Utilizing conservation genetics as a strategy for recovering the endangered Candy Darter (Etheostoma osburni) in West Virginia

Abstract

Utilizing conservation genetics as a strategy for recovering the endangered Candy Darter (Etheostoma osburni) in West Virginia Brin Kessinger The Candy Darter (Etheostoma osburni) is a small freshwater fish native to the New River drainage in West Virginia and Virginia that was listed as endangered in November 2018. It has been extirpated from much of its historic range in West Virginia, restricting it to the Gauley and Greenbrier river drainages. In addition to extirpations, the species is threatened by introgressive hybridization with the invasive Variegate Darter (E. variatum). Previous research primarily focused on hybridization, but population genetic analyses were limited. Population genetic analyses aim to identify distinct populations through genetic structure and characterize the levels of genetic diversity amongst those populations. A series of reintroductions of wildcaught individuals from the Greenbrier River drainage was performed to create new populations that were not under threat of hybridization. Fish were stocked into Camp Creek and the Little Bluestone River in the Bluestone River drainage of southern West Virginia. Individuals from throughout the Greenbrier and Gauley River drainages along with the newly introduced individuals were genotyped with 12 microsatellite loci to assess their population structure and diversity. These results were used to make recommendations about conservation units and future reintroduction efforts. A watershed-level landscape assessment was performed on the Camp Creek and Little Bluestone River watersheds to compare the source habitat to the new habitat. There is strong evidence that the Greenbrier drainage population and the Gauley River drainage population are highly distinct and represent separate ESUs that should be treated as separate Recovery Units (RUs). The reintroduced population's genetic diversity captures the diversity of the source (Greenbrier drainage), but the landscapes of the new watersheds present some challenges to managers with higher levels of agriculture, resource extraction, and private land. The long-term persistence of E. osburni populations relies on continued monitoring and management of their genetics.