OXYGEN CONSUMPTION AND AMMONIA EXCRETION BY EURASIAN PERCH (PERCA FLUVIATILIS L.) REARED UNDER OPTIMAL THERMAL CONDITIONS
Zdzisław Zakęś*, Krystyna Demska-Zakęś**
*Department of Aquaculture, The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn, Poland
**Department of Ichthyology, University of Warmia and Mazury in Olsztyn, Poland
ABSTRACT. The aim of the study was to determine the oxygen consumption (OC, mg O2 kg-1 h-1) and ammonia production (AE, mg TAN kg-1 h-1) of perch reared in a recirculating system at the optimal temperature for this species of 23°C. The studies were conducted when the fish were undergoing intense fattening on artificial feed. Measurements of metabolic rate were taken 24 hours per day in six size groups of fish (mean body weights (BW) in each group – 18.4, 30.7, 46.4, 56.5, 67.8, 82.3 g). Within the studied perch size range, OC decreased from 336.2 to 185.0 mg O2 kg-1 h-1, and AE from 22.0 to 5.6 mg TAN kg-1 h-1. An increase in body weight by 1 g led to an average decrease in oxygen consumption by a mean of 2.53 mg O2 kg-1 h-1 and ammonia excretion by 0.28 mg TAN kg-1 h-1. During the analyzed period, the body weight of perch, the arithmetic dependence between OC-BW and AE-BW, was linear and the determination coefficients R2 of the linear regression equations describing these relationships were highly statistically significant at a value exceeding 0.9.
Keywords: PERCH (PERCA FLUVIATILIS), OXYGEN CONSUMPTION, AMMONIA EXCRETION, RECIRCULATING SYSTEMS
Prof. dr hab. Zdzisław Zakęś, Instytut Rybactwa Śródlądowego, Zakład Akwakultury, ul. Oczapowskiego 10, 10-719 Olsztyn, Tel./Fax: +48 89 5241022, +48 89 5240505;