l8o TWELFTH ANNUAL REPORT OF THE 



by the Commission for supplying a number of outdoor trout races, has 

 been purchased at a small cost, and is now available for permanent use. 

 Other springs in the hatchery grounds have been brought together and 

 are now used for supplying trout rearing races and ponds. A large quan- 

 tity of spring water which formerly was wasted in the hatcher} 7 creek has 

 now been diverted into the rearing basins. It is thought that the hatchery 

 and all the necessary races and ponds can be fully supplied with pure 

 spring water, and that the chief difficulties which have prevented the 

 development of the station have been removed. 



The old ponds which are known to be full of disease-producing germs 

 should be discarded or they may be treated with quicklime and by winter 

 killing before introducing spring water as a new supply. In this way it 

 is more than probable that we shall entirely eradicate the most trouble- 

 some source of mortality among the brown trout at the Pleasant Valley 

 station. So fatal is this ulcer disease to the brown trout that the station 

 lost nearly all of its brood fish before the ravages of the disease were checked. 

 It is known that a rapid flow of fresh water will ameliorate conditions pro- 

 duced by the ulcer disease. Acting upon this knowledge, the brood brown 

 trout were liberated in the creek, and many of them were restored to health 

 and were captured during the fall of 1906, when the spawning season com- 

 menced. Some of these trout were, of necessity, kept in the old ponds 

 from which they had previously been removed, and they immediately 

 began to show evidence of the ulcer disease. Many of them died, and the 

 remainder were released, as before. 



The best account of the ulcer disease is that of Dr. Hofer in his Fisch 

 Krankheiten, pages 4-9, from which certain extracts have been translated 

 and sent to stations at which the same trouble has been observed. These 

 notes are in the chapter on Diseases. 



The repairs at Pleasant Valley station included new work on the 

 hatchery floor and roof, the icehouse and other outbuildings, the walks, 

 painting, and other customary station improvements. There is some 

 doubt as to whether brook trout can be handled as effectively at Pleasant 

 Vallev as at some of the other trout establishments, but with the new and 

 improved conditions, an effort will now be made to increase the efficiency 

 of this station. 



