Evaluation of phenotypic traits of two strains of the Kumamoto oyster (Crassostrea sikamea)

The phenotypic traits of two strains the Kumamoto oyster Crassostrea sikamea were evaluated by the reproductive biology method according to the number of radiation ribs from left shell with the Zhangjiang population as base stocks in May 2013. Results showed that the fresh weight, shell weight and fecundity of mulit-radial ridge parents were significantly greater than those of non-radial ridge, while no significant difference in the egg diameter, fertilization rate, hatching rate, D larval size and metamorphic size was found between two strains. However, the survival ability and growth potential of multi-radial ridge strain were both better than those of non-radial ridge strain. Growth traits of two strains were affected by the culture conditions, while hardly any effect was observed on the viability of the environment during grow-out stage at two different sites. The radial ridge of the left shell of oyster is dominant and it is mainly controlled by a dominant gene, while the multi-ridge trait is recessive trait, which can be stably inherited. This study provided a solid theoretical foundation and practical experience for the cultivation of the multi-ridge culture and the genetic mechanism of the left shell of the oyster.