To aid in the growth of juvenile oysters before they’re ready to be transferred to grow-out equipment, producers are beginning to adopt the use of an Upweller or FLUPSY (Floating Upweller System). Upwellers (FLUPSY) and Downweller Systems Most hatcheries are now offering triploid oyster seed, given the benefits. They can be harvested at any time, including the summer months (depending on local conditions). Triploids do not spawn and continue to grow throughout the year. Invented in 1979 by Standish Allen, triploid oysters have three sets of chromosomes which making them sterile. Technological advances have been made to develop non-spawning oysters. Using hatchery spat allows oyster Farmers to cut down on labour costs while beginning the growing process with healthy, certified seed that are resistant to disease. Hatchery spat are grown in laboratory conditions and fed nutrients that can enhance growth. In most all situations, the collector is covered in a thin layer of a cement, lime and sand mixture to assist in setting. The use of these methods is subject to an oyster Aquaculturist’s own personal preference in collection, depending on the conditions in the area. Oyster spat collector trays are used primarily on tidal flats to collect seed in the intertidal zone. Long lines and raft culture are other methods of collection. More modern methods of seed collection include using oyster (Chinese) hats, coupelles, and modified drain pipes. Although still widely used, these methods of tradition collection leave the oysters susceptible to predators in the wild and have made way for more advanced options for oyster seed collection. They have been a mainstay in Australian and Japanese oyster farming for centuries. Oyster sticks are another method of traditional seed collection in the wild as well as in hatcheries. These oyster beds are most often situated in an intertidal zone to prevent fouling and strengthen the abductor muscles of the oysters. Over time, spat (oyster seed) settle on the empty oyster shells, maturing to a harvestable size.
On-bottom traditional seed collection includes the spreading of cultch, recycled oyster shells, on the sea bed. Oyster seed collection can occur in a variety of ways.
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