St. Mary's River Watershed Association, Inc., Post Office Box 94, St. Mary's City, MD 20686 emmasmrwa@gmail.com
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.
The Maryland Department of Natural Resources is currently establishing a program to monitor submerged aquatic vegetation in the state’s waterways. This program is a citizen science community initiative and individuals who want to be involved can take a day-long training session to help with the monitoring process.
There are currently no efforts actively underway in Southern Maryland for SAV restoration, although the St. Mary’s River Watershed Association and other Bay partners are making SAV restoration a priority in their efforts to improve water quality. SMRWA is currently establishing interest in hosting a local training session. Please contact us if you are interested.
You can access an interactive map of SAV in the Chesapeake Bay and its tributaries here.
Seagrass bed restoration (photo courtesy of Flickr)
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St. Mary's River Watershed Association, Inc., Post Office Box 94, St. Mary's City, MD 20686 emmasmrwa@gmail.com