Marine microorganisms associated with the food of young salmon.

The biomass of microorganisms in the digestive tracts of young salmon in the sea of Saanich Inlet was examined by (i) the direct microscopic method, (ii) the plate count method and (iii) the physiological method (microbial biomass assumed from the release of carbon dioxide). By all methods, most microbial biomass in foods was shown to decrease during its stay in the digestive organ. This observation was supported by the detection of many bacteria at different stages of digestion. The microbial biomass was quantitatively influenced by the composition of food ingested and by the sampling time.