Arctic habitats are changing at previously unheard-of rates due to rapid climate change. These changes to the physical environment could allow species to spread into new areas, which would significantly impact ecosystems and communities that depend on subsistence farming. Rising incidental Pacific salmon harvests by subsistence fishermen have been seen during the past 20 years in an expanding area across several land claim jurisdictions in Arctic Canada.
The Arctic Ocean and its watersheds have never been known to host significant populations of salmon, but in recent years, accidental catches made by subsistence fishermen have periodically increased. In collaboration with communities in the western Canadian Arctic, researchers from Fisheries and Oceans Canada and the University of Alaska Fairbanks linked those salmon booms to a series of warm, ice-free days in the Arctic Ocean north of Alaska.
Their research has linked rising Pacific salmon numbers in the Canadian Arctic to warmer ocean temperatures. It suggests climate change opens up new pathways for the fish to spread throughout their range.
The study found that the existence of salmon in the Canadian Arctic was associated with a two-part mechanism. Salmon were drawn into the Arctic by warm late-spring weather in the Chukchi Sea, northwest of Alaska. Salmon may reach Canada if the midsummer Beaufort Sea, northeast of Alaska, continues to have those warm conditions.
Researchers found a link p between salmon abundance and the ocean conditions that supported their migration into the Arctic by comparing catch rates of salmon with satellite data from the National Oceanic and Atmospheric Administration recorded since 2000.
Curry Cunningham, an associate professor at UAF’s College of Fisheries and Ocean Sciences, said, “You need both gates to be open, which is fascinating. Salmon don’t turn that corner if they don’t align in terms of having open, ice-free water.”
As part of the Arctic Salmon Program, Fisheries and Oceans Canada and indigenous communities in the Canadian Arctic have been documenting incidental salmon catches. For over twenty years, subsistence harvesters targeting other Arctic species, such as Arctic char and Dolly Varden, have reported salmon captured outside their normal range.
The most common salmon species to be captured are chum, sockeye, and pink salmon. Most of those catches align with other studies that demonstrate chum and sockeye salmon’s greater ability to withstand colder temperatures than other salmon species, facilitating their easier passage into Arctic waters.
Karen Dunmall, a Fisheries and Oceans Canada research scientist, said such range expansion concerns many people in the region.
“It helps to address some questions from community members about biodiversity change and subsistence and how they feed their families,” said Dunmall, the study’s co-lead author. “Some years there were salmon, some years there were no salmon. No one wanted the salmon, but they wanted to know what was going on.”
Although the study focused on western Canada, those changing conditions are causing range expansion throughout the region.
Journal Reference:
- Dunmall, K. M., Langan, J. A., Cunningham, C. J., Reist, J. D., & Melling, H. (2024). Pacific salmon in the Canadian Arctic highlights a range-expansion pathway for sub-Arctic fishes. Global Change Biology, 30(6), e17353. DOI: 10.1111/gcb.17353