Validation of the Growth Equation Applicable to the Eastern Atlantic Bluefin Tuna,Thunnus thynnus(L.), UsingL_max, Tag-Recapture, and First Dorsal Spine Analysis

Review of Recent Studies on the Absolute and Relative Growth of Atlantic Bluefin Tuna: Similarities with the Pacific Bluefin Tuna

“…The previous coincidences do not occur with the growth models used for ABFT Cort et al, 2014) and PBFT (Shimose et al, 2009;Anonymous, 2016). The three models show differences for ages up to 10 years and from that age the trend towards L ∞ also differs.…”

“…After analyzing 43 ABFT growth equations, Cort et al (2014; found nine studies (from eastern and western stocks) in which the values of L ∞ lie within the limits of L max : Bard et al (1978); Hattour (1984); Cort (1991;Cort et al, 2014); Negli and Naour (2014); Parrack and Phares (1979); Farber and Lee (1981)…”

“…The growth equation for the eastern Atlantic bluefin tuna stock (Cort, 1991;Cort et al, 2014) is a combined growth curve using modal progression data for ages 1 to 8 (53.5-177.2 cm) from the Bay of Biscay (Cort, 1990) and direct age-length observations (fin spine sections) for ages 9-15 (190-247 cm) from the traps of southern Spain (Rey et al, 1987;Cort, 1990). Samples used correspond to the month of June, the month of birth for the ABFT in the western Mediterranean (García et al, 2003 and2005); this makes the sampling season equivalent in both areas.…”

“…By grouping the mean values at age from the Bay of Biscay with those of the traps, the von Bertalanffy growth model could be applied. Cort et al (2014) used the same data and tag-recovery data from tagging surveys in the Bay of Biscay, western Mediterranean and western Atlantic (n= 131). Restrepo et al (2010) used combined otolith-based age readings with the size frequency distributions of small (ages 1-3) ABFT caught by purse seiners in the 1970s; the accuracy of the age readings has been validated with bomb radiocarbon dating (Neilson and Campana, 2008).…”

“…The age and growth of ABFT, which began to be studied almost a century ago, are of great importance for the correct evaluation of the species' resources. In this sense, since the meeting of the ABFT assessment group in 2010 (ICCAT, 2010a) two very similar growth equations have been applied to the two stocks for the first time: to the western stock, L t = 314.90 [1-e -0.089 (t +1.13) ] (Restrepo et al, 2010), and to the eastern stock, L t = 318.85 [1-e -0.093 (t + 0.97) ] (Cort, 1991;Cort et al, 2014). The latter has been applied in the SCRS ABFT group since 1991.…”