OCEANOGRAPHY 165 



grow it in pure culture and to i-einfect fisli with it so as to prove that 

 tlie death of the sahnon was due to a particular bacterium, which was 

 found in the lesions, in the skin. He has been interested in pursuing 

 this work over several years" time and as a result has come to the 

 conclusion, with quite a bit of supporting data, that the columnaris 

 organism is present at all times, that there are many strains of this 

 bacterium. Some of them are lethal and some are quite harmless. 



When the water temperature in a river system or a stream rises above 

 a certain critical point, and this may dilfer for dilferent species or 

 different strains, but for the particular strain in the Columbia River 

 I believe tlie temperature is 18° C- — I could be wrong on that — at any ■ 

 rate, vvdien the water temperature rises above that particular point, 

 there is a mutation that takes place and the organisms become virulent. 

 When they become virulent, they are callable and have caused a 

 mortality in the fish as high as 98 to 100 percent. 



There are two possibilities for the explanation for the virulence. 

 One is that it is a temperature effect and there are warm- water pockets, 

 building of dams slows the water down, and the appearance of the 

 virulent attacks on the fish have been correlated very closely with the 

 increase in water temperature. 



A second factor enters here: that is that the introduction of radio- 

 active waste from the plant at Hanford not only increases the water 

 temperature itself, but also increases the radioactive isotopes and it is 

 also a possibility that the presence of the radioactive materials may 

 themselves be responsible for inducing mutations in the bacterium, 

 which in turn becomes then virulent to the fish so that one must keep 

 an open mind, let us say, about the effects of radiation. 



If one studies just the fisli alone and finds that the fish are dying 

 from a bacterium disease and experience shows there is no direct effect 

 on the fish from the radiation itself, one must still not rule out the 

 possibility that there may be an effect which is due to another factor, 

 in this case the possibility of nuitation of bacteria which then become 

 virulent, and we come back down to the contribution of the pollnting 

 radioactive materials. 



I think this is a case where it is reasonable to look more closely into 

 the entire ecology^ of the river itself and to the entire picture of what 

 has caused the virulence of the vindent strains to appear and result in 

 the last analysis in the mortality of the fishes. 



Mr. Bauer. It is still within tlie realm of possibility. Doctor, is it 

 not, that there might be a resistant group of salmon that could carry 

 this disease and effect the entire salmon crop in the Pacific? Is that 

 not a possibility? 



Dr. Ray. I do not know whether any work has been done to follow 

 along the lines of that possibility. The fact that we know that the 

 bacteria are present at all times and only become virulent under cer- 

 tain conditions and we know for sure, I should not say for sure but 

 it seems reasonable that the main cause of virulence should be the in- 

 creased temperature, the radioactivity or both, and making a com- 

 parison from other studies with streptococcus, for example, it is shown 

 that many different environmental and biological factors can cause 

 a change from a non-pathogenic to a pathogenic strain. It means 

 that the carrying of the non- i^athogenic strain from one body of water 

 to another, let us say, if in the second body of water the conditions 



