Direct ageing of Thunnus thynnus from the eastern Atlantic Ocean and western Mediterranean Sea using dorsal fin spines. Issue 6 (June 2014)

• Record Type: Journal Article
• Authors: Luque, P. L.; Rodriguez‐Marin, E.; Landa, J.; Ruiz, M.; Quelle, P.; Macias, D.; Ortiz De Urbina, J. M.
• Is Part Of: Journal of fish biology. Volume 84:Issue 6(2014)
• Page Start: 1876
• Page End: 1903
• Publication Date: 2014-06
• Subjects: Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.12406
• Languages: English
• ISSNs: 0022-1112

Abstract

<abstract abstract-type="main" id="jfb12406-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="jfb12406-para-0001">This study deals with important methodology issues that affect age estimates of eastern Atlantic bluefin tuna <italic>Thunnus thynnus</italic> using dorsal fin spines. Nearly 3800 spine sections were used from fish caught in the north‐east Atlantic Ocean and western Mediterranean Sea over a 21 year period. Edge type and marginal increment analyses indicated a yearly periodicity of annulus formation with the translucent bands (50% of occurrence) appearing from October to May. Nucleus vascularization seriously affected specimens older than 6 years, with the disappearance of 40–50% of the presumed annuli by that age. An alternate sectioning location was a clear improvement and this finding is an important contribution to the methodology of using this structure for ageing the full‐length range of eastern <italic>T. thynnus</italic>. Finally, there were no significant differences between the coefficients of von Bertalanffy growth model estimated from mean length at age data (<italic>L</italic>_∞ = 327·4; <italic>k</italic> = 0·097; <italic>t</italic>₀ = −0·838) and those estimated from the growth curves accepted for the eastern and western <italic>T. thynnus</italic> management units.</p> </abstract>