CHRONIC EXPOSURE OF CHANNEL CATFISH, ICTALURUS-PUNCTATUS, TO AMMONIA - EFFECTS ON GROWTH AND SURVIVAL

The growth of juvenile channel catfish (Ictalurus punctatus) was reduced in a linear manner during a 31 day growth trial when exposed to concentrations of ammcnia ranging from 48 to 989 μg/l NH3N (0.31 to 5.71 mg/l NH+4N). On a wet weight basis, growth was reduced by 50% at 517 μg/l NH3N and the no growth occured at 967 μg/l. The no growth level was 60% of 96-h LC50 value. Mortality was increased significantly at 989 μg/l NH3N and above. The sublethal effects of ammonia may depend, in part, on the concentrations of NH4+ and and Na+ in solution. © 1978.