WATEE FOE TEOUT CULTUEE 89 



As an axiom, a fish-culturist should bear in 

 mind that if losses occur they are almost sure 

 to be wholesale and not retail, so to speak. 

 Trifling changes in the character or conditions 

 of the water-supply may mean the loss of every 

 fish. In 1889, the Pennsylvania Fish Commis- 

 sion lost over 2,000,000 advanced fry, partly be- 

 cause, during a thaw after a severe snow-storm, 

 a vast quantity of surface water flowed into the 

 spring which supplied the hatching troughs, 

 and so diminished the supply of oxygen that 

 there was not sufficient to sustain the lives of 

 the little creatures. Hence, when a station is 

 located, it is advisable to so guard and wall in 

 the spring that little or no snow, or in fact, 

 surface water of any kind, can flow into it. 

 What is of equal importance, drainage from 

 barnyards, tanneries, or any industrial estab- 

 lishments, must be carefully excluded from all 

 water used, for pollution of that character is 

 fatal to trout. Such pollution, indeed, is to be 

 guarded against in all pisciculture. 



It is not absolutely necessary that water be 

 very cold to raise trout successfully. Nor is it 

 essential, as before stated, that it be of an even 



