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Oyster Mariculture is Growing in South Carolina

By Joey Holleman

Frank Roberts established the Lady’s Island Oyster hatchery on the banks of McCalley’s Creek in Beaufort County to provide seed oysters for the expanding mariculture industry in South Carolina, including his own farm. In-state hatcheries were critical after state officials banned the importation of seed oysters from outside the state in 2014 due to disease concerns. Growing single oysters for sale in restaurants depends on the availability of seed oysters. The S.C. Sea Grant Consortium provided expertise and guidance to help Roberts get his hatchery started. In 2018, it was the only hatchery selling seed to South Carolina farmers.

The hatchery process at Lady’s Island Oyster begins in a row of containers. One adult oyster is placed in each container. As the temperature of the water in the container warms, the oyster spawns, releasing either eggs or sperm. Hatchery workers then carefully mix eggs and sperm together in another container, leading to fertilization of the eggs. The resulting larvae grow in larger containers for about two weeks before they develop a sticky foot and are ready to attach to a hard surface. The larvae are then placed in containers with finely ground oyster shells. The tiny shell pieces are just large enough to serve as a hard-structure base for an individual larva, creating single oysters rather than clusters.

After another week in the inside portion of the hatchery, the young oysters have begun forming shells and are moved outside to larger silos. They feed on nutrients in water pulled out of the neighboring creek for about another five weeks, growing to about the circumference of a standard writing pen. At that point, they are ready for farmers to pick them up and take them to farms.

Farming businesses, such as the Barrier Island Oyster Company, obtain permits to grow oysters in specific locations on tidal creeks. Thousands of seed oysters are put in plastic containers, called bags, with mesh small enough to keep them from falling out but large enough to allow plenty of water to flow through. The bags are then slid into cages equipped with floats to keep the growing oysters suspended off the silty creek bottom. Barrier Islands’ team launches its boats from Rockville, and the cages are anchored in Ocella Creek.

The farmers check their cages routinely. They pull the bags out, take them back to the dock, sort the oysters based on how quickly they grow, and then return them to the creek to grow some more. The cages also are flipped for a few hours occasionally to allow sunlight to kill the growth, or biofouling, that builds up on the structures. Biofouling can get so thick it restricts water moving through the oyster gills and stunts growth.

As the oysters grow, they are spread out in more bags, slowly stepping up from 5,000 oysters per bag to about 200 per bag. When the oysters grow to three inches in length – a process that takes 12 to 18 months – they are ready to be sold by farmers to local restaurants.

Local single oysters can be ordered raw on the half shell in dozens of restaurants in South Carolina. They often are offered, as they are here at The Obstinate Daughter on Sullivan’s Island, alongside oysters from farms outside the state. Oyster lovers say the various brands have distinct tastes derived from the environment in which they grow.

Barrier Island markets its oysters as Sea Clouds. Lady’s Island Oyster sells its product as Single Lady oysters. Toogoodoo Oyster Company on Yonges Island grows Toogoodoozies, and Charleston Oyster Company on the Stono River has Mosquito Fleet Petites. Look for these and other South Carolina-farmed oysters on raw bar menus with the knowledge they were born and raised in local waters.