140 FISH CULTURE. 



waters. "Where such communication, however, is im- 

 practicable, then the best unmigratory fish that can be 

 introduced should be procured and encouraged. 



Few lakes exist that are not favourable to the 

 breeding or introduction of the trout, and I have 

 already shown the best methods of proceeding with 

 them. It will, however, be found that many small 

 and even large lakes abound to profusion in very 

 small trout. The smallness of these trout no doubt, 

 in a great measure, proceeds from their being too 

 numerous for the food found in the lakes. If the 

 introduction of an extra amount of food, by the various 

 means I have pointed out, be either impracticable or 

 not thought worth the trial, the only way left is to 

 reduce the number of trout ; this can be done by 

 netting, or by putting into the lake a certain number 

 of jack, in order to keep the small trout down. But 

 this last is a dangerous experiment, and, if decided on, 

 these jack should he ALL males, in order that they 

 may not breed, so as to increase their number ; for if 

 this be not attended to they will in time get so far 

 ahead as almost to exterminate the trout; keeping 

 them down will be an endless task, and they can 

 never after be got rid of. Therefore the greatest atten- 

 tion should be paid to this point. The way to be sure 

 on this head is to select the fish at spawning time, 



