February, 1943 
somewhat inaccurate. In a few instances 
the censuses correlated nicely with verbal 
historical information. Usually, however, 
the older waters had been stocked so many 
times, and from so many sources, that it 
was impossible to determine the origin of 
their fish. In a few instances this historical 
information indicated that unfavorable 
changes in fishing had taken place within 
the past 5 or 6 years: earlier these lakes 
had produced good fishing, but gradually 
had changed until they produced little or 
none. 
A perusal of fish censuses of the 22 lakes 
gives information not only as to what spe- 
cies do well in artificial lakes but also 
something of their potential value in fish 
management. For example, if green sun- 
fish, Lepomis cyanellus Rafinesque, were 
found in nearly all lakes, but never of sizes 
large enough to interest fishermen, it might 
be conceded that stocking this fish in other 
artificial lakes would offer little in return 
for the effort. With the purpose of mak- 
ing a rough evaluation of common fishes, 
the censuses were carefully studied. 
Tables 1 and 2 present a partial sum- 
mary of these lake censuses. Table 1 lists 
the lakes and ponds with the composition 
of their fish populations for more common 
species given as per cents of total weight 
of fish. Table 2 lists the same lakes and 
ponds with their locations, areas, types of 
basins, transparencies in feet at the time 
their fish populations were removed, and 
the total poundage of fish removed per 
acre, 
The status of the more important species 
could have been expressed: in table 1 as 
per cents of the total populations by num- 
bers instead of by weights, but it is felt 
that the use of weights rather than num- 
bers gives a better indication of the im- 
portance of individual species. 
The designation of “old” and “new” 
under types of basins in table 2 is as fol- 
lows: “New” lakes and ponds are less 
than 5 years old, while “old” are from 5 
to 50 years. The transparencies listed in 
the next column are only relative, as con- 
siderable variation may be found during 
any year. However, it may be seen that 
there is some correlation between low 
transparencies given in table 2, and high 
percentages of carp, buffalo, bullheads and 
gizzard shad, listed in table 1. The 
column “Total Weight of Fish, Pounds 
BENNETT: MANAGEMENT OF ARTIFICIAL LAKES 359 
per Acre,” table 2, is the result of dividing 
the total poundage of fish taken from the 
lake by its surface area in acres. It will 
be noted that the older waters usually sup- 
port the higher poundages of fish and that 
lakes containing large percentages of rough 
and forage fish show greater poundages 
than those containing mostly desirable fish. 
In the following paragraphs, important 
species are considered separately and on the 
basis of the census work outlined in tables 
1 and 2. The status of each species was 
determined in each lake where it occurred, 
and each species was considered in relation 
to other species present. The arrangement 
of these fish in the following paragraphs 
Is not systematic. 
Largemouth Bass 
Huro salmoides (Lacépéde ) 
Contrary to general belief, the large- 
mouth bass does not require a habitat of 
large size. It was found in 18 of the 22 
Illinois lakes censused, and the bass popu- 
lations averaged better in small than jn 
large lakes, both in numbers and in size 
of individuals. Population densities varied 
from a fraction to 129 fish per acre of 
water. In five lakes, the bass population 
made up from 14 to 25 per cent of the 
weight of the total fish population. Only 
one of these five lakes contained more than 
a very few rough fish. Forage fish were 
present in only one of the three lakes con- 
taining the highest percentages of bass. 
Bass made up 25 per cent of the total 
population (by weight) in a lake that was 
overfished. Here angling was restricted 
during the spawning season, but intensive 
at other times. 
In the 13 other lakes in which they 
were found, bass were less numerous. By 
weight they represented less than 4 per 
cent of the fish populations. All of these 
lakes contained large poundages of rough 
fish and forage fish (gizzard shad, golden 
shiners and other minnows) and all but 
three contained large populations of crap- 
ples. Most of these lakes were muddy 
throughout the year. 
Successful largemouth bass populations 
were found in clear water. Repeated 
stocking of bass in muddy lakes containing 
large numbers of rough fish did not in- 
crease the bass population permanently. 
Small bass populations are frequently asso- 
