612 Marine Microbiology 



habitat relationship on the normal, non-pathogenic flora of fish, 

 which appear to have yielded such contradictory results in pre- 

 vious studies, inspired them to carry out the studies reported 

 here. These investigations were designed to provide information 

 on the nature of the bacterial floras associated with vertebrate 

 and invertebrate animals in the Pacific Ocean, north of the equa- 

 tor.* It was hoped that some information might be obtained on: 



(a) the differences between the floras of different animal types 

 in the same area and the same animal types in different areas; and 



(b) what reasons exist for such differences, if they occur. 



MATERIAL AND METHODS 



The animals, both vertebrate and invertebrate, were sam- 

 pled in the field by the sterile swab technique using cotton swabs, 

 sterilized in separate 16 x 150 mm screw-capped culture tubes 

 containing 1 to 2 cc of aged sea water plus 0.5 per cent peptone. 

 The fish species caught in the northern areas of the Pacific Ocean 

 were taken in Puget Sound, i.e., from the waters off Port Orchard, 

 Gig Harbor and Golden Gardens, and from oceanic waters off the 

 Washington Coast. The swabs were transported to the laboratory 

 and streaked on seawater agar plates. The seawater agar con- 

 sisted of 0.5 per cent yeast extract, 0.8 per cent nutrient broth 

 (Difco), 1.5 per cent agar (Difco) and aged seawater (7). 



Cultures of littoral zone animals and of floating trav-grown 

 invertebrates were also obtained by the swab technique; after 

 aseptically opening the shell in the case of molluscs. In no case 

 did sampling and streaking on agar involve a greater delay than 

 twenty-four hours. 



The cultures from the southern Pacific Ocean areas were ob- 

 tained by the swab technique; the vertebrate and invertebrate 

 specimens were sampled directly in the field and the swab 

 streaked onto the surface of slanted agar in small ( V'^ oz. ) pre- 

 scription bottles. The bottles were transported by air to the labor- 

 atory and restreaked onto the maintenance medium described. 



The colonies appearing on the streak plates after five days at 



* The terms northern Pacific and southern Pacific are used in this paper to 

 designate areas more and less distant from the equator, respectively. 



