should be greater than our collections indicate. Prob- 
lems are excessive siltation, agricultural pollution, and 
desiccation of small streams during drought periods. 
18. La Moine River system (including McKee, 
Sugar, Crooked, and Bay creeks ).—Rating fair. 
Species present, 78. Problems are siltation, severe 
agricultural pollution, and desiccation of small streams 
during drought periods. A few small streams in the 
area are spring fed and have clear, gravelly riffles. 
19. Mackinaw River system (including nearby 
small, direct tributaries of the Illinois River).—Rating 
good to excellent. Species present, 100. Unusual habi- 
tats are sandy and gravelly riffles and pools, and 
extensive areas with marginal aquatic vegetation. Un- 
usual species: rosyface shiner, silver redhorse, and 
freckled madtom. Problems are siltation, dredging, 
and agricultural pollution. Many habitats are pres- 
ent, and species diversity in the Mackinaw River 
proper is quite high. 
90. Sangamon River system.—Rating variable. 
Species present, 94. Unusual habitats are sand-bot- 
tomed pools, submerged aquatic vegetation, gravelly 
riffles, and some deep pools. Unusual species: high- 
fin carpsucker, silver redhorse, ironcolor shiner, 
spotted sunfish, and banded darter. Problems are 
siltation; the Lake Decatur dam; industrial, domestic, 
and agricultural pollution; and dredging. Because 
of the size of the basin, many different habitats are 
available and there is a high diversity of species. 
Salt Creek and its tributaries are less altered than 
the Sangamon River proper, although both branches 
have lost some of the species they once had. The 
headwaters of the Sangamon, Kickapoo Creek, and 
some small tributaries near the mouth of the Sanga- 
mon support particularly rich assemblages of fishes 
and are rated good; other areas are rated fair. 
9]. Indian-Sandy-Apple-Macoupin- Otter creeks 
(including other small, direct tributaries of the lower 
Illinois and Mississippi rivers ).—Rating variable. 
Species present, 87. Unusual habitats include some 
cold springs and sand-bottomed pools. Unusual 
species: hornyhead chub, bigeye shiner, redbelly dace, 
and banded sculpin. Problems are siltation, desicca- 
tion during droughts, and agricultural pollution. Otter 
and Mill creeks have good species diversity; the other 
streams in the area are rated poor. 
99. Wood River-Cahokia Creek (including other 
small tributaries of the Mississippi River in Madison, 
St. Clair, and Monroe counties).—Rating poor. Species 
present, 64. Problems are extensive industrial pollu- 
tion, siltation, and desiccation of small streams during 
drought periods. The streams in the area lack variety 
in aquatic habitats and would not have great species 
diversity even if they were not polluted and otherwise 
altered. 
93. Kaskaskia-Marys River system.—Rating vari- 
able. Species present, 104. Because of the size of the 
basin and large variety of habitats, an exceptionally 
6 
large number of species occurs in this system. Ui 
usual habitats include swamp, sand-gravel riffles an 
pools, and deep pools. Unusual species: blue sucke 
freckled madtom, slender madtom, bigeye shine 
sauger, and river darter. The headwaters of tl 
Kaskaskia are periodically dredged, and the upper se 
tion receives much agricultural pollution and some i 
dustrial pollution from a manufacturing plant ne 
Tuscola. The middle section of the river receiy 
mine wastes and oil-field pollution. The lower secti 
has been channelized for barge traffic. Many of t! 
tributaries are low-gradient, brushy sloughs that ha 
a limited number of habitats. Such tributaries 
Shoal Creek, Crooked Creek, and Silver Creek 2 
swampy with usually turbid water. Until receni 
the least disturbed part of the basin was the Kaskas} 
River and its tributaries in Moultrie, Shelby, a 
Fayette counties, but the recent creation of La 
Shelbyville destroyed most of the habitats upstre: 
from Shelbyville. Although there is a long list 
species recorded from the Kaskaskia system, ma 
species will probably disappear soon. The Ma 
River would have very poor species diversity w 
it not for several large-river species that ascend ° 
Marys from the Mississippi River. 
24. Big Muddy River system.—Rating good 
lower reaches, very poor upstream from Murphysb« 
Species present, 88. The marginal swamps of 
lower course are rich in species. Until the recent ¢ 
ation of Lake Kinkaid, Kinkaid Creek was the ¢ 
standing tributary of the Big Muddy. Other tr 
taries such as Beaucoup Creek, Little Muddy Ri 
and Crab Orchard Creek are low-gradient, bru 
streams with little habitat variety, and Crab Orch 
Lake has destroyed many of the smaller stream: 
the system. Most of the basin suffers from siltat 
desiccation during drought periods, and oil-field 
other industrial pollution. The low quality water : 
ports only the most ecologically tolerant and tenac 
species of fishes in the middle and upper parts of 
basin. 
95. Clear Creek-Horseshoe Lake system.—Ra 
excellent. Species present, 99. Unusual habitats 
clude the nearly unique Pine Hills swamp, luxw 
beds of aquatic vegetation, many cold springs, ¢ 
gravelly tributaries, and a large-river habitat neat 
mouth of Clear Creek. Horseshoe Lake is a ty] 
cypress-lined oxbow with good populations of sw 
species. Unusual species in the system: spring ¢ 
fish, spotted gar, starhead topminnow, banded py 
sunfish, bantam sunfish, flier, blacktail shiner, ce 
mudminnow, and river darter. Although muc 
Clear Creek appears to be a lowland stream, it 
its clear, gravelly tributaries have an incredible 
of species, some of which do not occur anywhere 
in the state. 
96. Cache River system.—Rating good. Sp 
present, 81. Although the lower and middle stre 
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