The Extirpation of Orconectes limosus (Spinycheek Crayfish) Populations in West Virginia

Introductions of nonnative crayfish species have resulted in the global decline of native crayfish populations, including those in North America. Historically, the North American range of Orconectes limosus (Spinycheek Crayfish) extended from Maine, southward into northern Virginia, including West Virginia's eastern panhandle. A 1988-1989 survey of the eastern panhandle of West Virginia resulted in the capture of only 14 O. limosus, but an abundance of the nonnative Orconectes virilis (Virile Crayfish). These data along with additional unpublished accounts of declines of O. limosus populations prompted our survey of eastern West Virginia. In 2005 and 2006, crayfishes were collected from streams within the West Virginia range of the O. limosus, including historic capture locations. Our collection of 600 individuals comprised crayfishes from 3 species: O. virilis, Orconectes obscurus (Allegheny Crayfish), and Cambarus bartonii bartonii (Common Crayfish). The nonnative O. virilis was present at 26 of the 30 sites, whereas O. limosus was absent from all collections. Our results may indicate extirpation of some or all populations of O. limosus in eastern West Virginia, but absence data may also reflect a low detection probability of individuals from small populations. Competition between the nonnative O. virilis and O. limosus have been reported elsewhere, and likely explains the extirpation of populations of O. limosus in West Virginia.