Removal and utilization of nutrients by Chinese waterchestnut in catfish ponds

Abstract

The effect of Chinese waterchestnut ( Eleocharis dulcis) on production of channel catfish ( Ictalurus punctatus) and resulting water quality were studied in 1975 in 0.04-ha earthen ponds at Clemson University. Ponds containing waterchestnut had significantly lower levels of nitrate nitrogen and ammonia nitrogen. These lower nitrient levels resulted in lower phytoplankton levels in ponds with waterchestnut. Data indicated that Chinese waterchestnut had no effect on channel catfish production. Poor fish survival may have prevented detection of any effect of waterchestnut on catfish production. Chinese waterchestnut removed nutrients from the pond water. Mean nutrient removal per ha for the 201-day growing season was 108.06 kg of nitrogen, 6.90 kg of calcium, and 37.46 kg of magnesium. Mean corm production was 4664 kg per ha. These data indicate that Chinese waterchestnut should remove nutrients in sufficient quantities to improve water quality and allow increases in feeding rates and greater catfish production.