Effects of Different pH on Embryo Development and Larval Growth of Bay Scallop (Argopecten irradia)

Abstract:

To explore the influence of pH on embryo development and larval growth of bay scallop (Argopecten irradia), pH 8.0~8.2 was set as the control group to analyze the influence of different pH (7.6~7.7, 7.3~7.4, 7.0~7.1, and 6.7~6.8) on the development of embryos and larva of bay scallop. The results showed that with decrease in pH, the hatching rate of embryos in each experimental group decreased, the deformity rate increased, hatching time was prolonged, and the larva were significantly smaller than those in the control group (P<0.05). The survival rate and growth rate of D-larvae and top umbo larvae were significantly lower than those of the control group (P<0.05). The survival rates of the pH 7.0~7.1 and pH 6.7~6.8 experimental groups were 6.1% and 5.6%, respectively, and 75.2% in the control group on the 8th day of larva development. The growth rates of each experimental group were 3.4 μm/d and below, except for the pH 7.6~7.7 group, which basically showed a state of growth stagnation. There was a significant difference in the adhesive rate between the experimental group and the control group (P<0.05). On the 7th day, the adhesive rate of the pH 6.7~6.8 experimental group was only 31.7%. The results showed that the change in seawater pH had a significant effect on early embryo and larva development in bay scallop, which provides a reference for the evaluation of the effects of pH change on economic shellfish resources, such as bay scallop and others in the aquaculture industry.