Effects of Water Exchange on Water Quality in Channel Catfish Ponds

摘要

Nutrient and organic matter removal from catfish ponds by water exchange or biological extraction was investigated. Separate trials were conducted to determine losses of added phosphours, nitrate, nitrite, ammonia, and chemical oxygen demand. Chloride was added to ponds as an inert tracer to estimate the efficiency of water exchange. In spring (March-April), average water temperature and plankton biomass were low (15.1C and 10 micrograms/1 chlorophyll a), and water exchange at 134 m3/hour per hectare for 72 hours removed concentrations faster than in situ biological processes. In summer average water temperature and plankton biomass were high, (29.5C and 101 micrograms/1 chlorophyll a), and biological extraction of nutrients and organic matter was equally as effective as water exchange in reducing concentrations.