South Carolina Oyster Restoration and Enhancement
South Carolina Department of Natural Resources

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Oyster Biology & Ecology (cont)

Life Cycle

Adult oysters begin reproduction when water temperatures become greater than 68F (~20C). In South Carolina this generally occurs from May through October. Oysters are broadcast spawners, meaning they release eggs and sperm into the water column. A fertilized egg develops into a planktonic (free-swimming) trochophore larva in about 6 hours. A fully shelled veliger larva is formed within 12 to 24 hours. The larva remains planktonic for about three weeks. Towards the end of this period it develops a foot (hence, pediveliger) and settles to the bottom of the water column where it seeks a hard substrate. When a suitable surface (ideally adult oyster shell) is located, the larva cements itself and metamorphoses to the adult form. This newly attached oyster is known as a "spat."

Figure of the oyster life cycle, from egg to veliger larva to pediveliger stage to attached juvenile (spat) to adult, and back to egg.

Reef Ecology

Oysters are the building blocks of one of the most important benthic communities in South Carolina estuaries, the oyster reef. Formed as a result of years of oyster production and settlement in concentrated areas, reefs have become home to a complex assemblage of animals and plants. Benefits of oyster reefs to the coastal environment include the following:

  • Providing solid structure within the water column for sessile (permanently attached or fixed) organisms (for example, barnacles and sea anemones)
  • Creating homes and hiding places for organisms seeking refuge from predation (for example, polychaete worms and soft-shell blue crabs)
  • Providing spawning substrate for fishes (for example, gobies, blennies, and skilletfish)
  • Stabilizing bottom sediments for benthic organisms (for example, hard clams) and aquatic plants
  • Concentrating prey (food) species for larger predator fishes (for example, striped bass)
  • Serving as breakwaters to protect adjacent shorelines from erosion
  • Filtration and clarification of water

Some of the information in this section is modified from Oysters in the Environment found at

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