THE GERMAN CARP IN THE UNITED STATES. 



629 



where food is abundant. An exception to this is when a stream of 

 water is pumped in steadily for a time; then the fish begin to come 

 from distant parts of the pond to the place of the incoming stream, as 

 has already been described (p. 560). This tendency of the carp to 

 gather around the place where the fresh water comes in is taken 

 advantage of when it is desired to seine them out, the net being hauled 

 in the dredge cut when the fish have congregated there. 



Another pond, near the Raisin River, below Monroe, Mich., and but 

 a short distance from Lake Erie, differs in some ways in method of 



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Diagrammatic plan of carp pond near Monroe, Mich.: o, outer embankment; b, dam; c, engine 

 house; d, d', water elevators; e, inner embankment; /, chute arranged for carrying water either into 

 dredge cut (g) or into central area (fc); g, circular dredge cut; h, outlets; i, dredge cut from river; 

 j, outside dredge cut; k, central area (water 1 to 2 feet deep); I, marsh (barely covered with water). 



construction from the one just described, and for this reason seems 

 worthy of mention. (See fig. above.) This pond is smaller than the 

 other, and is of interest as showing how a pond can easily be built in 

 the middle of an extensive flat marsh. This was done by starting with 

 a dredge at the river and cutting a channel straight into the marsh for 

 a short distance. A large circle was then made, the greater part of the 

 mud brought up being placed on the outer side of the cut, thus form- 

 ing a high embankment, while on the inner side a smaller one was 

 built up, in which, however, several breaks were left. After it had 

 completed the circle the dredge was taken back outside and a shortcut 

 was made on the outside and parallel to the outer embankment. When 

 a dam had now been built at the only opening, it was possible to raise 





