Ame?'icaii Fisheries Society. 79 



Mr. Xevin: At Bayfield Ave do not have the loss until the 

 spring of the year. The water goes down to 33 or 34 degrees and 

 as soon as it begins to warm up in the early summer our loss 

 commences. At Madison we have our greatest loss in January 

 and February while in Bayfield it is in May and June. 



Prof. Marsh: Mr. Clark's experience is that this disease 

 affects yearlings especially and that he has never had it in the 

 adult crop. The yearling appears to be especially susceptible^ 

 but later the disease attacks the fry, and we have never had it in 

 fish over two years old. It comes in yearlings more than in other 

 fish. 



Mr. ]\Iatbewson : In Connecticut we lost lots of our fry in 

 the troughs before we got them out into the ponds at all — lost 

 them by thousands — and we were using the same water as with 

 yearlings, but we did not lose any of our yearlings. We have not 

 been able to account for this fact. 



Prof. Marsh : Was it brook trout ? 



Mr. Mathewson : A^es, we lost thousands of frv in the trough. 



Mr. Titcomb : We have not had what we call an epidemic 

 either at the state hatchery or the national hatchery, but we have 

 had in two or three instances cases where the fry in one trough 

 supplied with water from the supply trough would turn right 

 over and all die, where the fry in the other troughs right next to 

 them would be strong and lu'althy and go through all right. We 

 could not account for that. 



Mr. Mathewson : That was our experience this year. 



Mr. Sykes : The change of environment has brought them 

 out all right at Madison. Even a fry that is a little weak, when 

 taken out into the pond receiving water from the hatchery, comes 

 out all right. The change of environment seemed to be what 

 was required. 



Prof. Marsh: There was no greater amount of water but 

 more room. 



Mr. Sykes: That is true. There was a different bottom, as 

 they were taken from a gravel bottom and put on a mud bottom. 



Prof. Marsh : There might be something I suppose in mere 

 change. 



The President: This discussion is very interesting to the 

 Michigan Fish Commission, because we have just secured an 



