Effects of parent acclimation and heat-shock at gastrula on growth and developmentof sea cucumber larvae

This study investigated the effects of parent-acclimation and heat-shock at gastrula stage on growth and developmentof sea cucumber (Apostichopus japonicus) larvae. The adult sea cucumbers were split into two groups: DA group and XP group, eachwith two treatments: control (C) and heat-shock (H). Gastrula larvae of H were heated at 26 ℃ for 45 min and then reared at 18 ℃ and 23 ℃ separately until metamorphosis. Results show that the specific growth rate at 23 ℃ was higher than that at 18 ℃ in the control, but the trend was opposite in heat-shock treatment.Since the 2nd day of auricularia, the maximum body lengthhad been observedin heat-shock treatment for both DA and XP group, which was due to the ingestion of food. The setting rate of heat-shock treatment was significantly lower than that of the control due to the high rate of deformed individuals caused by heat-shock. Thus, high temperature-resistant sea cucumbers can be acquired via the following steps: first, obtain a certain number of high temperature-resistant juveniles by heat-shock at gastrula stage; then, culture these individuals in southern China until sexual maturity; finally, fix the high temperature-resistant properties by generation selection.