Relative growth and morphological sexual maturity of Ilyoplax frater (Brachyura: Ocypodoidea: Dotillidae) from mangrove area of korangi creek

The relative growth and size at morphological sexual maturity of mangrove crab,ilyoplax frater were studied. the crabs were monthly collected from korangi creek through quadrate method. the morphometric measurement of carapace,abdomen,cheliped and male gonopod were related to carapace width as an independent variable. the growth was isometric with no significant difference in the carapace growth for male and female crabs. the size at onset of sexual maturity in males was estimated as 4.7 mm cw and it was 4.6 mm cw in females. the positive allometric growth of the abdominal width for the females was observed and is likely due to reproductive advantages forming the incubatory chamber. the positive relationship of cheliped length and the gonopod for male crabs were related to mating and other antagonistic behavioral adaptations. copyright 2011 zoological society of pakistan.