Management of effluents from channel catfish ( Ictalurus punctatus) embankment ponds in the southeastern United States

Abstract

The unique nature of channel catfish ( Ictalurus punctatus) ponds in the southeastern United States is a challenge for effluent management. Most catfish ponds are used for many years without intentional discharge, but the region receives abundant rainfall, making it impractical to grow catfish in ponds without some water being discharged when ponds overflow. Overflow is, however, sporadic and infrequent, and the effluent is dilute with respect to nitrogen, phosphorus, organic matter, and solids. Furthermore, most of the organic matter and nutrients in pond effluents are associated with phytoplankton and other solids that do not readily settle. Overall, these characteristics make it difficult to formulate affordable post-discharge treatment technologies for effluents. The best approach to reducing mass discharge of substances from catfish ponds is to reduce effluent volume. This can be accomplished most effectively by increasing the interval between pond drainings and maintaining water storage capacity in ponds to capture rainfall. Mass discharge can be further reduced by draining ponds into low-gradient ditches with sufficient length to allow solids to settle before entering a public waterway.