Fraser River sockeye salmon: data synthesis and cumulative impacts

PrefaceFraser River sockeye salmon are vitally important for Canadians. Aboriginal and non-Aboriginalcommunities depend on sockeye for their food, social, and ceremonial purposes; recreationalpursuits; and livelihood needs. They are key components of freshwater and marine aquaticecosystems. Events over the past century have shown that the Fraser sockeye resource is fragileand vulnerable to human impacts such as rock slides, industrial activities, climatic change,fisheries policies and fishing. Fraser sockeye are also subject to natural environmental variationsand population cycles that strongly influence survival and production.In 2009, the decline of sockeye salmon stocks in the Fraser River in British Columbia led to theclosure of the fishery for the third consecutive year, despite favourable pre-season estimates ofthe number of sockeye salmon expected to return to the river. The 2009 return marked a steadydecline that could be traced back two decades. In November 2009, the Governor General inCouncil appointed Justice Bruce Cohen as a Commissioner under Part I of the Inquiries Act toinvestigate this decline of sockeye salmon in the Fraser River. Although the two-decade declinein Fraser sockeye stocks has been steady and profound, in 2010 Fraser sockeye experienced anextraordinary rebound, demonstrating their capacity to produce at historic levels. The extremeyear-to-year variability in Fraser sockeye returns bears directly on the scientific work of theCommission.The scientific research work of the inquiry will inform the Commissioner of the role of relevantfisheries and ecosystem factors in the Fraser sockeye decline. Twelve scientific projects wereundertaken, including:Project1 Diseases and parasites2 Effects of contaminants on Fraser River sockeye salmon3 Fraser River freshwater ecology and status of sockeye Conservation Units4 Marine ecology5 Impacts of salmon farms on Fraser River sockeye salmon6 Data synthesis and cumulative impact analysis7 Fraser River sockeye fisheries harvesting and fisheries management8 Effects of predators on Fraser River sockeye salmon9 Effects of climate change on Fraser River sockeye salmon10 Fraser River sockeye production dynamics11 Fraser River sockeye salmon – status of DFO science and management12 Sockeye habitat analysis in the Lower Fraser River and the Strait of GeorgiaExperts were engaged to undertake the projects and to analyse the contribution of their topic areato the decline in Fraser sockeye production. The researchers’ draft reports were peer-reviewedand were finalized in early 2011. Reviewer comments are appended to the present report, one ofthe reports in the Cohen Commission Technical Report Series.