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 will 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 
