(CN) — Thanks to warming ocean temperatures, Pacific salmon can now swim in the Canadian Arctic, an area where large numbers of salmon did not historically venture.
In a study published Wednesday in Global Change Biology, researchers at Fisheries and Oceans Canada, the University of Fairbanks and western Canadian Arctic communities connected the surges of salmon sightings with a two-part sequence of warm, ice-free conditions in the Arctic Ocean and its watersheds north of Alaska.
The first part of the sequence involves warm, late-spring conditions in the Chukchi Sea, northwest of Alaska, that draw salmon into the Arctic. When those warm conditions then continue in summertime in the Beaufort Sea, northeast of Alaska, the salmon travel to Canada, researchers say.
Curry Cunningham warned via email that increasing numbers of salmon in the Arctic will have an environmental impact.
“Often when species appear in a new habitat in increasing abundance, there are impacts on either that species’ prey or its competitors for prey,” said Cunningham, an associate professor at the university's college of fisheries and ocean sciences. “As salmon expand their presence in an increasing range of Arctic marine and freshwater environments, there is concern over how the ecosystem, other species and the broader trophic structure may be impacted. Time will tell what the realized impacts will be.”
Local indigenous communities are also concerned about increased salmon sightings.
Typically, subsistence harvesters find chum and sockeye salmon more frequently than other salmon species. Per the researchers, this is largely consistent with previous research that chum and sockeye can transition more easily into Arctic waters due to their higher tolerance for cold temperatures compared to other salmon species.
However, the indigenous communities spent 20 years tracking incidental salmon catches with Fisheries and Oceans Canada as part of the Arctic Salmon program. With that data, the indigenous communities said there is a rising trend of unknown salmon wandering into their waters.
One incident involved Frankie Dillon, an Indigenous fisherman who helps conduct fish surveys for Fisheries and Oceans Canada. He recalled in a statement his first salmon sighting around 2010 on the Big Fish River in northern Yukon while tagging Dolly Varden trout, a fish species more common in the area.
“I had to ask, ‘What kind of fish was that?’,” Dillon said. “It’s the first time I’d seen it in my life. I’d only seen them on TV before.”
Since 2010, subsistence harvesters sighted salmon more frequently and without enthusiasm, according to Karen Dunmall via email.
“A key point here is that Pacific salmon are not necessarily wanted by the Indigenous communities in the Canadian Arctic,” said Dunmall, a research scientist at Fisheries and Oceans Canada. “While salmon are preferred and wanted throughout their usual distribution, range expansion of salmon to the Arctic is not seen as a positive outcome of climate warming from the perspective of those who prefer char and other Arctic fishes.”
Furthermore, Dunmall said that while salmon can make it to the Canadian Arctic, the team needs to conduct more research to determine any success from their travels.
“We know salmon can access the Canadian Arctic because people are catching them. However, the appearance of adult salmon does not mean they are spawning successfully,” said Dunmall via email.
“We need to look more closely at this establishment phase and better understand if it is possible for salmon to establish populations in new areas, and if so where. We also need to better understand and characterize interactions among salmon and culturally important Arctic fishes,” she added.
Follow @kndrleon
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