Some biological parameters of silverstripe blaasop, Lagocephalus sceleratus (Gmelin, 1789) from the Mersin Bay, the Eastern Mediterranean of Turkey

Abstract

A total of 208 individuals of silverstripe blaasop, Lagocephalus sceleratus were caught by trawl hauls from Mersin Bay in the years of September 2014 and April 2015. The samples ranged from 14.9 cm to 67.6 cm in fork length and 32.0 g to 4540.0 g in total weight. The ages of silverstripe blaasop population were determined between 1-6 using vertebra. As the silverstripe blaasop population in Mersin Bay consisted of 98 females and 110 males, the sex ratio was calculated as 0.88: 1(F:M) with 52.88% of the population were males and 47.12% of the population were females (p>0.05, t-test). The length-weight relationship of all individuals was calculated as Lt=118.71(1-e -0.115(t-0.178) ). According to the length-weight relationships, an isometric growth was confirmed for both sexes, except for those estimated in female and male. The monthly values of gonadosomatic index (GSI) of females indicated that spawning occurred mainly between March and April. Gastrosomatic Index (GaSI) was found to be the highest in December and the least in October that is before and after the spawning season. Analysis of the diet composition showed that silverstripe blaaosop is carnivorous and the food spectrum of L. sceleratus consists of fishes 41%, molluscs 19%, crustacea 12% digested items 26%, and others 2% (parts of fish line and nematodes).