Temporal Changes in Genetic Diversity of Fenneropenaeus chinensis Populations from Jinzhou Bay: Implications for Management

Fenneropenaeus chinensis is an important fishery species in China. Hatchery-reared seeds have been released into the wild for improvement of shrimp productivity. Jinzhou bay is the major natural habitat and we used this location to temporally monitor the genetic effects of release of hatchery stocks on local F. chinensis populations across five years. A set of 13 microsatellite markers were used to evaluate genetic patterns across 2015, 2016 and 2019. We observed a significant Hardy-Weinberg disequilibrium across all stocks. The inbreeding coefficient (Fis) was positive (0.121-0.131) for all stocks. A loss of genetic diversity was detected in the 2019 stock and significant differences were observed for number of different alleles, number of effective alleles, allelic richness and unbiased expected heterozygosity in the 2019 stock (P < 0.05). The highest pairwise relatedness and the lowest observed heterozygosity were also observed in 2019 stock. Moreover, a small but significant genetic differentiation was detected between the 2019 stock and the stocks of the previous two years. Given the continuously large scale of artificial enhancements in this area, these data may indicate that releases of hatchery-reared F. chinensis individuals may be associated with inbreeding and potentially the reduction in genetic diversity of the F. chinensis population.