Serum biochemical profiles of captive and wild northern bluefin tuna (Thunnus thynnus L. 1758) in the Eastern Mediterranean

2008 ◽  
Vol 39 (9) ◽  
pp. 945-953 ◽  
Author(s):  
Fatih Percin ◽  
Sibel Konyalioglu
Keyword(s):  
Eastern Mediterranean ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Serum Biochemical ◽  
Biochemical Profiles

Evidence of a spawning area for the bluefin tuna (Thunnus thynnus L.) in the eastern Mediterranean

2004 ◽  
Vol 20 (4) ◽  
pp. 318-320 ◽  
Author(s):  
S. Karakulak ◽  
I. Oray ◽  
A. Corriero ◽  
M. Deflorio ◽  
N. Santamaria ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Spawning Area

Natal origin of Atlantic bluefin tuna (Thunnus thynnus) from Canadian waters based on otolith δ13C and δ18O

2010 ◽  
Vol 67 (3) ◽  
pp. 563-569 ◽  
Author(s):  
Ryan W. Schloesser ◽  
John D. Neilson ◽  
David H. Secor ◽  
Jay R. Rooker
Keyword(s):  
Eastern Mediterranean ◽  
Bluefin Tuna ◽  
Maximum Likelihood Estimates ◽  
Thunnus Thynnus ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna ◽  
Declining Populations ◽  
Catch Rates ◽  
And Migration ◽  
Stock Mixing

Increased knowledge of stock mixing and migration of Atlantic bluefin tuna ( Thunnus thynnus ) is required to properly manage and conserve declining populations. Here, we predicted the nursery origin of giant bluefin tuna (n = 224) present in samples from Canadian waters using stable δ13C and δ18O isotopes in otoliths. The isotopic composition of milled otolith cores (corresponding to the first year of life) of giant bluefin tuna from three decades (1970s, 1980s, 2000s) and three regions within or adjacent to the Gulf of St. Lawrence was compared with otolith δ13C and δ18O of yearling bluefin tuna collected from eastern (Mediterranean Sea – eastern Atlantic, n = 136) and western (western Atlantic, n = 103) nurseries. Maximum likelihood estimates indicated that greater than 99% of bluefin tuna in our Canadian samples originated from the western nursery. No significant differences in estimates of origin for bluefin tuna were detected among decades or among regions, suggesting little to no mixing of eastern and western populations in the Canadian samples examined. These findings justify the use of catch rates from the Gulf of St. Lawrence area as an index of abundance for the oldest members of the western population.

scholarly journals Origin of Atlantic bluefin tuna (Thunnus thynnus) in the Bay of Biscay

2014 ◽  
Vol 72 (2) ◽  
pp. 625-634 ◽  
Author(s):  
Igaratza Fraile ◽  
Haritz Arrizabalaga ◽  
Jay R. Rooker
Keyword(s):  
North Atlantic Ocean ◽  
Eastern Mediterranean ◽  
Reference Sample ◽  
Bluefin Tuna ◽  
Maximum Likelihood Estimates ◽  
Bay Of Biscay ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna ◽  
Carbon And Oxygen Isotope ◽  
Δ13c And Δ18o

Abstract We used carbon and oxygen isotope ratios (δ13C and δ18O) in otoliths as a tool for identifying the nursery origin of Atlantic bluefin tuna (Thunnus thynnus) caught in the eastern North Atlantic Ocean (Bay of Biscay). Juvenile and adult bluefin tuna were collected over three consecutive years (2009—2011) using the regional bait boat fleet. Otolith δ13C and δ18O values of bluefin tuna were measured by mass spectrometry, and values were compared with a reference sample of yearling bluefin tuna from eastern (Mediterranean Sea) and western (Gulf of Mexico) nurseries to determine nursery origin. Maximum likelihood estimates based on otolith δ13C and δ18O values indicated that the overall contribution of western migrants to the Bay of Biscay fishery was <1% and varied over the years assessed. A small number of potential western migrants (2.7%) was detected in 2009, and most of these fish appear members of the abundant 2002 and 2003 year classes. In contrast, the Bay of Biscay fishery was composed exclusively (100%) of eastern origin bluefin tuna in 2010 and 2011, suggesting that this fishery is supported almost exclusively by the eastern spawning area but transatlantic western population may contribute to this fishery in a few years.

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.

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