As a part of the survey on environmental pollution of the Seto Inland Sea, Japan, a survey on the ecology of Salmonella and fecal indicator organisms in the sea water samples collected at eight stations (A to H) located on the coast of Fukuyama, was conducted in June 1972 through March 1974.
The results obtained were as follows:
1. The positive rate for occurrence of Salmonella in the samples collected at the eight stations was 12.1% (28/232) in average.
2. It was observed that the frequency of occurrence of Salmonella in the samples varied depending on the sampling stations and on the seasons. Positive rates in Salmonella detection as high as 23.9% (11/46) at St. A, 21.7% (10/46) at St. B, and 25.0 % (3/ 12) at St. E were observed. In the seasonal observations, a higher positive rate of occurrence of Salmonella was observed in the samples collected during May through October.
3. The frequency of incidence of Salmonella in the samples lowered as the sampling station went from the inner part of Fukuyama Port to the outer part of the Port and the offshore area.
4. Some of the forty-two strains of Salmonella isolated were serotyped to S. typhimurium, S. thompson, S. anatum, S. infantis, S. give, S. schleissheim, S. schwarzengrund, S. derby, S. montevideo, S. meleagridis, S. binza and S. senftenberg, and the O-groups B, C1 , D and E 1.
5. Most of the serotypes isolated in the present study were similar to those isolated previously from the river waters and feed-stuffs in this district by the authors. According to the results, it was proved that those serotypes of Salmonella contaminating the terrestrial environment have also contaminated the coastal marine environment as a terminal stage in the pollutive circulation.
6. The marine contamination with Salmonella may result into the contamination of marine products.
7. The higher values of the MPN and frequency of occurrence of the fecal indicator organisms were observed according to the order to coliforms, E. coli and enterococci. The incidence of coliforms was positive in most of samples examined, but those of the others were negative in some cases.
8. A high tendency of Salmonella recovery was observed in cases that represented high values in the MPN of fecal indicator organisms.
9. As a results of consideration on the relationship between the sea water temperature and the frequency of occurrence of Salmonella and of fecal indicator organisms, it was recognized that there is a high tendency of Salmonella recovery in the sea water samples that showed a high MPN value of fecal indicator organisms and were on a temperature higher than 19° C.