Comparison of the culture performance of wild-caught and artifical breeding Chinese mitten crab megalopae reared in the grow-out ponds during the adult Eriocheir sinensis culture stage

Abstract:

Although the wild Yangtze Eriocheir sinensis juveniles (coin-sized seed) have the better culture performance than the artifically pond-reared juveniles during the adult crab breeding stage, the culture performance of wild-caught megalopae was largely unclear. Therefore, this study was designed to compare the growth, gonadal development, survival, crab yield, feed conversion rate (FCR), final mean body weight and size distribution between wild population (WP) and artificial breeding population (AP) of E. sinensis megalopae for the Yangtze population during the adult crab culture stage. The results show that: despite of males or females, the mean body weight of WP was significantly higher than that of AP during the mid-late culture stage. It was the evidence that the males of WP had the significantly higher body weight gain rate (WGR) and specific growth rate (SGR) than those of AP duiring the periods of May-July and July-August, while the females of WP had the significantly higher WGR and SGR than those of AP duiring the period of August-September (P<0.05). Although WP had the significantly higher final mean body weight than AP, the AP had a slightly higher survival than WP, leading to the similar crab yeilds between two populations. As for the size distribution of adult crabs, WP had the higher percentage of large size crabs (male ≥175 g; female ≥125 g), but the lower proportion of middle size crabs (male: 125-174.9 g; female: 100-124.9 g) than AP for both males and females. In conclusion, wild -caught megalopae of Yangtze E. sinensis had the better culture performance than the artificial breeding population, and the selective breeding program of Yangtze E. sinensis could be based on the wild populations by the exploitation and enhancement of their excellent germplasm resources.