Salt Dependency of the Bacterial Flora of Marine Fish

Abstract

SUMMARY: The bacterial flora on the skin of plaice (Kareius bicoloratus) caught in coastal regions of Japan was composed of bacterial groups heterogenous to the concentration of salt in their growth behaviour. Each bacterial group had a different minimum and/or maximum salt concentration for growth, and different groups were selected by media with different salt concentration. In the media based on two complex salt solutions, including an artificial sea water, the maximum bacterial counts were obtained at concentrations corresponding to about 25% dilution of sea water. During the storage of fish at 24° and 2°, bacteria which required higher salt concentrations for growth increased faster than that of non-halophilic bacteria. The microflora of the digestive tract of the fish was composed almost exclusively of halophilic vibrios.