The commercial salmon harvest in Alaska’s Bristol Bay, site of the world’s largest sockeye salmon runs, held a mixture of good news and bad news this year.
The sockeye run exceeded preseason expectations and totaled 56.7 million fish, the seventh highest since 2005, the Alaska Department of Fish and Game reported in its preliminary summary of the summer harvest.
The commercial harvest was also bigger than expected, totaling 41.2 million fish. That was 18% above the preseason forecast and 23% higher than the recent 20-year average.
The total amount of money paid to fishers delivering their catches totaled $215.3 million, about 7% above the 20-year average of $200.7 million, the department said in its summary.
The bad news is that while Bristol Bay sockeye salmon continued what has been a streak of huge runs — and while sockeye dominate the commercial harvest — other salmon species there continued to falter. Bristol Bay’s harvest of king salmon hit a 20-year low this year, totaling only 6,148 fish, compared to the most recent 20-year average of 33,469, the department reported.
King salmon runs have been weak across much of Alaska and the North Pacific, so the decline is not unique to Bristol Bay.
The opposite trends of Bristol Bay sockeye and kings have not been fully explained. One hypothesis is that climate change currently favors sockeye, which spawn in warming lakes where habitat may be expanding, over river-spawning kings.
Tim Sands, a Bristol Bay area management biologist with Fish and Game, believes that warming has something to do with the sockeye-king divergence.
He said warmer winters at the higher elevation lakes in Bristol Bay’s Wood River and Nushagak River systems have expanded the ice-free growing season for young salmon.
“These slightly longer growing seasons allow for slightly larger juveniles that are a tad bit more competitive when they enter the ocean and survive at a little higher rate,” he said by email.
Why that is true for sockeye but not kings is something he does not know, he said.
Another important trend was the average size of Bristol Bay salmon.
The harvested sockeye weighed in at an average of 5.1 pounds, above last year’s record-small average of 4.53 pounds and slightly above the 4.9-pound average of the past five years, according to the department.
Still, Bristol Bay sockeye are significantly smaller now than they were decades ago, when fish typically weighed in at 6 to 6.5 pounds.
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