RANGE EXTENSION OF THE NORTHERN CRAYFISH, ORCONECTES VIRILIS (DECAPODA, CAMBARIDAE), IN THE WESTERN PRAIRIE PROVINCES OF CANADA

The northern crayfish, Orconectes virilis (Hagen, 1870), is the northernmost-ranging crayfish species in North America. However, little is known of the distribution of O. virilis in the western Prairie Provinces of Canada, which comprise the northwestern portion of the species' contiguous range. We combined extensive sampling data with confirmed reports of crayfish to describe a recent westward range expansion and the current distribution of O. virilis in Saskatchewan and Alberta. The reports suggest that the vast majority of colonization of the western Prairie Provinces may have resulted from natural movement, although anthropogenic introduction may be, in part, responsible for the described expansion of O. virilis. The description of potential movement patterns and current range has implications for the continued monitoring and management of the species across the region.