The Effect of Substrate Type on the Ovarian Maturation of Penaeus japonicus Bate

Unilaterally eyestalk ablated female Penaeus japonicus produced more spawns per shrimp and more eggs in total in maturation tanks with a hard substrate than in tanks with a sand substrate. There was no significant difference (P>0.05) in mean fe­cundity (eggs per spawn)1 hatch rate and larval survival rates between the two substrates. The difference in spawning rate and total egg production reflects the higher food consumption of shrimp on the hard substrate. Shrimp on a hard bottom remain active and eat day and night, while on sand they bury and will not eat during the day. Thus a lower intake of dietary nutrients appears to account for the lower rate of ovarian maturation on the sand substrate. There is no evidence from this study that a sand substrate is necessary for the ovarian maturation of eyestalk ablated P. japonicus.