438 BULLETIN OK THE BUREAU OF FISHERIES. 



ery, and many larger and smaller springs in the pond itself, and that this supplies the 

 greater portion of the water to the hatchery. This water is supplemented by a large 

 spring B, forming one system of water supply, while the water from springs C and F 

 forms the other, the two systems uniting in race 12. The water coming from the large 

 pond is aerated in fountains K and L. Springs D and E tap a vein running in a northerly 

 direction at a depth of about 15 to 25 feet. The water from these two springs is now 

 used exclusively in the hatchery building for hatching this season's spawn. The large 

 pond A maintained in 1907 an unknown number of fish Uving under wild conditions, 

 being fish which from time to time were placed in the pond, where they had then shifted 

 for themselves. The pond is grass-grown about the banks, has a plentiful growth 

 upon its bottom, and presents practically an ideal approach to wild conditions. (Fig. 82.) 



In 1906 a brown trout approximately 2 years old was found dead at the outlet 

 of the big pond, and on examination presented two well-developed tumors at the junc- 

 tion of the gills. This was the first evidence of the disease which the superintendent 

 had noted. In September, 1907, pond A was emptied, a large portion of the fish in it 

 escaping into the brook. After cleaning the bottom, removing the grass, etc., the 

 pond was stocked with about 6,000 brook trout fry hatched in the hatchery, and sys- 

 tematic feeding with liver was, for the first time, practiced in this pond. From August 

 to October, 1908, a few of the yearling fish in the large pond were found dead with visi- 

 ble tumors. In October the fish in the lower races supplied from the big pond also began 

 to die in sufficient numbers to attract attention, and a large proportion of these were 

 found also to have visible tumors. During the summer of 1908 not less than 3,000 fish, 

 exclusively brook trout, died in this hatchery with visible tumors. During this period 

 of the outbreak some 175 adult rainbows held in one of the lowermost ponds, to which 

 ran the water from the spring running through the races seriously affected, remained 

 free from the disease, with the exception of i fish found late in the season. Some 

 4,000 yearling brown trout from Caledonia remained free from evidence of visible 

 tumors, as did also some 220 four-year-old brown trout from the same source. 



During the summer of 1909 epidemic conditions obtained in this hatchery in more 

 aggravated form than in any previous year. The stock fish as well as the fry were fed 

 almost exclusively on beef livers, obtained twice a week from the Buffalo abattoirs. A 

 large proportion of this liver fell to the bottom of the large pond and there decayed. 

 The food not eaten up in the races was brushed out frequently enough to prevent con- 

 tamination. About 200 pounds of beef livers were fed weekly in the hatchery. A 

 number of times livers were found with large single or multiple abscesses. 



The stock fish in the hatchery in 1909 consisted of the following, some lots of which 

 may be recognized as having figured in the occurrences in the hatchery of 1908 — 125 to 

 150 rainbows held in concrete race 13; 3,000 two-year-old brown trout from Caledonia 

 in races 22 and 23; 76 older brown trout; and 700 to 750 brook trout of varying size 

 and age. During the course of the summer the rainbow trout retained their relative 

 immunity to the disease, only 7 developing visible tumors during the summer, notwith- 

 standing the position of pond 13, receiving water from both water supplies, all of it 

 running through troughs and concrete tanks above, in which the disease was very active. 



