Chesapeake Bay underwater grasses increase amidst regional variation
Summary and headline written by AI from the source article. How we work
Researchers at William & Mary’s VIMS & Batten School found that underwater grasses in the Chesapeake Bay, a vital sign of ecosystem health, grew by 7% in 2025.
The annual survey revealed a total of 89,385 acres of submerged aquatic vegetation across the bay and its tributaries, the most since 2018. This increase brings the Bay closer to its 2030 goal of 90,000 acres, though still short of the long-term target of 196,600 acres.
The gains were largely driven by expansion in the Bay’s saltier waters, with the Polyhaline and Mesohaline Zones reaching record and near-record levels respectively. Scientists connected this growth to consistent improvements in water clarity throughout the Bay. Eelgrass meadows grew both in size and depth, mirroring these improvements, while widgeon grass also recovered from past declines. However, not all areas of the Bay saw improvements.
The Tidal Fresh Zone, comprised of rivers and embayments, experienced a slight decrease in coverage due to fluctuations in an invasive plant, Hydrilla verticillata, also known as water thyme. Despite these regional differences, the overall trend indicates that decades of work to reduce pollution and restore habitats are yielding positive results in the Chesapeake Bay watershed, a 64,000-square-mile area.
