Abstract
This study dealt with the egg development and incubation period of the swimming crab Portunus trituberculatus reared in the laboratory. Egg volume increased twice throughout development and the rate of increment was higher after the metanaupliar stage. Two embryonic growth indices which were expressed as respective relative areas of embryonic body and eye pigment in lateral profiles of the egg increased as the relative egg age advanced. Newly hatched larvae body size correlated with egg size. Smallersized larvae tended to be produced at higher egg incubation temperatures. The number of days from spawning to hatching decreased with increasing incubation temperature and the Belehradek's equation was the best non-linear regression model to describe the relationship between temperature and egg incubation period.
