Warmer ocean temperatures have likely caused the sudden and shocking disappearance of billions of snow crabs in Alaska, which had previously baffled scientists and environmentalists, a new study has shown.
The eastern Bering Sea snow crabs, once thought to be overfished, actually starved to death en masse because the change in water temperature “increased their caloric needs considerably”, scientists at the National Oceanic and Atmospheric Administration said in the study.
The years 2018 and 2019 saw record-breaking ocean temperatures, which at first led to a boom in the snow crab population before it quickly plummeted. Then 2022 saw a sharp decline of 10 billion crabs.
A marine heatwave, which happens when ocean temperatures are persistently and anomalously warm, causes stress to corals and other marine ecosystems, leaving sea life vulnerable and causing chaos across food chains. The phenomenon is a product of the climate crisis since “the ocean absorbs 90% of the excess heat associated with global warming”, the Noaa said.
Arctic temperatures have warmed four times faster than those of the rest of the planet, scientists said.
The lack of sea ice due to global warming contributed to the decline in the arctic species, which matures in cold pools on the ocean floor. Less ice combined with warmer waters made much of the snow crabs’ habitat inhospitable, making way for many to die off.
The snow crab stock shortage has economic consequences. The crabs play a vital role in the Alaskan commercial fishing industry valued at over $150m. With fewer snow crabs, revenue has been slashed and financial pressure has been placed on those who make a living out of it.
For the first time, the Alaska department of fish and game closed crucial Bering Sea snow crab harvests in 2022, leaving crab fishers out in the cold.
Noaa says the shortage of snow crabs “appears to be one of the largest reported losses of motile marine macrofauna to marine heatwaves globally”.