Analysis of the Genetic Variability of the Captured Population of Japanese Flounder Paralichthys olivaceus in the Coastal Releasing Area of Qinhuangdao

Abstract:

Japanese flounder Paralichthys olivaceus is the major species of released fish in the coastal area of Qinhuangdao. In recent years, the ecological and genetic risks caused by releasing a large number of hatchery-reared fish to the sea have attracted more and more attention. In this study, we used 12 microsatellite markers to analyze the genetic variability of the captured population of P. olivaceus from the coastal releasing area of Qinhuangdao. We also compared parameters of genetic diversity among the brood stock, the pre-releasing population and the captured population. The mean number of alleles was between 11.917 and 22.167, and the maximum and minimum values were found in the captured population and the pre-releasing population respectively. The mean observed heterozygosity (Ho) ranged from 0.800 to 0.836, and the mean expected heterozygosity (He) was between 0.814 and 0.845. The brood stock had the highest He value, and the pre-releasing population had the lowest value. The mean polymorphism information content (PIC) ranged from 0.775 to 0.818. Twenty-three out of 36 group-loci combinations were significantly deviated from the Hardy-Weinberg equilibrium (P<0.05). The Gst values among the five populations varied from 0.005 to 0.043, indicating a low level of differentiation. Results of this study suggested the high genetic diversity of these three populations. Moreover, no obvious genetic risk was caused by the large-scale releasing of hatchery-reared fish in the coastal releasing area of Qinhuangdao.