November, 1954 
it was believed that, unless the numbers 
were greatly reduced, food competition 
would become severe and growth would 
be slow. Consequently, 335 yearling bass 
were introduced into Ridge Lake on June 
18, 1941. This introduction of yearling 
bass was ineffectual in thinning the num- 
bers of bass fingerlings sufficiently, and, 
by 1942, bass of the 1941 brood had 
stopped growing. 
In 1943, a culling technique, in which 
small or otherwise undesirable fish were 
permanently removed from the lake, as 
described in the section titled ‘“The Drain- 
ing Census,” was adopted and used in al- 
ternate years to allow bass spawners to pro- 
duce an abundant crop of young at inter- 
vals of 2 years. The culling technique 
allowed no single year-class to become 
dominant, because many large bass were 
present and actively preying upon the 
young as they reached fingerling sizes. 
This technique could be depended upon to 
assure the production of bass to replace 
those caught by anglers (who after 1945 
were not restricted to the 10-inch length 
limit for bass) and those removed with 
other small fishes in the biennial culling 
operations. 
The present publication is essentially 
a description of the culling technique of 
management and its effect upon the large- 
mouth bass in Ridge Lake for an approxi- 
mate 10-year period beginning with the 
spring of 1941 and ending after the bass 
spawning season but before the angling 
season of 1951. This technique, which is 
being employed in all recreational lakes 
built by the state of Illinois, may be de- 
pended upon not only to maintain good 
bass fishing over an indefinite period but 
to produce superior angling for fish of 
other warm-water species inhabiting these 
lakes. 
Acknowledgments 
Nearly everyone who has been em- 
ployed on the permanent or temporary 
staff of the Aquatic Biology Section of 
the Illinois Natural History Survey since 
1941 has assisted in some capacity in the 
Ridge Lake investigation. In the early 
years, Mr. Bruno von Limbach, Dr. Louis 
A. Krumholz, and Dr. Philip W. Smith 
Benibuted much time to general collec- 
BENNETT: LARGEMOUTH Bass IN RipcE LAKE 
Paks 
tions. On draining censuses, the staff usu- 
ally consisted of six to eight individuals, 
and over the five censuses (1943-1951) 
included Dr. Donald Hansen, Mr. von 
Limbach, Dr. Krumholz, Mr. Jacob H. 
Lemm, Mr. Daniel Avery, Mr. Paul G. 
Barnickol, Dr. Arthur Witt, Jr., Mr. 
Leonard Durham, Dr. R. Weldon Lari- 
more, Dr. William C. Starrett, Dr. James 
S. Jordan, Mr. Walter H. Hart, and Mr. 
William Nuess. Included among the sev- 
eral members of the staff of the State 
Department of Conservation who helped 
with these censuses were Mr. Sam A. 
Parr, Mr. William J. Harth, Mr. Glee 
Fogelman (deceased), Mr. James Holmes, 
Mr. Quentin Pickering, Mr. George 
Kuhn, Mr. Ora Price, and Mr. Bruce 
Muench. 
As members of the staff of the Illinois 
Natural History Survey, several persons 
made special contributions to this study. 
Mr. Robert G. Rennels, Dr. Smith, Mr. 
Vernon A. Anderson, Mr. Charles D. 
Kemp, Mr. John Jedlicka, Jr., and Mr. 
W. W. Fleming took limnological samples 
and statistics on the anglers’ catch. Mr. 
Frank C. Bellrose, Mr. G. H. Boewe, 
and Mr. Fleming made special studies on 
the flora of the lake. Dr. Witt and Mr. 
Durham studied the growth of Ridge Lake 
bass and bluegills from scale collections. 
Mr. James S. Ayars edited the manuscript. 
The author fully acknowledges the assist- 
ance given by those listed above. 
Characteristics of Ridge Lake 
Ridge Lake, fig. 1, was constructed by 
damming Dry Run Creek, an intermit- 
tent stream flowing through a_ steep- 
sided ravine within the boundaries of 
Fox Ridge State Park, 7 miles by road 
south of Charleston. The original area of 
the lake at overflow level in late 1941 was 
18.1 acres. Water is supplied by drainage 
from 902 acres of the watershed of Dry 
Run Creek, which is a small tributary of 
the Embarrass River. Much of the land 
within the watershed of the Embarrass 
River in this immediate region is unusual 
in that medium slopes are rare; level lands 
break into steep-sided ravines with slopes 
of more than 30 per cent. In the Ridge 
Lake watershed, slopes of less than 4+ per 
cent are found on 64.6 per cent of the area; 
