Hydroelectricity and fish: a synopsis of comprehensive studies of upstream and downstream passage of anadromous wild Atlantic salmon, Salmo salar, on the Exploits River, Canada

Government (Fisheries and Oceans Canada) and industry (Abitibi Consolidated Company of Canada) have been working cooperatively to protect and enhance wild Atlantic salmon populations on the Exploits River, insular Newfoundland, Canada. Since the mid-1960s, enhancement programmes and construction of fish passage facilities at natural and man-made barriers in the watershed have expanded the range and increased the returning adult population from 1200 fish (circa 1960) to 22,000 fish, on average. Since 1997, attention has been paid to improving passage and survival of downstream migrating smolts and kelts at two hydroelectric facilities at Grand Falls-Windsor and Bishops Falls. At Grand Falls-Windsor a floating louver and bypass system was installed in a power canal and extensive biological, hydraulic, and modelling studies have been conducted to assess, modify, and optimize fish passage. At Bishops Falls, a retrofitted surface spill bypass system was installed in an existing spill gate and similar studies have been conducted to improve passage success. Studies have also been conducted on the upstream migrating adults at these facilities and associated fishways, using conventional and physiological telemetry, to assess tailrace attraction and residency, and the relative energy cost of upstream migration to bypass the hydro plants and fishways. This article reviews the results of these various studies to demonstrate how cooperative work has improved passage of anadromous salmon in coexistence with hydroelectric development.