A study of potential new habitat for Pacific salmon in western North America following glacial retreat to 2100 has benefits for salmon, but also warns of the need for forward-looking management decision and conservation planning.
The study, recently published in the journal Natureprojects that by the year 2100, retreating glaciers will create 6,146 kilometers (3,818 miles) of new waterways accessible to colonization by Pacific salmon, of which 1,930 km (1,200 miles) have potential for spawning and rearing of juveniles in 18 sub-regions.
“With climate change, the distribution of salmon habitat in the future will likely be different from the current distribution of salmon, due to changes in temperature and precipitation that affect stream flow,” said Daniel Schindler, who studies the causes and consequences of ecosystem dynamics at the School of Aquatic and Fisheries Sciences at the University of Washington in Seattle.
“We show that the loss of glaciers opens up opportunities for salmon in the future,” said Schindler, who participated in the study. “This is especially important for Southeast Alaska. Western Alaska doesn’t have as many glaciers to disappear and create new habitat.
In Southeast Alaska, the headwaters of many of these rivers are still under ice and this habitat is rapidly disappearing due to climate change.
“What we’ve done is predict what these watersheds will look like in the future under a warmer climate,” Schindler said. “As watersheds open up, these streams will be colonized by fish, insects, algae. We see that fish like salmon will become established within a decade of opening, mainly in coastal areas, but it shows that the ice is currently preventing fish from entering these streams.
About two-thirds of man’s effects on the Earth’s climate system relate to heat stored in ocean water and that heat is released to the atmosphere, Schindler said, adding that salmon encounter this change. climate in the ocean and in fresh water. because the heat of the ocean has an effect on the atmosphere, which affects precipitation.
The study warns that predicting the location of emerging salmon habitat is imperative because while such climate change may present opportunities for salmon, it also creates opportunities for resource extraction industries to scale such as mining, which have the potential to degrade these emerging salmon habitats.
The research, funded by the Gordon and Becky Moore Foundation, has identified 315 retreating glaciers upstream of current streams that will create streams accessible to salmon assuming a 10% gradient threshold for salmon migration upstream, plus 603 glaciers assuming a 15% stream. gradient threshold.
Gains in salmon habitat, even over a kilometer of stream, can produce 500 to 1,500 juvenile coho salmon, the researchers note. So, with hundreds to thousands of miles of new habitat created from retreating glaciers, it’s possible to produce hundreds of thousands to millions of additional juvenile salmon, depending on the species, the study found.