Scientists reveal why billions of Alaskan crabs died in 'mass starvation event'
Scientists have linked warmer sea temperatures to the mass starvation of billions of crabs, in a warning that climate change is the "next existential crisis" for fishing communities globally.
More than ten billion snow crabs have disappeared from the eastern Bering Sea in Alaska since 2018, as the population collapsed to historic lows in 2021.
The Alaskan harvesting season of the crab was cancelled for the second year in a row earlier this month due to the low population levels, potentially having a "staggering blow" to rural communities in the area.
In research published on Thursday, scientists at the National Oceanic and Atmospheric Administration said climate change caused by humans had created marine heatwaves in the Bering Sea during 2018 and 2019.
The increase in water temperature in turn "considerably" increased how many calories the crabs needed to survive, leading to the "unexpected mass starvation event".
The 2021 survey found the fewest snow crabs on the sea shelf since the survey began in 1975.
The researchers added the starvation has left the short-future of snow crab in the area "precariously uncertain" and it will have an impact on fishing communities.
"In 2020 and 2021, 59 boats fished for snow crab, which brought $227 million into fishing communities," the study said.
"The disappearance of snow crab will be a staggering blow to the functioning of some communities in rural Alaska, such as those on Saint Paul Island, which rely strongly on the revenue derived from the capture and processing of snow crab.
"Climate change is the next existential crisis for fisheries, and snow crab are a prime example for how quickly the outlook can change for a population.
"In 2018, catches were projected to increase to levels not seen in decades. Three years later, the population had collapsed."
Scientists considered possibilities the crabs had moved to other parts of the sea, but population surveys in other areas did not support that explanation.
They concluded the "unprecedented" caloric demands, combined with a smaller area to forage for food, caused the mass starvation.
Researchers noted the similarity to the marine heatwave–related collapse of Pacific cod in the Gulf of Alaska in 2016.
The report ended with a warning to the rest of the world about climate change and said: "The Bering Sea is on the frontlines of climate-driven ecosystem change, and the problems currently faced in the Bering Sea foreshadow the problems that will need to be confronted globally."
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