Spatial Distribution of Native and Nonnative Salmonids in Streams of the Eastern Slopes of the Canadian Rocky Mountains

Abstract

Abstract We surveyed 53 stream reaches from the eastern slopes of the Canadian Rocky Mountains and examined the distribution of native and nonnative salmonids as related to habitat variables measured at the reach scale (100 m). The most common fishes encountered in these surveys were cutthroat trout Oncorhynchus clarki, bull trout Salvelinus confluentus, brook trout S. fontinalis, and rainbow trout O. mykiss. Of these salmonids, only cutthroat and bull trout are native to Kananaskis Country; however, cutthroat trout have also been extensively stocked throughout the region. Reach elevation, which strongly influenced mean summer stream temperatures, was the only habitat variable that was significantly related to the presence of all four salmonids. Both cutthroat and bull trout were more likely to occur in the higher elevations, whereas brook and rainbow trout were more likely to occur in the lower elevations. Because the distribution of stocked fishes is not independent of their original stocking locations,...