Chesapeake Bay Underwater Grasses Show Mixed Recovery: Gains Offset by Declines
Results Point to Need for Reaffirmation of Chesapeake Bay Agreement Goals
The checkered recovery of underwater grasses in the Chesapeake Bay persisted this year, with declines in some Maryland waters offsetting promising increases in the Bay’s Virginia portions, according to results released today of the annual 2024 Chesapeake Bay underwater grasses survey in Maryland and Virginia.
Overall, in 2024, the Bay’s underwater grasses decreased by 1 percent when compared to the previous year.
These underwater meadows have many benefits. They improve water quality and provide critical shelter and food for Bay species like the blue crab, migrating water birds, and juvenile fish. They also mitigate climate change through carbon uptake and sequestration, as well as diminish Bay acidification caused in part by greenhouse gas emissions. Sensitive to pollution but rapid responders to water quality improvements, underwater grasses serve as effective barometers of the Bay’s health.
The recent survey shows the federal-state Bay restoration partnership is off track in meeting targets for grasses, reaching only 64 percent of the Chesapeake Bay Watershed Agreement goal of 130,000 acres of underwater grasses by 2025.
In the moderately salty zone of the Bay, the largest of the zones, underwater grasses decreased by 14 percent, from 38,371 acres to 33,031 acres. The Eastern Shore of Maryland in the Choptank, Little Choptank Rivers, and the Tangier Sound saw the biggest losses.
In the salty portion of the Bay that extends near Virginia Beach up to Maryland-Virginia border, these underwater meadows increased to 24,800 acres in 2024, the highest coverage since annual mapping began in 1984. The largest gains, according to the survey, took place in Mobjack Bay, Poquoson Flats and nearby Western Shore areas. Eelgrass in particular surpassed all previous monitoring records.
Reducing pollution to the Bay is critical to increasing underwater grass coverage. This restoration work is guided by the Chesapeake Bay Watershed Agreement. The federal and state Bay restoration partners have committed to revising the Bay Agreement by the end of 2025. A draft update is open for public feedback through Sept. 1, and people are encouraged to urge leaders to adopt a stronger Bay Agreement.
The updated agreement must not only commit to vital goals for grasses and other habitats, but also affirm commitments to reaching the pollution reductions the federal government and states are legally required to meet under the Clean Water Act.
Chesapeake Bay Foundation (CBF) Virginia Senior Scientist Joe Wood said in a statement:
“Underwater grasses are essential not only to Bay critters like the blue crab, but also critical in our fight against climate change. They act as temperature refuges and reduce acidification caused in part by greenhouse gas emissions. Virginians should celebrate the eelgrass boom in the lower Bay, particularly in Mobjack Bay, that is creating new housing for crabs, fish, and shrimp. But the recovery is far from certain.
“Clean water and bountiful grasses are inextricably linked. Virginia and states around the region must commit to a stronger Chesapeake Bay Agreement to leave a healthy Bay for future generations. The Bay agreement goal is more than just a number—it’s a key outline for managing many species in the Bay and the industries that depend on healthy fisheries.”
CBF Maryland Coastal Resource Scientist Julie Luecke issued the following statement:
“Thriving underwater grasses mean a healthy Bay. But grass declines are a warning sign of deeper problems. Though aquatic grasses flourished in parts of Maryland, they took a big hit along parts of the Eastern Shore, including the Choptank River. Eastern Shore rivers have suffered from increasing pollution in recent years from both development and agriculture.
“As leaders update the Bay Agreement this year, a strong agreement is critical to holding states accountable and working together for a healthy Chesapeake Bay.”
