Investigation of Genetic Diversity between Wild-caught and Hatchery-reared Rock Bream (Oplegnathus fasciatus) Using Microsatellite DNA Analysis

摘要

Marine fisheries are important natural resources and must be maintained, especially fish species that are important sources of food. Despite the increase in stocking programs to maintain fisheries with artificially raised fish, the genetic impact stocking has on the wild fry population has not been addressed. Genetic variation in rock bream, Oplegnathus fasciatus, within and between wild-caught parents and the F_1 generation produced by them in 1 day was assayed using nine highly variable microsatellite markers. The nine microsatellite loci used in this study displayed diverse polymorphisms, and in total, 98 different alleles were observed over all loci. Differences in genetic variability of the F_1 offspring compared to their wild-caught parents (brood stock) were observed in terms of allele frequency, gene diversity, and heterozygosity. Although the F_1 generation of rock bream was missing 16% of the microsatellite alleles, no significant reduction was found in mean heterozygosity of the F_1 population compared to the brood stock. Eight of nine loci showed significant Hardy-Weinberg equilibrium (HWE) deviations in the F_1 population, while the brood stock deviated from HWE at three microsatellite loci (KOF85, KOF360 and KOF374). These deviationsshowed mostly a deficit of heterozygotes. Our results provide evidence for genetic differences in the F_1 hatchery offspring compared to their wild-caught parents and reinforce the need for a series of consecutive egg collections to avoid the loss of genetic variability. This also further underscores the importance of monitoring genetic variability of hatchery populations for the conservation of natural rock bream resources.