A glimpse of the future: Coho salmon response to Alaska’s recent snow-free winters

Abstract

The Earth’s climate is warming most rapidly in the high latitudes of the polar and subpolar regions. Winter temperatures, in particular, are increasing.This trend is being observed in Alaska’s Copper River Delta, where scientists Steve Wondzell, Gordon Reeves, and Luca Adelfio conducted a multiyear study on the effects of changing stream temperatures on the incubation duration and emergence times of coho salmon.During their 5-year study, winter conditions shifted from cold and snowy to cool and rainy. Modeling results showed that this would dramatically change the incubation time of coho salmon eggs in streams primarily fed by precipitation. During the warm winters of 2014, 2015, and 2016, simulated incubation time shortened in these streams by as much as 3 months whereas incubation time barely changed in streams fed by groundwater. The winter warming experienced from 2014–2016 was equivalent to the climate projected to be the norm for the area by 2040.Significant shifts in the timing of life history events for coho salmon could create ripple effects throughout the delta ecosystems. In light of the habitat variability identified in this study, the USDA Forest Service Pacific Northwest Research Station, along with the Chugach National Forest and external partners, are investigating the genetic diversity of local coho salmon to help inform management strategy.

Citation

Kirkland, John; Wondzell, Steve; Reeves, Gordon; Adelfio, Luca. 2022. A glimpse of the future: Coho salmon response to Alaska’s recent snow-free winters. Science Findings 251. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6p.