ABSTRACT
Until recently, environmental assessments were conducted without regard to either upstream or downstream developments, such that the relative contributions of individual developments could not be separated. The environmental legislative agenda in Canada has been proceeding at a pace where there is an expectation to address the cumulative effects of existing developments prior to the development of methodology 150 for conducting these assessments. We initiated a long-term study in 1991 which is attempting to address the cumulative aquatic effects of hydroelectric facilities and pulp mill discharges on fish populations within the Moose River basin in Northern Ontario. The focus is placed on the top-down interpretation of the impact of alterations in habitat and fish energetics associated with damage at the fish population level and not on detailed initial characterization of stressors. This approach allows follow-up studies to focus on the critical areas associated with responses of surviving fish within the watersheds in an attempt to identify limiting environmental conditions and the responsible stressors. The objectives of the project are to provide an interpretation framework using traditional fisheries information to assess the integrated effects of all stressors on the populations at risk and to isolate key areas and critical stages in life history associated with those changes in fish populations.
