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Article Dans Une Revue Marine and Freshwater Research Année : 2016

Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)

Deirdre Brophy
  • Fonction : Auteur
Paula Haynes
  • Fonction : Auteur
Haritz Arrizabalaga
  • Fonction : Auteur
Igaratza Fraile
  • Fonction : Auteur
Fulvio Garibaldi
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Ivan Katavic
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Fausto Tinti
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F. Saadet Karakulak
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David Macias
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Dheeraj Busawon
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Alex Hanke
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Ai Kimoto
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Osamu Sakai
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Simeon Deguara
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Nouredinne Abid
  • Fonction : Auteur
Miguel Neves Santos
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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.

Dates et versions

hal-04201711 , version 1 (11-09-2023)

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Citer

Deirdre Brophy, Paula Haynes, Haritz Arrizabalaga, Igaratza Fraile, Jean-Marc Fromentin, et al.. Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus). Marine and Freshwater Research, 2016, 67 (7), pp.1023-1036. ⟨10.1071/MF15086⟩. ⟨hal-04201711⟩
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