Melting glaciers could create more than 3,000 miles of new Pacific salmon habitat

Melting glaciers could create more than 3,000 miles of new Pacific salmon habitat

A few days after a 7-day float trip on the Chitina River in Wrangell-St. Elias and Jonathan Moore ran out of food when they encountered a creek near the riverbed. Usually, streams near glaciers are filled with sediment and appear to be devoid of life, but this one was clear and teeming with salmon. Moore took out his fishing rod, caught one, and cooked it for dinner.

According to Moore, the experience is “from the heart,” professor Department of Biological Sciences, Simon Fraser University, British Columbia. “These landscapes are changing so fast that salmon are taking advantage of it,” he told Glacier Hub.

Moore attributes the experience in 2005 to his research on Pacific salmon.but until Kara Pitmana postdoc at Simon Fraser University, linked her interest in glaciers and his interest in salmon, and they decided to study how these glacial valleys, once filled with ice and now increasingly flowing, would be affected by climate change. Warmer conditions change salmon habitats.

in their recent LearnA team of glaciologists, climate scientists and “salmon people” such as Moore, led by Pitman, found that, with moderate emissions, more than 3,700 miles of new Pacific salmon habitat — larger than the Mississippi River — could be created by 2100 longer. Moore explained that the study also highlights the need to manage not just current salmon conservation plans, but future salmon conservation plans, especially as glaciers peel back to reveal potential mining sites.

At first, these newly frozen streams were not suitable for salmon. They are usually too cold and very cloudy. But over time, the ecosystem began to stabilize: water temperatures increased to temperatures suitable for salmon, sediment loads decreased, vegetation grew around the riverbed, and insects settled to form food webs. In just a few decades, Moore explained, this process could allow salmon to enter new rivers.

The researchers expected some salmon to colonize faster than others. At first, salmon lay their eggs in freshwater, and when the eggs hatch, young salmon remain in freshwater year-round, depending on the species. In spring, they head to the ocean, where they will spend one to five years, before returning to their freshwater spawning beds. Of the five species of Pacific salmon that live in the North Pacific waters of the United States and Canada, populations of pink and sockeye salmon are expected to settle the fastest, as they do not require the same stable habitat as coho or chinook salmon. Moore added that salmon populations are expected to increase the most in the western regions with the largest glaciers, such as British Columbia and south-central Alaska.

Sockeye salmon is a species that is expected to grow rapidly because of their ability to quickly colonize and migrate to the ocean as juveniles. CEDIT: Oregon State University/ Wikimedia Commons

At first glance, the study appears to highlight a silver lining of climate change—more habitat for Pacific salmon. But the story is much more complicated, Matthew Sloter Tell GlacierHub. Sloat is the scientific director of the Wild Salmon Center, a nonprofit conservation organization in Portland, Ore., and a co-author of the study. Salmon are no strangers to dynamic and changing habitats.Due to climate change, the species faces new and unfamiliar risks, such as marine heatwaves, ocean acidification, sea level rise and drought. Rapid glacier retreat could also trigger natural disasters such as landslides and glacier eruptions, adding to uncertainty about how fast salmon populations will grow, he explained.

Slaughter said the study highlights what’s going on beneath receding glaciers to inform proactive management of future salmon habitats. Predicting that salmon may end up in warmer climates could inform environmental risk assessments and prevent approvals for harmful human development projects such as mining, he noted.

As the glaciers retreated, new territories were exposed, providing opportunities for local mining companies to tap into minerals such as gold.Currently, there are mineral rights in southeastern Alaska and Mines approved in areas where glaciers have recently retreated At the source of the transboundary Unuk River.

While mining can provide economic benefits to local communities, Sloat warns of its potential negative impact on salmon populations. When mining minerals, mining companies often use harmful chemicals, such as cyanide, that can contaminate local and downstream water sources. This can adversely affect water quality and salmon habitat. “If we want to be able to use salmon for fisheries in the future, we need to weigh in on other forms of development,” he added.

The Tulsequah drainage system on the Taku River is an example of a new glacial river and salmon habitat. Courtesy of Jonathan Moore, Simon Fraser University

In the future, policymakers will have to choose what they value more: gold or “red gold,” with reference to salmon, Sue Mogg Tell GlacierHub. Mauger is the scientific and executive director of Cook Inletkeeper, a community-based nonprofit that protects the Cook Inlet watershed in Alaska, but was not involved in the study. In the communities around Cook Inlet, salmon is part of everyday life and an important source of food security for Aboriginal and subsistence communities, Mauger said. To maintain this food source, decisions must look at salmon habitats as a holistic system, she noted.

“Salmon are inspiring because they use so much of our landscape and ocean,” Mog said. “The idea that we have emerging habitats is really exciting. However, I’m afraid we’re going to forget the importance of connectivity.” As new rivers open up, infrastructure in lower watersheds where most people live may prevent Salmon return upstream to spawn and spawn.

While retreating glaciers offer salmon some new possibilities, climate change and choices about how their habitats are managed remain the greatest source of uncertainty affecting their future well-being. “If we only look at individual projects without considering the full context of the project, we will not be successful. [climate impacts] It could happen,” Mauger concluded, reiterating the value and safety salmon brings to local communities in the Northwest Territories.