Beginning on May 13, 1980, prawns were cultured at the Rockefeller Wildlife Refuge for 140 days from postlarvae and fed. Production in ponds receiving Ralston Purina Experimental Marine Ration #25 averaged 408 kg/ha, 619 kg/ha and 510 kg/ha for the respective replicated stocking densities of 2.5/m2, 4.9/m2 and 7.4/m2. Average feed conversion factors were 1.0, 1.0 and 1.5. Average prawn weights at harvest decreased with increased stocking density and were 21 g, 17 g and 12 g, respectively. Production per pond ranged from 390 kg/ha to 832 kg/ha. An average of 77% of prawns stocked at 2.5/m2 exceeded 115 mm TL whereas the stocking densities of 4.9/m2 and 7.4/m2 yielded only 32% and 31% over 115 mm.
Extra postlarvae remaining after the stocking requirements for the feeding study were met permitting additional tests. Stocking rates selected for these additional studies were 1.2/m2, 2.5/m2 and 3.7/m2. Prawns in these ponds received no supplemental feed and yielded harvests of 124 kg/ha, 224 kg/ha and 292 kg/ha, respectively. These treatments, the first two of which were not replicated, resulted in production similar to that of an earlier study of prawn production on natural forage in brackish ponds at this facility. Average prawn sizes at harvest were 18 g, 15 g and 12 g, and were inversely related to stocking densities.