Bay grasses in Maryland’s Coastal Bays are increasing, according to the Maryland Department of Natural Resources (DNR).
Bay grasses, also known as submerged aquatic vegetation or SAV, are an important indicator of bay health. Results for the Coastal Bays show that bay grass acreage increased 18 percent from 2000 to 2001 to approximately 11,438 acres. The 2001 acreage represents the highest yet documented in the Coastal Bays, and a 245 percent increase since annual data collection began in 1986. Bay grass acreage in Maryland’s Coastal Bays has exhibited a steady increase since annual monitoring began, and has declined only three times in the 16 year history of the survey, the most recent being in 2000.
“This increase in grasses in the Coastal Bays mirrors increases in the Chesapeake Bay,” said DNR Secretary C. Ronald Franks. “The growth of these grass nurseries is absolutely essential for the continued improvement of our waters.”
Bay grasses are important to the Coastal Bays because they provide habitat, food, and oxygen for a variety of bay creatures, including crabs, fish, and waterfowl. Bay grasses also help protect shorelines from erosion by reducing wave energy, help to absorb nutrients, and trap sediments that cloud Bay waters.
Increases in bay grass coverage from 2000 were recorded in three of the four major Coastal Bays segments. Grasses in Chincoteague Bay increased 23 percent to 8,927 acres, Isle of Wight Bay increased 17 percent to 307 acres, and Assawoman Bay increased 7 percent to 550 acres. The largest increases in coverage and density were observed in the area of Tingles Island, South Point, and Mills Island in Chincoteague Bay, and near the eastern end of the Route 90 Bridge in Assawoman Bay.
Bay grass coverage in Sinepuxent Bay decreased approximately 2 percent from 2000 to a total of 1,654 acres. Decreases in bay grass coverage and density were observed in the Swan Point area of Assawoman Bay, and in several small pockets along the eastern portion of Sinepuxent and Chincoteague bays.
Although bay grasses are found in all four major segments of Maryland’s Coastal Bays, they are not distributed evenly. Almost 85 percent of all bay grasses occur along the Assateague Island shoreline.
“It’s not coincidental that we find relatively few bay grasses in the northern bays, ” said Dr. Robert Magnien, Director of DNR’s Tidewater Ecosystem Assessment Division. “These are the areas of greatest water quality impacts from various human activities.”
Increased sediment and nutrient inputs from runoff and wastewater treatment act to block sufficient sunlight from reaching bay grasses and are the primary threat to their health. Bay grasses in the Coastal Bays may also be damaged by blooms of macroalgae and other harmful algal species (which are stimulated by excess nutrients), and physically destroyed by recreational and commercial boating activity. Natural factors, such as sediment type and wave action also influence the health and location of bay grass beds.
The Maryland Coastal Bays Program is working with local, State, and federal partners to implement the Maryland Coastal Bays Comprehensive Conservation Management Plan, which identifies a variety of actions designed to restore and protect the Coastal Bays, including bay grasses.
“This is very encouraging news for the Coastal Bays, and shows our efforts have not been futile,” said Dave Blazer, Executive Director of the Maryland Coastal Bays Program.
Bay grasses have been monitored annually since 1986 through an aerial survey conducted by the Virginia Institute of Marine Sciences and funded by the States of Maryland, Virginia, and the federal government. General consensus among the scientific community is that, despite recent increases documented by the aerial survey, bay grass coverage is currently considerably less than in the early 1900s. A disease struck many bay grasses along the east coast in the early 1930s and virtually eliminated bay grasses from the Coastal Bays. The Maryland Coastal Bays Program and DNR are evaluating historic aerial photographs to determine the extent of bay grass coverage during the 1930s and 1960s.
DNR, in partnership with the Assateague Island National Seashore and others, initiated a comprehensive environmental monitoring program in 2001. Data collected as part of this program will allow identification of specific factors influencing bay grass coverage in different portions of the Coastal Bays and guide future restoration efforts.
For more information on Maryland’s Bay Grass Restoration efforts, visit the DNR website at: www.dnr.state.md.us/bay/sav/index.html
To view the entire 2001 Bay Grass Survey Report and associated maps, visit the Virginia Institute of Marine Science website at: www.vims.edu/bio/sav/sav01/
For more information on the Maryland Coastal Bays Program, visit: http://www.mdcoastalbays.org/
Posted: 3-7-2003
