CLIMATE CHANGE MEANS NEW SALMON HABITAT, NEW CHALLENGES
BY MARY CATHARINE MARTIN
A
laska is about to get thousands of miles of new salmon habitat – and how we manage that habitat will have long-term implications for the salmon that find it. By the year 2100, melting glaciers will open up new watersheds containing thousands of miles of salmon habitat across Alaska and the Pacific Northwest, according to an aptly titled scientific paper, “Glacier retreat creating new Pacific salmon habitat in western North America,” out recently in the journal Nature Communications. The study predicts that by 2100, glacial retreat will create more than 3,800 additional miles of streams accessible to Pacific salmon in western North America, plus or minus about 1,000 miles. Of those stream miles,
about 1,200 miles, plus or minus about 350 miles, could be used for salmon spawning and juvenile rearing. While those changes are far from a solution to the threats facing Alaska’s wild salmon populations, they do mean potential future “hot spots” of salmon production. “It’s really important to understand where the new habitat is going to be, so that we can plan for it,” said study co-author Eran Hood, professor of environmental science at the University of Alaska Southeast. “We not only have new streams, but we have new land that can be prospected for mineral development, or other uses, as well. … All these areas that are coming out, we have to think about what we want to use them for. Whether it’s recreation,
cultural and subsistence uses, or resource development uses.”
A CHANGING LANDSCAPE These changes, said co-author Jonathan Moore, a professor at Simon Fraser University in British Columbia, are “massive ecosystem transformations.” Throughout the study area of the Pacific Northwest mountain ranges, 46,000 glaciers currently cover a little more than 50,000 square miles, and 80 percent of those glaciers are within the range of salmon. Assuming salmon can migrate up a 10-percent stream gradient, there are 315 glaciers retreating at the headwaters of present-day streams that will create salmon-accessible streams; assuming salmon can migrate up a 15-percent stream gradient, that number
Trucks traverse an ice road over the Knipple Glacier to British Columbia’s Brucejack Mine in the Unuk watershed, which flows from B.C. into Southeast Alaska. By 2100, glaciers in western Canada are predicted to lose up to 80 percent of their ice mass in some places, which means managers have decisions to make about what that land will be used for. Much of that land could become new salmon habitat. (GARTH LENZ) aksportingjournal.com | MARCH 2022
ALASKA SPORTING JOURNAL
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