St. Mary's River Watershed Association's Elaine Szymkowiak, Emma Green Ewing, and John Spinicchia pose with their SAV Watchers Training Certificates on July 8, 2025.
Submerged aquatic vegetation (SAV) is a critical component of the health of the St. Mary’s River and the larger Chesapeake Bay watershed. SAV are aquatic plants that grow underwater throughout tidal and non-tidal waters in the Chesapeake. Many boaters claim that this vegetation is a nuisance. However, in many ways, SAV function in the same manner that our oyster reefs do. These ‘grasses’ (actually aquatic flowering plants) benefit our waterways by providing food and shelter for fish and other marine life, by releasing oxygen beneficial to these species, inhibiting erosion, and removing sediment from the water. SAV beds are the main nursery areas for the Blue crab. SAV also absorb nutrients like phosphorus and nitrogen that might otherwise promote the unwanted growth of algae in our waterways.
Through public education, we hope to get folks to appreciate SAV as much as they do oysters!
Eelgrass with Lined seahorse in Chesapeake Bay (Photo courtesy of Flickr)
The actions of hurricanes and declining water quality in Chesapeake waterways have led to considerable losses of bay grasses since the 1960s. As of 2022, a Maryland DNR survey of the Lower Potomac River watershed found around 1500 acres of SAV, far short of the 7,000 acre restoration goal.
Restoration efforts throughout Maryland are having a positive effect, however. The Maryland DNR states that “Maryland’s waterways experienced a slight (13%) increase of SAV between 2021 and 2022. 39,760 acres of SAV were mapped in Maryland’s waterways in 2022”. The St. Mary’s River shows good SAV coverage in some areas, but there is more to be done.
You can access an interactive map of SAV in the Chesapeake Bay and its tributaries here.
Seagrass bed restoration (photo courtesy of Flickr)
The Maryland Department of Natural Resources established the Chesapeake Bay SAV Watchers Program, which uses citizen science to monitor submerged aquatic vegetation in the state’s waterways. In 2025, two SMRWA board members, John Spinicchia and Elaine Szymkowiak, and Executive Director, Emma Green Ewing, were certified as Chesapeake Bay SAV Watchers Trainers. These certifications were the first step in starting our own SAV Watchers Program in the St. Mary's River. These data were desperately needed as there were no SAV Watchers data in the St. Mary's River before 2025. We hope to train citizen scientists on monitoring SAV in the spring of 2026.
St. Mary's River Watershed Association's Elaine Szymkowiak, Emma Green Ewing, and John Spinicchia pose with their SAV Watchers Training Certificates on July 8, 2025.
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St. Mary's River Watershed Association, Inc., Post Office Box 94, St. Mary's City, MD 20686 [email protected]