Tracking adult North Atlantic bluefin tuna ( Thunnus thynnus ) in the northwestern Atlantic using ultrasonic telemetry

2000 ◽  
Vol 137 (2) ◽  
pp. 347-358 ◽  
Author(s):  
M. E. Lutcavage ◽  
R. W. Brill ◽  
G. B. Skomal ◽  
B. C. Chase ◽  
J. L. Goldstein ◽  
...  
Keyword(s):  
North Atlantic ◽  
Bluefin Tuna ◽  
Ultrasonic Telemetry ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna

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

2016 ◽  
Vol 67 (7) ◽  
pp. 1023 ◽  
Author(s):  
Deirdre Brophy ◽  
Paula Haynes ◽  
Haritz Arrizabalaga ◽  
Igaratza Fraile ◽  
Jean Marc Fromentin ◽  
...  
Keyword(s):  
North Atlantic ◽  
Stock Assessment ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Shape Variation ◽  
Thunnus Thynnus ◽  
Mixing Rate ◽  
Otolith Shape ◽  
Atlantic Bluefin Tuna ◽  
Significant Difference

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 (200–297cm 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.

Active prey selection in developing larvae of Atlantic bluefin tuna (Thunnus thynnus) in spawning grounds of the Gulf of Mexico

2021 ◽  
Author(s):  
Akihiro Shiroza ◽  
Estrella Malca ◽  
John T Lamkin ◽  
Trika Gerard ◽  
Michael R Landry ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Prey Selection ◽  
Bluefin Tuna ◽  
Gut Contents ◽  
Physical Factors ◽  
Larval Rearing ◽  
Thunnus Thynnus ◽  
Small Copepod ◽  
Atlantic Bluefin Tuna ◽  
Larval Stages

Abstract Bluefin tuna spawn in restricted areas of subtropical oligotrophic seas. Here, we investigate the zooplankton prey and feeding selectivity of early larval stages of Atlantic bluefin tuna (ABT, Thunnus thynnus) in larval rearing habitat of the Gulf of Mexico. Larvae and zooplankton were collected during two multi-day Lagrangian experiments during peak spawning in May 2017 and 2018. Larvae were categorized by flexion stage and standard length. We identified, enumerated and sized zooplankton from larval gut contents and in the ambient community. Ciliates were quantitatively important (up to 9%) in carbon-based diets of early larvae. As larvae grew, diet composition and prey selection shifted from small copepod nauplii and calanoid copepodites to larger podonid cladocerans, which accounted for up to 70% of ingested carbon. Even when cladoceran abundances were <0.2 m−3, they comprised 23% of postflexion stage diet. Feeding behaviors of larvae at different development stages were more specialized, and prey selection narrowed to appendicularians and primarily cladocerans when these taxa were more abundant. Our findings suggest that ABT larvae have the capacity to switch from passive selection, regulated by physical factors, to active selection of presumably energetically optimal prey.

Effects of local scale perturbations in the Atlantic bluefin tuna (Thunnus thynnus L.) trap fishery of Sardinia (W. Mediterranean)

2008 ◽  
Vol 92 (2-3) ◽  
pp. 242-254 ◽  
Author(s):  
Piero Addis ◽  
John Mark Dean ◽  
Paola Pesci ◽  
Ivan Locci ◽  
Rita Cannas ◽  
...  
Keyword(s):  
Bluefin Tuna ◽  
Local Scale ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna ◽  
Trap Fishery

scholarly journals Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0141478 ◽  
Author(s):  
Enrique Rodriguez-Marin ◽  
Mauricio Ortiz ◽  
José María Ortiz de Urbina ◽  
Pablo Quelle ◽  
John Walter ◽  
...  
Keyword(s):  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna

scholarly journals Combining genetic markers with stable isotopes in otoliths reveals complexity in the stock structure of Atlantic bluefin tuna (Thunnus thynnus)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Deirdre Brophy ◽  
Naiara Rodríguez-Ezpeleta ◽  
Igaratza Fraile ◽  
Haritz Arrizabalaga
Keyword(s):  
Genetic Markers ◽  
Bluefin Tuna ◽  
Integrated Model ◽  
Stock Structure ◽  
Thunnus Thynnus ◽  
Integrated Method ◽  
Atlantic Bluefin Tuna ◽  
Spawning Areas ◽  
Otolith Core ◽  
First Year Of Life

Abstract Atlantic bluefin tuna (Thunnus thynnus) from the two main spawning populations in the Mediterranean and Gulf of Mexico occur together in the western, central and eastern Atlantic. Stock composition of catches from mixing areas is uncertain, presenting a major challenge to the sustainable management of the fisheries. This study combines genetic and chemical markers to develop an integrated method of population assignment. Stable isotope signatures (δ13C and δ18O) in the otolith core of adults from the two main spawning populations (adult baselines) showed less overlap than those of yearlings (12–18 months old) from western and eastern nursery areas suggesting that some exchange occurs towards the end of the yearling phase. The integrated model combined δ18O with four genetic markers (SNPs) to distinguish the adult baselines with greater accuracy than chemical or genetic markers alone. When used to assign individuals from the mixing areas to their population of origin, the integrated model resolved some (but not all) discrepancies between the chemistry and genetic methods. Some individuals in the mixing area had otolith δ18O values and genetic profiles which when taken together, were not representative of either population. These fish may originate from another Atlantic spawning area or may represent population contingents that move away from the main spawning areas during the first year of life. This complexity in stock structure is not captured by the current two-stock model.

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