Alaska’s Snow Crabs Vanish Due to Warmer Oceans

Billions of snow crabs have disappeared from Alaskan waters, leaving scientists to attribute this loss to the impact of rising ocean temperatures. This revelation follows the cancellation of Alaska’s snow crab harvest season for the second consecutive year. Researchers from the National Oceanic and Atmospheric Administration (NOAA) have unveiled a significant connection between marine heatwaves in the eastern Bering Sea and the dramatic decline in snow crab populations.

The Study’s Startling Findings

In 2021, survey data revealed a shocking reduction in snow crab numbers. While there was initial hope that this could be an anomaly, the subsequent year confirmed the ongoing trend, leading to the first-ever closure of the US snow crab fishery in Alaska. The population’s decline had initially been attributed to overfishing, but experts now recognize the multifaceted role of climate change in the issue.

Climate Change: A New Challenge

Fishery scientists have historically focused on overfishing as a primary concern, climate change is now creating substantial disruptions. Climate-driven events are challenging existing models and management systems. This shift necessitates an urgent reassessment of the impact of climate change on marine life.

Understanding the Crab Disappearance

Scientists considered two main scenarios for the crab population drop in 2020: either the crabs migrated or they experienced a significant increase in mortality. After examining various factors, including migration patterns, they concluded that increased mortality was the more likely explanation.

The Culprit: Starvation

Snow crabs thrive in cold waters below 2 degrees Celsius but can tolerate temperatures up to 12 degrees Celsius. However, warmer ocean temperatures disrupted their metabolism, causing a surge in their caloric requirements. During the two-year marine heatwave of 2018 and 2019, crabs likely needed up to four times more energy from food than in previous years. Unfortunately, the heatwave also disrupted the Bering Sea’s food web, making it challenging for snow crabs to find sufficient nourishment. Starvation is believed to be the primary cause of the crab population decline.

Other Species Take Advantage

In addition to starvation, other factors exacerbated the crab’s plight. During the heatwave, species like Pacific cod, which typically couldn’t access the crabs’ extremely cold habitat, ventured into the warmer waters to prey on the weakened crab population. This phenomenon further intensified the crab population’s decline.

Climate Change Impact on the Arctic

The Arctic, including Alaska’s Bering Sea, is warming four times faster than the rest of the planet. This warming has led to the rapid loss of sea ice, contributing to global warming. The Bering Sea experienced an unprecedented reduction in ice coverage in 2018 and 2019, with only about 4% of historical ice coverage. The ongoing changes in the Arctic due to climate change emphasize the urgency of addressing climate-related challenges.

Month: Current Affairs - October, 2023