rate of growth and the reduction of the number of 
bass has resulted from competition and predation 
by the crappies, as well as from fishing. Hook-and- 
line fishing has apparently removed a larger percent- 
age of the bass than of the crappies. In June, 1934, 
a group of wardens under the direction of Chief In- 
spector Erio contacted 2,097 fishermen and enumera- 
ated their catch during the first three days of the 
first open season. Their catch included 2,544 bass, 
but only 74 crappies. This is because bass seem to 
bite better than crappies in summer. The growing 
scarcity of bass in this lake does not seem to be due 
to their failure to spawn or to lack of spawning 
places. 
The best way to reestablish the bass in satisfactory 
numbers would seem to be (1) to relieve them from 
competition and predation by taking out more crap- 
pies and (2) to plant bass too large to be swallowed 
by crappies. 
CRAPPIES 
Crappies made up 46 percent of all the larger fish 
taken in the four surveys. The facts about their 
growth and numbers are shown in the accompanying 
diagrams. Of the very large carnivorous fishes, the 
white crappie is most numerous. It may be noted 
that the decline in abundance of bass has taken place 
at the same time as a corresponding increase in the 
number of white crappies. 
Within the past few years, larger crappies of both 
species have been caught or handled in Horseshoe 
Lake than in other Illinois waters in recent decades. 
A few of the very largest of these have been identi- 
fied as hybrids between the two species. The larg- 
est hybrid was 17.1 inches long and weighed 4.3 
pounds. It was caught in March, 1936. 
Fishermen have noticed that large specimens of 
most kinds of fish are usually females. For example, 
23 out of 27 of these large white crappies were fe- 
Below.—In the spring of 1932 the breeder bass previously 
placed in the lake spawned successfully. In the absence of 
many ‘predators a large part of this brood survived. At the 
same time a large brood of crappies was also produced and 
survived. In succeeding years the bass spawned, but nearly 
all of the young have disappeared—probably eaten by the 
crappies. In each year since 1934, the number of legal-sized 
bass has been reduced to one-half or two-thirds of the 
number present the preceding year. The original 1932 brood 
still makes up over 90 percent of the bass population as 
shown by the 1936, 1937 and 1938 surveys. 
LARGEMOUTH BLACK BASS 
No 
PERCENT OF ALL FISH TAKEN IN NETS 
1935 
RELATIVE NUMBERS OF DIFFERENT SIZES OF 
\ WHITE CRAPPIES 
\ 
y IN HORSESHOE LAKE 
\ 
\ 
\ 1934 SURVEY 
1933 \ 
BROOoN ee ORIGINAL STOCK 
No SURVEY MADE IN 1935 
| 
| 
SURVEY 
| 
| (934 1933 ORIGINAL 
BROOD BROOD 
1933 BROOD 
1938 
SURVEY 
VO we les RG Wileh IN) ANG Aah ie Ss 
The white crappie, in contrast to the largemouth bass and 
the black crappie, produced a rather small brood in 1932 
when the lake was new. Unlike these other species, it has 
produced moderate-sized broods each year which have es- 
caped destruction. This has resulted in a progressive increase 
in their numbers which is shown in the diagram below. 
n ~ 
a = 
Zo ie WHITE CRAPPIE 
Zz = 
oa 
WJ = 
x 
q 15—= 
my ee 
is 
a 
k. j9o— 
nee 
eal | = 
< 3 
Riots 
eee No 
rere 
me 
5 SURVEY 
hi _ ez 
ae 1934 1935 
if 
