scholarly journals Modeling terminal-year fishing mortality rates in western Atlantic bluefin tuna virtual population analyses

2012 ◽  
Vol 25 (4) ◽  
pp. 333-340 ◽  
Author(s):  
John F. Walter ◽  
Clay E. Porch
Keyword(s):  
Bluefin Tuna ◽  
Mortality Rates ◽  
Fishing Mortality ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna ◽  
Population Analyses ◽  
Virtual Population

A sequential Bayesian methodology to estimate movement and exploitation rates using electronic and conventional tag data: application to Atlantic bluefin tuna (Thunnus thynnus)

2009 ◽  
Vol 66 (2) ◽  
pp. 321-342 ◽  
Author(s):  
Hiroyuki Kurota ◽  
Murdoch K. McAllister ◽  
Gareth L. Lawson ◽  
Jacob I. Nogueira ◽  
Steven L.H. Teo ◽  
...  
Keyword(s):  
Auxiliary Information ◽  
Bluefin Tuna ◽  
Mortality Rates ◽  
Fishing Mortality ◽  
Thunnus Thynnus ◽  
Multiple Sources ◽  
The West ◽  
Movement Rates ◽  
Bayesian Methodology ◽  
Atlantic Bluefin Tuna

This paper presents a Bayesian methodology to estimate fishing mortality rates and transoceanic migration rates of highly migratory pelagic fishes that integrates multiple sources of tagging data and auxiliary information from prior knowledge. Exploitation rates and movement rates for Atlantic bluefin tuna ( Thunnus thynnus ) are estimated by fitting a spatially structured model to three types of data obtained from pop-up satellite, archival, and conventional tags for the period 1990–2006 in the western North Atlantic. A sequential Bayesian statistical approach is applied in which the key components of the model are separated and fitted sequentially to data sets pertinent to each component with the posterior probability density function (pdf) of parameters from one analysis serving as the prior pdf for the next. The approach sequentially updates the estimates of age-specific fishing mortality rates (F) and transoceanic movement rates (T). Estimates of recent F are higher than the estimated rate of natural mortality and higher in the east than in the west. Estimates of annual T from the west to the east are higher for larger fish (6% for ages 0–3 to 16% for ages 9+). These estimates are also higher than those obtained from tagging studies before the 1990s and could be associated with changes in stock composition.

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
Keyword(s):  
Sexual Maturity ◽  
Bluefin Tuna ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna

Diet of young Atlantic bluefin tuna (Thunnus thynnus) in eastern and western Atlantic foraging grounds

2010 ◽  
Vol 158 (1) ◽  
pp. 73-85 ◽  
Author(s):  
John M. Logan ◽  
Enrique Rodríguez-Marín ◽  
Nicolas Goñi ◽  
Santiago Barreiro ◽  
Haritz Arrizabalaga ◽  
...  
Keyword(s):  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna

scholarly journals Erratum to: Diet of young Atlantic bluefin tuna (Thunnus thynnus) in eastern and western Atlantic foraging grounds

2011 ◽  
Vol 158 (9) ◽  
pp. 2147-2148 ◽  
Author(s):  
John M. Logan ◽  
Enrique Rodríguez-Marín ◽  
Nicolas Goñi ◽  
Santiago Barreiro ◽  
Haritz Arrizabalaga ◽  
...  
Keyword(s):  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna

Complex migration routes of Atlantic bluefin tuna (Thunnus thynnus) question current population structure paradigm

2010 ◽  
Vol 67 (6) ◽  
pp. 966-976 ◽  
Author(s):  
Benjamin Galuardi ◽  
François Royer ◽  
Walt Golet ◽  
John Logan ◽  
John Neilson ◽  
...  
Keyword(s):  
Site Fidelity ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Migration Routes ◽  
Western Atlantic ◽  
Spawning Period ◽  
Atlantic Bluefin Tuna ◽  
Spawning Site ◽  
Archival Tags ◽  
Spawning Areas

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.

Ridge virtual population analysis to reduce the instability of fishing mortalities in the terminal year

2017 ◽  
Vol 74 (9) ◽  
pp. 2427-2436 ◽  
Author(s):  
Hiroshi Okamura ◽  
Yuuho Yamashita ◽  
Momoko Ichinokawa
Keyword(s):  
Ridge Regression ◽  
Population Analysis ◽  
Japan Sea ◽  
The Sea Of Japan ◽  
Fishing Mortality ◽  
Population Analyses ◽  
Virtual Population ◽  
Stock Assessments ◽  
Abundance Indices ◽  
Stable Estimation

Abstract Tuned virtual population analyses are widely used for fisheries stock assessments. However, accurately estimating abundances and fishing mortality coefficients in the terminal year using tuned virtual population analyses is generally difficult, particularly when there is a limited number of available abundance indices. We propose a new method of integrating the tuned virtual population analyses with a ridge regression approach. In our method, penalization in the ridge regression is applied to the age-specific fishing mortalities in the terminal year, and the penalty parameter is automatically selected by minimizing the retrospective bias. Therefore, our method is able to simultaneously obtain a stable estimation of fishing mortality coefficients in the terminal year and reduce retrospective bias. Simulation tests based on the northern Japan Sea stock of walleye pollock (Gadus chalcogrammus) in the Sea of Japan demonstrated that this method yielded less biased estimates of abundances and avoided overestimations of fishing mortality coefficients in the terminal year. In addition, despite limited abundance indices, our method can perform reliable abundance estimations even under hyperstability and hyperdepletion conditions.

A Commentary on Western Atlantic Bluefin Tuna Assessments

1998 ◽  
Vol 127 (5) ◽  
pp. 838-855 ◽  
Author(s):  
Michael P. Sissenwine ◽  
Pamela M. Mace ◽  
Joseph E. Powers ◽  
Gerald P. Scott
Keyword(s):  
Bluefin Tuna ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna

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.

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