Disinfection of Hatchery Water Supply by Ultraviolet (U. V.) Irradiation-II

U. V. Susceptibility of Some Fish Pathogenic Fungi

Abstract

Cidal effect of ultraviolet irradiation on 10 strains of fish pathogenic aquatic fungi and 6 specises of bacteria including fish pathogens were examined.
The results obtained are summarized as follows :
1) The punched agar medium disk covered with fungus hyphae was employed for the measurement of susceptibility to ultraviolet irradiation of aquatic fungi. The hyphae of 10 strains of aquatic fungi, i. e. Saprolegnia parasitica IFO 8978 etc. show relatively lower susceptibility to ultraviolet irradiation compared with the bacteria. The minimal fungicidal dosage of ultraviolet irradiation, inhibition of growth of hyphae, was 154-252×10³μW·sec/cm².
2) This dosage was about 50 times higher than the minimal bactericidal dosage of ultraviolet irradiation for destruction, at least 99.9% of viable bacterial cells.