Conservation Commission 353 



banks. The rest of the food will usually be divided among thirty 

 species, more or less, according to the various chances of wander- 

 ing, weediness of feeding grounds, time of feeding, etc Scap- 

 holeberis, as observed by the writer in the case of about fifty 

 young bass, is about 1 per cent, of their food. 



" Very respectfully, 



"( Signed) A. A. DOOLITTLE." 



Flatfish 

 During the month of March, 1913, Foreman Walters, of Cold 

 Spring Harbor Hatchery, hatched and planted 70,000,000 flatfish. 



Fish Enemies 



At the Chautauqua Station, in 1913, a shitepoke (a species 

 of heron) destroyed a number of trout, but was finally captured 

 and destroyed. The crow blackbird was also frequently seen 

 taking trout in the cement ponds outside of the hatchery building 

 and many of these birds were killed to protect the trout. 



In May, 1913, the foreman of the Adirondack Hatchery re- 

 ported that the young Chateaugay Lake whitefish which he was 

 trying to rear in the hatchery were killed by hydra which are 

 very numerous in the lake water which comes into the deep pipe. 

 Through the courtesy of the assistant secretary of the Smith- 

 sonian Institution, in charge of the V. S. National Museum, this 

 was identified as Hydra fusca. 



Fish Diseases 

 An epidemic among trout at the Caledonia hatchery broke out 

 early in July, 1913. Fingerling brook trout, brown trout and 

 rainbow trout were affected by a vegetable parasite known as 

 Bacterium truttae which originates in putrefying organic wastes. 

 It was a surprise to see the rainbow trout attacked because this 

 trout is generally immune to such parasites. The damage caused 

 was considerable; but was partially controlled by the free use of 

 salt, and by thinning out the fish. The conditions were aggra- 

 vated by the intensely warm weather. At this time the trout at 

 the auxiliary station, at Guthrie's, were all in prime condition 

 owing to the lower temperature and purity of the spring water. 

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