ON LAKES, POOLS, ETC. 165 



tributary head waters ; and every possible means 

 should be adopted to render the sahnon a tenant 

 of such waters. Where communication, however, is 

 impracticable, 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 smaUness of these trout no doubt, 

 in a great measure, proceeds from their being too 

 numerous for the food found in the lakes. If the in- 

 troduction of an extra amount of food, by the various 

 means I have pointed out, be either impossible 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 attention 



