Sibship reconstruction and effective population size estimation in mass spawning ark shell, Scapharca broughtonii based on microsatellite analysis

Five highly polymorphic microsatellite loci were utilized to reconstruct sibship during a mass spawning event of ark shell, Scapharca broughtonii and to estimate the genetic variability between the D-shaped larvae and metamorphosed juvenile stage. The allelic diversity, and observed and expected heterozygosities exhibited similarity between the two sampling stages. The sibship reconstruction results of 180 offspring in each stage demonstrated that the effective population size was 20 in the D-shaped larvae stage and decreased to 16 in the metamorphosed juvenile stage. The inferred number of parents at the metamorphosed juvenile stage decreased 16.13 % and the inbreeding rate increased 0.6 % comparing to the D-shaped larvae stage. Multiple matings were detected both in males and females, and the reproductive success of both sexes in the two stages was positively correlated to the number of individuals with which it had mated. The results lend insight to S. broughtonii cultivation in China and provide a genetic guide for the development of more effective spawning techniques in the future.