Mass extinction off the coast of Alaska: billions of snow crabs are said to have starved to death. Reason: Researchers suspect climate change.
Juneau – The effects of climate change do not stop at the animal kingdom. Heavy rain, floods and particularly extreme temperatures endanger the populations of various species. Researchers suspect that the loss of around ten billion snow crabs off the coast of Alaska is also due to heat.
Mass extinction: Researchers observe drastic decline in snow crabs
Almost five years ago, the population of snow crabs (Chionoecetes opilio) was still at its peak. In 2018, some of them were the size of a dinner plate and weighed up to a kilogram. Today things are different, as the population size has shrunk significantly since then. Already in 2021 they were Inventory is lowest ever since records began in 1975. A team of US researchers shared this development in the specialist journal Science.
The loss of around ten billion snow crabs in the eastern Bering Sea off Alaska amounts to a full 90 percent. “That’s nearly four times the amount of crabs caught combined between 1977 and 2022,” writes Gordon Kruse of the University of Alaska Fairbanks in an accompanying commentary.
The research team led by Cody Szuwalski from the Alaska Fishery Science Center found that certain factors probably do not have a major influence on the mass extinction of snow crabs. These include fishing, the spread of predators such as Pacific cod, cannibalism and disease.
High water temperatures: starved crabs due to increased energy requirements
The animals starved to death more often because of their increased energy requirements. Reason: the water temperatures. “Several observations confirm the theory that temperature and high population density were the main drivers of the collapse,” the team writes. Temperatures that had risen by a few degrees would have massively increased energy requirements. The crabs had to eat more – but there was no food supply.
“We assume that hunger played a major role in the population collapse,” says Szuwalski from the online platform NewScientist quoted. The crabs’ need for calories quadrupled from 2017 to 2018.
“Temperatures have already had an impact on the crabs: Snow crabs are an Arctic species whose distribution has been shifting north for decades as the Bering Sea is getting warmer,” Kruse wrote in his commentary.
Fish stocks: Climate change is now a greater threat than overfishing
It was a long time Overfishing is the biggest threat to fish stocks around the world, according to the research team. That’s why the authorities have banned crab fishing in Alaska since 2022 – with an impact on an entire industry because the animals are caught for consumption.
But research shows: “Climate change is the next existential crisis for fish stocks. The snow crabs are a prime example of how quickly forecasts for a given population can change.” (dpa/HK)
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