30 



no matter how they are bred; suppose that one-half of 

 all that are born perish before attaining a marketable 

 condition. In one case thai half has to be taken from a 

 supply already decimated, in the other nearly the full 

 number is to be drawn upon. Often thousand eggs de- 

 posited in the natural method, only twenty or thirty 

 hatch, one-half of these would give us but ten or fifteen 

 full grown salmon, whereas with the care of man nine 

 thousand can be hatched, and it one-half perish we 

 should have remaining four thousand five hundred, a 

 difference so great as to be almost incredible, yet these 

 results are obtained with reasonable certainty by trained 

 fish culturists who understand their business. 



CHAPTER III. 

 TROUT PONDS. 



LOCATION. It is very easy with good spring water to 

 raise 'dfew trout anywhere in temperate latitudes. But 

 to raise a large number requires care in the selection of 

 a location. Plenty of pure spring water is the first and 

 most essential requisite. The spring, or one of the 

 springs, if there are several, should have a fall of two or 

 three feet, and a fall of five to ten feet of the whole vol- 

 ume of water is decidedly advantageous. If the supply 

 of water is very large, it diminishes the necessity of a 

 fall. The water from a spring remains (near its source) 

 at nearly the same temperature during the whole year, 

 and is the best for Trout raising. The water from a 

 brook which does not rise higher than sixty five degrees 

 in summer, may be used to supply ponds for adult Trout ; 

 but spring water is not absolutely necessary for hatching 

 purposes. It is not a good plan to dam up a stream which 



