Title: Mass balance and water quality in aquaculture tanks

Total nitrogen, total phosphorus and total energy balance models were established for rainbow trout in aquaculture tanks and water quality was evaluated. Weight gain, energy consumption, and fish composition were measured and their dependence on fish weight was assessed. Using known feed inputs of nitrogen, phosphorus and organic matter together with nutrient retention and energy consumption, models were established to quantify the waste discharges from rainbow trout in aquaculture tanks. The waste discharge was found to be strongly dependent on feeding ration.