THE SEX RATIO, GONADOSOMATIC INDEX AND STAGES OF GONADAL DEVELOPMENT OF SADDLE GRUNT FISH, POMADASYS MACULATUM (BLOCH, 1793) OF KARACHI COAST

摘要

The sex ratio, gonadosomatic index, stages of gonadal development and fecundity of saddle grunt fish, Pomadasys maculatum (Block, 1793) of the Karachi coast were investigated. Pomadasys maculatum had a sex ratio of 1: 1.36 (male to female). The difference in sex ratio was not significantly different (p > 0.05) from the expected theoretically 1: 1 distribution except June, September and December. Gonadosomatic index value in males during August – November were 3.109 to 5.630, while in females the high values during August – December were found to be 3.542 to 6.679, which suggested the spawning period. The highest GSI value in males was 5.967 in stage VI and the lowest GSI value was 1.256 recorded during VII stage. GSI values in males increased slowly reaching for maximum in 5.967 in (stage VI), while in females at high value was 6.630 during stage VI and the lowest GSI values were 1.625 and 1.124 during stages I & II respectively. Seven stages of gonadal development were observed in male and female fish. Pomadasys maculatum is found in coastal waters over sand near reefs or muddy bottoms. The results will increase our knowledge of reproductive biology of Pomadasys maculatum which is relevant for fisheries and aquaculture management as well as breeding programs.