Abstract
Fish farmers have the desire to increase productivity but are constrained by high cost of formulated feeds. This study quantified the performance and production cost of tilapia cultured in unfertilized and fertilized ponds in six earthen ponds with sizes between 200 m2 and 300 m2. All ponds were stocked with all-male Nile tilapia (Oreochromis niloticus) fingerlings (average size = 25.4±0.56 g) at 2 individuals per m2 and fed at 3% of their body weight for the unfertilized and fertilized ponds, respectively. The results showed a comparable mean weight gain of 204.2±36.3 g and 202.9±23.8 g for the unfertilized and fertilized ponds, respectively. Similar results were obtained for the specific growth rate (1.0±0.4; 1.1±0.4 %day-1), feed conversion ratio (1.1±0.2; 1.2±0.3) and feed intake with values of 0.7±0.5; 0.7±0.3 for unfertilized and fertilized ponds respectively. Total cost of production for the unfertilized treatment was USD$ 832.00 (273.97±86.48) and the unfertilized treatment amounted to USD$ 834.72 (274.88±60.34). A profit of USD$ 319.42 (106.48±90.99) and USD$ 353.05 (120.59±98.09) were realized for the unfertilized and fertilized treatments, respectively. The results of this study indicate that farmers could increase their pond's productivity and profit marginally through pond fertilization and feeding with formulated feed.

Key words: feeding level, inorganic fertilizer, tilapia, pond culture, cost-effectiveness