THE INFLUENCE OF THERMAL CONDITIONS DURING TANK REARING ON FURTHER GROWTH OF WHITEFISH LARVAE (COREGONUS LAVARETUS L.) IN ILLUMINATED CAGES
Dariusz Dostatni, Andrzej Mamcarz, Jacek Kozłowski, Paweł Poczyczyński
Department of Fisheries, Warmia and Masuria University in Olsztyn
ABSTRACT. Whitefish larvae were reared in tanks and cages for 8 weeks. Tank rearing lasted 3 weeks and was carried out in two tanks, at 14oC (tank A), and 18oC (tank B). The larvae were fed artificial feed. Higher temperature resulted in better fish growth (17.4 mm, 27.9 mg) comparing to lower one (15.7 mm, 19.1 mg). Subsequent rearing was carried out in illuminated cages; it lasted 5 weeks. The fish fed only on zooplankton attracted by light. Results of the experiment revealed considerable impact of water temperature during tank rearing on later growth of whitefish larvae in cages. Average body weight of the fish pre-reared at 18oC was 380.0 mg at the end of the experiment, and length 37.6 mm, and of the fish from 14oC – 232.2 mg and 32.6 mm respectively.
Key words: WHITEFISH LARVAE, REARING, WATER TEMPERATURE, ILLUMINATED CAGES