Cambarus callainus

Analyses by Fetzner and Thoma (2011) as well as R. F. Thoma and Z. J. Loughman represent the first time specimens from both the Big Sandy and Guyandotte River systems were examined together in a single analysis, resulting in the formal description of the Big Sandy population as a species separate from Cambarus veteranus (Thoma et al. 2014).

Cambarus callainus appears to have been lost from over 70% of its historic range in the past half century (Thoma 2009, 2010; Loughman 2013) (Thoma et al. 2014). Although the species still occupies sites located throughout the breadth of its historical range, the remaining sites are significantly reduced to only the higher elevations within the watersheds; the remaining habitat and populations are threatened by a variety of factors acting in combination to reduce the overall viability of the species. The risk of extinction is high because the remaining populations are small and isolated, and because there is limited potential for recolonization (USFWS 2015).

Cambarus callainus is endemic to the Levisa Fork, Tug Fork, and Russell Fork watersheds in the upper Big Sandy River basin of Kentucky, Virginia, and West Virginia. Kentucky populations occur in Floyd, Johnson, and Pike counties, with animals collected from the mainstem of both Levisa and Russell Forks, Knox Creek, Shelby Creek, Blackberry Creek, and the Tug Fork mainstem. Virginia counties harboring C. callainus include Buchanan, Dickenson, and Wise, with populations occurring in Russell Fork and its tributaries. In Virginia’s Levisa Fork basin, only Dismal Creek harbors the species. In West Virginia, populations have only been recorded from McDowell County in the Tug Fork mainstem and Dry Fork, a major tributary to the latter (Thoma et al. 2014).