Bay grasses in the Chesapeake Bay were up twelve percent in 2009–the most grass found in the bay since 2002, according to scientists at the Chesapeake Bay Program. The results of the annual aerial grass survey are giving scientists hope that the health of the bay is improving.

“Because bay grasses are sensitive to even small changes in water pollution, they serve as a key indicator of Chesapeake Bay health,” Maryland Department of Natural Resources Secretary John Griffin said. “Healthy bay grass beds protect shorelines from erosion, produce oxygen and filter polluted water,” Griffin continued.

The underwater grasses are essential for fish and blue crab habitats. And with the crab population up 60 percent in the Bay this year, more grass is needed for the additional creatures.

Maryland Gov. Martin O’Malley said the grass increase is a good sign for the state’s efforts. “This expansion is an encouraging sign that our pollution control efforts are working,” he said, “A trend that we hope to sustain with accelerated efforts to restore the Bay.”

Although overall the bay grass population is up, there were some areas of the bay that saw a decrease. Anne Arundel County encountered a huge disappointment in the amount of grass seen in its rivers. “There were dramatic declines in grass beds in the Magothy and Severn rivers, and no grass beds were documented at all in the South, West and Rhode rivers,” according to The Capital. Scientists are still working to determine why these rivers did not see an increase in bay grass.