U.Va. Seeks to Restore Seagrass to Eastern Shore Bays

Aug. 2, 2007 -- Karen McGlathery slips from the side of the boat into the shallow, murky waters of Hog Island Bay, one of three major lagoons on the oceanside of Virginia’s Eastern Shore. “Oh, that’s cold,” she says as the chill of the morning water hits her. McGlathery, an environmental scientist, is the University of Virginia’s lead investigator on a project to restore seagrasses to the region.

Last fall she worked with a team of scientists from the Virginia Institute of Marine Science to seed a 500-acre area of Hog Island Bay with eelgrass – a submerged seagrass that is common in temperate waters worldwide – hoping to establish a meadow that may eventually spread outward, potentially propagating new areas. McGlathery and her team of graduate students, a few undergrads, and even a couple of local high school students, are now back to see if the grass is growing.

The team finds the site using GPS – the Global Positioning System – to pinpoint their plots, which are not visible from the surface of the turbid water. They wade, after a few pointed comments about the chilly temperature of the water, and snorkel along the beds, taking measurements of the length of the grass and the extent to which it has spread. They also take core samples from the muddy bottom, and water samples for later analysis.

“What we learn from these studies will help us determine the baseline conditions for future restoration efforts,” McGlathery says.

Seagrass once flourished in the seaside bays of the Eastern Shore. But in the late 1920s and early 1930s a pathogen began killing the grasses. A hurricane in 1933 essentially finished them off. In the years since, the bay bottoms have been mostly muddy and barren. A once thriving scalloping and fishing industry collapsed.

“I’ve read accounts by old watermen of how the water here was once crystal clear and that the seagrass meadows were so extensive and visible from the surface that it looked like a lawn of long grass,” McGlathery says.

Not anymore. The water is murky green most days and even muddy on windy days. Without extensive seagrass beds to stabilize the bottom, the sediment is continually stirred up, blocking out the sunlight needed by eelgrass to photosynthesize and flourish. But when grasses grow well, they stabilize the bottom, clear up the water, and serve as habitat for an assortment of creatures: scallops, crabs, shrimp, mollusks, and the fish that feed on these animals.

McGlathery is encouraged by what she is finding. Most of the one-half and one acre plots in the 500-acre area are doing well.  Apparently, about 10 percent of the 1.5 million seeds that were scattered last fall took root and the plants are growing well. Already many of the plants are 12 to 18 inches long. McGlathery is not surprised. Prior to the seeding, she and her team surveyed the area, tested the sediment and the water quality, and determined that the area might be receptive to a crop of eelgrass.

VIMS has conducted similar work during the past ten years in South Bay, a lagoon to the south of Hog Island Bay.

“In areas of South Bay there are now lush seagrass beds as far as you can swim, continuous meadows,” McGlathery says. “It shows that we can not only get these grasses to grow, but we can also get them to thrive.”

And recently, a few sparse natural areas of eelgrass were discovered in Hog Island Bay, likely seeded by tide and current from the beds of grass originally created by scientists in South Bay.