Billions of Snow Crabs Disappear Due to Warmer Ocean Temperatures, NOAA Study Finds
In recent years, billions of snow crabs have vanished from the waters around Alaska. Scientists now believe that warmer ocean temperatures are to blame, leading to starvation and mass mortality among the crabs. This discovery comes soon after the Alaska Department of Fish and Game announced the cancellation of the snow crab harvest season for the second consecutive year due to the alarming decrease in crab numbers.
The National Oceanic and Atmospheric Administration (NOAA) published a study on Thursday that reveals a significant link between marine heat waves in the eastern Bering Sea and the sudden disappearance of snow crabs first observed in 2021. Cody Szuwalski, lead author of the study and fishery biologist at NOAA, expressed astonishment upon receiving the 2021 survey data, stating, “My mind was just blown. Everyone hoped it was an error, but unfortunately, subsequent years confirmed the decline.”
Alaska experienced its first-ever closure of the snow crab fishery in 2022. While overfishing has been blamed for the population decline, experts emphasize that this explanation does not fully account for the collapse. Climate change, according to Szuwalski, poses a significant challenge to fishery management systems that historically focused on overfishing.
The NOAA study analyzed potential causes for the disappearance of snow crabs starting in 2020 and determined that the crabs did not migrate but most likely perished. Researchers linked warmer temperatures and increased population density to higher mortality rates among mature crabs. The study suggests that warmer waters disrupted the crabs’ metabolism and significantly increased their caloric requirements, exacerbating their struggle to find enough food and ultimately leading to starvation.
Szuwalski explained, “The crabs simply couldn’t keep up with their caloric demands. The heat wave severely disrupted the Bering Sea’s food web, leaving the crabs with limited foraging opportunities.” The study also reveals that other species, such as Pacific cod, took advantage of the weakened crab population, accessing their habitat due to the warmer waters and consuming the remaining crabs.
Szuwalski further commented that the Arctic has experienced four times the warming rate compared to the rest of the planet. The loss of sea ice, particularly in Alaska’s Bering Sea, has contributed to this accelerated warming. The disappearance of snow crabs serves as evidence of the rapid and devastating impacts of the climate crisis on livelihoods in the region.
Looking forward, Szuwalski anticipates the northward migration of snow crab populations as the ice recedes. However, he predicts that the eastern Bering Sea may no longer be a viable habitat for these cold-water species in the future.
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