Microsatellite Analysis of the Influence of Sebastes schlegelii Restocking on the Genetic Structure of Stocks in Rongcheng Bay

The black rockfish Sebastes schlegelii, a valuable commercial fish, is one of the most important fish species for marine fishery stock enhancement in China. In this study, genetic diversity of the hatchery-released stock and two restored-natural stocks (SSNAC1 and SSNAC2) of S. schlegelii from Rongcheng Bay, Yellow Sea, China was analyzed using 15 microsatellite DNA loci, and the genetic differentiation between natural and hatchery-released stocks was also investigated. The mean effective number of alleles (Ae) in the hatchery-released stock was 3.6, the observed heterozygosity (Ho) was 0.506, and the expected heterozygosity (He) was 0.606, while the Ae, Ho and He values in the SSNAC1 and SSNAC2 stocks were 2.9 and 3.9, 0.381 and 0.577, and 0.569 and 0.692, respectively. The F_ST values between the hatchery-released and natural stock and the natural stocks before and after restocking were 0.055 and 0.013, respectively. The results showed that there was low differentiation between the natural and hatchery-released stocks even though the hatchery stock displayed slightly higher genetic diversity and heterozygosity than the natural stock. Furthermore, there was no differentiation on genetic diversity indices between the S. schlegelii natural stock before release and the mixed stocks after release in the short term. However, larger differentiation was found between the natural stock and restored-natural stock SSNAC2. Consequently, more detailed surveys are required to elucidate the long-term genetic effects of the stock enhancement. The present study would be helpful for the future stock enhancement strategy of black rockfish.