ABATING DISEASE AMONG BROOK TROUT. 945 



until about June i , when all the trees had leaved and water cress had grown to 

 good size, then losses in fry would cease until fall. 



In the fall of 1 906 I secured complete possession of the plant and at once cut 

 out this reservoir, laying dry the ponds it fed, disposed of all brook trout finger- 

 lings on hand and contracted all eggs taken excepting 18,000 eyed eggs from 

 wild stock. 



In the spring of 1907 I ordered made a galvanized iron raceway 277 feet 

 long, 18 inches wide, and 5 inches deep. This was put in place about June 10, 

 and fry were placed in the pond about June 15. The water entering the raceway 

 comes some 700 feet across the marsh, through a solid bed of water cress, and 

 is very cold. 



The loss in brook trout fry before they left the hatchery had been very slight, 

 and the still smaller losses outdoors were agreeably surprising. In fact, from 

 June 15 to September 15 the total loss was 152 fry. This pond was drawn once 

 a week and thoroughly cleaned. The fish were fed sheep's liver, always abso- 

 lutely fresh, and the pond was literally alive with water fleas and pond snails. 

 About this time we became so busy with other work that this pond was not 

 cleaned for about four weeks and the result was a loss of no fish, which had 

 become fungused, confirming my theories that unsanitary conditions had been 

 the cause of all this waste of fish and time. 



These fish were moved and sorted into two ponds farther down and esti- 

 mated, by counting a series, at 14,000 in number. A finer lot of fry it would be 

 hard to find. They were of a good size and color. I looked forward eagerly to 

 spring, as I was not satisfied that this would be a permanent success. They 

 were again moved and reassorted into larger ponds about April 22, 1908. As 

 a matter of course there is some loss in these fish — kingfishers, herons, snakes, 

 etc., destroying some, and a few dying of disease. 



In addition to the above I have about 450 two, three, and four year old fish. 

 The losses in these have been about two fish per month since spawning, last 

 fall. I have kept all of the hatch of brook trout, this season some 75,000. I am 

 thoroughly convinced that they can be reared successfully. In order to accom- 

 plish this desirable result the water must be pure and cold, the ponds kept 

 absolutely clean, and the food perfectly fresh and sweet. 



I believe that if conditions permit of changing the application of the water 

 supply these results can be obtained at other stations that have had this trouble, 

 provided the water is suitable to start with. At stations which derive their 

 water supply from brooks or ponds that heat and dry up in summer and freeze 

 hard in winter, it will be obvious that the case is hopeless. 



In conclusion, I will state that I will be pleased to give personally any further 

 information that may be desired. 



