256 
viduals of the various broods of bass at or 
approximately at the ends of the various 
growing seasons are shown in table 13. 
Growth for the first year was fairly uni- 
form for all broods; average lengths at 
approximately the end of the year ranged 
between 7.4 and 8.8 inches. Growth tor 
the second year was slow for the 1941 
brood, which was stunted in this year ot 
life, but the average lengths for second- 
year bass of other broods ranged between 
10.1 and 12.0 inches. All broods except 
that of 1941 attained an average length 
of at least 13.0 inches the third year, and 
the 1945 brood averaged 15.8 inches the 
fourth year. After the slow start made 
by the 1941 brood during its first + years, 
the rate of growth improved, so that, dur- 
ing the next + years, the average weight 
of individuals of this brood increased from 
about 1 pound at the beginning of the 
1945 growing season to about + pounds 
at the beginning of the 1949 season. 
Fishermen prefer to catch large bass 
but are satisfied with fish of sufficient size 
to produce an appreciable bend in a fly 
rod or bait rod. Small bass ordinarily 
strike more readily than do large ones 
and for this reason are easier to catch. 
Thus, from the standpoint of bass man- 
agement, the growth rate of a bass after 
the fish has reached a catchable size is of 
secondary importance; the primary ob- 
jective is to bring the maximum number 
of bass fingerlings up to sizes attractive 
to fishermen in the shortest possible time. 
Growth of Bluegills 
Except for a short period in 1949, Ridge 
Lake probably contained fairly large popu- 
lations of bluegills after the spawning 
season of 1945. In the draining operation 
of March, 1949, the bluegills were re- 
duced to a low population level because 
an attempt was made at that time to get 
rid of them completely. 
The growth rates of the several year- 
classes or broods of bluegills produced in 
the lake have been determined by aging 
scales from 1,947 of these fish collected 
in the years 1946-1950, table 14. 
Growth of the first two year-classes of 
bluegills produced in the lake was rapid, 
fig. 14. In the 1946 growing season, 1944 
year-class fish averaged 6.9 inches total 
InttNois NaturAL History Survey BULLETIN 
Vol. 26, Art. 2 
length (at about 32 months of age) and 
1945 fish averaged 5.8 inches (at about 
19 months of age). Bluegills representing 
1946, 1947, and 1948 year-classes grew 
less rapidly than those representing pre- 
ceding year-classes, and fish of each of 
these year-classes grew at a less rapid 
rate in their first year than fish of the 
year-class preceding, fig. 1+. Poorest re- 
corded first-year growth occurred in 1948; 
bluegills spawned in that year averaged 
only 3.6 inches total length in March, 
1949, before second-year growth had 
started. 
The growth stimulus produced by the 
severe thinning of the bluegill population 
in 1949 is shown clearly in the 1947, 
1948, and 1949 year-classes among fish 
that were spawned after, or that managed 
to escape, the draining operation of 1949, 
fig. 14. Bluegills of the 1947 year-class, 
which averaged 5.3 inches in length in 
March of 1949 (equivalent to end of 
second growing season), had grown to an 
average length of 8.0 inches by May of 
1950 (shortly after start of fourth grow- 
ing season); fish of the 1948 year-class, 
which averaged about 3.6 inches in length 
after one season of growth, grew to an — 
average length of 7.6 inches before the — 
third growing season was well under way; 
and fish spawned in 1949 matched second- — 
year growth with the 1945 year-class by 
reaching 6.4 inches in length within the — 
1950 season. In 1949, the year in which 
maximum growth rates were attained by — 
bluegills, the total number of these fish 
was so small that, creel records indicate, 
few could be caught by anglers, table 3. 
Catch Rate Versus Fishing 
Pressure 
: 
| 
| 
In observing the catch of largemouth 
bass at Ridge Lake year after year, it was 
noticed that the rate of catch dropped 
off rather rapidly early in the season and 
that, after about the first 3 weeks, most 
of the bass taken were caught by a rela- 
tively small number of fishermen. This 
phenomenon was particularly pronounced 
in 1949 when, following the March drain- 
ing census, the bass returned to the lake 
were concentrated in a reduced volume 
of water. At this time Ridge Lake con- 
tained at least 1,046 bass large enough to 
