Genetic diversity maintained in comparison of captive-propagated and wild populations of Lampsilis fasciola and Ptychobranchus fasciolaris (Bivalvia: Unionidae)1

Abstract

We compared the genetic diversity and structure of wild versus captive-propagated at-risk species of freshwater mussels in Canada, Lampsilis fasciola (wavy-rayed lampmussel; WRL) and Ptychobranchus fasciolaris (kidneyshell; KS), using microsatellite-generated genotypes. No significant differences were detected using Kruskal–Wallis tests that compared the genetic diversity metrics of wild and captive-propagated WRL (from 12 mothers) and KS (from seven mothers). After effective population size (Ne) was estimated, considerable overlap was found in the estimated Ne between wild and captive populations of both species. Pairwise FST and Dest values among wild WRL, hatchery-raised WRL juveniles, and across different time periods (2008–2018) were generally low (FST = 0.007–0.043, Dest = 0.005–0.282). Pairwise FST and Dest for KS were not significant and low (0.012, 0.017). When comparing captive-reared offspring with the wild population, STRUCTURE analysis revealed strong support for a single genetic population. With at least seven females contributing to brood stock, genetic diversity was maintained. Further research is needed to assess the male contribution to each glochidial brood as well as the variability of genetic diversity in individual glochidial broods.