UILU-WRC-77-0005
SPECIAL REPORT NO. 5
LU3C
Environmental Inventory and Assessment
of Navigation Pools 24, 25, and 26,
Upper Mississippi and Lower Illinois Rivers
An Electrofishing Survey of the
Illinois River
By Richard E. Sparks
UNIVERSITY OF ILLINOIS
AT URBANA CHAMPAIGN
WATER RESOURCES
CENTER
RIVER RESEARCH LABORATORY
ILLINOIS NATURAL HISTORY SURVEY
HAVANA, ILLINOIS
JUNE 1977
SI? 6*tTTb
^(sertraline HO)
This report is the second edition.
The first edition was published by
the U.S. Army Engineer Waterways
Experiment Station as Contract
Report Y-75-4, dated December 1975.
WRC SPECIAL REPORT NO. 5
ENVIRONMENTAL INVENTORY AND ASSESSMENT OF NAVIGATION
POOLS 24, 25, AND 26, UPPER MISSISSIPPI AND LOWER
ILLINOIS RIVERS: AN ELECTROFISHING SURVEY OF THE ILLINOIS RIVER
Richard E. Sparks
River Research Laboratory
Illinois Natural History Survey
Havana, Illinois 62644
This report is the second edition. The first
edition was published by the U. S. Army
Engineer Waterways Experiment Stations as
Contract Report Y-75-5, dated December 1975.
Funding for reprinting was provided with
support from the Illinois Institute for
Environmental Quality.
June 1977
PREFACE
The 1974 electrof ishing survey, the preparation of the report, and the
publication of the first edition were sponsored by the U. S. Army Engineer
District, St. Louis, through the U. S. Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi, as part of an overall investigation entitled
"Environment Inventory and Assessment of Navigation Pools 24, 25, and 26,
Upper Mississippi and Lower Illinois Rivers: An Electrof ishing Survey of the
Illinois River."
The Water Resources Center with partial support from the Illinois
Institute for Environmental Quality, is pleased to reprint this valuable
inventory and assessment since the document should be useful to other people
interested in the Illinois River. The original distribution was quite limited
due to a small initial printing, limited funds of the contract, and a loss in
the mailing of a number of copies to the sponsor.
The report demonstrates the importance of the long-term sampling program
of the State Natural History Survey in evaluating the changing environmental
conditions of the Illinois River. It also illustrates the magnitude of man's
influence on the river, and the complexity of water problems.
Glenn E. Stout
Director
Water Resources Center
ABSTRACT
The effect of municipal and industrial discharges from the Chicago-Joliet
area was evident in electrof ishing catches from the Des Plaines River — only the
introduced carp and goldfish and hybrids of these two pollution-tolerant species
were abundant, and most were diseased. There was a greater variety and abun-
dance of fishes in the Illinois, compared to the Des Plaines, and the fish were
generally in better condition. The Upper Illinois River has improved for fish
life since the 1920' s, when no fish were taken throughout much of this section.
The improvement is attributable to improved oxygen levels as a result of im-
proved waste treatment. From the 1900 's to the 1950' s, the backwater areas and
bottomland lakes along the river served as nurseries and havens for fish and
fish food organisms. In the mid-1950' s, the aquatic plants and food organisms
in many of these areas died out, and the areas have been seriously diminished
and degraded by accumulations of sediment, with a consequent decline in the fish-
eries. During a drought period in the mid-1960' s oxygen and water levels were
low, and game fish populations declined. A resurgence in the fish populations
occurred in 1973 and 1974, following high water levels and greater dilution of
pollution from 1971 through the spring of 1973.
Richard E. Sparks
ENVIRONMENTAL INVENTORY AND ASSESSMENT OF NAVIGATION POOLS 24, 25, AND 26,
UPPER MISSISSIPPI AND LOWER ILLINOIS RIVERS: AN ELECTROFISHING SURVEY OF
THE ILLINOIS RIVER
Special Report No. 5, Water Resources Center, University of Illinois,
June 1977, Urbana, Illinois
KEYWORDS — electro-fishing/ fish population/fish harvest/turbidity/navigation/
fish food organism/Illinois River/pollution effects
ACKNOWLEDGEMENTS
The electrof ishing survey of the Illinois Rivev was conceived in
1957 and wad carried out, for the most part, by Dr. William C. Starrett,
Aquatic Biologist, Havana Field Laboratory, Illinois Natural History
Survey. Mr. Dennis L. Dooley worked on the electrof ishing survey and
other Illinois River studies, for 11 years. Following Dr. Starrett 's
death in December 1971, the electrof ishing survey was resumed in 1973
by the writer and Mr. Kenneth Walker, with assistance in locating sta-
tions and information on previously established methods from Mr. Dooley.
