Winter 2022-23’s Warm Water May Have Reduced Blue Crab Overwintering Mortality

Submitted by Kim on 04/06/2023

The Chesapeake Bay experienced a sharp decline in water temperature in late December, when record-low air temperatures swept into the area. However, record-high air temperatures in January and February led to above-average water temperatures for the season.


Warmer water temperatures over the winter can help blue crabs survive through to the following spring. But the sudden cold snap in late December–early January may have caused a significant mortality event. We will learn more about the effects of this cold snap when results of the Winter Dredge Survey are released in the coming weeks. 


Map of the Chesapeake Bay with shading over the water areas indicating that water temperatures were slightly above average for the time period December 2022 through February 2023.

Overall, Chesapeake Bay water temperatures were about 1 degree warmer than average from December 2022 through February 2023.


Winter 2022-23 was also characterized by above-average salinity, especially in the lower Chesapeake Bay. Bay anchovy prefer winter waters with higher salinity, so this may have supported this species. Bay anchovy are important because they are an important forage species for Bay predators including striped bass. 


For more information on winter 2022-23 conditions and how they may have affected living resources in the Chesapeake Bay, see the full winter 2022-23 scientific seasonal summary.