100 NEW YORK ZOOLOGICAL / SOGIETY. 
WHITE PERCE: 
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 overfiow of the upper ponds will serve to 
feed those below. The more fall there is to the water 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 diff- 
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 
young 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 
