Climatic influences on salmon populations in the Northeast Pacific


Francis, R.C., Mantua, N.J. 2003. Climatic influences on salmon populations in the Northeast Pacific. pp. 37-67. In A.D. MacCall and T.C. Wainwright (eds.). Assessing Extinction Risk for West Coast Salmon. U.S. Department of Commerce, NOAA Technical Memo, NMFS-NWFSC-56, 198 pp.


A number of recent studies have verified the fact that many stocks of Pacific salmon are threatened with extinction. For example, the Wilderness Society (1993) estimates that naturally reproducing Pacific salmon are mostly extinct or imperiled in 56% of their historic range in the Pacific Northwest and California. This undesirable state of affairs has developed in response to both natural variability and a legacy of human activities that are related to land use, harvest and hatchery practices (National Research Council [NRC] 1996). In this document, we examine the role that climate variability plays in driving salmon population changes. Ultimately, we develop a paradigm for the role of climate variations in the concern over future salmon extinctions.