Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition.
The compiled data for this study represents the first Atlantic and Mediterranean-wide effort to pool all available biometric data for Atlantic bluefin tuna (Thunnus thynnus) with the collaboration of many countries and scientific groups. Biometric relationships were based on an extensive sampling (over 140,000 fish sampled), covering most of the fishing areas for this species in the North Atlantic Ocean and Mediterranean Sea. Sensitivity analyses were carried out to evaluate the representativeness of sampling and explore the most adequate procedure to fit the weight-length relationship (WLR). The selected model for the WLRs by stock included standardized data series (common measurement types) weighted by the inverse variability. There was little difference between annual stock-specific round weight-straight fork length relationships, with an overall difference of 6% in weight. The predicted weight by month was estimated as an additional component in the exponent of the weight-length function. The analyses of monthly variations of fish condition by stock, maturity state and geographic area reflect annual cycles of spawning and feeding behavior. We update and improve upon the biometric relationships for bluefin currently used by the International Commission for the Conservation of Atlantic Tunas, by incorporating substantially larger datasets than ever previously compiled, providing complete documentation of sources and employing robust statistical fitting. WLRs and other conversion factors estimated in this study differ from the ones used in previous bluefin stock assessments.
Instituto Español de Oceanografía, C.O. Santander, Santander, Spain.
Enrique
E
Rodriguez-Marin
International Commission for the Conservation of Atlantic Tunas, Secretariat, Madrid, Spain.
Mauricio
M
Ortiz
Instituto Español de Oceanografía, C.O. Málaga, Málaga, Spain.
José María
JM
Ortiz de Urbina
Instituto Español de Oceanografía, C.O. Santander, Santander, Spain.
Pablo
P
Quelle
National Marine Fisheries Service, Southeast Fisheries Center, Sustainable Fisheries Division, Miami, Florida, United States of America.
John
J
Walter
Institut National de Recherche Halieutique (INRH), Regional Centre of Tangier, Tangier, Morocco.
Noureddine
N
Abid
University of Cagliari, Department of Life Science and Environment, Cagliari, Italy.
Piero
P
Addis
Instituto Español de Oceanografía, C.O. Málaga, Málaga, Spain.
Enrique
E
Alot
Fisheries and Oceans Canada, St. Andrews Biological Station, St. Andrews, New Brunswick, Canada.
Irene
I
Andrushchenko
Federation of Maltese Aquaculture Producers, Valletta, Malta.
Simeon
S
Deguara
International Commission for the Conservation of Atlantic Tunas, GBYP Program, Madrid, Spain.
Antonio
A
Di Natale
Fisheries Resource Unit, Department of Fisheries and Aquaculture, Marsa, Malta.
Mark
M
Gatt
Gulf of Maine Research Institute, Portland, United States of America.
Walter
W
Golet
Istanbul University, Faculty of Fisheries, Istanbul, Turkey.
Saadet
S
Karakulak
National Research Institute of Far Seas Fisheries, Fisheries Research Agency, Shizuoka, Japan.
Ai
A
Kimoto
Instituto Español de Oceanografía, C.O. Málaga, Málaga, Spain.
David
D
Macias
Universidad de Málaga, Departamento de Biología Animal, Málaga, Spain.
Samar
S
Saber
International Commission for the Conservation of Atlantic Tunas, Secretariat, Madrid, Spain.
Miguel Neves
MN
Santos
Institut National des Sciences et Technologies de la Mer, Mahdia, Tunisia.
Rafik
R
Zarrad
D000818:Animals; D001267:Atlantic Ocean; D005247:Feeding Behavior / Q000502:physiology*; D005398:Fisheries; D008522:Mediterranean Sea; D014413:Tuna / Q000033:anatomy & histology* / Q000502:physiology*