Age growth sex spawning season and mortality of annular bream diplodus annularis linneaus 1758 pisces sparidae in Edremit Gulf Aegean Sea

Abstract

The study was conducted with specimens (N=652) collected from Northern Aegean coasts of Turkey. Females made up 49.38 % and males 50.62 % of the species. The fork length of females varied between 7.3 and 13.8 cm, and of males, varied between 7.5 and 14.0 cm. The von Bertalanffy growth equation was fitted on the basis of mean length-at-age data resulting in parameter values of parameters of L ∞ = 18.36 cm, K= 0.14 1/y, t0= 2.93 for males, L ∞ =17.21 cm, K= 0.21 1/y, t0= -1.73 for females and L ∞ =16.62 cm, K=0.20 1/y, t0= 1.96 for combined sexes. D. annularis was grown allometrically for both sexes together with b= 2.75 (SE= 3.1854) and relatively rapidly, achieved 26.77 % of the growth during the first year. The comber was a relatively long-lived species. The oldest male and female were estimated to be 7 and 6 years old, respectively. The overall sex ratio males:females was 1:1 The total (Z) and natural (M) mortality rates were 1.15 and 0.37 per year, respectively. The exploitation rate indicates that the population is overexploited (E=0.68). Mean condition factor of annular bream was calculated as 1.281. The seasonal values of gonadosomatic index (IG) of females indicated that spawning occurred mainly in spring and summer.