628 



EEPORT OF THE COMMISSIONER OF FISHERIES. 



level, but during drier times these were not sufficient, and it became 

 necessary to pump water in from outside. This was done for a season 

 or so by means of an "elevator" in a wooden trough or chute in which 

 run endless-chain belts with closely fitting boards forming a series 

 of buckets as they move upward through the trough. (See fig. 2, 

 pi. III.) The motive power at first was a span of horses, but later a 

 7-horsepower gasoline engine was installed, which does the "pumping" 

 or elevating much more expeditiously. The amount of pumping 

 required to keep the water at the proper height and suificiently fresh 



H i y e r 



Diagrammatic plan of carp pond near Port Clinton, Ohio: a, embankment; b, dam; c, engine-house; 

 d, water elevator; e, ehnte through which fish are slid into pond; /, chute through which fresh 

 water enters pond; g, dredge-cut; /(, outlet. The figures indicate depth of water. 



depends very closely upon the weather conditions and to some extent 

 upon the number of fish in the pond. It is seldom that so much as 

 two or three hours a day is required. 



The water in the dredge cut is about 12 feet deep, but in other 

 portions of the pond there are few places more than 5 or 6 feet in 

 depth, and much of the water is considerably shallower. In all the 

 shallower parts is a rank growth of aquatic vegetation (sweet flag, cat- 

 tails, deer's tongue, wild rice, bulrushes, burr reed, etc.) which sup- 

 plies so much natural food that the fish are seldom or never fed arti- 

 ficially. With the maintenance of the water level, thus avoiding the 

 rushing of the water in and out through a grating, the fish remain dis- 

 tributed most of the time throughout the marshy parts of the pond 



