December 8, 2025 — A new study addresses one of the largest mass mortality events in recent marine history—the abrupt collapse of the snow crab population in the eastern Bering Sea. The research team was led by NOAA Alaska Fisheries Science Center fishery biologist Erin Fedewa. They set out to identify potential factors driving the increased mortality, population collapse, and recovery potential of Bering Sea snow crab.
Erin and her team measured snow crab energy reserves during and after the 2018–2019 marine heatwave and population collapse. This approach is the first of its kind for Bering Sea crab stocks. Findings show that warmer conditions and high population density led to energetic limitations—likely causing the snow crab population collapse.
A New, Rapid Energetic Condition Metric for Fisheries Management
Poor energetic condition is a state in which crabs have low energy reserves. This can increase starvation and mortality risk, emphasizing the importance of monitoring the energetic condition of individuals in marine populations. Techniques used to monitor energy reserves in fish often rely on data collected rapidly during annual scientific surveys, such as the weight-at-size of individual fish.
However, snow crabs have exoskeletons; they molt as juveniles, which uses a lot of their energy stores. They require more sensitive techniques to detect energy reserves beyond simple length-weight measurements. These techniques are often time-intensive and costly. Scientists have not routinely monitored energetic condition in Bering Sea crab populations to date.