Most marine and freshwater fishes depend on plankton for food during a period shortly after birth until they are large enough to switch to other prey. At the Inland Fisheries Research Station, Narrandera (NIFRS), native fish are spawned and the larvae transferred to rearing ponds for approximately six weeks before the fingerlings are harvested. These ponds are managed to promote growth of the appropriate zooplankton so that the larvae can feed and grow.

Four larval rearing ponds were studied from when they were filled in early November 1986 until just before harvesting in late December 1984.