Mr. Carl M. Thompson assisted with the 1974 electrof ishing and helped
compile and analyze data for this report. Miss Judith L. Breckenridge
did the typing. We are grateful to all the students and other assistants
who helped with the program from 1959 to 1974. Finally, the electro-
fishing survey could not have been continued in 1974 without the support
of the U. S. Army Corps of Engineers, St. Louis District, and the
Waterways Experiment Station, Vicksburg, Mississippi. Special thanks
for advice and editing are due to the project supervisors from the
Waterways Experiment Station, Mr. R. Charles Solomon and Mr. Billy K.
Colbert.
CONTENTS
Page
ACKNOWLEDGEMENTS 1
LIST OF TABLES 5
LIST OF FIGURES 7
PART I: INTRODUCTION 8
Background 8
The Study Area 9
PART II: METHODS 13
Sampling Stations and Schedules 13
Fish Population Sampling 14
Physical-Chemical Measurements 15
PART III: RESULTS 16
Physical-Chemical Measurements 16
Water temperature 16
Dissolved oxygen 16
Transparency 17
Electrofishing Results, (1959-1974) 17
Gar (Lepisosteus spp.) 19
Bowf in (Amia calva) . 20
American eel (Anguilla rostrata) 20
Skipjack herring (Alosa chrysochloris) 21
Gizzard shad (Dorosoma cepedianum) 21
Goldeye (Hiodon alosoides) and Mooneye
(Hiodon tergisus) 22
Grass pickerel (Esox americanus vermiculatus) 22
Northern pike (Esox lucius) 22
Goldfish (Carassius auratus) and Carp x gold-fish
(C. carpio x C_. auratus) 23
Carp (Cyprinus carpio) 24
Minnows (Family Cyprinidae) 26
Carpsuckers (Carpiodes spp.) 26
River carpsucker (Carpiodes carpio) 27
Quillback (Carpiodes cyprinus) 27
Highf in carpsucker (Carpiodes velifer) 28
Smallmouth buffalo (Ictiobus bubalus) 28
Bigmouth buffalo (Ictiobus cyprinellus) 28
Black buffalo (Ictiobus niger) 29
Shorthead redhorse (Moxostoma macrolepidotum) 29
White catfish (Ictalurus catus) 29
Page
Black bullhead (Ictalurus melas) 29
Yellow bullhead (Ictalurus natalis 30
Channel catfish (Ictalurus punctatus) 30
Flathead catfish (Pylodictis olivaris) 30
White bass (Morone chrysops) 31
Yellow bass (Morone mississippiensis) 31
Rock bass (Ambloplites rupestris 31
Green sunf ish (Lepomis cyanellus) 31
Pumpkinseed (Lepomis gibbosus) 32
Warmouth (Lepomis gulosus) 32
Orangespotted sunf ish (Lepomis humilis) 32
Bluegill (Lepomis macrochirus) 33
Longear sunf ish (Lepomis megalotis) 33
Smallmouth bass (Micropterus dolomieui) 33
Largemouth bass (Micropterus salmoides) 33
White crappie (Pomoxis annularis) and Black
crappie (Pomoxis nigromaculatus) 34
Yellow perch (Perca f lavescens) 34
Sauger (Stizostedion canadense) and Walleye
(Stizostedion vitreum vitreum) 35
Freshwater drum (Aplodinotus grunniens) . 35
Discussion of electrof ishing results 35
Temporal distribution 36
Spatial distirubtion 38
PART IV: IMPACTS ON THE FISH POPULATIONS OF THE ILLINOIS
RIVER 43
Historical Impacts 43
The Illinois-Michigan canal (1848) 43
Chicago River reversal (1871) 43
Low navigation dams (1871-1899) 45
European carp (1885) 45
Sanitary and ship canal (1900) 46
Increased sewage pollution beginning c. 1910 47
Leveeing and draining (1903-1926) 48
High navigation dams (1930's) 49
Changing agricultural practices — beginning c. 1940 ... 50
Fingernail clam die-off (1955) 53
Aquatic vegetation die-off (1920's and 1950's) 54
Summary 56
Present Impacts 56
Industrial and municipal wastes 57
Pesticides 60
Sediment 62
Page
Future Impacts 63
Improvements in waste treatment 63
Proposed channel improvements 65
Land use in the drainage basin 67
Proposed increase in diversion 68
Introduced species 69
Recommendations 70
Restore lakes 70
Predict impacts 71
Coordinate management for multiple use 72
PART V: SUMMARY 74
LITERATURE CITED 77
TABLES 1-36
LIST OF TABLES
1 Electrofishing Sampling Stations on the Illinois
Waterway, 1959-1974
2 Physical-Chemical Measurements, Illinois River, 1974
3 Phylogenetic Listing of Fish Species Taken by
Electrofishing, 1959-1974
4 Fish Species Extirpated from the Illinois River and
Its Bottomland Lakes Between 1908 and 1940
5 Shortnose Gar (Lepisosteus platostomus) Taken by
Electrofishing
6 Bowf in (Amia calva) Taken by Electrofishing
7 Gizzard Shad (Dorosoma cepedianum) Taken by
Electrofishing
8 Mooneye (Hiodon tergisus) Taken by Electrofishing
