The Effect of Production Intensification on Water Quality in Pond Growout of the Freshwater Prawn, “Macrobrachium Rosenbergii”.

The freshwater prawn, Macrobrachium rosenbergii, is becoming a commercially important species in the south central United States including Kentucky. In pond production, several different management techniques and levels of production are being employed by growout farmers. This study compared the relative effect of production levels commonly used by growers in the region on pond water quality. Three different stocking densities (35,000, 48,000 and 61,000/ha and corresponding increased feed rates) were evaluated in 0.04 ha with two, three, and two replicate ponds per treatment, respectively. A 28% protein steam pellet diet was fed twice daily according to a feed chart based on the number and size of prawn. The effect of these management practices on water quality was measured as total ammonianitrogen, nitrite-nitrogen, and pH which were taken once per week. After 106 days, the overall means for total ammonia-nitrogen were significantly higher (P\u3c0.05) in ponds stocked at 61,000/ha (0.69mg/L) than ponds stocked at either 35,000 (0.51mg/L)or 48,000/ha (0.47mg/L); which were not significantly different (P\u3e0.05) from each other. Nitrite-nitrogen was also significantly higher (P\u3c0.05) for prawn stocked at 61,000/ha (0.04mg/L) than for prawn stocked at either 35,000 (0.01mg/L) or 48,000/ha (0.01mg/L); which were not significantly different (P\u3e0.05) by treatment and averaged 8.3 for all three treatments combined. These data demonstrate that stocking densities and feed rates used in commercial production and nutrient inputs can significantly impact water quality; however, the measured values in this study were probably not sufficient to cause negative impacts on prawn health or growth