June 29, 2022 — 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.