Hard-Shell Tactics

"It is exactly the type of activity we wanted to encourage, where everyday citizens get involved in putting oysters back into the bay at some level," O'Donnell said. "My vision is that every waterfront property owner who has a pier would have an oyster float hanging underneath it."

The floats are designed to suspend the oysters in water near the surface, where diseases that threaten them are less prevalent, said Rich Pelz, president of Circle C Oyster Ranching Association in St. Mary's County.

Pelz provided the oyster-filled floats to participants at a discounted rate of three for $500. Each float, which has three mesh bags containing the oysters and some straw, must be flipped once a month to dry out organisms that grow on the outside of the bags. That growth can prevent water from flowing through the bags and slow the oysters' maturation.

In addition to being natural water filters, the oysters help usher in "a whole cascade of life," said McVey. The Hellen Creek resident is the former head of the National Oceanic and Atmospheric Administration's oyster disease research program.

For five years, McVey has been growing about 4,000 oysters in floats under his pier. He said his floats have designs that are different from the ones he helped launch last week -- more like slings that hold the bags of oysters.

The effects on water quality are already visible, McVey said.

"I have the first submerged aquatic vegetation," he said of underwater grasses, which provide food and habitat to other organisms. "I don't see it anywhere else on my part of the creek."

There also are more grass shrimp, top water minnows and juvenile eels around his piers, he said.

McVey plans to plant his older oysters, which will be ready to reproduce next spring, on an old six-acre oyster bed under the creek as a test to see if the spat -- oyster babies -- will attach to the hard shell surface and grow, creating a natural reef.

If that happens, it will mean the neighborhood oysters can be added to the natural sanctuary.

"We know if we grow these oysters in surface floats they can reach adulthood. If they land on lower areas where the water quality is not so good, they might not do as well," said McVey, who took his oysters to local labs to test for safe eating and as a measurement of the creek's water. "They were quite safe," he said. "They are the canary in the mine."

The conservation group's Patuxent River Chapter has formed a committee to search out other old oyster leases and potential sites for sanctuaries to expand the project, Moe said.

The group already has more than 30,000 oysters floating in St. Thomas Creek in St. Mary's County.

"They want the bay fixed, and this is the way to do it," Pelz said.