Effects of salinity on early activities of artificial hybridization between Crassostrea ariakensis and c . gigas

Abstract

The hybridization experiments have been made between Crassostrea ariakensis and C. gigas several times. However, it is difficult to obtain a large number of hybrid offspring, which becomes the bottleneck of subsequent cross-breeding. To explore whether the production of hybrid larvae is affected by salinity, we investigated the effects of salinity (16, 20, 24, 28 and 32 psu) on the early activities of artificial hybridization between C. ariakensis and C. gigas at 23–24°C. In this study, the results showed that during artificial insemination, the appropriate salinity of high-quality gametes in C. ariakensis and C. gigas was 20–32 psu and 24–32 psu respectively. Besides, the fertilization rate of AG (C. ariakensis♀ × C. gigas♂) and GA (C. gigas♀ × C. ariakensis♂) at 24–28 psu was significantly (p < .05) higher than that at 16–20 psu. For incubation, the optimal salinity of embryo incubation was 28 psu, under which all embryos of AG and GA can develop rapidly to the D-larvae and yielded a high hatching rate. During larval rearing, the larval shell height and survival rate of AG were of no significant difference (p > .05) at all salinities, and the optimum salinity for larval growth and survival of GA was 24–28 psu. These findings can contribute to the increase in the hybrid progeny yield, which can serve as the new resource for genetic improvement of oyster germplasm.