TABLE 6—Fall standing crops by age groups in numbers 
and kilograms per hectare for largemouth bass (LMB) 
and bluegills (BG) after two growing seasons in the stock- 
ing combinations shown. Listed weights and numbers rep- 
resent averages for two populations of each of the types 
indicated. )+) 
es 
Age 0 Age 1 and Older 
Total 
Species Measured Number Weight Number Weight Weight 
LMB (when in pond 
with BG) 3,212 14.83 136 57.40 72.23 
LMB (when in pond 
with BG and 
caged CC) W725 24 oO 4 56.38 80.68 
LMB (when in pond 
with BG, caged 
and free CC) 3,963 20.76 1338 59.38 80.14 
with LMB) 88,968 130.14 687 102.41 232.55 
BG (when in pond 
with LMB and 
caged CC) 70,060 99.05 613 105.32 204.37 
BG (when in pond 
with LMB, caged 
and free 'CC) 40,206 178.31 709 123.64 301.95 
types of bass populations the difference was not 
significant at the .05 level. The results suggest that 
coexistence with a rather intensive culture of channel 
catfish had no measurable influence on the production 
of bass. 
It was of further interest to observe that adults 
of both bass and bluegills were fatter in the presence 
of uncaged catfish than when separated from them. 
Bluegills intermixed with both bass and catfish had 
an average coefficient of condition (C) of 8.57; blue- 
gills with bass only had an average condition of 7.41. 
For bass the averages were 5.07 when with both blue- 
gills and catfish, and 4.74 when with bluegills only. 
In 1971, mortalities averaged 1.0 percent in caged 
catfish populations and 5.4 percent in free populations. 
Among caged populations the difference between the 
highest and lowest rate of survival was only 12 fish 
(less than a 2-percent difference); among the un- 
caged populations the difference was only 26 fish, 
or less than a 4-percent difference. Average rates of 
survival of the two types of populations differed by 
less than 5 percent. Differences in weights, however, 
were considerably larger. Among the caged catfish the 
greatest weights were in those populations sharing 
the pond with uncaged catfish and in the absence of 
bass and bluegills. Among the uncaged catfish popu- 
lations the greatest weights were made in those ponds 
containing bass and bluegills, but these were only 
slightly larger, and not significantly different from 
weights of those populations sharing the pond with 
caged catfish. Between caged and uncaged popula- 
tions there was an average difference of 153.5 pounds 
(69.6 kilograms), or more than 19 percent. In terms 
of individual weights, uncaged catfish averaged about 
6 
0.29 pound (131.5 grams) heavier than those con 
fined to cages. 
Standing crops of bluegills in the ponds wer 
considerably larger than those in a sampling of othe 
unfertilized Illinois waters, and standing crops o 
bass were somewhat above average. At the end o 
two growing seasons our six populations of bluegill 
had standing crops ranging from 168 to 308 pound 
per acre (188.3 to 345.3 kilograms per hectare ), witl 
an average of 219.7 (246.3) (Table 7). This compare 
with an average of 123.1 pounds per acre (13 
kilograms per hectare) of bluegills obtained in seve: 
censuses of bass-bluegill populations in 16-acre (6. 
hectare ) Ridge Lake in central Illinois (Bennett et a 
1969); with 104.9 pounds per acre (117.6 kilogram 
per hectare) of bluegill obtained in three censuse 
of mixed populations (predominantly bluegill) i 
2.6-acre (1.05-hectare) Arrowhead Pond (Benne' 
1971), also in central Illinois; with 168 pounds pe 
acre (188.3 kilograms per hectare) obtained in thre 
ponds in southern Illinois (Hansen et al. 1960) whic 
averaged 0.83 acres (0.34 hectares) at the time ¢ 
census; and with 125.3 pounds per acre (140.5 kil 
grams per hectare) obtained by Buck & Thoits (197( 
in four single species populations in l-acre (0. 
hectare) ponds in northern Illinois. 
Our six bass populations averaged 69.3 pounc 
per acre (77.7 kilograms per hectare), compare 
with 40.2 (45.1) in nine censuses of Ridge Lak 
27.5 (30.8) in three censuses of Arrowhead Pon 
70.0 (78.5) in Hansen’s three ponds in southe: 
Illinois; and 75.3 (84.4) in 11 single species popul 
tions in northern Illinois. 
Our standing crops of channel catfish rangi 
from approximately 1,200 to 1,600 pounds per ac 
(1,345 to 1,794 kilograms per hectare), with : 
average of about 1,370 (1,536). These fell somewh 
short of the range of 1,500 to 2,000 pounds per ac 
(1,682 to 2,242 kilograms per hectare) as predict 
by Lewis (1969), because numbers stocked in 0 
ponds were reduced to 1,400 per acre (3,459 p 
hectare) in 1971, and the fish were fed only 5 da 
each week. For the production of food fish in Illino 
Lopinot & Fisher (1969) have suggested stocki 
1,500 fish per acre (3,707 per hectare) and feedi 
6 days each week. 
As pointed out earlier, all units of populatic 
both caged and uncaged, received the same rati¢ 
but the amount of the ration was determined fr 
sampled weights of caged catfish only. Thus t 
faster-growing catfish free in the ponds were giv 
less food in terms of percentage of body weight th 
were the caged individuals. It is therefore interesti 
to observe that the uncaged individuals had not © 
a markedly greater average weight by 0.29 pou 
(131.5 grams), but a more efficient rate of conversi 
Among the caged fishes, conversion rates for in 
vidual populations ranged from 1.41 to 1.77, with 
average of 1.56; for the fish free in the pond 
