Oysters farming

Oysters have been prized as a food for millennia. Carbon dating of shell deposits in middens in Australia show that the aborigines took the Sydney rock oyster for consumption in around 6000 BC. Oyster farming, nowadays carried out all over the world, has a very long history, although there are various thoughts as to when it first started.

Traditionally, many oyster farmers grew their seed in-house, but there is now increasing demand for large quantities of seed from specialists who can develop greater expertise, varieties, and economies of scale.

The process starts when baby oysters, commonly known as spat, settle on wooden sticks set by farmers in the ocean. The wooden sticks are then nailed onto racks built so the oysters sit just above water level at low tide.

Oyster farming is dependent on a regular supply of small juvenile animals for growing on to market size. Hatcheries play an increasingly important role in bivalve culture in the northern hemisphere. A reliable source offering sufficient quantities of spat of the desired species is critical to successful oyster culture. Spat may be obtained from natural sources or from a hatchery.

Rafts, floating longlines and bottom longlines are used to suspend cultch. The choice of method depends upon cost, durability of materials, and environmental conditions such as wave exposure and water depth.

Monitoring and managing water conditions is crucial for growing oysters, which thrive or survive only in certain ranges of temperature, salinity, oxygen, pH, and nutrients.

The oysters should grow more quickly because they are permanently submerged but the shell may be thinner and therefore more susceptible to damage.

Cultured oysters reach marketable size 9-12 months after stocking. Grow-out time depends on initial stocking size. The usual market size is 9-12 cm.
Oysters farming