Assessing the impacts of stream habitat and land use variables on population and community structure of salmonids of Prince Edward Island

To determine the impact of land use practices and run-off events on salmonid communities, I examined salmonid populations (Atlantic salmon, Salmo salar, brook trout, Salvelinus fontinalis, and rainbow trout, Oncorhynchus mykiss) at twenty-seven sites on nine rivers located across Prince Edward Island throughout the summers of 2001 and 2002. Multiple regression models were developed using various stream and watershed characteristics to predict biotic variables (density, percent habitat saturation, and condition factors) and stable isotope values. Five rivers were sampled in 2002 to use in a cross-validation study to test the models. Six models were developed (brook trout density, variability in total density, total percent habitat saturation, variability in total percent habitat saturation, 1 + brook trout condition factor, and δ15N values). Although all models explained a significant proportion of the variability in the nine original rivers (r2 values ranging from 0.374 to 0.985), only that describing δ 15N values proved valid when tested in the cross-validation study.

Two pesticide runoff events resulting in the death of thousands of salmonids occurred 9 July and 19 July 2002 on the Wilmot River, one of the nine original rivers. Five additional sampling sites were added after the second pesticide runoff event to better determine the extent and effects of the pesticide runoff. (Abstract shortened by UMI.).