364 
produced every year, or if produced do not 
survive. Carp and buffalo are responsible 
for much of the roily condition of the 
water in artificial lakes, as their removal 
is always followed by a pronounced in- 
crease in transparency. 
Redmouth Buffalo 
Megastomatobus cyprinella (Valen- 
ciennes ) 
Eight of the 22 lakes contained red- 
mouth buffalo, constituting from 2.5 to 
73 per cent of their total populations. 
These and other kinds of buffalo enter 
lakes on flood waters. Sometimes, how- 
ever, lakes containing these fish were some 
distance from rivers and it is impossible to 
say how they had entered, unless through 
irresponsible stocking. 
Mongrel Buffalo 
Ictiobus niger (Rafinesque) | 
Ten of the 22 lakes contained this spe- 
cies, although it was rarely as numerous 
as the redmouth. The mongrel buffalo 
made up from 0.4 to 12 per cent of the 
populations containing them. 
Smallmouth Buffalo 
Ictiobus bubalus (Rafinesque ) 
Smallmouth buffaloes were present in 6 
of the 22 lakes and were usually large in 
size. Iwo fish from Upper Twin Lake 
averaged 25 pounds each; 24 fish averag- 
ing 12.1 pounds each made up 37 per cent 
of the fish population of Lower “Twin 
Lake. This buffalo is usually less numer- 
ous than the other two, but all three often 
are found together. “The buffaloes should 
be excluded from artificial lakes, as they 
are rarely caught on hook-and-line and, 
like the carp, are associated with roily 
water and poor populations of game and 
pan fish. 
Gizzard Shad 
Dorosoma cepedianum (Le Sueur) 
Gizzard shad were present in 10 of the 
22 lakes. In some cases they were intro- 
duced by floods from nearby streams. In 
others they were stocked as forage fish. 
They are not satisfactory for this purpose 
in artificial lakes because they reproduce 
Ittino1is NATURAL HIsToRY SURVEY BULLETIN 
Vol: 22;Art.e 
‘1 tremendous numbers and rapidly be- 
come too large to be eaten by the game fish 
present. In almost every case, large shad 
populations were associated with small 
numbers of bass. In 5 of the 10 lakes the 
shad constituted from 48 to 65 per cent 
of the entire fish populations (by weight), 
and the game and pan fish were small and 
stunted. This species is obviously not use- 
ful in artificial lake management. 
Golden Shiner 
Notemigonus crysoleucas auratus (Ra- 
finesque ) 
The golden shiner, found in 17 of the 
22 lakes, was probably introduced as for- 
age for bass. In these lakes there was no 
correlation between good bass populations 
and an abundance of golden shiners. In 
the six lakes containing the largest num- 
bers of shiners, only one was maintaining 
a good bass population. Shiners may serve 
as forage fish when they are small, but 
often become too large to be useful. They 
seem to serve little purpose in artificial 
lakes and they compete with more desir- 
able fish for food. 
Other Fish 
Other fish found in small numbers in 
one or several of the 22 Illinois lakes 
censused are listed in table 3. Most of 
these species are relatively unimportant, 
either because of their lack of angling 
value, inability to compete with other spe- 
cies or inability to reproduce successfully 
in the artificial lake habitat. The list con- 
tains several fish of economic importance, 
namely the channel and flathead cats, 
white bass and sheepshead, which are un- 
able to maintain their numbers. It also 
includes several minnows of relatively 
small size which reproduce successfully 
and are therefore suitable as forage species 
for bass and crappies, if furnished adequate 
protection. 
Many of these fish were introduced into 
the lakes through actual flooding of these 
bodies of water by nearby streams in times 
of high water. When the water receded 
the stream fish were left stranded in the 
lakes. Others probably represent escaped 
bait, brought in by fishermen. | 
Small numbers of hybrid sunfish were 
present in six lakes. Most of these were 