9 Goldeye (Hiodon alosoides) Taken by Electrofishing
10 Goldfish (Carassius auratus) Taken by Electrofishing
11 Carp x Goldfish (Cyprinus carpio x Carassius auratus)
Taken by Electrofishing
12 Carp (Cyprinus carpio) Taken by Electrofishing
13 River Carpsucker (Carpoides carpio) Taken by
Electrofishing
14 Quillback Carpsucker (Carpoides cyprinus) Taken by
Electrofishing
15 Smallmouth Buffalo (Ictiobus bubalus) Taken by
Electrofishing
16 Bigmouth Buffalo (Ictiobus cyprinellus) Taken by
Electrofishing
17 Black Buffalo (Ictiobus niger) Taken by
Electrofishing
18 Shorthead Redhorse (Moxostoma macrolepidotum) Taken
by Electrofishing
19 Black Bullhead (Ictalurus melas) Taken by
Electrofishing
20 Yellow Bullhead (Ictalurus natalis) Taken by
Electrofishing
Table
21 Channel Catfish (Ictalurus punctatus) Taken by
Electrofishing
22 Flathead Catfish (Pylodictis olivaris) Taken by
Electrofishing
23 White Bass (Roccus chrysops) Taken by
Electrofishing
24 Green Sunf ish (Lepomis cyanellus) Taken by
Electrofishing
25 Bluegill (Lepomis macrochirus) Taken by
Electrofishing
26 Largemouth Bass (Micropterus salmoides) Taken by
Electrofishing
27 White Crappie (Pomoxis annularis) Taken by
Electrofishing
28 Black Crappie (Pomoxis nigromaculatus) Taken by
Electrofishing
29 Freshwater Drum (Aplodinotus grunniens) Taken by
Electrofishing
30 Average Number of Fish (Including Adult and Young)
Taken Per 30 Minutes of Electrofishing, by Year,
in Each Navigation Pool of the Illinois River,
1959-1974
31 Average Pounds of Fish (Adult Only) Taken Per
30 Minutes of Electrofishing, by Year, in Each
Navigation Pool of the Illinois River, 1959-1974
32 Average Number of Fish of Selected Species Taken
Per 30 Minutes of Electrofishing on the Illinois
River, 1959-1974
33 Average Number of Fish, by Species, Taken Per
30 Minutes of Electrofishing in Each Navigation
Pool of the Illinois River, 1959-1974
34 Average Number of Pounds of Fish, by Species, Taken
Per 30 Minutes of Electrofishing in Each Navigation
Pool of the Illinois River, 1959-1974
35 Summary of the Commercial Catch of Fish from the
Illinois River and the Mississippi River Bordering
Illinois, and the Number of Illinois River Fishermen,
1959-1974
36 Organochlorine Insecticide and Mercury Levels in Fish
from the Illinois River
LIST OF FIGURES
Map of Study Area, Showing Sampling Stations,
Navigation Pools, and Sections of the Illinois River ... 10
Map of Study Area, Showing Cities, Lock and Dam Sites,
and the Drainage Basin 11
Mean Water Levels, Mean Discharge, and Mean Dissolved
Oxygen Levels During July and August and the Number of
Largemouth Bass Taken Per 30 Minutes of Electrof ishing
in the Fall at Chillicothe Island Chute (Mile 180) on
the Illinois River 39
Minimum Dissolved Oxygen Levels in the Illinois River
in 1965 and 1966 58
Dissolved Oxygen Concentrations and Turbidity in the
Middle of the Navigation Channel of the Illinois River
at Mile 25.9, During Passage of Towboats on Three
Occasions on November 7, 1963 64
PART I: INTRODUCTION
Background
For as far back as historical accounts date, the Illinois River
Valley has been described as unusually productive of fish and wildlife.
The French explorer Marquette wrote in 1673 (Mills, et al. , 1966):
"We have seen nothing like this river that we enter,
as regards to its fertility of soil, its prairies and
woods; its cattle, elk, deer, wildcats, bustards, swans,
ducks, par roquets, and even beaver."
When Illinois was a territory, the Illinois River Valley was con-
sidered one of the most important sources of furs in the Northwest part
of the United States (Starrett, 1972). During the early part of this
century, the Illinois River ranked as a major inland commercial fishery.
The economic importance of fish and wildlife to river towns was evi-
denced by the regular transport of live fish to Chicago, Boston, and
New York, and by a train scheduled especially to bring sportsmen into
the area. Many people made a living outfitting and guiding fishermen
and duck hunters.
The previously abundant wildlife in the Illinois Valley has also
contributed much to the development of local folklore of the Havana area.
President Benjamin Harrison came there several times to hunt duck.
