Genetic status and broodstock maintenance of the endangered Pahranagat Roundtail Chub, Gila robusta jordani, of the lower Colorado River basin

Authors: Wade Wilson, Tracy Diver, Sandra Bohn

Year: 2016 (xlviii)

Abstract

The Pahranagat Roundtail Chub (Gila robusta jordani) is currently restricted to springs and associated outflows in the Pahranagat Valley (Lincoln County, NV), where its entire range consists of approximately 3.5 km (2.2 mi) of the Pahra nagat River and an additional 2.5 km (1.6 mi) of a cement-lined irrigation channel (Pahranagat Ditch). Assessments of census size are dated, but estimated to be on the order of several hundred individuals. The U.S. Fish and Wildlife Service established a refuge stock, which is maintained at the Southwestern Native Aquatic Resources and Recovery Center (Southwestern ARRC; Dexter, NM), as part of recovery actions outlined in the original recovery plan. In addition, a refuge population is managed at the Key Pi ttman Wildlife Management Area (WMA) in the Pahranagat Valley. To obtain a genetic diversity baseline to aid the genetic management of the species, this project genotyped 576 individuals from the refuge population at Southwestern ARRC and 70 wild individua ls at 18 microsatellite loci. Results (e.g., heterozygosity and allelic richness) and future genetic management plans will be discussed.