Save Those Shells! Seafood Trash Becomes Oyster Reef Treasure

Beth Darrow, Chief Scientist

Though unassuming in appearance, oysters are nature’s unsung heroes. They offer both important ecological and economic benefits. Oysters have helped human societies survive and thrive for many centuries. The Eastern Oyster, Crassostrea virginica, is a bivalve mollusc that is native to the East Coast of Canada and the US, Gulf of Mexico and Caribbean. Oyster reefs are located in salt or brackish water: in Bald Head Creek at low tide, you can see our extensive (and sharp!) reefs. Oysters are sessile, or immobile, animals once they reach their adult stage. They settle on hard structures (i.e., piers, rocks, and old shells) and form these reefs, intricate structures that form a habitat for fish, crabs, shrimp, and other animals. These structures can protect coastal areas from erosion and stabilize vegetation from being uprooted due to storm surge.

Fall 2023 Coastal Environmental Science Interns Charlene Trippeda and Jonathan Saldeen sample a wild oyster reef in Bald Head Creek. They collect reef material in a 30×30 cm quadrat and bring it to the lab, where they count and measure oysters and identify and count reef-associated fauna.

Oysters are suspension feeders, meaning that they filter floating plankton from the water column. This helps remove algae and clear the water column. These “ecosystem services” are some of the many reasons that the Conservancy and other conservation organizations focus on enhancing and restoring oyster reefs.

Did you know that in North Carolina, it is illegal to throw oyster shells away in the landfill? This is because these shells are a valuable natural resource. Throughout the state, oyster shells are recycled and used to build artificial oyster reefs. The Conservancy, with the assistance of volunteers, built three artificial oyster reefs in fall 2021. We request that households and restaurants on BHI place oyster and clam shells in our yellow bin at the Village Creek Access or bring them to the Conservancy campus.

We have had a series of fall interns working on our oyster reef restoration project, quantifying the success of the sites for attracting new oysters and providing habitat. In 2022, Cade Cobbs found that even after one year, oysters were growing on the new reefs, and that a number of other invertebrate species were using the reefs as a home (such as crabs, snails, worms, and barnacles!). This year, Jonathan Saldeen and Charlene Trippeda are resampling these reefs and pre-sampling a new proposed site. They are comparing the restored sites to wild and bare sediment sites to quantify this habitat enhancement after two years.

On October 7, Chief Scientist Beth Darrow gave a presentation at Cape Fear River Watch in Wilmington all about oyster shells and their importance. Check out the recording here!