Warming climate may be detrimental to some salmon populations, but it’s creating opportunities elsewhere. A 2021 study forecasted that retreating glaciers in Alaska and western Canada could open thousands of miles of streams by the end of the century and create new habitat suitable for salmon spawning. Thousands of miles of new freshwater streams could mean millions of juvenile salmon, depending on the species.
There’s precedent for salmon colonizing new streams following glacial retreat. In one area of Glacier Bay, a stream that was created by retreating ice provided habitat for more than 5,000 spawning pink salmon within 15 years of its appearance. The study’s authors acknowledge that other climate-induced changes over the next century, like drought, heatwaves, and ocean acidification could suppress the abundance of new salmon. But they argue that modeling the possibilities allows for informed decision making.