Population Genetic Analysis of the Wild Hard-shelled Mussel, Mytilus Unguiculatus(Valenciennes 1858) in South Korea Using a Microsatellite Multiplex Assay

The Korean or hard-shelled mussel, Mytilus unguiculatus, previously known as Mytilus coruscus, is one of the most economically and ecologically important bivalves in South Korea. However, the population size of this species has drastically reduced owing to overharvesting and habitat shrinkage. Because its genetic information is poorly documented, we contributed, in this study, the genetic diversity and structural analyses of 246 adult samples of M. unguiculatusfrom seven populations along the coastal areas of the mainland and islands of South Korea using a microsatellite multiplex assay. Genetic diversity analyzed from eleven polymorphic microsatellite loci was consistently moderate (0.50–0.57) in all populations. No recent bottleneck was found, indicating that the number of the studied populations did not decrease to an extent that resulted in a reduction of genetic diversity. Additional tests did not reveal any genetic structure across them, possibly resulting from constant gene flow, strong dispersal of planktonic larvae, and genetic admixture between wild populations. These results suggest that M. unguiculatuspopulations along the coastal areas of South Korea should be managed as a single unit. Our study provides crucial information for future genetic monitoring, conservation management, and population restoration plan in preparation for the rapid decline in bivalve resources.