WATER QUALITY AND MASS BALANCES IN A CULTURE OF JAPANESE FLOUNDER USING A CLOSED RECIRCULATING SYSTEM WITH FOAM-SEPARATION AND NITRIFICATION UNITS
Y. Suzuki, T. Maruyama, D. Sato, T. Kanda, T. Michishita-2000
Nippon Suisan Gakkaishi, 66 (1): 1-9 (from Current Contents)
Abstract:
In this study, water quality and mass balances in the closed recirculating culture of Japanese flounder were examined. The closed system consisted of rearing thank, foam-separation and nitrification units, pH and temperature controlling units, and a circulation pump. Fish were fed commercial pellet diet for 90 days. Average values of oxygen saturation and turbidity in the rearing water through the culture were 96% and 3.1 TU, respectively. Ammonia was mostly kept at less than 1 mg-N/l, and nitrate increased linearly according to the amount of diet supplied. It is estimated that 33% of dietary carbon (C) was accumulated in the fish, as well as 52% of nitrogen (N), and 26% of phosphorus (P). The carbon released as CO2 was 63%. Nitrate in the rearing water corresponded to 28% of N-input, and 66% of P was settled in the nitrification unit as precipitate.
(Suzuki Y, Miyazaki Univ, Dept Civil & Environm Engn, Miyazaki 8892192, Japan)