Stream channelization is a common form of anthropogenic disturbance, whose impacts on cold water salmonid communities have received little attention in comparison to the body of work demonstrating its negative effects on low land, warm water systems. Here, I compared the effects of stream channelization on fish and invertebrate communities and their habitats in disturbed and undisturbed cold-water mountain streams in southern Alberta. I demonstrate that stream channelization has imposed significant alterations to stream habitat, most notably a loss of deep habitat, and that these alterations have led to a statistically significant decline in abundance and biomass of Rainbow Trout and Mountain Whitefish, as well as a significant decline aquatic invertebrate biomass. Because of the importance of monitoring fish abundance in deep pools, I used snorkel surveys instead of electrofishing. In shallow, disturbed streams, however, snorkel surveys may be less effective and should be used with caution. / ix, 104 leaves : col. ill., col. maps ; 29 cm