92 American Fisheries Society. 



Pacific Coast Fisheries College to examine the rainbows in their native 

 haunts. 



Mr. Doze : Is there any indication that Octomitus has ever attacked 

 our scale fishes of the warmer waters, including the sunfish, or the cat- 

 fish? 



Dr. Moore: There are no records in this country of its occurrence 

 in any fish except trout. In Europe however, its presence, or that of 

 a similar organism, has been noted in a carp feeding at a hatchery outfall 

 where infection by Octomitus was prevalent. It has also been found in 

 the marine fishes, Box and Motella, in the Mediterranean. 



Dr. Embody: Through the kindness of Mr. Hayford and the Fish 

 Commissioners of New Jersey, I was fortunate to have placed 

 at my disposal a number of specimens of trout infested with 

 this particular organism, Octo^nitus. Upon referring to Dr. Moore's 

 paper, we were able to identify it definitely. There was one 

 diagnostic character that I noticed which I should like to mention. It 

 refers to the greatly distended condition of the upper intestine, giving 

 the appearance of a fish that has been greatly overfed. I thought, 

 when I first obsei'ved it, that the fish was gorged with food, but, on 

 examination, I found that the intestine was destitute of food, and filled 

 Mnth gas. In nearly all the fish in which we found the intestine dis- 

 tended, there were large numbers of this particular organism. If it 

 proves to be a good diagnostic character, coupled with the other diag- 

 nostic characters that have been mentioned, it would be a very good way 

 to tell whether or not the disease occurs naturally. However, the only 

 sure way of recognizing the disease is to examine the intestinal fluid 

 with the microscope. Even then, unless you have had the organism 

 pointed out to you before, it may not be possible to tell whether this is 

 the particular organism that is causing the trouble. 



Another point has come to my attention which bears upon the 

 question of how this organism can be carried. Dr. Moore has stated 

 that it exists in the encysted form which is resistant to influences that 

 will destroy other active organisms. If such is the case, would it be neces- 

 sary for it to exist in the egg of a fish in order that it might be trans- 

 mitted from one hatchery to another? In connection with our method 

 of dipping eggs out of a tray, dumping them on another tray and sur- 

 rovinding them with moss for shipment, would it not be possible to 

 transfer some of the encysted forms in this way from one hatchery to 

 another? Might not that have been the case in the transportation of the 

 brown trout from Europe to this country? 



Dr. Moore: It seems quite probable. Your observation regarding 

 the distended appearance of the intestine due to an accumulation of gas 

 seems to me not altogether trustworthy as a general symptom, though it 

 may be found so locally. Gas accumulations occur apparently in 

 connection with the development of yeasts in the intestine. These 

 I find do accompany the organism Octomitus at times in great quantity. 



