Abstract: The specific growth rate of heterotrophic bacteria is determined by dividing the production between the biomass, is an indicator of the capacity of the bacterial population to replace its biomass. The eukaryotic heterotrophic flagellates and ciliates are important grazers on bacteria, thus potentially influencing the abundance by selective feeding within the ‘microbial loop’. Mid stream surface water samples from all the water courses selected were collected in a sterile glass bottles. Water samples were screened through Whatman GF/A (1.63 µm nominal pore size) glass micro fibre filters.