Distribution and Taxonomy of Fishes in the Mackenzie Drainage of British Columbia

Abstract

New and previously published records are listed for 28 species of freshwater fishes in tributaries of the Mackenzie River in northern British Columbia. Distribution patterns are discussed for all species reaching the continental divide at the Peace River headwaters; some are restricted to one or other side, but 17 species are common to the Peace and Fraser Rivers, suggesting that mountain ranges have served as a check but not an insurmountable obstacle to postglacial expansion. Five species indigenous to the Pacific slope—Catostomus macrocheilus, Richardsonius balteatus, Ptychocheilus oregonense, Mylocheilus caurinum, and Cottus asper—have evidently penetrated to the Peace River in comparatively recent times. Three species—the flathead chub Platygobio gracilis, the trout-perch Percopsis omiscomaycus, and the spoon-head sculpin Cottus ricei—have not previously been recorded from the province. Evidence is presented that subspecific distinctions are invalid in Couesius plumbeus (Agassiz) and Lota lota (Linnaeus). Coregonus coulieri and Hybognathus hankinsoni are reported for the first time from the Mackenzie drainage.