Shellfish culture begins in the hatchery with the production of seed. While hatchery techniques are well defined, they are complex. In addition, a hatchery operation requires capital investment in property, facilities, equipment, and skilled labor. For these reasons, most growers prefer to purchase seed from a hatchery. There are 14 hatcheries in the state, ranging from small backyard operations to commercial-sized facilities.
In the hatchery, adult shellfish, or broodstock, are induced to spawn by manipulation of water temperatures. Fertilized eggs and resulting free-swimming larval stages are reared under controlled conditions in large tanks filled with filtered, sterilized seawater. Cultured marine phytoplankton, or microalgae, are fed at increasing densities during the 10 to 14-day larval culture phase.
After which, pediveliger larvae (larva with a foot) begin to settle out of the water column or metamorphose. Oyster larvae require a suitable hard surface to set; micro cultch (oyster shell) is used to create single spat. Even though a true shell is formed at this time, post-set seed are microscopic and vulnerable to fluctuating environmental conditions. They are maintained in the hatchery for another 30 to 45 days in downwellers until they reach about 1 mm in size.
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