Fishing was so good that the railroad put on the Fisherman's Special, a
regularly scheduled train that ran between Springfield and Havana. The
gangster Al Capone belonged to the gun club at Patterson's Bay and shot
duck there.
From 1874 to 1927, the Illinois State Laboratory of Natural History
and its successor, the State Natural History Survey, intensively studied
the resources of the Illinois River and its bottomland lakes
(Richardson, 1928) . Fish population surveys have been conducted reg-
ularly from the 1940 's to the present. The Natural History Survey
therefore welcomed the opportunity to contribute to an environmental
inventory of the lower portion of the Illinois River, undertaken by the
St. Louis District, U. S. Army Corps of Engineers.
The Study Area
The Illinois River begins at the confluence of the Des Plaines and
Kankakee Rivers. Navigational locks and dams along the rivers impound
waters, called pools, which provide convenient reference to the geo-
graphic location of various sections of the study area (see Figures 1
and 2).
The lower part of the Illinois, the area of principal interest in
this study, is influenced by the Alton Dam on the Mississippi. In the
middle portion are the pools formed by the LaGrange Dam and the Peoria
Dam. Pools sampled in the upper portion are, in upstream order, Starved
Rock, Marseilles, and Dresden. The Dresden Dam is located 1.4 miles from
the rivers' confluence and the Dresden Pool actually extends into the
Des Plaines and Kankakee Rivers. The one sampling station in the Dresden
Pool is located in the Des Plaines River.
The Illinois River, the Des Plaines River, the Chicago Sanitary and
Ship Canal, and the Chicago River form the Illinois Waterway, which pro-
vides a navigation channel 9 ft deep and 160-300 ft wide, connecting the
Mississippi River and Lake Michigan. Charts of the Illinois Waterway
have been prepared by the U. S. Army Engineer District, Chicago (1970)
and locations are given in river miles, starting from mile 0.0 at the
confluence of the Illinois and Mississippi Rivers, at Grafton, Illinois,
and proceeding upstream to Chicago. Along the river itself, mileages
are often given on navigation aids such as buoys, markers, and lights.
River mileages provide an accurate means of locating sites along the
Illinois Waterway, and are used throughout the text.
The Des Plaines River receives municipal and industrial effluents
from the Chicago area, while the Kankakee is relatively unpolluted. The
Des Plaines also contributes more to the total flow of the Upper
Illinois River than the Kankakee. During the lowest flows expected for
LAKE MICHIGAN
OR SHIP CANAL
Figure 1. Map of study area, showing sampling stations, navigation
pools, and sections of the river.
10
NDICATES THE LOCATION OF CITIES
NDICATES LOCK AND DAM SITES
'igure 2. Map of study area, showing cities,
and the drainage basin.
lock and dam sites.
a 7-day period at a recurrence interval of 10 years, the Illinois State
Water Survey (Singh and Stall, 1973) calculated that the Des Plaines
and Kankakee would contribute 1926 and 455 cfs of water, respectively,
to the Illinois.
Approximately 93 percent by volume of all waste flowing to the
upper portion of the Illinois Waterway (mile 179.0 at Chillicothe to
mile 292.1 at Lockport) , including all of the Upper Illinois River,
originates from three treatment plants of the Metropolitan Sanitary
District of Greater Chicago (Butts, et al., 1975). As a consequence,
thick oxygen consuming sludge and sediment deposits exist in the
Dresden and Starved Rock Pools, and a portion of the Peoria Pool; there
is a significant carbonaceous oxygen demand exerted in the Dresden Pool;
and a significant nitrogenous oxygen demand exerted in much of the
Illinois River (Butts, et al. , 1975; Butts, et al., 1970). These de-
mands cause low oxygen levels to occur in much of the Illinois River
during summer low-flow periods, with the upper and middle sections more
severely affected than the lower section. Thermal effluents in the
vicinity of Joliet (mile 284.0) raise the whole temperature profile of
the Des Plaines and Upper Illinois Rivers downstream to miles 200-180
(Butts, et al. , 1975).
The upper section of the Illinois River may also be differentiated
from the other two sections by its lower turbidity. Turbidity is less
there because above Hennepin (mile 207.5) the river bottom is generally
rocky, although in some sections the rock is overlain with sediment.
In contrast, the Alton, LaGrange, and Peoria Pools are more turbid be-
cause of soft mud bottoms and heavy silt loads from tributary streams
that have drained agricultural areas. These muds are kept in suspension
by current and wave action produced by wind, towboats , and pleasure
craft.
For fish and wildlife, the most productive portions of the Illinois
are the middle and lower sections below Hennepin. Here, the river flows
through a large, late Pleistocene valley: lateral levee lakes, side
channels, backwaters, and marshes fill the valley and provide an excel-
lent habitat for fish and wildlife.
