South of Cape Fear to northeastern Florida, most oysters grow intertidally, in the area exposed between high and low tides, although there are some isolated subtidal oysters growing in South Carolina. Intertidal oysters are frequently subjected to rapidly changing temperatures, including freezing air during the winter months. However, they are rarely killed by either low or high temperatures. Typically in South Carolina, a number of sounds, bays and river mouths are connected by an intricate system of creeks and rivers separated by extensive saltwater marsh. Oysters occur along most of these creeks and riverbanks and on exposed mud flats.
Oysters reach a harvestable size in South Carolina at an age of about three years.
Shapes of intertidal oysters are varied. The ultimate shape of the shell depends upon growing conditions. The most common intertidal growth is that which produces oyster clusters. These are formed by successive sets, one upon another. Each oyster in a cluster is used by succeeding generations.