• Marine currents;
  • microsatellites;
  • population structure


As a commercially important fisheries resource in East Asia, the Chinese surf clam Mactra chinensis has experienced severe population declines in the past decades, probably due to over-exploitation. To provide scientific bases for fisheries management and artificial breeding, we investigated genetic variation and population structure of Mactra chinensis in Northern China using microsatellites. Samples collected from eight localities throughout natural habitats of the species in Northern China were genotyped. Nine microsatellites revealed high allelic diversity with 14–36 alleles per locus. Observed and expected heterozygosity varied from 0.593 to 0.945 and from 0.638 to 0.958, respectively. Pairwise FST values indicated that all population pairs had small but significant genetic differentiation. A Mantel test showed statistically significant correlations between genetic distance and geographical distance, indicating that genetic differentiation of the Chinese surf clam conformed to a pattern of isolation-by-distance. Cluster analysis using neighbor-joining separated the eight populations into three groups. The three areas of low gene flow identified by barrier analysis corresponded with local oceanographic features, suggesting that marine currents and peninsulas play an important role in population structuring of this species.