12
PART II: METHODS
Sampling Stations and Schedules
Twenty-four sampling stations were selected in 1959 and a twenty-
fifth, Big Blue Island Chute, was fished once, in 1974. A listing and
description of the stations is given in Table 1. In considering loca-
tions for sampling, those that provide a desirable habitat for adult
fish and a good distribution along the river were chosen. There are
fewer stations in the upstream pools because those pools are shorter
than downstream ones.
The stations are located most accurately by river mile. The river
mile designation indicates the approximate area fished: for example,
at the first station listed, that part of Mortland Island Chute ex-
tending from mile 18.7 to 19.4 was fished (Table 1).
Most of the stations were in chutes (i.e. side channels of the
river), and contained habitats (brushpiles, undercut banks, and holes)
where a variety of fish were expected to congregate. The four stations
not in chutes were: (1) the station above Pekin, where both sides of
the main channel were fished; (2) the station along the shore of lower
Peoria Lake; (3) the station in middle Peoria Lake, where docks and rip-
rapping in various marinas were fished in the 1960's and where riprap-
ping at a State conservation landing in Detweiller Park was fished in
the 1970' s; and (4) a station in the Des Plaines River, where the wide
mouth of the DuPage River and a boat yard were fished.
The Des Plaines River station was fished only in 1959, 1962, 1973,
and 1974. Since it is not part of the Illinois River proper, the sta-
tion was omitted whenever sampling time was limited. Results from the
Des Plaines station were excluded when computing averages for the whole
Illinois River.
In order to sample under similar environmental conditions each
year, electrof ishing was conducted from late August to mid-October, but
only when the river was at pool stage behind the navigation dams. The
dams help to maintain a 9-ft-deep navigation channel by impounding water
1 5
during low-flow periods. When impounded, the river is said to be in
pool. All stations could not be fished every year because of high-
water levels; no stations were sampled in 1971 and 1972.
Fish Population Sampling
Fish populations were sampled by means of electrof ishing. Fish
were stunned by an electric current produced by a 230-volt, 180 cycles/
sec, AC generator (Homelite 9HY-1) , and transmitted through the water
via 3 cables suspended from booms in the front of an 18-ft aluminum boat.
Electrof ishing was conducted in 15-minute segments, and a total of
60 minutes was spent electrof ishing at most stations. In small chutes,
or where an abundance of fish was collected quickly, only 30 minutes was
spent electrofishing.
The stunned fish were dipped from the water and placed in plastic
garbage cans containing water. Fish were identified, counted, weighed,
checked for disease, and returned to the river. The few fish that died
were buried on shore.
There are problems associated with any sampling technique, including
electrofishing. In a turbid river such as the Illinois, fish must be
within a few inches of the surface to be seen and netted. Bottom-
dwelling species such as catfish and bullhead do not always surface
when shocked, and they are underrepresented in electrofishing catches.
Gars, such as the short-nose gar, arid bigmouth buffalo are not as vul-
nerable to electric shock as other species, such as sunfish. Gizzard
shad are often only momentarily stunned and occur in such large numbers
that it is impossible to net them all before they recover. Since the
electrofishing program was designed to sample populations of adult fish,
dip nets of %-in. mesh size were used; hence, small fish such as minnows
often were not retained in the nets. In addition, electrofishing was
conducted only in areas that were connected to the river at all times of
the year, so that species occurring primarily in lateral lakes which
were either permanently or intermittently cut off from the river were
not represented or were underrepresented in electrofishing collections.
14
Although the present report concerns the electrof ishing survey,
other sampling techniques such as trawling, seining, and trapping in
both the river and lateral lakes were used during the same period, and
information on the relative abundance of certain species in commercial
catches was obtained from commercial fishermen. Hence, it was possible
to judge whether a low number of a certain species in the electrof ishing
catch was due to low populations in the river or to biases in the sam-
pling technique.
Physical-Chemical Measurements
In 1974, before sampling fish populations, several physical-chemical
measurements were made at each station. Dissolved oxygen (DO) concentra-
tions at a depth of 3 ft and at the bottom in the deepest part of the
station were measured by the Winkler method or with YSI Model 57 dis-
solved oxygen meter. Surface water and air temperatures were measured
with a mercury thermometer. Wind direction and velocity and cloud
cover were noted. Transparency was measured with a Secchi disk.
The same measurements were made during some of the electrof ishing
surveys prior to 1974. In addition, turbidity of the river was measured
with a Jackson turbidimeter during earlier surveys.
13
PART III: RESULTS
Physical-Chemical Measurements
The data for water temperature, dissolved oxygen, and transparency
obtained in 1974 are given in Table 2.
Water temperature
The water temperatures in Starved Rock, Marseilles, and Dresden
Pool were generally higher than in the upper part of Peoria Pool, even
though the readings in the upper pools were taken two weeks later and
the weather had turned colder. The upper river is evidently warmer be-
cause of warm industrial and municipal discharges. Starrett (1971) re-
ported the same trend of warmer temperatures in the upper river in July
and August, 1966; Butts, et al. (1975) report data collected in 1971
which show that the mean temperature profile of the Upper Illinois and
Des Plaines Rivers was significantly increased by thermal discharges
near Joliet (mile 284.0).
