Study: Melting glaciers temporarily open new salmon habitat

University of Montana researcher part of scientist team

By: - December 31, 2021 8:34 am

While newly created habitat may be a ray of light for salmon in some locations, climate change continues to pose grave challenges for salmon and other fish. (Provided by the University of Montana.)

Scientists have found a silver lining for salmon in the retreat of glaciers in Alaska and British Columbia — although it might be short-lived.

A new study with a University of Montana Flathead Lake Biological Station researcher found shrinking glaciers in the Pacific mountains could produce more than 6,000 kilometers of new salmon habitat by the year 2100, according to a news release from the University of Montana.

“Most of the time, when you hear glaciers retreating from climate change, it’s all gloom and doom,” said Diane Whited, the biological station scientist and an author of the study. “In this instance, for Pacific salmon, for a window of time, it’s going to offer up potentially new habitat.”

The news release from UM noted the new habitat represents a stretch nearly as long as the Mississippi. UM noted the work was led by Simon Fraser University and recently published in Nature Communications, a science and research journal.

Climate change alters stream ecosystems, and in an interview, Whited said the information from the study is crucial for managing salmon habitat. Past studies showed that within 10 years of glacier retreat in Alaska’s Glacier Bay, salmon had colonized a portion of the new exposed streams, she said.

At the same time, she said areas in the Pacific Northwest that are good for salmon can also be big for mining, so the retreat of glaciers also will open up more available grounds for mineral exploration. She said proactive legislation for future salmon habitat might be in order.

“So there’s that dynamic, and (conservation) managers should be aware of this conflict,” she said.

The news release from UM said the scientists used computer models to peel back the ice of 46,000 glaciers between southern British Columbia and south-central Alaska. They looked at how much potential salmon habitat might be created when bedrock is exposed and new streams flow.

“According to the team, desirable stream habitat for salmon is connected to the ocean, maintains low-gradient slope of 10 percent or less and has retreating glaciers at its headwaters,” UM said. “By the end of the study, the researchers found 315 of glaciers examined could fit those requirements.”

The study didn’t include Montana, and Whited said glacier melt in this state is different for a couple of reasons.

“This (study) was mostly focused on Pacific salmon,” she said. “Since our glaciers are pretty darn small here and where those are receding is in pretty steep terrain, I don’t think it would open up more fish habitat.”

In the news release, however, the researchers also said climate change generally poses “grave challenges” for salmon populations. If warning trends continue, any new habitats would eventually overheat and disappear, the way current salmon habitats are going, UM said.

“On one hand, this amount of new salmon habitat will provide local opportunities for some salmon populations,” said Simon Fraser University spatial analyst Kara Pitman, the lead author on the study, in a statement from UM. “On the other hand, climate change and other human impacts continue to threaten salmon survival via warming rivers, changes in stream flows and poor ocean conditions.”

The complete study is titled “Glacier retreat creating new Pacific salmon habitat in western North American” and is available online.

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Keila Szpaller
Keila Szpaller

Keila Szpaller is deputy editor of the Daily Montanan and covers education. Before joining States Newsroom Montana, she served as city editor of the Missoulian, the largest news outlet in western Montana.