December 14, 2023 — Thousands of salmon on the West Coast of North America are finding their way into new streams left behind as glaciers retreat. But a new study suggests mining companies are too keen on the newly exposed mineral deposits beneath the shrinking glaciers — and few policies are in place to protect the emerging habitats.
The paper led by researchers from Simon Fraser University, the University of Montana, Taku River Tlingit First Nation, and Gitanyow First Nation Hereditary Chiefs highlights a broad global challenge as many environmental policies struggle to keep pace with climate change.
Just a couple decades after some new streams were created, researchers have found thousands of fish, said Jonathan Moore, the lead researcher on the paper and a professor at Simon Fraser University. Salmon have evolved through dynamic landscapes with glaciers’ ebbs and flows and are specially equipped to find new habitats where they can flourish.
Most North American salmon watersheds or regions are being influenced by contemporary glacier retreat. These glaciers are rapidly declining in volume, thickness and area, accelerated by recent human-caused climate warming. About 60% to 100% of glaciers are predicted to disappear from western Canada by 2100.
As glaciers shrink, some of the streams they feed will become warmer, flows depleted and salmon will become stressed and in some situations die.
Although the loss of glaciers will decrease water storage nd cooling capacity that threatens people and aquatic ecosystems downstream, researchers have found that some glacial retreat will leave behind thousands of miles of new salmon rivers over the coming decades in western North America.
Overall, the net effects of glacier retreat on salmon will likely depend on the phase of glacier retreat, the traits of salmon species, and local environmental, geographic and ecological characteristics of watersheds.