In 2024, the Chesapeake Bay’s underwater grasses, a vital indicator of the estuary’s health, dipped slightly, with Maryland’s portion dropping from 38,188 acres in 2023 to 36,794 acres, according to the Maryland Department of Natural Resources (DNR). This decline, detailed in the annual survey by the Virginia Institute of Marine Science (VIMS), keeps the region far from Maryland’s 2025 restoration goal of 79,800 acres. Despite gains in freshwater grass beds, significant losses in saltier mid-Bay waters highlight ongoing challenges for Southern Maryland’s coastal ecosystems.
The VIMS survey, conducted between May and October 2024, fully mapped the Chesapeake Bay’s underwater grasses, known as submerged aquatic vegetation (SAV). These grasses are ecological powerhouses, providing habitat for blue crabs, fish, and waterfowl, while improving water quality by absorbing nutrients, stabilizing sediments, and reducing shoreline erosion. They also combat climate change by sequestering carbon and buffering water acidity. The survey revealed a Bay-wide 1% decline in Chesapeake Bay underwater grasses, from 83,419 acres in 2023 to 82,778 acres in 2024, achieving only 64% of the Chesapeake Bay Watershed Agreement’s 2025 target of 130,000 acres.
In Maryland, freshwater SAV populations showed resilience. Rivers like the North East (165%), Bush (133%), Back (275%), upper Chester (274%), and Mattawoman Creek (110%) surpassed their restoration goals. The Susquehanna Flats area, part of the northern Chesapeake Bay segment 2, reached 90% of its 12,149-acre goal, while segment 1 hit 88% of its 754-acre target. Other upper western shore rivers, including the Gunpowder and Middle Rivers, also saw recoveries from losses in 2022 and 2023, driven by the diversity of freshwater species like wild celery and hydrilla, which bolster resilience.
However, these gains were offset by sharp declines in the mid-Bay’s moderately salty mesohaline zone, where Chesapeake Bay underwater grasses fell 14%, from 38,371 acres to 33,031 acres. The Eastern Shore bore the brunt, with losses in Eastern Bay (-36%), the Choptank River (-41%), Little Choptank River (-83%), Fishing Bay (-83%), and Tangier Sound (-8%). Widgeon grass, a dominant species in these areas due to its salinity tolerance, suffered after storms in spring and early summer 2024 brought fresh, turbid water. “The resilience we’re seeing in freshwater SAV beds is encouraging,” said Brooke Landry, DNR’s SAV Program Chief, “but sharp declines in widgeon grass across the mid-Bay are concerning, especially given how quickly this species can respond to changes in water quality”.
Widgeon grass’s struggles may also stem from reduced seed production in 2023, potentially linked to abnormally high water temperatures. Seeds are critical for this species’ annual expansion, and DNR scientists are investigating whether warming waters are disrupting this cycle. Meanwhile, in Virginia’s saltier polyhaline zone, Chesapeake Bay underwater grasses soared to 24,800 acres, the highest since VIMS began mapping in 1984. Eelgrass, thriving in areas like Mobjack Bay and Poquoson Flats, drove this growth, expanding into deeper waters and signaling improved water clarity.
The Chesapeake Bay Watershed Agreement, guiding restoration since 2014, faces a critical update by late 2025. With only 64% of the 130,000-acre goal met, the federal-state partnership is off track. “Thriving underwater grasses mean a healthy Bay, but grass declines are a warning sign,” said CBF Maryland Coastal Resource Scientist Julie Luecke. “Eastern Shore rivers have suffered from increasing pollution from development and agriculture”. Virginia’s CBF Senior Scientist Joe Wood added, “Underwater grasses are essential not only to Bay critters like the blue crab, but also critical in our fight against climate change”.
For Southern Maryland, where the Bay’s health shapes local fisheries and tourism, these trends matter. Nutrient pollution from agriculture and development, coupled with climate-driven storms, threatens progress. Public feedback on the Bay Agreement update is open until September 1, urging stronger commitments to pollution reduction under the Clean Water Act. As Landry noted, “Sustained investment in science-based management, conservation, and public engagement will be essential to protect and accelerate not only the recovery of Chesapeake Bay underwater grasses, but the entire Chesapeake Bay”. With collaborative action, Southern Maryland’s waters can support thriving ecosystems for generations.
