Bacteria Associated with the Gills of Salmonid Fishes in Freshwater


  • This work was supported in part by the Fish and Wildlife Branch of the Department of Recreation and Conservation, Government of the Province of British Columbia. The author thanks J. Terpenning and R. A. H. Sparrow for their assistance in collecting samples and to Karen Hastings Bartlett, Diane Chipman, Vida Money, Beverley Noton and David Burdge for their assistance in this laboratory. Dr A. J. Wood is thanked for helpful discussions, criticisms and suggestions during the progress of this work.


The bacteria on the gills of 7 species of freshwater salmonid fishes were examined qualitatively and quantitatively. Both wild and hatchery cultured salmonids were examined. The former were obtained from 12 different locations in British Columbia. Species of Pseudomonas and Cytophaga predominated on both groups of fish. The microflora of the wild fish also contained Aeromonas and members of the Brevibacterium–coryneform–Erysipelothrix group. The microflora of cultured fish was less varied. As many as 106 viable organisms/g wet weight of gill tissue were recovered.