| Chronic effects of ammonia were studied in juvenile seabass, Dicentrarchus labrax (mean weight= 11 g), exposed for 63 days to eight stable ammonia concentrations, ranging from 0.24 to 0.90 mg l(-1) unionised ammonia nitrogen (UIA-N), respectively, from 6.1 to 22.3 mg l(-1) total ammonia nitrogen (TA-N). Temperature (21.8 degreesC), pH (8.0), salinity (37.0 ppt), and oxygen concentration (over 80% saturation at the outlet) were maintained constant. Fish were fed using a self-feeder device, and they were starved during the last 8 days. Mortality of 28.9 and 42.6% occur-red within the first 8 days at the two highest UIA-N concentrations, respectively, 0.90 and 0.88 mg l(-1). From days 0 to 55, a 1.8-fold increase in weight gain was observed under the 0.90-mg... |
