Scientists like to say that climate change is creating winners and losers in Alaska: Some species will struggle, while others could benefit from warmer habitats.
One of those climate change winners could be pink salmon in the Arctic, according to a new paper published by U.S. and Canadian scientists in a journal called Deep Sea Research Part II.
The study provides new evidence that global warming could produce higher numbers of pink salmon in the region, by making previously too-cold rivers and streams more hospitable for spawning.
The findings bolster reports by Alaska subsistence fishermen that the species’ numbers have been increasing as the Arctic warms at more than double the rate of the rest of the globe.
“Maybe in the past, they’d see a few adult pink salmon here and there every few years. Now they’re seeing them every year,” said Ed Farley, a federal fisheries scientists who works at the Auke Bay Laboratories in Juneau. “And so, the question becomes: Is this a signal for what might be happening for pink salmon in terms of their production for the future?”
Some Arctic residents are already changing their fishing techniques to target what they say are the increasing numbers of pink salmon arriving on their shores.
On Alaska’s North Slope, in the village of Kaktovik on the Beaufort Sea, Sheldon Brower said he normally fishes for Dolly Varden, a type of char; the mesh in his net is too small to catch salmon.
Next year, he said, he’ll use a net with larger mesh, in hopes of snagging more pinks. Brower said he doesn’t normally eat much salmon, but he’s eager to catch some.
“I’ve had some salmon strips and smoked salmon — I want to start trying to make that,” he said. “So, I want to try to catch as much as I can.”
Farley’s paper examined temperature observations in the hub town of Nome, on the Bering Sea.
And the scientists found that when it’s warmer, young pinks do better — which in turn makes it more likely for a larger number of adult fish to spawn the following summer.
Nome is more than 500 miles southwest of Kaktovik, near the Bering Strait, where pink salmon are actually spawning. That’s not happening yet where Brower is catching them — those salmon are just “straying” up there periodically, Farley said. But, he added, that could change.
“It’s likely in the future we could see successful spawning — when that happens, you’re going to see more pink salmon in the High Arctic,” Farley said.
While Farley’s paper documents one particular species faring better in the Bering Sea as global warming continues, other populations have suffered.
Farther south, in the Gulf of Alaska, the marine heat wave known as “The Blob” hurt salmon and cod stocks. Farley said he thinks that farther north, there’s more room for ocean temperatures to warm before fish are harmed.
“The Bering Sea was a little cooler than the Gulf of Alaska, and with this warming, we seem to be moving into a sweet spot for salmon,” he said. “Whereas when we got really warm in the Gulf, we exceeded that sweet spot.”
Even in the Bering Sea, other species of salmon are not faring as well — namely, chinooks, Farley said.
The number of adult chinooks in the Bering Sea has declined over the past couple of years; there’s no obvious scientific explanation, but one possibility is that warming has negatively impacted a smaller fish called capelin that are an important prey for the chinooks, Farley said.
Farley said scientists are continuing to study warming in the Bering Sea, and their next focus is looking at how changes in the abundance of prey could lead to more salmon growth.
While Brower, the Kaktovik fisherman, said he’s looking forward to catching more pink salmon, he also said he doesn’t see the warming happening in the region as entirely positive. Residents of the coastal village are seeing foggier and rainier summers that are making hunting more difficult and pushing caribou farther away, he said.
“We used to see the big Porcupine herd going by right along the coast, but we rarely see that now,” he said. “We have to go a lot farther to hunt caribou — we’ll have to go inland.”