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Auteur 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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Auteur institutionnel Thèse
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 1323-1650 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 1681
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Auteur Cahill, A.E.; De Jode, A.; Dubois, S.; Bouzaza, Z.; Aurelle, D.; Boissin, E.; Chabrol, O.; David, R.; Egea, E.; Ledoux, J.-B.; Mérigot, B.; Weber, A.A.-T.; Chenuil, A.
Titre A multispecies approach reveals hot spots and cold spots of diversity and connectivity in invertebrate species with contrasting dispersal modes Type Article scientifique
Année 2017 Publication Revue Abrégée Mol. Ecol.
Volume 26 Numéro 23 Pages 6563-6577
Mots-Clés genetic diversity; dispersal; life-history traits; reef fishes; marine connectivity; pelagic larval duration; mediterranean sea; amphipholis-squamata; brooding brittle star; coralligenous assemblages; larvae; marine invertebrates; phylogeographical breaks; population structure; population genetic-structure; species genetic diversity correlation
Résumé Genetic diversity is crucial for species' maintenance and persistence, yet is often overlooked in conservation studies. Species diversity is more often reported due to practical constraints, but it is unknown if these measures of diversity are correlated. In marine invertebrates, adults are often sessile or sedentary and populations exchange genes via dispersal of gametes and larvae. Species with a larval period are expected to have more connected populations than those without larval dispersal. We assessed the relationship between measures of species and genetic diversity, and between dispersal ability and connectivity. We compiled data on genetic patterns and life history traits in nine species across five phyla. Sampling sites spanned 600km in the northwest Mediterranean Sea and focused on a 50-km area near Marseilles, France. Comparative population genetic approaches yielded three main results. (i) Species without larvae showed higher levels of genetic structure than species with free-living larvae, but the role of larval type (lecithotrophic or planktotrophic) was negligible. (ii) A narrow area around Marseilles, subject to offshore advection, limited genetic connectivity in most species. (iii) We identified sites with significant positive contributions to overall genetic diversity across all species, corresponding with areas near low human population densities. In contrast, high levels of human activity corresponded with a negative contribution to overall genetic diversity. Genetic diversity within species was positively and significantly linearly related to local species diversity. Our study suggests that local contribution to overall genetic diversity should be taken into account for future conservation strategies.
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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 0962-1083 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2262
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Auteur FROMENTIN, J.-M.
Titre Lessons from the past: investigating historical data from bluefin tuna fisheries Type Article scientifique
Année 2009 Publication Fish and Fisheries Revue Abrégée
Volume 10 Numéro 2 Pages 197-216
Mots-Clés Thunnus thynnus; Retrospective analysis; Population structure; Migration patterns; Fisheries collapse
Résumé In 1963, the leading fisheries targeting Atlantic bluefin tuna (Thunnus thynnus) in the Norwegian Sea and North Sea suddenly collapsed without any warning. Little is known about this collapse and several hypotheses have been put forward, such as changes in migratory routes, recruitment failure or eradication of a sub-population: all of these hypotheses could result from natural causes and/or from overfishing. To help explain this mysterious event, an original data set of the main bluefin tuna fisheries of the 20th century, including total catch and size composition of the catch, has been compiled and analysed. The results reveal a strong and unambiguous link between the Nordic purse seine and Spanish trap fisheries during the 1950s and 1960s. However, this link vanished during the 1970s. In addition, the North-west Atlantic and Mediterranean trap fisheries appeared also to be partially connected to the Nordic fisheries. During the 1950s and 1960s, the main migration routes of bluefin tuna were probably from the Mediterranean spawning grounds and from the West Atlantic coasts to the Norwegian coast and North Sea, which were probably a key feeding ground at that time. The analyses also lead to the conclusion that interactions between environmental, trophic and fishing processes have probably affected bluefin tuna migration patterns which would have finally caused the Nordic fisheries collapse. This retrospective analysis finally leads to an original – albeit more speculative – hypothesis concerning Atlantic bluefin tuna population structure, therein conjectured as an assemblage of at least three sub-populations.
Adresse IFREMER, Ctr Rech Mediterraneen & Trop, F-34203 Sete, France.
Auteur institutionnel Thèse
Editeur Wiley / Blackwell 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 1467-2960 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 6425 collection 1026
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Auteur FROMENTIN, J.-M.; ERNANDE, B.; FABLET, R.; DE PONTUAL, H.
Titre Importance and future of individual markers for the ecosystem approach to fisheries Type Article scientifique
Année 2009 Publication Aquatic Living Resources Revue Abrégée
Volume 22 Numéro 4 Pages 395-408
Mots-Clés Genetic marker; Biochemical marker; Electronic tag; Otolith; Isotope; Population structure; Statistical and mechanistic model; Fisheries
Résumé The use of genetic, biochemical and electronic markers in population biology and ecology has been growing tremendously during the last two decades. The first part of this paper aims at reviewing the main principles and advances of these individual markers through a few key applications on exploited marine fish populations. The second part is more prospective and investigates some possibilities that could arise in the near future through: (i) the development of new markers, (ii) the combination of different markers and (iii) the combination of quantitative approaches-whether classical or new-with individual markers. It is finally stressed how crucial individual markers will be to unravel the biocomplexity of wild fish populations and the key role they should play in the implementation of the ecosystem approach to fisheries.
Adresse IFREMER, STH, LASAA, F-29280 Plouzane, France.
Auteur institutionnel Thèse
Editeur Edp Sciences S A 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 0990-7440 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 11163 collection 1012
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Auteur GAGNAIRE, P.-A.; BROQUET, T.; AURELLE, D.; VIARD, F.; SOUISSI, A.; BONHOMME, F.; ARNAUD-HAOND, S.; Bierne, N.
Titre Using neutral, selected, and hitchhiker loci to assess connectivity of marine populations in the genomic era Type Article scientifique
Année 2015 Publication Revue Abrégée Evolutionary Applications
Volume 8 Numéro 8 Pages 769-786
Mots-Clés connectivity; gene flow; marine conservation; population genomics; Population structure
Résumé Estimating the rate of exchange of individuals among populations is a central concern to evolutionary ecology and its applications to conservation and management. For instance, the efficiency of protected areas in sustaining locally endangered populations and ecosystems depends on reserve network connectivity. The population genetics theory offers a powerful framework for estimating dispersal distances and migration rates from molecular data. In the marine realm, however, decades of molecular studies have met limited success in inferring genetic connectivity, due to the frequent lack of spatial genetic structure in species exhibiting high fecundity and dispersal capabilities. This is especially true within biogeographic regions bounded by well-known hotspots of genetic differentiation. Here, we provide an overview of the current methods for estimating genetic connectivity using molecular markers and propose several directions for improving existing approaches using large population genomic datasets. We highlight several issues that limit the effectiveness of methods based on neutral markers when there is virtually no genetic differentiation among samples. We then focus on alternative methods based on markers influenced by selection. Although some of these methodologies are still underexplored, our aim was to stimulate new research to test how broadly they are applicable to nonmodel marine species. We argue that the increased ability to apply the concepts of cline analyses will improve dispersal inferences across physical and ecological barriers that reduce connectivity locally. We finally present how neutral markers hitchhiking with selected loci can also provide information about connectivity patterns within apparently well-mixed biogeographic regions. We contend that one of the most promising applications of population genomics is the use of outlier loci to delineate relevant conservation units and related eco-geographic features across which connectivity can be measured.
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Editeur 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 1752-4571 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1434
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