scholarly journals Sexual maturity in western Atlantic bluefin tuna

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Gilad Heinisch ◽  
Hanna Rosenfeld ◽  
Jessica M. Knapp ◽  
Hillel Gordin ◽  
Molly E. Lutcavage

2010 ◽  
Vol 158 (1) ◽  
pp. 73-85 ◽  
Author(s):  
John M. Logan ◽  
Enrique Rodríguez-Marín ◽  
Nicolas Goñi ◽  
Santiago Barreiro ◽  
Haritz Arrizabalaga ◽  
...  


2011 ◽  
Vol 158 (9) ◽  
pp. 2147-2148 ◽  
Author(s):  
John M. Logan ◽  
Enrique Rodríguez-Marín ◽  
Nicolas Goñi ◽  
Santiago Barreiro ◽  
Haritz Arrizabalaga ◽  
...  


2010 ◽  
Vol 67 (6) ◽  
pp. 966-976 ◽  
Author(s):  
Benjamin Galuardi ◽  
François Royer ◽  
Walt Golet ◽  
John Logan ◽  
John Neilson ◽  
...  

Movements of Atlantic bluefin tuna ( Thunnus thynnus , ABFT) from specific western Atlantic forage grounds are not well described, and the extent of their spawning areas is mainly surmised. In 2005 and 2006, we deployed 41 pop-up satellite archival tags (PSATs) on adult Atlantic bluefin tuna off the coast of Nova Scotia, Canada, and on Georges Bank. During the assumed spawning period, 56% of the tagged ABFT occupied a known spawning area, while 44% were located in distant oceanic regions. Assuming obligate annual spawning, these results are inconsistent with the notion of spawning site fidelity to the Gulf of Mexico. The ocean-wide migrations of adult ABFT tagged on a common forage ground suggest evidence of a metapopulation requiring more spatially explicit management than the current simple two-stock structure.





Author(s):  
Michael P. Sissenwine ◽  
Pamela M. Mace ◽  
Joseph E. Powers ◽  
Gerald P. Scott


2010 ◽  
Vol 67 (3) ◽  
pp. 563-569 ◽  
Author(s):  
Ryan W. Schloesser ◽  
John D. Neilson ◽  
David H. Secor ◽  
Jay R. Rooker

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.



Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 390
Author(s):  
Giambattista Bello ◽  
Nicoletta Santamaria ◽  
Aldo Corriero

Most fish undergo distinct growth phases during ontogenesis. An extremely important passage from the juvenile to adult phase occurs at the onset of sexual maturity, which shows in body proportion and/or growth rate changes. These can be detected as change-points in biometric relationships. In this paper, the Atlantic bluefin tuna was analyzed to verify whether its somatic proportions show any sign of discontinuity during growth, i.e., whether any change-points may be detected in its somatic proportions. This fish has never been examined in this respect, and single-phase models, which are indeed easier to both compute and apply, are used in stock analyses. The following somatic relationships were analyzed in Atlantic bluefin tuna captured in the Mediterranean Sea between 1998 and 2010: “fork length–weight” regression, the von Bertalanffy growth equation, and “first dorsal spine cross section surface–fork length” regression. All of the examined relationships were found to be best modelled by multiple-phase regression equations, and all of them showed a change-point within the range of 101–110 cm fork length, which corresponds to 3–4 years of age. The present results, based on reproductive state-independent analyses, corroborate the disputed hypothesis that Atlantic bluefin tuna from the eastern stock in fact reproduce for the first time at this age.



Author(s):  
Gregory Neils Puncher ◽  
Alex Hanke ◽  
Dheeraj Busawon ◽  
Emma Sylvester ◽  
Walter Golet ◽  
...  

Identifying the origin of fish contained in a mixed fishery is critical for accurate stock assessments and the subsequent development of appropriate management strategies. Using a panel of 92 SNPs developed to differentiate Atlantic bluefin tuna (Thunnus thynnus) from the two main spawning areas (Gulf of Mexico and Mediterranean Sea), we used individual assignment to determine composition of feeding aggregations in the northwestern Atlantic Ocean (Gulf of Maine, Bay of Fundy, Scotian Shelf, Gulf of St. Lawrence, coastal Newfoundland). Among the 3,163 individuals collected between 2004 and 2018, we found that among lower age groups (<15 years) the spawning stock providing the most recruits to the Canadian fishery transitioned from Western Atlantic to Mediterranean origin over time. While the majority of older adults (>15 years) have consistently been of Western Atlantic origin, the disparity in the proportional contribution of western and eastern spawning groups narrowed significantly over the 14-year study period. Our results can be used to inform population-specific exploitation rates, improve stock assessments, identify age-dependent habitat use and areas suitable for additional conservation efforts.



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