Glacier Retreat and Pacific Salmon

Kara J Pitman; Jonathan W Moore; Matthew R Sloat; Anne H Beaudreau; Allison L Bidlack; Richard E Brenner; Eran W Hood; George R Pess; Nathan J Mantua; Alexander M Milner; Valentina Radić; Gordon H Reeves; Daniel E Schindler; Diane C Whited

doi:10.1093/biosci/biaa015

Glacier Retreat and Pacific Salmon

Bioscience. 2020 Mar 1;70(3):220-236. doi: 10.1093/biosci/biaa015. Epub 2020 Mar 11.

Authors

Affiliations

¹ Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
² Earth2Oceans Research Group, Simon Fraser University, Burnaby, Canada.
³ Wild Salmon Center, Portland, Oregon.
⁴ College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska.
⁵ Alaska Coastal Rainforest Center, University of Alaska Southeast, Juneau, Alaska.
⁶ Alaska Department of Fish and Game, Juneau, Alaska.
⁷ Environmental Science Program, University of Alaska Southeast, Juneau, Alaska.
⁸ National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington.
⁹ Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Santa Cruz, California.
¹⁰ School of Geography, Earth, and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.
¹¹ Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska.
¹² US Department of Agriculture's Forest Service, Corvallis, Oregon.
¹³ School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington.
¹⁴ Flathead Lake Biological Station, University of Montana, Polson, Montana.

Abstract

Glaciers have shaped past and present habitats for Pacific salmon (Oncorhynchus spp.) in North America. During the last glacial maximum, approximately 45% of the current North American range of Pacific salmon was covered in ice. Currently, most salmon habitat occurs in watersheds in which glacier ice is present and retreating. This synthesis examines the multiple ways that glacier retreat can influence aquatic ecosystems through the lens of Pacific salmon life cycles. We predict that the coming decades will result in areas in which salmon populations will be challenged by diminished water flows and elevated water temperatures, areas in which salmon productivity will be enhanced as downstream habitat suitability increases, and areas in which new river and lake habitat will be formed that can be colonized by anadromous salmon. Effective conservation and management of salmon habitat and populations should consider the impacts of glacier retreat and other sources of ecosystem change.

Keywords: Oncorhynchus; Pacific salmon; climate change; glaciers; watershed.