376 
are probably not so efficient as some other 
small fish in utilizing the food resources of 
a lake, their nutritive value as forage for 
larger bass is certainly equal to that avail- 
able from so-called forage species. 
5. The use of a single large species 
like the bass relieves the feeding pressure 
on the small aquatic animals and may al- 
low the development of stocks of larger 
predatory invertebrates which furnish food 
for bass. 
6. Reasonable cropping of adults 
should insure the survival of enough 
young to maintain a well-balanced popu- 
lation from the standpoint of the theoreti- 
cal pyramid of numbers. 
7. An abundance of crayfish may play 
a significant role where bass are used alone, 
as they form an important source of food 
and thereby increase the survival of young 
bass. 
Other combinations of fishes are being 
tested in 10 new farm ponds built by the 
U. S. Soil Conservation Service. These 
are as follows: 
1. White crappies and bluegills. 
2. Black crappies and bluegills. 
3. White and black crappies and blue- 
gills. 
4, Black bullheads and bluegills. 
In these lakes, now followed for 3 years, 
the original stock grew very rapidly, fig. 
7, and produced large broods of young 
during the first year. Young fish were 
stunted during the second and third years 
because their food requirements became 
greater than the lakes could supply. Un- 
Ittinois NATURAL History SURVEY BULLETIN 
Vol 22-4 
less efficient methods of limiting the spawn 
are intensively applied, the combinations 
listed above will invariably result in large 
stunted populations of small fish, value- 
less to hook-and-line fishermen. 
Summary 
1. ‘The chief causes for poor hook-and- 
line fishing in Illinois artificial lakes are 
past improper stocking, large populations 
of rough fish, or other species of little 
value in angling, and stunting as a result 
of overpopulation. 
2. Fishes well suited to Illinois arti- 
ficial lakes are largemouth bass, white and 
black crappies, bluegills and black and 
yellow bullheads. Other fish are apparent- 
ly of little value in hook-and-line fishing. 
3. Lakes should be cropped in order 
to produce and maintain good yields. A 
cropping plan should include measures to 
control the numbers of fish of small size 
as well as the total poundage of large fish 
taken by anglers. 
4, Simple combinations of fishes are 
being tested to determine their value in 
angling. The bass-bluegill combination ap- 
pears to be one of the most satisfactory. 
Information on the use of largemouth 
bass alone is as yet inconclusive. Combina- 
tions of crappies and bluegills or bluegills 
and bullheads result in stunted popula- 
tions. Unmanaged but heavily fished wa- 
ters containing bass, crappies, bluegills and 
bullheads show marked fluctuations in 
numbers of bass, crappies and bullheads. 
LITERATURE CITED 
Bennett, George W., David H. Thompson and Sam A. Parr 
1940. 
Hansen, D. F. 
RK 
lished. 
Swingle, H. S., and E. V. Smith 
1938. 
SIN). 
Illus. 
1941. 
1942. 
Illus. 
Thompson, David H., and George W. Bennett 
IYO) 
Biol. Notes 9. 14 pp. Illus. 
Thompson, David H. 
— 2 Pe 
Low *) 
UNIVEPSITY NEG ILLINOIS 
Lake management reports. 4. A second year of fisheries investigations at Fork Lake, 
1939. Ill. Nat. Hist. Surv. Biol. Notes 14. 24 pp. Illus. 
Studies on the white crappie, Pomoxis annularis Rafinesque, in Illinois. Ms. Unpub- 
Management of farm fish ponds. Ala. Poly. Inst. Ag. Exp. Sta. 6 pp. Mimeographed. 
Increasing fish production in ponds. Fourth N. Am. Wildlife Conf. Trans, 4:332-8. 
The management of ponds for the production of game and pan fish. A symposium 
on hydrobiology, pp. 218-26. Wis. Univ. Press. 
5 figs. 
Management of farm fish ponds. Ala. Poly. Inst. Ag. Exp. Sta. Bul. 254. 23 pp. 
Lake management reports. 2. Fork Lake near Mount Zion, Ill. Ill. Nat. Hist. Surv. 
Creel census of Rinaker Lake near Carlinville, Ill., 1932-1939. Ms. Unpublished. 
i ih Ss 
is 
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