Dissolved oxygen
Since the DO levels at both the 3-ft depth and at the bottom were
approximately the same within each station, the water was presumably
well-mixed.
In the Lower Illinois (Alton Pool), the DO concentration was 77 to
97 percent of saturation ; in the Middle Illinois
(LaGrange and Peoria Pools) , it ranged from 56 to 122 percent of satura-
tion; and in the Upper Illinois (Starved Rock, Marseilles, and Dresden
Pools), it ranged from 47 to 104 percent of saturation.
The untypically high oxygen values exceeding saturation at Ballard
Island Chute and in Lower Peoria Lake were probably due to algal photo-
synthesis, which was also indicated by the greenish or brownish color
of the water. Ballard Island Chute is shallow and, with its large sur-
face area, slow current, dissected shoreline, and numerous marshy
pockets, provides an environment suitable for phytoplanktonic develop-
ment.
16
Transparency
The Secchi disk visibility measurements indicated that generally,
the Upper Illinois was more transparent than the lower portions of the
river. The anomalously low measurements at Ballard Island Chute on the
Upper Illinois can be attributed to the effects of wave action on the
shallow bottom and to phytoplankton. During the period 1963 to 1966,
similar observations were recorded by a Jackson turbidimeter: turbidity
readings were higher in the lower three pools than in the upper three
pools (Starrett, 1971). The softer mud bottoms and influx of silt from
agricultural activities, particularly below Hennepin (mile 207.5), con-
tribute to the higher turbidity of the Lower Illinois.
Electrofishing Results, (1959-1974)
A total of 67 species of fishes were taken from the Illinois River
by electrofishing from 1959 to 1974 (Table 3) . The list includes 16
commercial species, 16 sport species, 8 species considered as both
commercial and sport fish, and 27 other species. This categorization
of the species is based upon lists contained in 1974-1975 Illinois
Fishing Information, published by the Illinois Department of Conserva-
tion (1974), and upon the author's personal knowledge of the species
sought by sport fishermen along the Illinois River. For example, the
Department of Conservation publication does not specifically mention
bullheads as sport fish, yet there are sport fishermen who seek bull-
heads. (As with many common names used by fishermen, the name "bull-
head," actually includes several species: the black, yellow, and brown
bullheads. )
During approximately the same period covered by the electrofishing
survey, a total of 101 fish species have been taken by Illinois Natural
History Survey crews employing various types of sampling gear, or by
commercial fishermen. Not all 101 species were taken by electrofishing,
due to sampling biases, which were discussed in Part II.
Scientific collections of fishes of the Illinois River were made
well before the electrofishing survey commenced. This background data
17
was used by Starrett (1972) in a summary assessment of changes that had
occurred in fish populations of the Illinois River:
"During the past hundred years 121 species of fishes
have been collected from the Illinois River and its
bottomland lakes (Starrett and Smith, unpublished).
Between 1957 and 1970 we took 101 species, nine of
which had not been taken in the period before 1908
(including two species not recognized in 1908 and
three exotic species) . Twenty species of fishes
were extirpated from the river between 1908 and 1970.
Several of the extirpated species were considered
rare or accidental species in the river. On the
other hand, many species of fishes common in the
river before 1908, including the walleye
(Stizostedion vitreum vitreum) and northern pike
(Esox lucius) , now are rare or limited in their
distribution. The changes which have occurred in
the fish fauna of the Illinois River reflect some
of the drastic effects modern man has had on the
ecology of the river."*
The fish species extirpated from the river between 1908 and 1970 are
listed on Table 4. The impacts of both natural environmental changes
and man-made changes on the fishes of the Illinois River are discussed
in Part IV.
Detailed electrof ishing results are given in Tables 5 through 29,
and are summarized below by species, in phylogenetic order. Not all
the 67 species listed in Table 3 are discussed below because the sam-
pling technique was not appropriate for these species and because they
occurred in a few collections by chance, as when small fish happened to
be retained in the dip nets, as a result of the %-in. mesh nets becoming
plugged with leaves. Tables are not presented for species represented
by only a few individuals from the entire river.
* An error was probably made in totaling the number of species in 1970.
A total of 100 species had been obtained from 1957 through 1970. A
species believed extirpated by 1970, the longear sunfish (Lepomis
megalotis) , was taken in the 1973 electrof ishing survey, making the
total 101, as of 1974.
18
Gar (Lepisosteus spp.)
Shortnose gar were taken infrequently in the three lower pools of
the river (Table 5). Other members of the gar family occur, or once oc-
curred, in the Illinois River, but were rare or absent from the electro-
fishing collections. Gar are not as vulnerable to electrof ishing as
other species and both shortnose and longnose gar are probably more a-
bundant in the river and backwaters than the collections indicate. A
few longnose gar (Lepisosteus osseus) were taken by electrof ishing before
1970. No spotted gar (Lepisosteus oculatus) have been taken by electro-
fishing, but two have been taken by a commercial fisherman at Havana.
