Published Sep 5, 2023 by Joshua A. Bickel Scientists say two years of low sea ice cover and abnormally warm ocean temperatures due to climate change in 2018 and 2019 may have altered the ecosystem in a way that snow crab couldn't survive, said Mike Litzow, lab director at the Kodiak Fisheries Science Center. Their annual survey, which was skipped in 2020 due to COVID, found total crab populations in the Bering Sea plummeted from an all-time high of 11.7 billion in 2018 to 940 million in 2021, the lowest ever recorded.
Researchers this year brought samples of crab back to Kodiak for further analysis, exploring how snow crab respond to stress in their environment, including rising heat.
Snow crab are typically found in a cold pool—water in the Bering Sea that stays below 35.6 degrees Fahrenheit (2 degrees Celsius) throughout the year. Researchers have found these crab can survive in water warmer than this, leading them to speculate that rising ocean temperatures alone aren't to blame for the collapse. Instead, researchers think the warmer water may have allowed more predators into the habitat, facilitated disease spread or made it harder for the crabs to catch enough prey to fuel an increased metabolism.
"They're an Arctic animal," Litzow said. "Longer term, what we expect is that the fish will be moving farther north as those Arctic characteristics recede in the Bering Sea."
|