PICES Advisory Report on the decline of Fraser River sockeye salmon Oncorhynchus nerka (Steller, 1743) in relation to marine ecology

Abstract

In the spring of 2010, the Government of Canada invited PICES to participate in a Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River by considering how marine ecology may have affected their abundance. A major objective that was achieved in this report was to assemble, within an eight week period, as comprehensive a summary as was possible of what is known about Fraser River sockeye salmon (Oncorhynchus nerka) in the ocean. While much of this effort involved summarizing information published in data/technical reports and the primary literature, where necessary, original data have been re-examined and new analyses conducted to fulfill the terms of the Statement of Work. The compilation provides a background of knowledge against which to judge what can be known regarding the two major questions posed by the Cohen Commission to PICES:-Can the decline in Fraser River sockeye in 2009 be explained by the conditions the fish experienced in the marine environment?-Is there any evidence for declines in marine productivity or changes in Fraser River sockeye distribution that can be associated with the 15-year gradual decrease in Fraser River sockeye productivity?