Save Those Oyster Shells!

by Joyce Deaton

October marks the beginning of North Carolina’s oyster harvest. Maybe you’re celebrating sometime soon at a local eatery with a tasty mouthful of the mellow mollusk. When you finish, your oyster shells may do a little celebrating of their own. With the help of dozens of human volunteers, they’ll likely be making their way back into the Cape Fear area waters where they’re helping the state’s oyster population thrive.

The N.C. Division of Marine Fisheries introduced the oyster shell recycling program in 2003. “At first it was small,” says Ted Wilgis, coastal outreach specialist with the N.C. Coastal Federation. “Our organization joined with volunteers from the NCDMF, Nature Conservancy and others. The first year we recycled 700 bushels, and by 2007 that total reached 30,000 bushels.”

Volunteers use their vehicles to tow an oyster recycling trailer to festivals and oyster roasts and visit restaurants in their area once or twice a week to pick up recycled shells. The shells are dropped off at special bins maintained by NCDMF, then placed back into the water in new reefs or oyster rehabilitation areas. NCDMF supplements the oysters that will appear naturally with others from the Oyster Relay. In this event, volunteers (always on short notice, due to the oysters’ growing habits) move bags of oyster shells with newly cultivated oyster larvae from settling tanks to holding tanks in Stump Sound and from polluted areas to the cleaner waters of state-supervised oyster management areas.

Baby oysters start out as free-floating organisms, but soon settle to the bottom and attach themselves to hard surfaces. If they can’t find a hard substrate, they die. They’ll grow on pilings and concrete, but their preferred spot is on oyster shells. A mound of shells placed in brackish water with a good tidal flow will soon become an oyster reef, hosting not only the young oysters but algae, worms, barnacles, crabs, minnows and fish. Soon a diverse marine habitat results from the simple act of depositing the shells.

In addition, the filter-feeding oysters make the water cleaner by feeding on plankton and waterborne detritus. “A healthy oyster will filter 15 to 35 gallons of water a day, besides helping create food and shelter for important species such as blue crab, shrimp, flounder and grouper. This habitat is important to coastal life both ecologically and commercially,” says Wilgis.

Along with the recycling effort, these conservation organizations have worked to promote bills in the N.C. General Assembly that now make it illegal for state agencies to use oyster shells in landscaping and prohibit the use of shells for anything except oyster restoration. (Previously they were used much like gravel in coastal landscaping and ground for a variety of products such as chicken feed.) In addition, the General Assembly established a $1 per bushel tax credit and banned oyster shells from landfills. “These actions really helped get the program going,” says Wilgis. “It’s been a real grassroots effort, and it’s grown steadily. Some schools have adopted restaurants for recycling, and other organizations have joined in such as CCA (Coastal Conservation Association), Fish for Tomorrow and the Pender Watch & Conservancy. Our goal is to get the shells back in the water in the area where they were collected, and this gives people a feeling of ownership.”

Wilgis estimates that North Carolina has lost about 50 percent of its original oyster habitat, and the state’s oyster harvest is down 90 percent from its peak in the 1880s. The declining habitat is the result of several factors: Intense harvest pressure during the 1880s, pollution from fertilizers and waste, sediment from coastal building and farm fields that buries oyster reefs, diseases such as MSX and dermo that kill oysters before they reproduce, and drought that increases the salinity of coastal waters. Recent rehabilitation efforts already are paying off, however. Last year’s oyster harvest was double that of the previous year, and oysters protected in several sanctuaries along the coast are helping to purify the water and protect other species.

Wilgis says the recycling program welcomes more volunteers. “Besides collecting from restaurants, we also need people for education and outreach at festivals and for helping to monitor new reefs,” he explains. To volunteer, visit www.nccoast.org or www.ncfisheries.net, where you’ll also find the locations of drop boxes so you can recycle your household oyster shells.