Nightly aeration to increase production of channel catfish.

Abstract Channel catfish (Ictalurus punctatus) were stocked in 0.02- and 0.04-hectare ponds at 20,385 fish per hectare and fed daily. Fish averaged 11 cm total length and 6.2 g at stocking. Six ponds received nightly aeration (2 to 6 hours) and six ponds received no aeration. A maximum feeding rate of 90 kg/hectare was reached in October. In aerated ponds, no dissolved oxygen (DO) problems occurred, and survival was 92%. Fish mortalities resulted from DO depletion in all unaerated ponds, and survival was 40%. Nitrite-nitrogen concentrations were significantly higher in the aerated ponds, though never at levels reported as lethal to channel catfish. Concentrations of un-ionized ammonia were high enough in both aerated and unaerated ponds to have adversely affected growth. Aerated ponds yielded an average of 5,307 kg/hectare of channel catfish and had a net economic gain of $1,500 per hectare. The unaerated ponds yielded an average of 1,400 kg/hectare and were an obvious economic failure. Direct extrapolati...