SURVIVAL OF THE FISH PATHOGEN AEROMONAS-SALMONICIDA IN THE MARINE-ENVIRONMENT

The fate of the fish pathogen Aeromonas salmonicida in the marine environment was examined by culture, epifluorescence microscopy, the indirect fluorescent antibody technique (IFAT), direct viable counts (= Kogure technique) and the assessment of respiratory activity by the reduction of tetrazolium compounds to coloured formazans. In laboratory-based systems containing sediment, water, algae and invertebrates, cells of A. salmonicida were observed microscopically after plate counts on tryptone soya agar declined to zero. Survival was maximal at a salinity of 25 part per thousand, and in wood and sediment, notably mud, rather than the water column.