Crustacean Decimation Due To Climate-Change-Driven Cannibalization

Last week, the Alaska Department of Fish and Game canceled the winter snow crab season in the Bering Sea due to their falling numbers. "Officials suggested that a combination of climate change and some kind of crustacean health crisis might be to blame," reports TIME Magazine. "But that's only part of the story, says Wes Jones, the Fisheries, Research, and Development Director for the Norton Sound Economic Development Corporation." The most immediate cause of their death: "a mass cannibalism frenzy." An anonymous reader shares an excerpt from the report: To understand what really happened in the icy depths of Alaska's Bering Sea this year means going back to 2017, when fishermen started reporting an unprecedented population explosion of juvenile snow crabs -- what is called, in crabber speak, a "recruit." The population boom continued into 2018 and 2019, creating what Jones says was the largest recruitment event on record. Jones is something of a local piscine historian. He can quote fishery statistics going back 30 years in the same way a Red Sox fan might quote batting averages. At the time the young crabs were too small for a legal harvest -- juvenile snow crabs take four to five years to mature -- but there were enough of them for seasoned crabbers to start the count-down to huge hauls starting in 2022. In the meantime, Bering Sea temperatures, which usually hover around freezing, were on the rise, spiking several degrees between 2017-2019. Unlike mammals, who use less energy when temperatures rise, cold-water fish and crustaceans speed up their metabolism. The faster the crabs grow and expend energy, the faster they have to replace it, says Jones. Some of the crabs may have headed north into cooler Russian waters, but most seem to have stayed put. "All of a sudden you had this huge number of little crabs coming up, eating themselves out of house and home," says Jones. "Then the water warmed, which meant they had to eat more." It was a double whammy, he says, and the results were inevitable for a hungry, omnivorous species that has run out of its usual food source: "They basically cannibalized each other."

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