One taken during a high-water period on February 26, 1973 at Havana was
the largest spotted gar reported for the state (7.5 lbs, 32.8 in. total
length) and was a female full of ripe eggs, indicating that she was ready
to spawn. Alligator gar (Lepisosteus spatula) were probably extirpated
from the Illinois River prior to 1970 (Starrett, 1972).
Shortnose gar are found in areas where there is a current, such as
the main channel, or side channel, whereas the other species favor clear
weedy backwaters and bottomland lakes. Since most electrof ishing was
conducted in side channels, it was not surprising that more shortnose
than longnose gar were taken.
Gar are generally considered a nuisance by sport and commercial
fishermen because they are not commonly used as food, become entangled
in nets, and prey on other fishes. Actually, such predation helps sta-
bilize the abundance of prey-species at a moderate level and is probably
advantageous to the prey-species. Gar are considered sight-predators,
and would thus be disadvantaged in turbid waters. Increasing turbidity
in the Illinois River and its lakes and backwaters probably accounts for
the decline in numbers of members of the gar family. Gar possess an air
bladder, open to the esophagus, and are capable of "air-breathing" when
dissolved oxygen levels are low, so low oxygen levels in the river and
lakes wouldnot be expected to have as drastic an effect on gar as on
other species.
19
Bowfin (Amia calva)
Bowfin is a commercial species that was not common in the Illinois
River collections (Table 6) . Bowfin were taken as far upstream as Peoria
Pool only in 1961 and otherwise were taken in collections from LaGrange
and Alton Pools. Bowfin numbers have been drastically reduced. Forbes
and Richardson (1908) reported that bowfin were abundant in sloughs and
lakes adjoining the Illinois River. In 1903 commercial fishermen took
1,097,050 lbs of bowfin from the Illinois River and its tributaries;
at the time the Illinois River furnished nearly all the bowfin marketed
in the United States (Forbes and Richardson, 1908).
Bowfin have a cellular air bladder, connected to the esophagus,
which can be used for "air-breathing" when dissolved oxygen levels in
the water are low. In addition, bowfin can use their highly vascularized
gill covers as an accessory respiratory organ (Lagler, et al . , 1962).
Bowfin construct nests for spawning on silt-free bottoms, often in beds
of vegetation.
Increasing turbidity, sedimentation, and the gradual loss of aquatic
vegetation in the Illinois River and backwaters were probably responsible
for the decline of this species. Trautman (1957) writes about the bow-
fin in Ohio:
"The bowfin was not adverse to waters made cloudy by the
abundance of plankton but normally occurred sparingly or
as strays in waters habitually turbid with clayey silts.
It displayed the greatest decreases in abundance in those
Ohio waters which formerly were clear and contained much
vegetation, but which during the survey had become silty
and almost vegetationless. "
American eel (Anguilla rostrata)
American eels were rarely taken. One was taken from Alton Pool at
mile 19 and two from Peoria Lake in 1974. None were taken in 1973. A
few were taken prior to 1973. Forbes and Richardson (1908) reported
that eels were taken regularly in small numbers from the Illinois River
at Havana.
20
Considering the remarkable migration of the eel, and the present ob-
stacles to its movement, it is not surprising that it is rare. Eels
spend most of their lives in freshwater streams and rivers. When they
are approximately a dozen years old, 2% to 4 ft long, 3% to 6 lb in
weight, they migrate downstream to the sea. They spawn in certain parts
of the Sargasso Sea, between the West Indies and the Azores, then die.
The young swim and drift back to continental waters, then ascend the
Mississippi River system. Physical or chemical barriers such as naviga-
tion dams and effluents may hinder the migration of eels.
Skipjack herring (Alosa chrysochloris)
Skipjack herring were taken sporadically throughout the river.
Large numbers apparently moved up the Illinois River during the spring
flood of 1973, and sport fishermen were catching them on minnows at
Havana.
Gizzard shad (Dorosoma cepedianum)
Gizzard shad were abundant in collections in all pools of the river.
The numbers and pounds reported in Table 7 do not begin to reflect the
actual abundance of the species for the following two reasons: (1) small
gizzard shad are stunned only momentarily by the electric shock and usu-
ally get away before they can be netted; and (2) so many gizzard shad
usually appear that it is futile to try to net them all, and so netting
efforts were concentrated on other species.
Gizzard shad are neither a commercial nor a game species, but small
shad are valuable forage for largemouth bass, crappies, and even species,
such as drum, that ordinarily prefer mollusks when they are available.
