Effects of chemical cues on larval survival,settlement and metamorphosis of abalone Haliotis asinina

Low larval survival,poor settlement,and abnormal metamorphosis are major problems in seed production of donkey-ear abalone Haliotis asinina.We examined the effects of chemical cues including epinephrine,nor-epinephrine,and serotonin on larval survival,settlement,and metamorphosis in order to determine the possibility of using these chemicals to induce the problems.The results show that epinephrine could enhance metamorphosis rate at 10-6 mol/L only but higher concentrations(10-3-10-4 mol/L);and nor-epinephrine could inhibit the performance significantly,and serotonin could increase significantly the performance at a wide-range concentration(10-3-10-6 mol/L).Treatment with serotonin at 10-5 mol/L for 72 hours resulted in the highest settlement rate(42.2%) and survival rate(49.3%),while at 10-4 mol/L for 72 hours resulted in the highest metamorphosis rate(38.8%).Therefore,serotonin may be used as a fast metamorphosis inducer in abalone culture.