Nursery Production of Golden Perch, Macquaria ambigua, at Two Densities in Ponds.

Golden perch, Macquaria ambigua (Richardson), is a freshwater percichthyid native to inland eastern Australia. Growth and feeding of this fish in pond aquaculture conditions was studied in nursery phase at high (95,300/ha) and low (32,800/ha) density over 126 days. Mean growth of golden perch at both densities was similar, but there were significantly more small fish in the high-density treatment. Coefficient of variation was high in both treatments (72-79%). After 126 days, 67% of the fish in both treatments reverted to natural foods. Reversion from pelleted diet to natural foods was very rapid in the low-density treatment (<14 days), but slower in the high-density treatment. Golden perch were found to be selective feeders. The smallest fish selectively ate water fleas, Moina sp., from the zooplankton, and larger fish ate chironomids and caddis flies (Trichoptera). Golden perch, which fed predominantly on pellets, grew 54% faster than those eating natural foods. Three to four months of an intensive nursery period, followed by grading for grow-out, is recommended to separate fast growing pellet feeding fish from slower growing fish that have reverted to eating natural foods. [ABSTRACT FROM PUBLISHER]