Reproductive biology, length-weight relationship and population parameters of a marine ornamental fish Abudefduf vaigiensis (Quoy & Gaimard, 1825) (Osteichthys, Pomacentridae) from the shallow waters of Visakhapatnam coast.

摘要

An attempt has been made to study the reproductive biology, length-weight relationship, relative condition factor and other population dynamics of Abudefduf vaigiensis of Visakhapatnam coast. The regression coefficients of length and weight in males and females showed a significant difference, hence separate equations were developed. The equations obtained were: males: log W=-4.6392+2.9681.log L (r=0.96); females: log W=-4.5023+2.9048.log L (r=0.95). The mean relative condition factor (Kn) values ranged from 0.992 to 1.027 in males and 0.983 to 1.019 in females. In males and females low Kn values were clearly related with the spawning season. Size at first maturity was estimated at 126 mm. Ripe specimens were observed in length groups 121-150 mm between October and March. The females marginally dominated the catch and the average sex ratio of males to females for the study period was 1:1.36. Fecundity ranged from 11,294 to 40,208 and average fecundity was estimated as 19,548. Fecundity increased with total length, fish weight and ovary weight. Population dynamics parameters estimated were: L infinity =180.27 mm, K=0.48 per year, O' (growth performance index)=2.508, natural mortality coefficient (M)=1.07377 per year, total mortality coefficient (Z)=1.29277 per year, fishing mortality (F)=0.219, exploitation ratio (E)=0.2039.