Disinfectant effects of low level of total residual oxidants in artificial seawater on fish pathogenic microorganisms

Abstract

The disinfectant effects of total residual oxidants (TROs) produced by ozonization of artificial seawater on fish pathogenic bacteria and viruses were investigated. A dose of 0.1 mg TROs/l was not stable in natural seawater, but was stable in artificial seawater with a bromine compound (sodium bromide). By the treatment with TROs of 0.1 mg/l for 30 to 120 seconds, more than 99.9% of viable cells of Vibrio anguillarum, Aeromonas salmonicida, A. caviae, A. hydrophila, and Escherichia coli were killed, and 99.9% of infectivity of hirame rhabdovirus (HIRRV), infectious hematopoietic necrosis virus (IHNV), infectious pancreatic necrosis virus (IPNV), and yellowtail ascites virus (YAV) were inactivated. HIRRV was more than 99.7% inactivated by a treatment with a dose of 3.5 g/m3 of ozone gas bubbles for 1 min.