Genetic diversity and population structure of the ark shell Scapharca broughtonii along the coast of China based on microsatellites

As a commercially important species in East Asia, the natural resources of Scapharca broughtonii have been suffering from severe population decline across its main habitats. In China, recovery efforts for S. broughtonii are in progress. To provide scientific bases for fisheries management and conservation program, genetic diversity and population structure of seven wild populations of S. broughtonii from the northern China coast was assessed using seven microsatellite loci in this study. High genetic diversity was present in all the seven populations, as observed in mean allelic richness per locus (11.3–12.5), and average expected heterozygosity (0.835–0.867). No significant difference in allelic richness or expected heterozygosity was observed among the seven populations. Pairwise F_ST estimates and NJ tree topologies based on D_C distances indicated that the seven populations fell into two groups, showing a clear division between the populations from the south and north of the Shandong Peninsula. Genetic differentiation was further analyzed using AMOVA and assignation tests. Genetic barrier analysis using Monmonier algorithm also confirmed that the Shandong Peninsula was the putative barrier separating the northern and southern populations. In addition, marine currents probably play an important role in high gene flow among three populations from the same marine gyre.