환경수의 수온과 암모니아 농도 변화에 따른 쥐노래미(Hexagrammos otakii Jordan et Starks) 육성어의 산소소비와 암모니아 배설

Abstract

This study investigated oxygen consumption rate (OCR), Q10 coefficient and ammonia excretion rate of the greenling, Hexagrammos otakii Jordan et Starks with the average body weight of 250 g in a semi-recirculated respiratory measuring system. The experiment was done under three different water temperatures (10, 15, 20℃) and five different ambient ammonia concentrations (0, 2.5, 5, 10, 20 mg/L). As the water temperature and ambient ammonia concentration increased the OCR has significantly increased (P<0.05). Given experimental conditions, the OCR of greenling were 50.8~159.4 mg O2 kg-1 hr-1 and the relationship of water temperature (T) and ambient ammonia concentration (C) on the OCR were following: OCR = 41.3 - 1.87T - 7.38C + 0.463T2 + 0.661C2 + 0.642TC - 0.011T3 - 0.010C2 - 0.031TC2- 0.001T2C (r2 = 0.9226). Q10 coefficients were 1.88~3.50 for 10℃ to 15℃, 1.03~2.73 for 15℃ to 20℃ and 1.40~1.90 for10℃ to 20℃, respectively. In general, the ammonia excretion rate tended to increase with increasing of the water temperature within normal ambient ammonia concentration. However, interestingly, it was observed that ammonia was absorbed rather than excreted above the ambient ammonia concentration of 2.5 mg L-1, regardless of the water temperature. Thus, the largest ammonia absorption rate (AAR) was obserbed at the level of 98.4 mg TAN kg-1 hr-1. The relationship ambient ammonia concentration (C) on AAR was following: Y = 1.61 + 10.9X0.7 (r2 = 0.889).