Melting glaciers will challenge some salmon populations and benefit others

A diverse team of 14 scientists (including researchers from the Moore Lab) with backgrounds ranging from salmon biology to climate change; glaciers to river systems, integrated these fields of study to synthesize the different pathways of effects that glacier retreat has on Pacific salmon and their habitats.

The researchers predict that some salmon populations in western North America may benefit, while others may struggle from the effects of glacier retreat over the coming decades.

The study shows that 85 percent of major salmon watersheds or regions in western North America currently have at least some glacier coverage. But glaciers in this region are expected to lose up to 80 percent of their ice volume by 2100, with significant implications for salmon habitat such as availability, water flows, and water temperatures.

The study predicted that in some inland arid watersheds in the southern portion of Pacific salmon’s range, the loss of cold glacier meltwater during summer months could lead to warmer waters and low river flows that challenge both adult and young salmon.

In regions where the landscape is still dominated by large glaciers, such as in south-central Alaska, glaciers are retreating from low-lying valleys, creating new rivers and lakes that can be colonized by salmon.

The relative benefits and challenges posed by the different phases of glacier retreat will also vary depending on the watershed context, the salmon species and life stage (adult or juvenile).

This study showcases the need for forward-looking perspectives on salmon conservation and management in an era of rapid global change. There is an urgent need to protect and manage for the future of salmon and their ecosystems, not just the present.

Pitman, Kara J, Moore, Jonathan W., Sloat, Matthew R., Beaudreau, Anne H., Bidlack, Allison L.,  Brenner, Richard E., Hood, Eran W., Pess, George R., Mantua, Nathan J., Milner, Alexander M., Radic, Valentina, Reeves, Gordon H., Schindler, Daniel E., and Whited, Dianne C. 2020. Glacial retreat and Pacific salmon. BioScience.  70(3): 220–236. (PDF).

Media: Vancouver Sun; CFAX 1070 Radio.

© 2015 by Salmon Watersheds Lab