WATER-QUALITY IN CHANNEL CATFISH PRODUCTION PONDS

A number of water variables were measured at 1- to 2-week intervals in five channel catfish (Ictalurus punctatus L.) production pond at Auburn, Alabama, during the 1978 growing season. Concentrations of most variables increased with time since feeding rates were progressively increased as fish grew. The DO concentration at dawn was often lower than 2.0 mg/liter during August and September. Emergency aeration was used one or more times in each pond to minimize the danger of fish kills because of low DO. In addition, unionized ammonia (NH3) and carbon dioxide concentrations were occasionally high enough to possibly have had adverse effects on fish. A computer simulation model for predicting the early morning DO concentration in ponds proved efficient. The average difference between measured and predicted DO concentration, disregarding sign, was 0.47 mg/liter for 30 trials. Spillway discharge from channel catfish ponds was more concentrated in pollutants than streams near Auburn, Alabama.