EFFECTS OF SUBSTRATE ON GROWTH AND SURVIVAL OF POSTLARVAE AND JUVENILES OF PENAEUS-JAPONICUS BATE (CRUSTACEA, PENAEIDAE)

The effects of different substrates on growth and survival of artifici ally reared Penaeus japonicus Bate postlarvae and juveniles were inves tigated. Survival was found to be significantly less for postlarvae an d juveniles reared without a substrate, due to an increase in cannibal istic behavior. Medium sand for postlarvae and fine sand for juveniles encouraged burrowing and reduced cannibalism among the prawns. Growth , expressed as the increase with time of carapace length, was signific antly different among the treatments. The highest growth for postlarva e and juveniles was attained with very coarse sand as the substrate. A significant linear relationship between carapace length and total len gth was also obtained for juvenile P. japonicus. The results of a choi ce experiment on substratum preference suggest that the particle size of the sand is important in affecting the distribution of juvenile P. japonicus.