Title: The effect of dissolved oxygen on fish growth in aquaculture

Commercial aquaculture is growing worldwide except in Africa where production is still low. With fisheries reaching a stagnating phase, the world and more so Africa will have to look to aquaculture in the future to provide fish products that will likely be needed. In view of this, a study on water quality management was done which specifically looked at the effects of dissolved oxygen saturation on fish growth. The study was done through a review of literature and a case study using Atlantic halibut. In the case study, halibut of 20-50 g in weight were reared in replicate at 60%, 80%, 100%, 120% and 140% oxygen saturation levels in a tank recirculation system. The subsequent effect of oxygen saturation levels on growth and feed conversion ratios were taken after two weeks. The results showed that oxygen saturation level had a positive effect on the growth and feed conversion ratio when it was set at 80%-120% saturation. At 140% the growth was slightly lower and the feed conversion ratio was higher at 60% and 140% compared to the other groups. The conclusion was that oxygen saturation level has an effect on growth and feed conversion ratios of fish, and in the case of Atlantic halibut, the growth rate is higher when the oxygen level is between 80% and 120%. The feed conversion ratio for halibut was lower at 120% oxygen saturation.