Optimal dose of total residual oxidants for hybrid tilapia (Oreochromis mossambicus × O. niloticus) and whiteleg shrimp (Litopenaeus vannamei) in ozone-treated sea water

Abstract

The purpose of this study was to use total residual oxidants (TRO) as an indicator for determining the optimal ozone dosage needed to control water quality and thereby enhance survival of cultivated aquatic organisms. When the TRO concentration was maintained at 0.16 mg/l for two hours, the total bacteria plate count dropped from 7.7 × 10 3 CFU/ml in the untreated sea water to less than 10 CFU/ml in the ozone-treated sea water. The TRO concentration in the ozone-treated water was well below the 96-h LC 50 for hybrid tilapia (Oreochromis mossambicus × O. niloticus) and whiteleg shrimp (Litopenaeus vannamei) determined in this study. Hence, adjustment of the ozone concentration in aquacultural sea water is a viable option that simultaneously kills the majority of harmful bacteria in the water and enhances survival of cultivated aquatic organisms.