The hatchery is a place where large broodstock oysters are spawned under controlled conditions to produce larval oysters for grow out. The broodstock are fattened up by providing water with plentiful microalgae so that they can produce the most high-quality eggs and sperm possible. Because oysters are broadcast spawners, they send out millions of eggs and sperm into the water at the same time to increase the chance of fertilization. Spawning is synchronized in the hatchery by placing the oysters under ideal spawning temperatures and then adding some gonadal tissue to the water to stimulate egg and sperm release. Once fertilized, the larval oysters remain in the water column for a period of days before settling on a hard surface, often oyster shell, to become spat. Individual oysters are created in a hatchery by allowing larval oysters to settle on microcultch, which are tiny oyster shell fragments that are about the size of a grain of sand. The newly settled oyster spat are then grown in a nursery setting with up or downwelling systems that draw food-rich water across them for the spat to consume. Once these juvenile oysters are large enough they are moved out to an oyster lease for growout.