Conservation Commission. 259 



Brook Trout. 



Mr. E. S. Casselman took some brook trout eggs in Lake Dela- 

 ware, "N. Y., in the fall of 1911 which were the largest he had 

 ever seen, some of them counting 280 to the fluid ounce. 



Considerable mortality has been caused at some stations by gill 

 inflammation due to the presence of a flagellate related to the 

 genus Costia. The remedy for this parasite is common salt. 



It is not uncommon to lose brook trout fry, as well as fry of 

 other species, through their failure to take liver which is the 

 usual food for young trout, and recourse must be had to some other 

 materials which will tempt their appetite. Mr. Walters, of Cold 

 Spring Harbor Hatchery, has sometimes coaxed the fry to feed 

 upon an emulsion of sand worms. Mr. Redband, at Caledonia, 

 has employed the juices of the freshwater shrimp for a similar 

 purpose, and Mr. Otis, of Upper Saranac, has fed the juices of 

 freshwater clams, Unio complanahis, to brook trout fry which 

 had refused to feed. 



Overcrowding in hatchery troughs and imperfect preparation 

 of food sometimes causes heavy loss of brook trout through in- 

 flammation of the gills and intestines. Trout of the same age 

 held in large fry ponds and fed more carefully have shown no 

 loss. Great care must be exercised in grinding the food and in 

 giving the fish an ample supply of water. 



Eggs taken from yearling female trout do not show as good a 

 percentage of fertilization as those obtained from older fish; but 

 the fry produced from eggs of young fish are just as vigorous as 

 those from eggs of older stock. 



When trout eggs have reached the age of forty-eight hours they 

 are in a critical stage for railroad transportation. Rough handling 

 has caused very heavy losses which may not be evident until after 

 about two weeks from the time they reach destination. This 

 trouble is obviated when the eggs are accompanied by trained 

 men. 



Lake Trout. 



During an inspection of Lake George, July 11 to 13, 1912. it 

 was learned that professional fishermen had caught a large num- 

 ber of lake trout during the season, and tliev were still taking 



