Influence of pond fertilization and feeding rate on growth performance, economic returns and water quality in a small‐scale cage‐cum‐pond integrated system for production of Nile tilapia ( Oreochromis niloticus L.)

The effects of pond fertilization and feeding rate on growth, economic returns and water quality were investigated to develop a low‐cost cage‐cum‐pond integrated system for production of Oreochromis niloticus (L.). Hand‐sexed male fingerlings averaging 19±0.39 and 32±0.69 g were stocked in cages and open ponds at 150 fish cage −1 and 2 fish m −2 respectively. Fish were cultured for 114 days in five triplicate treatments. Cages were installed into ponds and caged fish were fed a 24% protein diet at 3% (T1) and 6% (T2) body weight day −1 (BWD) without pond fertilization, and 6% BWD with pond fertilization (T3). The open water in the fourth treatment (T4) was not stocked but contained caged fish, which were fed 6% BWD for the first 57 days followed by 3% BWD for the remaining period. Ponds in the control (T5) had no cages and were neither fertilized nor open‐pond fish fed. Feeding rate and pond fertilization significantly ( P <0.05) affected fish growth, profitability and water quality among treatments. Fish growth, feed utilization, fish yield, water quality and profits were significantly ( P <0.05) better in T3 than the other treatments. It was concluded that fish production and economic returns were optimized at 6% BWD in fertilized ponds.