Abstract

• Reproductive biology of three crab species, Portunus sanguinolentus, P. pelagicus and Scylla serrata collected from Sittway area were studied. A total of 30 individuals of each species were monthly sampled from September to December 2015. Morphometric measurement of crabs, sex ratio and their reproductive development stages were examined. In Portunus sanguinolentus and P. pelagicus, female individual were abundantly occurred throughout the study period. In contract, high male ratio was recorded in Scylla serrata in which more than 25 individual per month are male crab. The fecundity of mud crabs is five times higher than the other two species. Poutunus sanguinolentus and P. pelagicus carried eggs throughout the study period but S. serrata carried egg only in the September 2015. Due to the migration behaviour of S. serrata, it is assumed that they migrate from brackish water to deep sea of high saline water at the time of spawning.