Abstract: In this study, six genotypes of young sea cucumber (Apostichopus japonicus) were exposed to three laboratory environments (high stocking density and natural light cycle, E1; low stocking density and dark, E2; and low stocking density and natural light cycle, E3) for 60 days, and a model was established to investigate the effects of environment, genotype, and their interaction on the survival rate and the specific growth rate (SGR) and coefficient of variation of growth traits (body length and body weight) of the young sea cucumbers. Environment, genotype, and their interaction had no significant effects on the survival rate of the sea cucumbers (P>0.05). Environment had significant effects on the SGR, but less effects on the coefficient of variation of growth traits, whereas genotype had significant effects on the SGR and the coefficient of variation of growth traits. No significant effects of genotype-environment interaction were recorded for the SGR and the coefficient of variation of growth traits (P>0.05). The SGR of the body length and body weight was the highest in the E3, with the average SGR being 0.03% and 1.58%, respectively. It was suggested that genotype × environment (light cycle and stocking density) interaction could be ignored when planning a breeding program for sea cucumber under laboratory conditions. This study provided theoretical basis for the family breeding of A. japonicus and the construction of healthy aquaculture mode.

Key words: alternative hypothesis, significance testing, decisivity., null hypothesis