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Developing economically viable pond production systems has been the focus of recently completed freshwater prawn (FWP) research at the Coastal Aquaculture Unit (CAU, Mississippi State University) in Gulfport, Mississippi, USA. Growers' interest in raising FWP depends on the economic viability of the enterprise relative to other aquaculture species. The overall goal of this experiment was to demonstrate the viability of low stocking density and low input use in FWP pond production. Four 0.10-ha ponds were used in the pilot demonstration project. Rotenone was applied in the ponds on May 21, 2004 to eliminate predators. Varying amounts of hydrated lime Ca(OH)2 were added to raise alkalinity to above 20 mg/L. Liquid fertilizer was applied in two treatments, June 3 and 16 at a rate of 2.5 qt/pond through a floating platform. FWP juveniles were stocked on June 17. The juveniles were purchased from a FWP hatchery/nursery in Ocean Springs, MS and were transported by truck to CAU. O2 was maintained during transport with the use of diffuser stones and oxygen bottles. DO was monitored in the holding tubs during transport with a DO meter. The average pond temperature during stocking was 28.7 oC. The water temperature of the transport tubs was 2 oC lower so the juveniles were acclimated for 30 min by replacing half the volume of water in the transport tubs with pond water. This raised the water temperature by 1 oC. The juveniles were then stocked at a rate of 1.13 kg/ha or 2,270 juveniles/pond. The average weight of the juveniles during the time of stocking was 0.50 g. Pond temperature and DO were recorded twice daily with an early morning reading and a mid afternoon reading. Conductivity, hardness, alkalinity, total ammonia nitrogen, nitrite, salinity, and pH were recorded weekly. The FWP were fed a diet of 32% sinking catfish feed at the ration of 3% total biomass three times/week. The projected feed conversion ratio was equivalent to 1:1. Sampling for average FWP weights in each pond was conducted monthly. Ponds were provided with constant aeration (1.62 hp/ha) during the entire experiment. The FWP will be harvested 120 days from stocking date. During harvest, the following data will be collected: yield, survival rate, size distribution, feed conversion, molting rate, gravid females and tail yield. |