FOREST, FISH AXD GAME COMMISSIONER. 205 



large quantities of shucks, and in soms instances many of their eggs develop 

 what is known as white sac. 



In exchange for smelt from the Cold Spring Harbor station, Foreman 

 Walters received some rainbows that were reared at the Bellefonte, Pa., 

 hatchery. Some eggs of this fish are purchased in Michigan. Thus an 

 attempt is made to introduce new blood and keep up a good supply of 

 healthy fish. 



Black Spotted Trout. 



Five thousand eggs of this species were taken in Little Green pond 

 at the Adirondack Hatchery, but all of the eggs which hatched died early. 

 The successful introduction of this species into New York waters has not 

 vet been accomplished. In many other localities it has been found extremely 

 difficult to obtain good eggs from black spotted trout retained in ponds. 

 A great drawback to the extensive distribution of this species is the late 

 spawning period. The eggs are taken in May or June, they have a short 

 incubation period, and on account of the high temperature of the water at 

 the time of spawning, the ova are transported only with great dimcultv. 



Browx Trout. 



The principal fatalities affecting this trout during 1906 were due to 

 the well-known ulcer disease, to a failure to feed in the early stages of 

 growth, and to acute inflammation of the gills and intestines caused by 

 feeding upon hard and rough particles of food. At the Pleasant Valley 

 station the greatest difficulty arose from the ulcer disease, already men- 

 tioned. This is thoroughly identified now as a disease due to pollution 

 by sewage or other foul matter. It is difficult to realize the injurious effects 

 of pollution by sewage in the trout waters of New York, and especially in 

 the streams which receive closet waste from residences, public institutions 

 and private establishments. In fact the work of fish culturists is so greatly 

 impeded from these causes as to seem almost hopeless, and there is no 

 reason why such pollution should be allowed to continue. It now causes 

 the death and disappearance of trout and other important game and food 

 fishes to such an extent as to render the future of fish cultural operations 



