Water renewal in static systems: Impacts on productivity and survival in Clarias gariepinus (Burchell, 1822)

Abstract

The impact of water renewal in a static system on the growth and survival of Clarias gariepinus fingerlings was investigated under six different treatments, namely: T₁ (daily water renewal), T₃ (three days water renewal), T₅ (five days water renewal), T₇ (seven days water renewal), T₉ (nine days water renewal) and T₁₄ (fourteen days water renewal). Results showed that growth performance and survival was significantly (P< 0.05) affected by the water renewal frequencies. After six weeks, weight gain, daily weight gain, specific growth rate, final body weight, was significantly higher in T₅ (P< 0.001). Likewise, survival in T₅ was significantly higher compared to other groups (P< 0.001). For all evaluated parameters, T₁₄ had the least performance. Slow response to feeding, slow movement and hanging on the water surface was observed in T₉ and T₁₄. Daily water renewal tank had significantly (p < 0.05) higher dissolved oxygen (04.52 mg L^-1) while electrical conductivity (800.00 μScm^-1) was significantly higher in T₁₄ (P< 0.001). From the result, the growth and survival of the catfish fingerlings in T₅ are superior to other renewal regimes. Therefore, for optimum growth and productivity of African catfish fingerlings reared in a static system, it is recommended that water renewal be performed every five days.

Key words: Clarias gariepinus, water renewal, weight gain, water quality, behaviour, feed conversion ratio, specific growth rate