A new study published in the journal Nature Climate Change completed by a team of scientists found that the retreat of glaciers in Alaska and British Columbia caused by global warming may open more than 3,800 miles of potential new Pacific salmon habitat by the year 2100.
The research team, led by scientist at Simon Fraser University in British Columbia, modeled the retreat of 46,000 glaciers from southcentral Alaska to southern British Columbia to look at how much potential salmon habitat would be created under different climate change scenarios. They found 315 glaciers that they believe will produce potential salmon habitat if they retreat. Most are located along the central Gulf of Alaska and would generate an additional 27 percent of salmon-accessible habitat.
“As glaciers melt, they expose new terrain including streams, which can be utilized by spawning Pacific salmon. Glacier retreat will create the most new salmon habitat in coastal, low-gradient streams (< 10% incline) with retreating glaciers at their headwaters,” said a release from the University of Alaska Southeast.
Most people believe salmon only return home to the streams they were born in, but newly exposed streams can be colonized relatively rapidly by opportunistic Pacific salmon.
“It’s a common misconception that all salmon return home to the streams they were born in,” lead author Kara Pitman says. “Most do, but some individuals will stray—migrating into new streams to spawn and, if conditions are favorable, the population can increase rapidly.”
For example, Stonefly Creek in Glacier Bay, Alaska where glacier retreat in the late 1970s revealed salmon spawning habitat in the new stream that was colonized within 10 years by pink salmon that grew rapidly to more than 5,000 spawners.
The findings are positive for Pacific salmon, the authors caution that salmon still face a host of climate-related challenges.
“The creation of habitat associated with glacier loss will benefit salmon, particularly in Alaska, however changes to stream temperatures and streamflow regimes as well as warming ocean conditions still pose grave threats to future salmon populations” said co-author Eran Hood, a professor at the University of Alaska Southeast. “Ultimately, understanding both the opportunities and challenges associated with glacier loss will benefit future efforts to manage and conserve salmon populations.”
Michael Paschall is the publisher of the Seward Journal and covers general news topics. He can be reached at news@sewardjournal.com.
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