During the cruise of R. V.' METEOR' in the northern Gulf of Oman from 25 to 30 March and from 14 to 16 April 1965, plate counts on ZoBell's Medium 2216 E were received from 95 water samples of 15 stations to study the distribution of saprophytic bacteria in this part of the Arabian Sea and their correlation with salinity, temperature, turbidity and oxygen concentration.

The highest bacterial numbers were usually found just above the thermocline in 20-30 m depth. The counts were significantly greater along the Arabian coast than on the Iranian side of the gulf. In the samples of the Persian Gulf higher bacterial numbers were present than in the surrounding Indian Ocean water of lower salinity. This may be explained by higher nutrient concentrations of the water coming from the Persian Gulf. Five to 20 per cent of the bacteria growing on ZoBell's Medium 2216 E were luminescent forms. However, only less than 5 % produced pigments. Most of the isolated Strains are motile gram negative rods, and strongly proteolytic.