American FisJicrics Society. 37 



bottom is near freezing — ordinarily it is between 34 and 36 de- 

 grees at the bottom. It stays there all winter, and the lake 

 reaches a temperature within a fraction of that a very short dis- 

 tance below the surface, so that you see it is not very much 

 warmer at the bottom. 



Mr. Davis: Is it not possible the death of these fishes is 

 caused more by epidemic than it is by what they live upon? Last 

 week I was north near Baldwin, in this State, and I learned there 

 that the trout were dying. A certain kind of trout, the brown 

 trout, were dying in considerable quantities in one of the streams. 

 I did not have an opportunity to see any of the dead fish, but I 

 made arrangements to have some of them sent here to Detroit. 

 A sort of epidemic seems to have attacked the brown trout there, 

 but none of the rainbow or brook trout died. Now, we consider 

 the waters of the Pere Marcjuette River and its branches pretty 

 pure water, and it strikes me there must be something- of an 

 epidemic. 



Professor Birge: There was evidently an epidemic here, to 

 cause the death of several millions of the population of this lake. 

 That was entitled to be called an epidemic, but the trouble was 

 to find out what the cause of the epidemic was. We looked for 

 all sorts of parasites, internally and externally, and we could not 

 find anything significant. 



Mr. Davis: I understand the brown trout up north are cov- 

 ered with sore spots. 



Professor Birge: That would indicate they are attacked by 

 a fungus, then. 



Mr. Davis: And by the lamprey eels. 



Chairman Whitaker: It is rather a singular thing, that only 

 the brown trout should be afifected. 



Mr. Clark: I do not suppose there is anything remarkable 

 about its affecting one kind of trout in a stream and not another. 

 VVe found that right in our ponds. We had an epidemic at 

 Northville over a year ago which simply depleted our ponds of 

 brook trout. Of course, we had to look around to see what 

 caused it. The brown trout in the same water were not afifected 

 at all. That is probably the case with this stream, it afifects the 

 brown trout and not the others. 



Dr. Parker: In mentioning whitefish, you spoke about their 

 food possibly being afifected by the condition of the water at the 



