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Age, growth, reproduction and feeding of J ohn D ory, Z eus faber ( P isces: Z eidae), in the S aros B ay ( N orth A egean S ea)
Author(s) -
Ismen A.,
Arslan M.,
Yigin C. C.,
Bozbay N. A.
Publication year - 2013
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12005
Subject(s) - biology , sexual maturity , gonadosomatic index , bay , zoology , reproduction , demography , geography , ecology , fecundity , population , archaeology , sociology
Summary The age, growth, reproduction, sexual maturity and stomach content of J ohn D ory ( Z eus faber ), caught in the B ay of S aros ( N orth A egean S ea) between September 2006 and September 2008, were investigated. The female‐male ratio was 1.6 : 1. The total length of females ranged from 13.8 cm to 52.8 cm, and of males from 12.2 cm to 42.9 cm. The length‐weight relationship was W = 0.0174*L 2.936 . Age data derived from vertebral centra readings were used to estimate the growth parameters of the von B ertalanffy equation. Growth parameters for females were L ∞ = 58.50 cm K = 0.11 year −1 , t 0 = −0.99 year and for males L ∞ = 45.01 cm, K = 0.13 year −1 , t 0 = −1.17 year. Maximum age was 18 years for females and 17 years for males. Length at first maturity for both females and males was 25.4 cm. Monthly values of the gonadosomatic index indicated that spawning occurred mainly in two peaks: one between January and June, and the other from August to September. Stomach content analysis showed the most‐preferred prey to be Pisces ( IRI % 97.3).