Anchorage, Alaska (AP) - U.S. scientists plan to survey the Bering Sea this summer and hope to shed light on why fish not normally seen in its northern stretches have been found there.
Cod are caught in large numbers by commercial boats in the Bering Sea but typically hundreds of miles south of Nome.
Yet, last fall, fisherman Adem Boeckmann, who lives outside Nome, said he found cod in some of his crab pots. He said he had never seen anything like that.
Lyle Britt, a federal fisheries scientist, said there aren't clear answers.
"Is this part of an environmental shift, where with the warming, the northern Bering Sea is going to become a top-down system?" he said. "Or, is this more like an ephemeral trend that just happened because we had an unusually warm year, and things will reset? We don't really know."
The surveys are being done by the Seattle-based Alaska Fisheries Science Center, which is an arm of the National Oceanic and Atmospheric Administration. They will include the northern part of the Bering Sea, full surveys of which have been done less frequently than those in the eastern Bering Sea, a region that also will be included in this summer's work.
The two most recent surveys of the northern Bering Sea occurred in 2010 and 2017, the latter of which was a warmer year with lower sea ice.
The year's surveys could shed light on whether 2017's results, which showed large amounts of pollock and cod in the northern Bering Sea compared to 2010, reflected an isolated event or the start of a long-term trend.
The eastern Bering Sea cod and pollock fisheries are worth an estimated $2 billion. Fishermen have seen a gradual shift northward in their cod fishing patterns, said Chad See, executive director of the Freezer Longline Coalition, an industry group.
Researchers and fishermen want to know more about where the northern Bering Sea cod came from. For example, did they swim from fishing grounds in the eastern Bering Sea or come from elsewhere, such as Russian waters to the west?
If they swam from the eastern Bering Sea, that would help explain why scientists didn't find more cod in the fishing grounds in their 2017 survey, See said.
"If it's the same stock, one might say that the health of the stock, at least from a biomass perspective, is still very strong," See said. "If the fish in the eastern Bering Sea just disappeared, we have a different problem entirely."
Boeckmann has considered spending $30,000 on new gear for commercial cod fishing but first wants reassurances that he could consistently make a profit.
He recalled speaking with a federal scientist who suggested that as quickly as the cod showed up off Nome, they could disappear.
"Things have changed, absolutely," Boeckmann said. "But there's nothing saying it's not going to flop right back to what it was for 100-plus years tomorrow."