March 09, 2022
By Mark Hume
The Inuit village of Sachs Harbor lies at the southern tip of Banks Island in the central Canadian Arctic, about 500 miles east of the Alaska-Yukon border. It is way out there in the middle of nowhere and about as far from salmon country as you can get.
A couple of decade ago, subsistence fishers who set nets for Arctic char at river mouths around Sachs Harbor pulled in some interesting fish. There, thrashing in the nets with the brilliantly colored char they’d come to expect, were eight beautiful silver and green fish of a kind they’d never seen before. The fish were later identified as sockeye and pink Pacific salmon—and they were sexually mature.
The Pacific salmon shouldn’t have been there—searching for spawning grounds around the usually frozen coast of Banks Island—but they were and that catch, as it turns out, is far from an isolated event in the rapidly changing Arctic.
All across the far north there have recently been similar incidental catches, enough to suggest that Pacific salmon are starting to colonize the high Arctic. All five species of salmon have been found in the Arctic, moving in from the west along the north coast of Alaska, while Atlantic salmon are straying in from the east, around the northern tip of Quebec.
Fisheries scientists who have been tracking the phenomenon say it is unclear yet whether there is a growing trend driven by global warming, or whether there are just more reports because people are looking harder. They do note, however, that if Arctic waters warm just a few degrees, vast new habitats will open up to both Pacific and Atlantic salmon.
Scientists studying marine mollusks recently noted that a coldwater wedge in the Bering Sea that has acted as a barrier to many species has begun to erode. That shift is literally opening the door to an “interoceanic invasion” by many species. Geerat Vermeiji, of the University of California, and Peter Roopnarine, at the California Academy of Sciences, forecast that a massive marine migration, similar to one that happened during the warm Pliocene epoch, 3.5 million years ago, could take place as early as 2050.
And if mollusks can make the move, so can salmon. With polar ice melting rapidly, and northern watersheds warming steadily, it’s possible that in the near future fly fishers will dream about salmon trips to rivers like the mighty Mackenzie, a brawling, silt-stained river in the western Arctic, or the Innuksuak, a char river that flows into Hudson Bay in the Nunavik region of Quebec.
In recent years Pacific salmon have been caught throughout the Mackenzie system, and in such numbers that breeding populations almost certainly exist, though the spawning beds haven’t been found yet. Smaller numbers of straying salmon have also been taken at the mouth of the Coppermine River on Canada’s Arctic north coast.
On the Innuksuak, native fishermen took 160 Atlantic salmon over a five-year period, suggesting the fish have established a pattern of running to that river, well west of what was thought to be the extreme range of Atlantics.
Researchers say that if Pacific and Atlantic salmon are beginning to colonize the Arctic, this only makes sense, because salmon naturally extend their range by wandering. They are now clearly roaming far north of their previous outer ranges of Kotzebue Sound, in Alaska, and Ungava Bay, in northern Quebec.
All five species of Pacific salmon have successfully spawned in rivers on Alaska’s north coast. It’s possible those rivers have been a jumping-off point for fish that are colonizing the Mackenzie system, which flows from Great Slave Lake and through Canada’s Northwest Territories to the Beaufort Sea, near Inuvik. DNA testing to address that theory is now underway.
Thousands of chum salmon have been caught at different times in subsistence fisheries at Akalvik, Fort MacPherson, and Fort Good Hope—three communities that lie along the Mackenzie. Many of those fish have been laden with eggs or milt. Smaller numbers of other species, including Chinook, coho, and sockeye, have been caught throughout the Mackenzie system, hundreds of miles from the ocean.
Although salmon numbers in the Mackenzie are small, they’ve been found far enough upstream, including in Great Bear and Great Slave lakes, to raise hopes that the second longest river in North America (after the Mississippi) might one day become a salmon producer. With rainbow trout also found straying into the Mackenzie system, Arctic steelhead fishing might one day be possible, as well.
Falling in Line with Climate Change
In a 2006 paper on climate change published by the Royal Swedish Academy of Sciences, a group of seven researchers, led by James Reist of Fisheries and Oceans Canada (DFO), noted that for fish to extend their range, “. . . habitat suitability, food supply, [and] predators and pathogens must be within the limits of the niche boundaries of the species.”
In other words, many things have to fall into line—or fall out of line—before salmon can colonize the Arctic. The paper concludes that climatic changes are making the North more favorable to the survival of many kinds of salmon and trout.
“Several species present in southern areas, such as native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) and introduced brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) are very likely to extend their ranges northward,” the scientists predict.
In a paper published by The Arctic Institute of North America, Alaskan researchers Peter Craig and Lewis Haldorson reported that by 1985 pink and chum salmon had already established themselves in a few north coast rivers.
“We suspect that they spawn successfully and maintain small but viable populations in at least some Arctic drainages,” they wrote.
Erin Hiebert-Linn, a graduate student at Royal Roads University in British Columbia, is studying Pacific salmon in Canada’s western Arctic. She says water temperatures are rising, but remain low enough to still present an environmental hurdle for salmon. Interestingly, the species with higher tolerances for cold water are showing up most frequently in the Mackenzie drainage.
“Chum salmon and pink salmon have the widest thermal ranges as to what they’ll accept for temperatures. So if there’s going to be anything [establishing viable runs] it will definitely be chum . . . and pink salmon would be the next most likely species,” she said in an interview.
If water temperatures rise two more degrees in the next five years, as expected, it would bring the Mackenzie within the tolerance range of sockeye, coho, and Chinook.
Future of Salmon in the Far North
Jim Irvine, a researcher with Canada’s DFO, says it is natural for salmon to wander, and it’s likely that a few always strayed into the Arctic. He’s not convinced there is a major species migration underway, but says it is fair to speculate salmon would colonize the Arctic if conditions were right.
“With retreating ice, it means you are getting more sunlight into Arctic waters, and presumably that will result in an increase in primary and secondary productivity and a warming of the waters. So it may make conditions more suitable for salmon rearing,” he said.
“Let’s not forget that ten thousand years ago Vancouver was covered by two thousand feet of ice,” he continued. “So basically all the salmon in British Columbia and the Yukon and Alaska have distributed themselves and developed over the last two thousand years. So it’s not difficult to think they are continuing that redistribution. And with climate change one would expect this would happen.”
Not everyone thinks fisheries managers should be waiting around to let nature take its course. As early as 1973, P. O. Salonius, a research officer with the Canadian Forestry Service in New Brunswick, noted the great potential of Arctic rivers in a paper titled “Barriers to Range Extension of Atlantic and Pacific Salmon in Arctic North America.”
The Ungava Peninsula appeared to have blocked Atlantic salmon from expanding into rivers in Hudson Bay that were ideally suited for them, he added, with clean water and extensive spawning gravel.
He also thought the western Arctic had huge potential, if Pacific salmon could make it around the northern tip of Alaska, and suggested Great Slave Lake, on the Mackenzie River, could be developed into a salmon factory to rival Bristol Bay.
“The area may have the capacity to support spawning runs numbering in the millions,” Salonius wrote.
Salonius suggested enhancement efforts to help establish salmon in the Arctic, but authorities were reluctant to introduce new species. Global warming, however, appears to have done just that.
It’s clear that massive change is coming to the Arctic, and while the melting ice pack will create perilous conditions for some species, it will create ideal habitat for others. For salmon, and for salmon anglers, it could well be that the future lies in the far north.
Mark Hume is a national correspondent for the Vancouver bureau of The Globe and Mail. He is author of River of the Angry Moon: Seasons on the Bella Coola (University of Washington Press, 2000).