Live animals and plants are used as food for many types of commercially important aquatic organisms, and although research continues, inert feeds have not fully replaced live foods. In particular, microalgae are of great importance to the commercial culture of bivalves, crustaceans, zooplankton, and to a lesser degree, finfish. Primary producers such as algae form the base of the pyramid, and as such constitute the largest link in the food chain. Zooplankton, specifically rotifers, are indispensable in the intensive culture of marine larval finfish and additionally serve as food for a number of other taxa. Therefore, the establishment of simple and reliable long-term preservation of these microalgae and zooplankton is indispensable to make the efficient larval rearing methods of marine finfish and invertebrates. Cryopreservation is one of the ideal methods, however, it is not entirely accomplished. Therefore, batch style culture and semi-continuous culture have been popularly used in the preservation of food organisms. In this paper, I will introduce the practical preservation methods which have been adopted in many hatcheries in Japan.
