‘More hungry mouths’: Bristol Bay sockeye are abundant but getting smaller

Salmon fry swimming through rocks. (Brian Venua, KDLG)

Bristol Bay is home to the largest sockeye run on the planet. But while the size of this year’s run broke records, the fish are getting smaller.

Last year’s average weight for sockeye was 5.1 pounds. But the 2021 average was just 4.5 pounds, according to the McKinley Research Group.

Jon Hickman, the executive vice president of operations for Peter Pan Seafoods, said the smaller fish play a role in how much time processors spend processing.

“Smaller fish are going to take longer to process,” he said. “So you’re handling a 4 pound fish or a 3 pound fish, as opposed to a 5 pound fish, so every time you handle one there’s a two pound difference. There’s more labor going into those smaller fish. You get more labor into them, there’s more costs associated with those smaller fish.”

Hickman said he isn’t worried about how the smaller fish will play in Peter Pan’s markets — demand is good, and he’s comfortable with the market for fish big and small.

But why are Bristol Bay’s salmon shrinking? First, the returning fish are younger than normal.

A salmon’s age is measured by how many years it spends in the ocean. A 2-ocean fish, for example, has spent two years in the ocean before returning to its spawning grounds.

Greg Buck, a biologist for the Alaska Department of Fish and Game, said most fish that returned this year only spent one or two years in the ocean instead of three.

“I’m gonna be gambling like it’s somebody else’s money when it comes to the age of 1-2s in the next year’s forecast,” he said. “I’ve been burned a couple of times. I’m normally kind of conservative when I forecast, but this year I might not be.”

But Dan Schindler, a researcher with the University of Washington’s Alaska salmon program, said fish are also smaller for their age.

“The size of fish has declined for their age,” he said. “So the size of 2-ocean fish has been declining slowly over time, and the size of 3-ocean fish has been slowly declining over time.”

The sheer number of fish can lead to more competition for food in the ocean. Large runs — like this year’s record — tend to have smaller fish.

There were record-high catches of salmon in the North Pacific in recent years, according to the North Pacific Anadromous Fish Commission. Last year was an anomaly in the trend toward larger populations, as catches dropped to the lowest levels in four decades.

Schindler thinks the recent abundance is due to an increase in hatchery pink and chum salmon.

“This declining size at a given age is really a function of more hungry mouths from lots of Bristol Bay fish, but also more hungry mouths that we’re dumping out into the ocean,” Schindler said.

Until recently, scientists and the fishing community didn’t pay much attention to the shrinking salmon trend. That’s because in the 1970s, more salmon started to spend an extra year in the ocean. And older fish usually come in bigger than their younger counterparts. But Schindler says in the last 10 years, more fish have returned after two years.

“So right now, we’re sort of seeing the effect of a double whammy on fish size,” says Schindler. “And the last four or five years — we’ve seen a lot of really small fish in the catches and the escapements,” he said. “That’s because there’s a lot of 2-ocean fish, and those 2-ocean fish are relatively small given the history of Bristol Bay.”

Warming oceans also may play a role. But Schindler said the connection is less direct. Warmer oceans have been correlated with increased survival for Bristol Bay salmon, which means more competition for food.

Correction: This article has been updated to reflect that while there were record harvest numbers for North Pacific salmon in 2018 and 2019, the 2020 catches were the lowest in four decades.

KDLG - Dillingham

KDLG is our partner station in Dillingham. KTOO collaborates with partners across the state to cover important news and to share stories with our audiences.

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