How Are Oysters Grown?

There are over a hundred types of oysters.

Oysters are shelled invertebrates that create their own shells by the secretion of substances, such as calcium, from their glands. There are over a hundred species of oyster. Oysters live in a variety of aquatic environments and oyster farmers use the process of "clutching" to grow oysters.

Life Cycle

Fertilized eggs hatch into larvae which go through several metamorphoses. The juvenile form of the oysters settle onto substances to which they then attach themselves.

Cultching

In a process known as clutching, oyster growers place materials into the water that the young oysters attach themselves to. The materials that catch the young oysters in this way are called "clutch" while the oysters that settle on the material are called "spat." Bottom culture involves placing clutched seed onto beds in protected bays with mud bottoms. This is the most common method of oyster farming as it does not require much maintenance, and the oysters are harvested when they reach medium size.

Seeds

Seed oysters can be sourced naturally or from a hatchery. Natural spat is collected on clutch material that is placed in the water and left there for several weeks. It is then taken to a nursery area. In a hatchery, the adults oysters spawn and the spat is put in a nursery tank where the young oysters then grow. Farmers can buy bags of both clutched oyster seed or oyster seed that is clutchless for their next crop of oysters.

References

• Washington Sea Grant: Small-Scale Oyster Farming For Pleasure And Profit In Washington

Resources

• Sea Science: Oysters and Clams