movements occur outside spawning time whereas natal homing maintains stock structure. Commercial fisheries may exploit a mixed assemblage of both stocks. The incorporation of mixing rates into stock assessment is precluded by uncertainties surrounding stock discrimination. Otolith shape descriptors were used to characterise western and eastern stocks of Atlantic bluefin tuna in the present study and to estimate stock composition in catches of unknown origin. Otolith shape varied with length and between locations and years. Within a restricted size range (200-297-cm fork length (FL)) the two stocks were distinguished with an accuracy of 83%. Bayesian stock mixture analysis indicated that samples from the east Atlantic and Mediterranean were predominantly of eastern origin. The proportion assigned to the eastern stock showed slight spatial variation; however, overlapping 95% credible intervals indicated no significant difference (200-297 cm FL: central Atlantic, 73-100%; Straits of Gibraltar, 73-100%; Morocco, 50-99%; Portugal 64-100%). Otolith shape could be used in combination with other population markers to improve the accuracy of mixing rate estimates for Atlantic bluefin tuna.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1323-1650 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1681
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Auteur (up) Bundy, A.; Shannon, L.J.; Rochet, M.J.; Neira, S.; Shin, Y.-J.; Hill, L.; Aydin, K.
Titre The good(ish), the bad, and the ugly : a tripartite classification of ecosystem trends Type Article scientifique
Année 2010 Publication Revue Abrégée Ices Journal of Marine Science
Volume 67 Numéro Pages 745-768
Mots-Clés approach; classification; comparative; decision; ecosystem; ecosystems; exploited; indicator; marine; tree
Résumé Marine ecosystems have been exploited for a long time, growing increasingly vulnerable to collapse and irreversible change. How do we know when an ecosystem may be in danger? A measure of the status of individual stocks is only a partial gauge of its status, and does not include changes at the broader ecosystem level, to non-commercial species or to its structure or functioning. Six ecosystem indicators measuring trends over time were collated for 19 ecosystems, corresponding to four ecological attributes: resource potential, ecosystem structure and functioning, conservation of functional biodiversity, and ecosystem stability and resistance to perturbations. We explored the use of a decision-tree approach, a definition of initial ecosystem state (impacted or non-impacted), and the trends in the ecosystem indicators to classify the ecosystems into improving, stationary, and deteriorating. Ecosystem experts classified all ecosystems as impacted at the time of their initial state. Of these, 15 were diagnosed as “ugly”, because they had deteriorated from an already impacted state. Several also exhibited specific combinations of trends indicating “fishing down the foodweb”, reduction in size structure, reduction in diversity and stability, and changed productivity. The classification provides an initial evaluation for scientists, resource managers, stakeholders, and the general public of the concerning status of ecosystems globally.
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Volume de collection Numéro de collection Edition
ISSN 1054-3139 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 60
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