Fisheries scientists plan for a changing Bering Sea

The North Pacific Fishery Management Council heard a draft plan for addressing climate change in the eastern Bering Sea earlier this month.

The plan was put together by scientists at the Seattle-based Alaska Fisheries Science Center, which is part of the National Marine Fisheries Service. Mike Sigler, program leader for the habitat and ecological processes research program at the science center, said the plan pulls together work that scientists there are already doing, and research they'd like to undertake.

"We have a clear understanding of species like walleye pollock, northern rock sole, red king crab, what will happen to them, and we can make quantitative forecasts of where they're going. They're not completely certain, but we have some good ideas of ecological processes," Sigler said. "But then, we don't have such good understanding for other species, like yellowfin sole, and we're making a qualitative assessment of their vulnerability to climate."

Eventually, the group wants to provide fisheries managers, like the North Pacific council, with a better look at what might be coming in 10 years -- or even further down the road. One of the first parts of the plan is just putting together that qualitative assessment for more than a dozen species, which he expects to happen this year.

"Once we do that, we also do some modeling of the current harvest policies that are applied to see how well they work if climate is affecting fish abundance and marine mammal abundance," Sigler said.

Together, Sigler said the two groups can use better projections of stocks in the future to come up with better management strategies.

"We can also simulate different management strategies, and then how would you change those management strategies in the future," he said. "We view that as a two-way street. The council can talk about what kind of strategies would they consider. We can think up our own."


As an example, Sigler said the plan helps address situations like the one managers faced with pollock in the past. Several years ago, abundance declined, and quotas went down 30 to 40 percent. When the Bering Sea got colder again, abundance rebounded. Sigler said that sort of thing is likely to happen again, and even more often in the future, and the plan could help the council figure out whether or not it should manage the fishery differently as a result.

One area that will likely receive attention is the harvest control rules that help the council determine how much of a given stock can be caught each year.

"A weak link is that we currently assume that we know what the optimum population size is, the biomass that the harvest rules aim for, but it's likely climate will affect those," he said. "In some cases it might not have any affect, like northern rock sole, but in others we think that walleye pollock will go down. We have to figure out rules that accommodate that change. It's actually a big part of our policy for managing Alaska fisheries, that target biomass."

Sigler said that accounting for that sort of uncertainty could mean more conservative management, but those sorts of decisions will likely be left to scientists, with his group just working to provide them with information.

The report also identifies several research projects that should be continued, including one looking at how coastal communities will fare as the Bering Sea changes.