Abstract
Variations in morphometric parameters in 488 males and 450 female individuals of Scylla serrata (Forskal, 1775) are presented. Males were larger than females. The male: female sex ratio was 1.1038 ± 0.08468 in 2009 and 1.1462 ± 0.09722 in 2010. The carapace width (CW) varied from 50 to 170 mm in males and 40 to 169 mm in females averaging to 103.8 ± 0.81 mm and 100.8 ± 0.87mm, respectively. The size-based compositional similarity amongst the various size classes of male and female crabs, as per Czekanowski (1913) index, was 93.2%. Sex ratio was uneven amongst the months. The overall male: female ratio was 1.1249± 0.0632. Male outnumbered the female in August, October and November in 2009 and in October and November only in 2010. The gonadal weight was quite low in males (6.57 ± 0.21g) than females (50.26 ± 0.25g). There was sexual dimorphism in S. serrata. It was evident from the analysis that females had larger abdominal length and width and larger gonadal size than that of the males. In other characters viz. CW, carapace length (CL), 3-Merus length, 5th dactylus length, left and right propodus lengths and widths, and left and right claw merus lengths and weights, the males had superiority over females. The condition factor of male mud crab averaged to 0.09831 ± 0.00108 varying from 0.0303 to 0.3375 (CV: 24.23%). The condition factor of female specimens (N= 449; one outlier sample excluded) averaged to 0.17115 ± 0.00138 varying from 0.0736 to 0.3640 (CV: 17.18%). The condition factor in both sexes related with carapace width in a model of cubic equation.
