"Oysters sequester pollutants in their bodies, or they bind them up with other materials and eject them so that they settle in the surrounding sediments. Doing that cleanses the water, allowing other species to thrive."
North Carolina is building drop-off sites where people can deposit shells. The plan mirrors programs in Maryland, Virginia, South Carolina, Georgia, Florida, Canada's maritime provinces, and France.
The state has also launched an advertising campaign to discourage restaurant owners from sending shells to local landfills and to encourage diners to ask restaurant owners what they do with their shells.
Alphin and Hardy believe North Carolinians will take to the oyster shell recycling effort.
"Twenty years ago, you didn't think anything of throwing an aluminum can in the trash," Hardy said. "Nowadays if you walk by a recycling container and throw that can in the trash, people ask, 'Why are you doing that?' It's just as easy to recycle as it is to throw it away."
Meanwhile, legislators in both North and South Carolina are considering laws that would ban the dumping of oyster shells in landfills and offer tax credits to people and businesses that donate shells for recycling.
Bonnie Swartzenberg and her husband Jim grow oysters in a tract of water they lease from the state of North Carolina.
"We have recycled shells and built reefs for several years," Bonnie Swartzenberg said. "But a concerted effort by the state would make our business more profitable."
She notes that shell recycling is the best way to breed oysters, because it is virtually impossible to buy oyster larvae on the commercial market.
"The biggest issue we have right now is getting larvae to start our seed," Swartzenberg said. "You can't have a crop if you don't have seed. Building reefs at least gives us some seed."
"If this program works the way it has in other states, in Canada and in Europe, more larvae will be generated. We hope the reefs become self-sustaining again."
Jim Swartzenberg says he harbors no illusions that recycling can completely counter the forces that have ravaged North Carolina's oyster stock.
But he added, "I am excited about what could happen if people who eat oysters, and restaurant owners who sell them returned those same shells to the water."
For the next several months, the state and private growers such as the Swartzenbergs will build oysters reefs using recycled shells along the North Carolina coast.
Meanwhile, researchers in Georgia and South Carolina say their restoration efforts are already succeeding in creating self-sustaining reefs.
Marine biologists say each time a new reef is created, larvae settle and oysters start growing within hours.
The U.S. National Atmospheric and Oceanic Administration recently launched an investigation to determine if the Eastern oyster should be placed on the federal government's Endangered Species List.
A decision is expected in January.
Were the Eastern oyster to be classified as endangered, a ban on U.S. harvests would apply to the species, which lives in North American estuaries from Canada's Gulf of St. Lawrence to Mexico's Yucatan Peninsula.
Free E-Mail News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).