Caged Tilapia aurea were cultured for a 10-week period in four experimental ponds (between 10 and 26 acres) to determine how efficiently these fish are able to use plankton as a source of food and to determine the value of Purina Trout Chow and Auburn No.2 as supplemental rations for caged T. aurea in two common types of fertile farm ponds. Fingerling T. aurea were stocked at the rate of 150 fish per 0.25-cubic meter cage (0.956 pounds per cage). There were four cages per pond. Blooms of plankton were produced by inorganic fertilizer in two ponds which contained established bluegill-bass populations, and blooms of plankton were produced by a combination of supplemental feeding of catfish and inorganic fertilizer in the other two ponds which contained catfish under intensive culture. One cage of T. aurea per pond received no supplemental ration. Three cages of T. aurea received supplemental rations six days per week. The three rations consisted of Purina Trout Chow at 3.0 per cent of the weight of fish per day, Auburn No.2 at 3.0 per cent, and Auburn No.2 at 1.5 per cent. T. aurea consumed plankton efficiently enough for considerable growth. The mean production of T. aurea which received no supplemental feed was 8.90 pounds of fish per cage in the bluegill-bass ponds and 24.39 pounds of fish per cage in catfish ponds. C feed conversion values (Swingle, 1958) indicated that Auburn No. 2 as a supplemental ration in all cases was unsatisfactory. C values for T. aurea which received the Purina Trout Chow ration in the bluegillbass ponds were 1.0 and 1.5. C values for T. aurea which received the Purina Trout Chow ration in the catfish ponds were 3.3 and 6.3. There was less variation in weight among harvested T. aurea than among the fingerlings which were stocked. There was less variation in weight among T. aurea in catfish ponds than among T. aurea in bluegillbass ponds.
