Pacific Salmon Climate Vulnerability

Our scientists assess the vulnerability of Pacific salmon to changing climate and ocean conditions to prepare the many diverse people and businesses that depend on them.

Changing climate and ocean conditions affect Pacific salmon and the people, businesses, and communities that depend on them. We expect these impacts to increase with continued changes in Earth’s climate.

We conducted two vulnerability assessments to help reduce impacts and increase salmon resilience to climate change:

● Threatened and endangered Pacific salmon and steelhead on the U.S. West Coast

● Other managed fish stocks

Map of West Coast showing number and risk level of 33 population groups of Pacific salmon. Chinook has 5 population groups at very high risk and 5 groups at high risk. Coho has 1 group at very high risk and 4 groups at high risk. Steelhead has 6 groups at high risk and 5 groups at moderate risk. Very high risk groups are depicted by red markers, high risk by orange, and moderate and low risk groups by yellow and green, respectively.

We found seven population groups of salmon and steelhead that were highly vulnerable to climate change (shown in red in the figure above), including our rarest life history types. The most significant threats were:

Ocean acidification
Rising sea surface temperatures
Rising stream temperatures and low summer flows
Flooding or snowmelt loss (depending on the population and life stage)

Life history types with longer residence periods in freshwater or estuaries were the most sensitive to climate, especially if they were already highly stressed from historical anthropogenic factors.

Reference

Crozier, L. G., M. M. McClure, T. Beechie, S. J. Bograd, D. A. Boughton, M. Carr, T. D. Cooney, J. B. Dunham, C. M. Greene, M. A. Haltuch, E. L. Hazen, D. M. Holzer, D. D. Huff, R. C. Johnson, C. E. Jordan, I. C. Kaplan, S. T. Lindley, N. J. Mantua, P. B. Moyle, J. M. Myers, M. W. Nelson, B. C. Spence, L. A. Weitkamp, T. H. Williams, and E. Willis-Norton. 2019. Climate vulnerability assessment for Pacific salmon and steelhead in the California Current Large Marine Ecosystem. Plos One 14(7):e0217711. https://doi.org/10.1371/journal.pone.0217711.

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