Determination of L (max) for Atlantic Bluefin Tuna, Thunnus thynnus (L.), from Meta-Analysis of Published and Available Biometric Data

Abstract

A meta-analysis of the straight fork lengths (herewith abbreviated as L) of 2,458,028 Atlantic bluefin tuna, Thunnus thynnus (L.), taken from 224 scientific publications and unpublished L data from scientific organizations and fishing companies spanning most of the known Atlantic and Mediterranean Atlantic bluefin tuna fisheries dating from 1605 to 2011, give L values ranging from L-min = 20cm and L-max = 330cm. The results indicate that the parameter L = 318.85cm of the growth equation used by ICCAT's Standing Committee on Research and Statistics Atlantic bluefin tuna assessment group for the eastern stock (Lt = 318.85 [1 - e(-0.093 (t + 0.97))]) lies within the confidence limits of the maximum Ls presented in the study: L-max = 319.93 +/- 11.3cm, confirming that this equation perfectly fits the biology of the growth of this species. These conclusions are also valid for the equation for the western stock (Lt = 314.90 [1 - e(-0.089 (t +1.13))]). The ICCAT Atlantic bluefin tuna database contains numerous records of Atlantic bluefin tuna L outside the biological feasibility, and solutions are provided to recognize and remove these outliers based on the application of fixed values of Fulton's condition factor (K) between 1.4 and 2.6 and appropriate L-W relationships to correct this situation in the future.