ELEVENTH ANNUAL REPORT. 97 
are useful in small ornamental ponds in destroying the larvee of 
mosquitoes. 
The full use of the fish crop of a 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. 
A deep spring-fed lake on Long Island had for years furnished 
only moderately good bass fishing and no one imagined its wealth 
of fishes until the embankment which formed it gave way and 
distributed hundreds of good sized black bass on the flats below, 
many of them weighing from four to six pounds. It is possible 
that these fishes were so well fed on the small fry of their own 
CROSS-SECTION OF THE DAM. 
A—Embankment. B—Ground-Ditch. C—Solid Ground. D—Water. E—Drain. 
F—Penstock. H—Sliding Water-Boards. 
kind, as well as other species coming over the dam from the pond 
above, that what the angler could offer did not tempt them. 
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 for which are thinning-out and re-es- 
tablishing 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 sunfish and catfish, 
have been overlooked. Other kinds such as the warmouth or the 
white bass, inhabiting waters of the south or middle west, are 
equally desirable. All of these fishes increase rapidly, take the 
hook readily and are good food-fishes. They will multiply in 
