Bharat R. Sharma

Water quality dynamics in secondary reservoir for intensive fish culture

Water quality management is a key factor in intensive fish culture. Higher stocking densities, intensive feeding and released metabolites may cause rapid deterioration of water quality (MILSTEIN 1990). Secondary reservoirs are mostly used to regulate and store water for irrigation to be used under unfavourable conditions ofwater availability. Water exchange due to irrigation water routing through such reservoirs provides an opportunity for maintaining a water quality regime at optimum level for intensive fish production. However, for groundwater-fed systems, some aeration mechanism is necessary to replenish dissolved oxygen (DO) levels in the pond water during water exchange (Bovo 1998). Hence, the two distinct uses of the secondary reservoir (irrigation regulation and fish culture) need to be balanced to accrue optimum benefits from each use. The concept o f fish pond-cum-secondary reservoir (Fig. l)