Higher Pacific Salmon Abundance in Canadian Arctic Linked to Warming Seas
A new study by researchers at Fisheries and Oceans Canada and the University of Alaska Fairbanks links higher Pacific salmon abundance in the Canadian Arctic to warming ocean temperatures.
The study, published June 5 in the journal Global Change Biology, found that a two-part mechanism was tied to the presence of salmon in the Canadian Arctic.
Warm late spring conditions in the Chukchi Sea, northwest of Alaska, drew salmon into the Arctic. When those conditions persisted in the summertime Beaufort Sea, northeast of Alaska, salmon could continue to Canada, researchers said.
Canadian and Alaskan scientists, working together with communities in the western Canadian Arctic, connected the salmon booms experienced by subsistence fishermen in recent years with a sequence of warm, ice-free conditions in the Arctic Ocean north of Alaska.
Researchers compared National Oceanic and Atmospheric Administration satellite data since 2000 to salmon catch rates and found a correlation between salmon abundance and ocean conditions that favored their movement into the Arctic.
“You need both gates to be open, which is fascinating in itself,” Curry Cunningham, an associate professor at UAF’s College of Fisheries and Ocean Sciences, said. “If they don’t align in terms of having open, ice-free water, salmon don’t turn that corner.”
Indigenous communities in the Canadian Arctic have been tracking incidental salmon catches with Fisheries and Oceans Canada as part of the Arctic Salmon Program. For more than 20 years, salmon caught outside their typical range have been recorded by subsistence harvesters who target other Arctic species, including Dolly Varden and Arctic char.
Chum and sockeye salmon have been the most frequently caught salmon species, followed by pink salmon. Those catches are largely consistent with previous research showing that chum and sockeye have more tolerance for cold temperatures than other salmon, allowing them to more easily transition into Arctic waters.
Karen Dunmall, a research scientist with Fisheries and Oceans Canada, said such range expansion is of concern to many people in the region.
“It really 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 really wanted the salmon, but they wanted to know what was going on.”
Salmon sightings have become more frequent in the years since then, and climate models predict that the conditions allowing salmon to migrate through the Chukchi and Beaufort seas will become common as early as the 2040s.
Although the study focused on western Canada, the changing conditions are surely causing range expansion throughout the region, researchers said.
“It’s not as if these fish are all skipping Alaska and heading to Canada,” said Joe Langan, who co-led the project as a UAF postdoctoral fellow. “Some of these salmon are ending up on Alaska’s North Slope too.”
