Lessons from the Alaskan snow crab collapse

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Earlier this month, officials in Alaska canceled the Bering snow crab fishing season after a precipitous decline in its population. The closure could lead to half a billion dollars in economic losses, according to an Alaskan crab trade association.

The question many have raised in Alaska is how the Bering snow crab population crashed so quickly.

“We’re still trying to figure it out, but certainly there’s very clear signs of the role of climate change in the collapse,” Michael Litzow, shellfish assessment program manager at the National Oceanic and Atmospheric Administration, said, as reported by Bloomberg. NOAA runs an annual survey of Bering Sea snow crab numbers, but it was the Alaska Department of Fish and Game that canceled the Bering snow crab fishing season on Oct. 10.

State officials also canceled the Bristol Bay red king crab season for the second year. Unlike the rapid drop in snow crab number, this king crab population has been in decline for some time.

Although Alaska is on the other side of the country, there are lessons that Maine fisheries managers and others can take from this worrisome situation.

One is the importance of good data. In 2018, a survey showed a population of 8 billion Bering snow crabs, the highest number in decades. The population began dropping the next year. No survey was done in 2020 because of the COVID pandemic. Then, a survey done in 2021, found only 1 billion snow crabs.

Perhaps, with a 2020 survey, the decline may have been spotted earlier, and different management measures, such as limiting snow crab harvesting rather than a complete closure of the fishery, could have been taken.

The second, more important lesson, is that the impacts of climate change are widespread and occurring now.

It’s clear that the effects of climate change are global, and that there are winners and losers in terms of species that are thriving and those that are in decline, Rick Wahle, director of the Lobster Institute at the University of Maine, told the Bangor Daily News editorial board in an interview.

Snow crabs, for instance, are a cold water species and as ocean waters — especially deeper waters — warm, their habitat is shrinking. Scientists have reported that temperatures around the Arctic have warmed four times faster than the rest of the planet. In addition, warming temperatures have contributed to a rapid loss in sea ice in the Arctic region, particularly in Alaska’s Bering Sea.

Lobsters live in shallower, warmer waters, but warming oceans and changing ocean circulation patterns are also impacting their habitat. In a warming climate, the lobster population is being pushed further north and deeper into the ocean, Wahle said. For example, there has been a decline in the lobster population in Long Island Sound and Massachusetts and growth in the population off the coast of Down East Maine and eastern Canada.

Wahle called this “a cresting wave,” with the northern extreme of the lobster population moving farther north as its southern extreme also moves north. Adapting to these changes will be critical for fishermen and associated industries.

Modeling and tracking such population shifts — work that the University of Maine is involved with — can allow fisheries regulators to develop and put in place targeted measures to conserve populations of lobsters, crabs and other marine species, both to maintain their populations for the health of the planet and to sustain the commercial fisheries and the jobs that they create.

There is hope, scientists say, that the Bering red crab population will rebuild in several years. But the lessons from the fishery far from Maine is that changes in our climate are impacting economically important industries today. Preparing for and adapting to those changes now can help improve the sustainability of those fisheries, and the communities that rely upon them.

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