11 
a 
bor the various forms of aquatic life on which they feed. Several kinds of 
common pond weeds will serve for this-purpose. The broad leaves of water 
lillies afford shelter in summer for the large fishes and should be intro- 
duced. If the pond be very small and unshaded some floating boards will 
afford shelter. Too many large fishes in a pond are detrimental since they 
are consuming the food supply and are themselves going to waste. When 
such fishes cannot be taken with a hook, as sometimes happens, they should 
be removed with a seine, if it is possible to do so, and marketed. It is im- 
portant that the mature fish crop of a pond be utilized and the young of the 
year be given a chance to develop. The accumulation of large fishes serves 
no useful purpose, but results in overstocking, exhaustion of the food sup- 
ply, cannibalism and stunted growth. 
If a natural lake or pond is already stocked with carp which are not de- 
sired and cannot be entirely removed, their further increase may be check- 
ed by the introduction of black bass, which feed freely on young carp. 
Black bass will also keep other species in check by devouring their young, 
and thrive amazingly in the process. If the waters contain black bass or 
other fishes, which have become stunted from overcrowding and the ex- 
haustion of the natural food supply it is important to reduce their number 
by any methods of fish catching that will prove effective, and to restore the 
food supply by introducing other species. 
If numerous adult yellow perch are added their young will contribute to 
the food of the bass and other large species. Experiments have shown that 
the fishes stunted from overcrowding are not necessarily permanent dwarfs, 
but will attain a large size if well fed or removed to more favorable waters. 
No fish could be more stunted and worthless than those swarming the lakes 
of Central Park. Yet we have succeeded in doubling the size of such fishes 
in two years. Stunted European rudd transferred from Central to Pros- 
pect Park began developing and later when we seined them out for exhi- 
bition at the aquarium it was found that their size compared favorably 
with that which they attained in Europe. 
All ponds, whether natural or artificial, containing food fishes should be 
stocked with brook minnows, shiners, chubs; fresh water killifish and other 
small species, to constitute the food supply. The killifish and other small 
species, it may be noticed in passing, are useful in small, ornamental ponds 
-in destroying the larve of mosquitos. 
The full use of the fish crop of the large natural pond or lake can seldom 
be secured by ordinary fishing. It is necessary that seines and trap nets 
be used. Experience has proved that such ponds usually contain many 
large fishes which will not take the hook. The introduction of new adult 
stock may be desirable in an old pond where there has been in-breeding, 
but overstocking is the main trouble, the remedies of which are thinning 
out and reestablishing the food supply. ; 
Owing to the customary preference for game fishes many excellent pond 
species such as rock bass, calico bass, yellow perch, white perch, long eared 
and blue gilled sun fish, and cat fish have been overlooked. Other kinds 
such as the war mouth or the white bas inhabiting waters of the south and 
middle west are equally desirable. All of these species increase rapidly, 
take the hook readily and are good fishes. They will multiply in favorable 
waters with less care than probably any other native fishes. With the ex- 
ception of the cat fish they will take the artificial fly and afford good sport. 
They are of considerable commercial importance, since according to Gov- 
ernment 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 pen stocks 
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 getting at them. The deepest portion of the pond should be at 
