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Spatial Distribution of Native and Nonnative Salmonids in Streams of the Eastern Slopes of the Canadian Rocky Mountains
Author(s) -
Paul Andrew J.,
Post John R.
Publication year - 2001
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(2001)130<0417:sdonan>2.0.co;2
Subject(s) - trout , stocking , salvelinus , rainbow trout , fontinalis , fishery , oncorhynchus , habitat , ecology , biology , streams , geography , fish <actinopterygii> , computer network , computer science
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, we tested the hypothesis that their distribution was simply an artifact of past stocking. Based on the historical stocking record for the surveyed region, brook and rainbow trout would be more prevalent in higher elevations if stocking location only dictated their presence. This expectation directly contradicts our observed results, suggesting there has been a preferential downstream movement of brook and rainbow trout to colonize streams at lower elevations. In contrast, the distribution of cutthroat trout predicted from the stocking record and observed from the stream surveys did not differ, suggesting their current distribution may reflect past stocking.