ABSTRACT
North America is second to no other land mass in its freshwater crayfish fauna. It includes two families, Astacidae and Cambaridae, 12 genera, Pacifastacus (Astacidae) and Barbicambarus, Bouchardina, Cambarus, Cambarellus, Distocambarus, Fallicambarus, Faxonella, Hobbseus, Orconectes, Procambarus, and Troglocambarus (Cambaridae), and well over 300 species (Hobbs 1988). The bulk of
the species belong to the family Cambaridae and are naturally distributed east of the great western mountains that divide the continent. However, one Orconectes species has naturally crossed that barrier and two other aggressive, large species, Orconectes virilis and Procambarus clarkii, have been successfully introduced (Bouchard 1978; Hobbs et al. 1989). The genus Pacifastacus is the only representative of the family Astacidae in North America. Native to the west coast from British Columbia well into California, at least one representative of the genus, P. leniusculus, is a large, aggressive species that has been widely introduced within the region but has yet to be moved eastward within the continent.
