Culture of rotifer and their nutritional enrichment- Winter School on Recent Advances in Breeding and Larviculture of Marine Finfish and Shellfish

Rotatoria (=Rotifera) belonging to the smallest metazoa consist of 1000 species of which 90% inhabit in freshwater habitats. In the fifties and sixties though Brachionus plicatilis was first identified as a pest in the pond culture of eels but soon the Japanese researchers realized that this rotifer could be used as a suitable live food organism for the early larval stages of marine fish. Later in China also B. plicatilis is used as food in local shrimp and crab hatcheries. The rotifers are considered as an important live feed in hatchery operation due to their planktonic nature, tolerance to a wide range of environmental conditions, high reproduction rate (0.7-1.4 offspring/female/day), small size and slow swimming nature. The animals reproduce rapidly and can thus contribute to the build up of large quantities of live food in a very short period of time. The possibility of rearing these animals at very high densities (2000 animals/ml ) have been reported by (Hirata, 1979) and the growth is assured by plasma increase and not by cell division. More over the filter-feeding nature of the rotifers facilitates the inclusion of specific nutrients essential for the larval predators through bioencapsulation into their body tissues.