of the Cache River consist of cypress swamp and mud- 
bottomed sloughs, many of the headwater streams 
are clear and gravelly, and some are spring fed. 
Unusual species: flier, blackspotted topminnow, 
“ypress darter, spottail darter, and stripetail darter, 
Problems are desiccation during drought periods and 
‘iltation. 
27. Massac-Bay-Lusk-Big Grand Pierre-Big Creek 
ystem (including many lesser direct tributaries of the 
Jhio River and some marginal lakes and swamps).— 
tating excellent to good. Species present, 79. The 
utstanding stream in the system is Big Creek, closely 
ollowed by Lusk Creek. Unusual] habitats are clear, 
ock-bottomed pools, gravelly riffles, and cold springs. 
Inusual species: black redhorse, rock bass, small- 
1outh bass, cypress darter, spottail darter, stripetail 
arter, and banded sculpin. The smaller streams in 
le area are rated fair, and those not fed by springs 
re subject to desiccation during drought periods and 
) some agricultural pollution. The lowland lakes 
id swamps have good populations of lacustrine 
ecies such as the pugnose minnow. 
28. Saline River system.—Rating poor. Species 
esent, 57. Problems are Stripmine wastes, siltation, 
I-field pollution, drainage of natural lakes and ponds, 
‘siccation during drought periods, and a paucity 
aquatic habitats. Some parts of the Saline River 
e devoid of fish because of the discharges of acid 
m coal mines, and its tributaries have rather low 
ecies diversity. Several species have been extirpated. 
29. Little Wabash River system.—Rating poor in 
ver reaches but very good in upper part of the 
stem. Species present, 78. Problems are oil-field 
lution, siltation, and desiccation during drought 
tiods. Tributaries such as the Skillet Fork, Elm 
ver, and Fox River are low-gradient, brushy streams 
th oil pollution and very low species diversity. The 
tle Wabash River between Louisville and Neoga 
alternating pools and sand or sand-gravel riffles 
1 high species diversity. Unusual species: spotted 
s, bigeye shiner, greenside darter, and dusky darter. 
butaries in the upper portion of the basin are 
llow, sandy streams with fair species variety; the 
dwaters of the Little Wabash above Lake Mattoon 
badly silted. 
30. Bonpas Creek system (including some small, 
ct tributaries of the Wabash River ).—Rating fair, 
cies present, 71, There is a limited number of 
itats available in this small watershed, and oil-field 
ution, drainage of natural lakes and ponds, and 
‘tion have taken their toll of native species. Un- 
ll species in the system are the pugnose minnow 
spotted sucker; the nearby Wabash River has an 
emely rich variety of species, 
31. Embarras River system.—Rating variable. 
‘i€s present, 92. The lowermost section of the 
arras has oil-field pollution and has been partly 
ameled, and the headwaters above Lake Charles- 
ton are badly silted. A major tributary, the North 
Fork, has severe oil-field pollution and siltation. These 
three areas must be rated fair to poor, but the major 
part of the Embarras River proper and especially the 
stretch from Charleston to Newton has an excellent 
variety of habitats and extremely rich species diversity. 
Unusual species: harlequin darter, dusky darter, east- 
ern sand darter, spotted bass, mountain madtom, and 
greenside darter. The harlequin darter does not occur 
anywhere else in the state. The middle section of 
the Embarras is one of the outstanding Illinois streams. 
32. Direct tributaries of the Wabash River in 
Crawford, Clark, and Edgar counties.—Rating good. 
Species present, 82. The outstanding streams in the 
system are Mill Creek, Big Creek, and Brouilletts 
Creek, all of which contain sandy and gravelly pools 
and riffles and water of high quality. Unusual species: 
blacknose dace, redbelly dace, greenside darter, and 
bigeye shiner. Some oil-field pollution exists in the 
watersheds, but the streams suffer most from desicca- 
tion during drought periods. 
33. Little Vermilion-Vermilion River system.— 
Rating variable. Species present, 86. The Little Ver- 
milion has been in part rechanneled and dredged 
and is subject to desiccation during low-water periods. 
The Vermilion is badly polluted by domestic sewage 
several miles downstream from Danville but recovers 
before it leaves the state. The North Fork is badly 
silted above Lake Vermilion and somewhat polluted 
below the lake. The West Branch is devoid of fish 
most of the year because of domestic sewage from 
Champaign-Urbana, and the East Branch receives 
some pollution from Rantoul and Chanute Air Force 
Base. The Salt Fork between Homer and Danville 
consists of clear pools, wide sand and gravel bars, 
and rubble-gravel riffles and has quite high species 
diversity. The outstanding stream in the system, and 
one of the finest in Illinois, is the Middle F ork, which 
in addition to the habitats listed for the Salt Fork 
has some boulder riffles and exposures of bedrock. 
Unusual species: bluebreast darter, river redhorse, 
dusky darter, eastern sand darter, mimic shiner, and 
rosyface shiner. The bluebreast darter does not occur 
anywhere else in the state. 
The number of species in a stream system de- 
pends on the number of relatively unmodified habitats 
available. In general, a large drainage system will con- 
tain a greater variety of habitats and more species 
than a small one. For example, the Kaskaskia River 
system is the largest in Illinois and has the greatest 
variety of fishes (104 species). However, the re- 
lationship is not absolute. Other stream systems with 
high species diversity are the Fox (102 species), 
Mackinaw (100 species), Clear Creek (99 species ), 
Rock-Green (98 species), Sangamon (94 species), and 
Embarras (92 species). The Fox, Mackinaw, and 
Embarras systems are moderate in size, and Clear 
Creek has a rather small drainage basin. 
