98 NEW YORK ZOOLOGICAL SOCIETY. 



favorable waters with less care than probably any other native 

 fishes. With the exception of the catfish, they will take the artifi- 

 cial fly and afford good sport. They are of considerable com- 

 mercial importance since, according to government statistics, the 

 quantity annually sent to market exceeds twenty-eight million 

 pounds. Nearly all of them are known to attain weights ex- 

 ceeding two pounds. 



Ponds Made by Damming Streams. — Ponds created in this 

 way should on no account be completed without the placing of 

 drain pipes and penstocks, so that the water can be lowered and 

 the fish life controlled. There are marketable fishes going to 

 waste in ponds everywhere for lack of simple facilities for get- 

 ting at them. The deepest portion of the pond should be at the 

 lower end, where the fish wull gather when the water is drained 

 down. Ditches dug in the bottom of the pond, leading to the 

 deep hole or "kettle," will greatly facilitate the concentration of 

 the fishes at that time. 



Two or three ponds will be found to be much more satisfactory 

 than one, since they will permit of the sorting of fishes according 

 to size. Angling or other fish catching would then naturally be 

 confined to the pond containing the large fishes. If properly 

 managed, a series of fish-ponds will naturally yield a surplus for 

 the market. 



It is dangerous to construct a fish-pond in a narrow ravine 

 as the dam is liable to be broken during spring freshets or ex- 

 ceptionally heavy rains, and the pond will gradually fill up with 

 silt. Even if the embankment is not broken during high water it 

 is difficult to screen it so that the fishes will not escape. A safe 

 plan is to make the pond at one side of the stream, by excavation 

 and embankments, leading the water to it through a ditch, and 

 damming the stream sufficiently at the ditch-head to divert a 

 portion of its flow. In case of freshets, the deep pool formed in 

 the stream by the dam at the ditch-head, naturally receives the 

 silt brought down stream : thus guarding against the filling up 

 of the fish-pond. The ditch itself should be screened at both 

 ends to prevent the ascent of fishes to the stream, and keep 

 floating drift out of the ditch. 



If the pond can be excavated in marshy ground, so much the 

 better. A layer of clay on the bottom will render it more water- 

 tight that it would be otherwise. The embankment should be 

 broad, and before it is thrown up, all sod should be removed so 

 that there will be no subsequent seepage caused by the decay of 

 vegetable matter. The earth used for the embankment should also 



