The total acreage of bay grass along Maryland’s coastal areas has dropped by nearly 4,000 acres since last year, indicating poor health for the Chesapeake Bay and its estuaries, researchers from the Virginia Institute of Marine Sciences reported Thursday.

Bay grass is sensitive to excessive nutrients and sediment in the water, which can be caused by sewage treatment plants, septic systems, industries, automobiles and erosion, according to the Maryland Department of Natural Resources.

In spite of a sharp fall in acreage since 2001, the amount of bay grass along Maryland’s waterways is twice what it was in 1986, when researchers began conducting annual surveys of the vegetation.

“We are hopeful that implementation of nutrient reduction strategies will help reverse this recent declining trend and accelerate progress toward our restoration goals,” said Dave Blazer, director of the Maryland Coastal Bays Program.

The combined total acreage of bay grass in Maryland and Virginia was 10,548 acres in 2006, down from a 19,000-acre peak in 2001. Chincoteague Bay in southeast Maryland has seen the greatest losses, according to the DNR.