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NEW YORK ZOOLOGICAL SOCIETY. 



WHITE PERCH. 



exposed for a time to the action of the sun and frost. It destroys 

 excessive plant growth and kills out destructive water beetles and 

 other enemies of young fishes and is approved by most profes- 

 sional fish culturists. With a series of ponds constructed at 

 different levels, the overflow- of the upper ponds will serve to 

 feed those below. The more fall there is to the v/ater the better 

 will be its aeration — a matter of great importance to small ponds. 



It is desirable that surface water caused by rainstorms be kept 

 out of small ponds by banking up or ditching. 



The following instances, among many which came under the 

 writer's personal observation, will serve to show some of the diffi- 

 culties in the way of successful management, where ponds are 

 constructed without provision having been made for drawing 

 down or seining : 



A certain deep lake of about two acres in Connecticut, formed at 

 great expense by damming a brook, is without any provision for 

 drawing down. The conditions prevailing in it are unknown, and 

 nothing but hook and line or some form of trap-net are available 

 for ascertaining its contents, since its borders will not permit of 

 the use of a drag net. In the meantime, snapping turtles kill the 

 voung ducks on it each summer, and there is no way of getting 

 rid of them. 



Another pond, which could not be lowered, was believed to be 



