TROUT CULTURE. 



7 $7 



among the amber ones, and an egg that has not been fertilized 

 often remains clear until the rest are nearly hatched, but it can 

 not stand any rough usage, and shows up in numbers after each 

 washing, and, if left for two or three days, will develop a fungous 

 growth that will attach the surrounding eggs in a mass and kill 

 them all. In our early work, when we hatched on fine gravel, 

 fungus was the bugbear : a dead egg would get down in the gravel 

 and send out its deadly tentacles unseen ; but with wire cloth and 

 daily supervision fungus is unknown. It is this that kills the 

 eggs in the brooks, and avoiding this cause of mortality from 



Front of Hatchery, showing Inlet Trunk from Reservoir. 

 By courtesy of Mr. W. H. Cooper, President of the Photo-Section, Brooklyn Institute. 



unimpregnated eggs is one of the reasons why we beat the meth- 

 ods of Nature in increasing a species by protection from its 

 enemies. 



At about fifteen days old the expert can take trout eggs in a 

 glass tube or vial and, by holding them above his eye, can see the 

 line of vertebrae which marks the impregnated egg ; a few days 

 later he can pick out the " ringers," or eggs which, having no fish 

 in them, retain the ring which they first had on top of the egg. 

 At thirty days, more or less, according to temperature, the eyes 

 show, and the development goes on until the hatching begins at 

 sixty to ninety or more days, according to the thermometer, but 

 the colder waters produce the strongest trout. 



