Significant bay grass declines in mid-Bay area overshadow gains

April, 2011 - Bay grasses in Maryland’s portion of the Chesapeake Bay and its rivers covered approximately 40,193 acres in 2010, down from 47,294 acres in 2009. This represents 35% of Maryland’s 114,000-acre bay grass restoration goal.

2010 was the first time in three years Maryland’s bay grasses decreased in abundance. However, Maryland’s 2010 bay grass coverage was the sixth highest recorded since the Virginia Institute of Marine Science began the annual bay grass survey in 1984.

While the Bohemia, Bush and Magothy Rivers lost significant percentages of bay grass acreage, much of Maryland’s losses occurred in the mid-Bay region (from the Chesapeake Bay Bridge south to the Potomac River and Pocomoke Sound). Large percentage declines were observed in the Honga River and Tar Bay area on the Eastern Shore. Bay grasses in the Choptank, lower Patuxent, and Potomac Rivers also declined. The dominant bay grass in this region, widgeon grass, is a boom or bust species and almost completely disappeared from these areas in 2010. Long-term reductions in water clarity, along with record-breaking hot summertime temperatures, may have contributed to the bay grass declines in this region.

The significant declines in the Honga River and vicinity overshadowed the gains in bay grass acreage observed in other areas. The upper Chesapeake Bay and its rivers (from the Chesapeake Bay Bridge north) met 90% of the 23,400-acre restoration goal for this region. Bay grass coverage in most upper Eastern Shore rivers, the upper Potomac River and the Susquehanna Flats met or exceeded restoration targets due in part to sewage treatment plant upgrades and long-term reductions in nutrients entering the water. Bay grass beds on the Susquehanna Flats, near Havre de Grace, have quadrupled in size since the early 1990’s and now cover approximately 11 square miles.

On the lower Eastern Shore, eelgrass continued to rebound in Tangier and Pocomoke Sounds and in the Manokin and Big Annemessex Rivers following the large-scale 2005 summer die-off. Bob Orth, lead scientist for the annual aerial surveys conducted by the Virginia Institute of Marine Science, is concerned, however, that the record-breaking hot summertime temperatures in 2010 may negatively affect eelgrass in 2011.

Bay grasses are important habitat in the Chesapeake Bay. They provide food and shelter for many animals, including blue crabs, largemouth bass and canvasback ducks. Healthy bay grass beds also protect shorelines from erosion, produce oxygen and filter polluted water.

Because bay grasses are sensitive to even small changes in water pollution, they serve as a key indicator of Chesapeake Bay health. Polluted runoff entering the Bay contains nutrients that can fuel algal blooms and sediments that block sunlight needed for bay grass growth. Further reductions in the amount of polluted runoff and sediment entering Maryland’s waterways are necessary for continued bay grass restoration success. Working through the Chesapeake and Coastal Bays Trust Fund, Governor Martin O’Malley is bringing together citizens, businesses, and local, state and federal government agencies to reduce polluted runoff. Programs to plant cover crops and restore natural filters, such as streamside vegetation and wetlands, as well as conserve high priority lands, restore habitats and foster smarter, greener growth and living in Maryland will benefit bay grasses and the Bay’s other natural resources.

For more information, visit:
Bay Grasses: identification, importance and status www.dnr.maryland.gov/bay/sav
Restoring the Chesapeake Bay: Maryland’s Actions and Progress: www.baystat.maryland.gov
What can you do to help the Bay: http://www.dnr.state.md.us/bay/education/programs.html