University of Idaho study shows climate change is shrinking natural habitat for salmon

The study illustrates how climate change led to a shift in habitat for the popular fish.
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Robert F. Bukaty

River herring, also known as alewives, swim in a stream, Sunday, May 16, 2021, in Franklin, Maine. The fish were once headed for the endangered species list but have been making a comeback in some U.S. states.

MOSCOW, Idaho — A new study from the University of Idaho finds climate change is shrinking the natural habitat for salmon. The university’s study, published by the American Geophysical Union journal Geophysical Research Letters, confirmed that lower water volumes and warm temperatures are dramatically shrinking spawning beds and nurseries for the fish. 

U of I Eco hydraulics Professor Daniele Tonina and her colleagues examined Bear Valley Creek which is known for its population of Chinook salmon. According to a university press release, the stream’s wide valley, meandering main river and cozy side-streams made the site “representative of ideal salmon habitats in the Pacific Northwest.” 

The team mapped the river’s channels and floodplain, and used 60 years of historical stream-flow data, from 1957 to 2016, to calculate trends in the flow. The team then used the data to predict estimated changes to salmon habitat up to the year 2090.  

The study period illustrated that the stream flow volume dropped by 19%, and slowed by 17%. That means less overall area suitable for salmon nests and a loss of off-channel havens as side-streams get cut off from the main channel. The salmon lost 23% of their spawning habitat as well. 

Because of the cultural and economic importance of the fish, this could be a huge loss.  

The same press release states that Lisa Crozier, a research ecologist at NOAA’s Northwest Fisheries Science Center, said Chinook salmon serve as useful ‘“indicators of enormous ecosystem change,’” and “‘every single species will be affected by these changes.’” 

Tonina said she hopes the study will inform “restoration efforts.”