Age growth and mortality of blotched picarel Spicara maena L. (Pisces : Centracanthidae) in the eastern central Adriatic

Age, growth and mortality of the blotched piearel, Spicara maena (L., 1758) , were determined from specimens (N=1130) collected on the eastern central coast of the Adriatic Sea from 16 September to 10 October 1996. Total lengt h ranged from 7.8 to 27.5 cm, while weight varied between 5.3 and 398.0 g. The von Bertalanffy growth equation was fitted on the basis of mean length- at-age data resulting in parameter values of L-infinity=24.82 (S.E.=0.369), K=0.532 (S.E.=0.0302), and t(0)=-0.089 (S.E.=0.0321) (R=0.9985). Weight gr owth constants were: W-infinity=211.17 (S.E.=14.843), K=0.504 (S.E.=0.0324) , and t(0)=0.099 (S.E.-0.0.076) (R=0.9627). Weight increased allometrically fur both sexes together with b=3.12 (S.E.=0.025). The blotched picarel is a relatively long-lived species. The oldest male and female were estimated to be 8 and 3 years old, respectively. Total (Z) and natural (hl) mortality were 1.18 and 0.98 per year, respectively. The exploitation ratio E=0.17 r evealed an underfished stock. The sex ratio was skewed in favour of malts ( 1.41:1). Sex reversal was mainly observed between 17.5 and 18.0 cm. Females were observed up to a total length of 19.8 cm. (C) 2000 Elsevier Science B .V. All rights reserved.