What it takes to build an oyster reef

North Carolina started oyster reef restoration projects in the Pamlico Sound in 1996 and 15 have been completed. The largest project, Swan Island, is underway. It will cover 50 acres. Find out how it’s done.

North Carolina’s estuaries and sounds, in fact the entire coastal ecosystem, used to be filled with oyster reefs. In fact the story goes that when European settlers first came to the area the water was so clear you could drop a gold coin and see it go all the way to the bottom of Pamlico Sound. That’s right, 26 feet down to the bottom and you could still see the coin. At least, that’s the story passed down through the centuries.

But even if it is not entirely accurate, it will gives a sense of just how clear the water was from all of the oysters filtering the water.

That’s changed of course.

Over the years, overharvesting, storms, disease and predation, and habitat destruction on land has had a devastating effect on North Carolina’s oyster population. And that’s why tons of granite rock is being loaded onto barges at the North Carolina Port in Morehead City. All of that rock is then dumped into a strategic place in Pamlico Sound. It’s part of the ambitious plan by the North Carolina Coastal Federation, the North Carolina Department of Marine Fisheries, and the National Oceanic and Atmospheric Administration to restore the oyster to North Carolina’s coastline.

“This rock is going to the Swan Island oyster reef. It’s the 15th oyster sanctuary that is located in Pamlico Sound,” explains Erin Fleckenstein, coastal scientist and oyster reef restoration project manager for the North Carolina Coastal Federation.

“The idea is the reefs create brood stock sanctuaries where we have these adult oysters that spawn and reproduce and help to seed our wild oyster beds as well as our shellfish managed areas.”

It will take 70 tons of granite to construct the 50-acre Swan Island oyster reef. The three-year project will result in 10 acres of oyster sanctuary and 40 acres of managed oyster reefs that will eventually be open to harvest.

On average, about one million oysters per acre have settled onto the artificial reefs built in the sound.

“So for every acre of oyster reef we create and every acre of oyster sanctuary that’s being built we have about one million baby oysters on them,” adds Fleckenstein. ”It’s pretty clear the restoration project works.”

The artificial reefs vary in height. Once a haven is built for oysters to repopulate, Mother Nature does the rest in the spring and the fall. All it takes it for the water temperature to hit 68 degrees. The adult oysters on the reefs spawn and then the baby oysters begin floating through the water. It’s a two-week floating journey before the baby oysters settle onto a hard surface. The artificial oyster reefs are strategically located so the currents help distribute the oysters to these managed oyster beds as well as the wild oyster beds.”

“There’s a lot of science and a lot of analysis that goes into the location of the reefs,” explains Kenneth Riley, Fisheries Biologist with NOAA’s National Marine Fisheries Service. “We space them out at appropriate distances, so that whatever occurs on the site spills over into the adjoining sites, and essentially we develop this oyster network or sanctuary network, or as some call it an oyster highway. It’s the connectivity of our sanctuaries that makes it all work.”

About 250 acres of oyster reef have been built. The long-term goal is to double that and provide oysters a strong foundation on which to grow. The health of the coastal economy and ecosystem depends on it.

“Oysters are critically important to North Carolina, in fact they are what is known as a keystone species,” said Jason Peters, a researcher with the North Carolina Division of Marine Fisheries.

“Besides being commercially and recreationally important species, oysters and oyster reefs filter water, provide habitat and refuge for fish and crustaceans, as well as coastal storm protection. Oysters are one of the important building blocks for the coastal ecosystem.“