Age, growth and mortality of the striped sea bream, Lithognathus mormyrus L., in the Northern Adriatic

Abstract

Data on age, growth, mortality and sex inversion were analysed for striped sea bream collected in the western Istrian coastal waters from 27 July to 24 August 1992. Total length ranged between 19.4 and 37.6 cm. The length-weight relationship was described for males ( a = 0.0106; b = 3.023) and females ( a = 0.0094; b = 3.063). Fish aged 3–12 years were present in the samples. Growth in length was expressed for the whole sample with von Bertalanffy's equation. Growth parameters L ∞ = 40.05 cm, K = 0.196 and t 0 = −0.945 were calculated. The overall male to female ratio was 1:1.62. Sex inversion occurred mainly at lengths between 24.1 and 35.2 cm, in age classes 4–8. Males were observed up to a length of 34.5 cm. Total and natural mortality were found to be Z = 0.77 1/year and M = 0.42 1/year. The exploitation ratio E = 0.45 suggests that the stock was almost fully fished.