pite the dams on the Rock River and the urbanization 
long its banks, the system has not been affected as 
sverely as many other drainages in the state. 
5. Edwards River system (including Copperas and 
ope creeks ).—Rating poor to fair. Species present, 
2. Habitats are limited, and many of the streams 
re sand choked and rather sterile. Problems are 
redging, agricultural pollution, siltation, and the 
ck of habitat diversity, 
6. Henderson Creek system (including Ellison 
id Honey creeks )—Rating poor to fair. Species 
esent, 57. Most of the streams contain excessive 
nounts of silt in their headwaters and sand in lower 
etches. Problems are siltation, agricultural pollu- 
m, and lack of habitat diversity. 
7. Bear Creek system ( including several small, 
rect tributaries of the Mississippi River ).—Rating 
or to fair. Species present, 54, Sand, gravel, and 
cky riffles and pools are present, but species di- 
rsity is low. Problems are desiccation during drought 
riods and rather severe agricultural pollution. 
8. The Sny-Bay Creek system (including several 
all, direct tributaries of the Mississippi River ),— 
ting poor to fair. Species present, 76. Many habi- 
s are available, and Bay Creek appears to be an 
standing stream with water of high quality. Prob- 
ns are desiccation during drought periods and agri- 
tural pollution, but these factors cannot account 
the low species diversity in the system. 
9. The Des Plaines River system (including Du- 
Ze River, Salt Creek, and other direct tributaries 
l canals of the Illinois River ).—Rating poor. Species 
sent, 63. Problems are domestic and industrial 
lution and extensive modification of streams and 
itats. It is remarkable that so many streams still 
tain fish, although some support only goldfish, 
dfish-carp hybrids, and green sunfish. Prairie and 
kson creeks have good species diversity, but Hick- 
Creek is the outstanding stream in the system 
contains populations of such unusual species as 
northern hogsucker, rosyface shiner, and slender 
ltom. 
10. Fox River system (including glacial lakes of 
e and McHenry counties and Aux Sable Creek ).— 
ing good to excellent. Species present, 102. Un- 
l habitats are the clear well-vegetated natural 
8, clear gravel-bottomed creeks, and spring-fed 
‘ms. Unusual species: blackchin shiner, banded 
tish, brown bullhead, Iowa darter, banded darter, 
mottled sculpin. The Fox River proper has some 
estie and industrial pollution, but most of its 
taries have a variety of habitats and rather high 
ies diversity, Many of the glacial lakes have 
'tuined by pollution and introduction of sport 
8; others, such as Channel, Grass, Loon, and 
ar lakes, contain a rich variety of native species. 
e of the species in this system do not occur any- 
fe else in the state. 
ll. Little Vermilion (of the north) system (in- 
cluding several nearby direct tributaries of the Illi- 
nois River ).—Rating fair. Species present, 52. Un- 
usual habitats include clear, gravelly streams. Un- 
usual species: mottled sculpin. The species diversity 
is rather low, despite the availability of relatively 
unaltered habitats, 
12. Big Bureau Creek (including the Illinois and 
Mississippi Canal and Senachwine Creek ).—Rating 
good to excellent. Species present, 74. Unusual habi- 
tats in the area are the fast, sandy and gravelly riffles 
and clear pools. Some of the streams are sand choked, 
and the canal is badly silted, Big Bureau Creek and 
its larger tributaries are relatively unaltered, and 
agricultural pollution has not had an appreciable 
effect on the species diversity. 
13. Kankakee-Iroquois River system (including 
marginal sloughs and drainage ditches in marshes and 
sand areas ).—Rating excellent. Species present, 72. 
Unusual habitats are swamps, marshes, clear well- 
vegetated streams, gravel-rubble riffles, and sand-bot- 
tomed pools. Unusual species: ironcolor shiner, weed 
shiner, blacknose shiner, lake chubsucker, starhead 
topminnow, northern longear sunfish, and least darter. 
The Kankakee River and most of its tributaries have 
excellent species diversity. The Iroquois River is 
rather sluggish, brushy, and turbid, but some of its 
tributaries, notably Beaver and Sugar creeks, contain 
rich assemblages and unusual species. 
14. Mazon Creek system (including nearby small, 
direct tributaries of the Illinois River ).—Rating good. 
Species present, 67. Unusual habitats include exten- 
sive beds of marginal aquatic vegetation and gravelly 
rifles and pools. Unusual species: black redhorse, big- 
eye shiner, and banded darter. Mining and agricultural 
practices in the area have not appreciably damaged the 
streams in the system. 
15. Vermilion (of the north ) River system (in- 
cluding Covel Creek and other nearby small, direct 
tributaries of the Illinois River ).—Rating fair. Species 
present, 80. Unusual habitats are gravelly and sandy 
riffles and pools, extensive areas of marginal aquatic 
vegetation, and rocky riffles. Covel Creek has such 
unusual species as the black redhorse and slender 
madtom. The Vermilion River has a variety of habi- 
tats and should have a richer fish fauna than it has. 
Tt has some domestic and agricultural pollution along 
its length, and its badly silted headwaters are peri- 
odically dredged. 
16. Kickapoo Creek (including Copperas Creek). 
—Rating good. Species present, 76. Unusual habitats 
are the clear, gravelly raceways and sand-gravel riffles. 
Unusual species: blacknose dace, redbelly dace, 
hornyhead chub. 
17. Spoon River system (including nearby direct 
tributaries of the Illinois River ).—Rating fair. Species 
present, 87. In view of the size of the watershed 
and number of habitats available, the species diversity 
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