The terms “spat” and “seed” are sometimes used interchangeably, however, spat tends to refer to post-metamorphosis oysters that attach to larger, empty oyster shells and are used to plant new oyster beds or reefs in creeks and rivers. Seed oysters usually start out around half a millimeter in size and quickly grow to several millimeters in just weeks. In this form oysters are sessile (not capable of locomotion) and feed by filtering the passing seawater, ingesting phytoplankton that passes over their gills. The post-metamorphosis form of the oyster. Once the larvae find a suitable attachment site, they settle, cement to the site, and metamorphose into seed oysters. As pediveliger larvae, oysters develop a foot-like structure, used to search the seabed for hard substrate for settlement. After about two weeks, larvae will more than quadruple in size and develop into pediveliger larvae. Oyster embryos will develop into trochophore larvae several hours after eggs are fertilized, and then ‘D-stage’ larvae with thin shells will develop within a day or two. Larval organisms are very small, and some, like oysters, are even microscopic. About 90% of oceanic species have a free-swimming larval stage at the beginning of their life cycle. This is the initial life stage of the oyster. At ABC, the best performing oysters or experimental variants are retained by the program and used as parents for future generations. This is an animal that is kept for breeding purposes. The hatchery is also equipped with a facility to grow microalgae-food for oysters. The building is equipped with water pumps, filters, and holding tanks to draw and store clean river water, heaters and chillers to control the water temperature, and plumbing to deliver the water to oyster larvae tanks. The hatchery is also capable of housing and feeding oyster parents (broodstock) and young oyster seed. At ABC, the eggs we hatch are oyster eggs, and fertilized eggs develop into oyster larvae. In general, this is a facility where eggs are hatched under artificial conditions, often to optimize production of delicate early life stages.
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