Shad are sensitive to low dissolved oxygen and probably sensitive
to cold temperatures. Die-off s of gizzard shad as a result of low dis-
solved oxygen levels sometimes occur in the bottomland lakes and back-
waters in mid-summer and usually occur in winter because of low tempera-
tures and perhaps low oxygen levels also. Nevertheless, because of
their high reproductive capacity, gizzard shad populations do not seem
to be much affected by these die-offs.
2]
Goldeye (Hiodon alosoides) and Mooneye (Hiodon tergisus)
These two species are the only members of their genus and of their
family, Hiodontidae. Both species are called mooneye by fishermen, and
both are considered commercial species (Illinois Department of Conserva-
tion, 1974). Adults are up to 15 in. in length and will take lures or
bait and furnish good sport for anglers.
Mooneye were taken infrequently and only from the Alton Pool until
1974, when one was taken from upper Peoria Pool at mile 215 (Table 8).
Goldeye (Table 9) were taken more frequently and ranged farther upstream
than their relative, the mooneye. However, in 1974 only two goldeye
were taken, all from one station at mile 261 in Marseilles Pool.
Mooneye were once caught fairly regularly in the Ohio and
Mississippi Rivers, but mooneye populations declined prior to 1908
(Forbes and Richardson, 1908) . Mooneye and goldeye have unusually large
eyes, and the "eye shine" is caused by a reflective layer in the retina
which may assist vision at night or in dim light in deep water. Since
both species appear to be sight predators, they have probably been ad-
versely affected by increasing turbidity. Trautman (1957) thought that
goldeye were more tolerant of turbid water than mooneye. Both species
inhabit the swift, open water of large rivers, and spawn in flowing water
over rocky and gravelly bottoms. High-water levels and swift currents in
the years 1972-1973 may have been temporarily beneficial to mooneye and
goldeye. The impounding of water behind navigation dams with the at-
tendent reduction in current and increasing siltation has probably con-
tributed to the reduction in mooneye and goldeye populations.
Grass pickerel (Esox americanus vermiculatus)
Grass pickerel were taken rarely by electrof ishing from the Illinois
River, and were never very abundant.
Northern pike (Esox lucius)
Northern pike were taken by sport fishermen in the river below
Marseilles Dam in 1973 and were netted in Lake Chautauqua in 1973 (river
mile 126.0), but have never been taken by electrof ishing. Northern pike
were common in the river before 1908 (Starrett, 1972). In the 1870's
22
and earlier, 1,000 lbs of northern pike were caught at a time at Havana
(Forbes and Richardson, 1908).
Pike are sight predators and often lie in ambush for prey in weed
beds in clear, shallow water. They spawn in marshes and backwaters
where the water is clear and there is abundant aquatic and flooded ter-
restrial vegetation. The decline in northern pike populations is prob-
ably attributable to increasing turbidity and to loss of suitable habitat
due to leveeing and siltation. The sporadic abundance of young northerns
in 1973 is attributable to favorable high-water conditions in 1972 and
1973.
Goldfish (Carassius auratus) and goldfish x carp hybrids
Goldfish were probably introduced to the Illinois River between
1908 and 1935 because Forbes and Richardson did not mention them in The
Fishes of Illinois (1908) and O'Donnell (1935) mentioned that they oc-
cur infrequently in the Illinois River. O'Donnell (1935) also mentioned
that two carp x goldfish hybrids were taken at Peoria.
Goldfish were abundant in the electrof ishing collections from the
polluted Upper Illinois River and the Des Plaines River (Table 10) . In
1962 for example, 101 goldfish were taken in 30 minutes of electrof ishing
in the Des Plaines.
Goldfish are more tolerant of low oxygen concentrations than many
native species, and appear to thrive where populations of native species
are sparse or absent. Goldfish are sometimes used as bait, so it is pos-
sible that native predators reduce goldfish populations in relatively un-
polluted areas. It is also possible that goldfish do not compete well
with native species of similar ecological habits in unpolluted areas,
but thrive in polluted environments where there is absence of competi-
tion.
If one uses goldfish as a pollution indicator and judges the quality
of the Upper Illinois by the catch of goldfish, then the low goldfish
catches in 1973 and 1974 in the Marseilles and Starved Rock pools indi-
cate that conditions improved during, and following, a high-water peri-
od. However, conditions in the Des Plaines River did not improve to an
extent that there was a marked reduction in goldfish.
2 3
Trautman (1957) reported that hybrids might be expected wherever
carp and goldfish occur together, and that in some areas in and near
Lake Erie the number of hybrids exceeds the number of both parent
species. In the Illinois electrof ishing collections, goldfish were
most abundant in the Dresden Pool, carp in LaGrange Pool, and carp x
goldfish hybrids in Starved Rock Pool and Peoria Pool (Tables 10, 11,
and 12).
Virtually all the goldfish and carp x goldfish hybrids taken in
the Des Plaines River had one or both eyes protruding, a condition re-
ferred to as "popeye" by fishermen. In the course of weighing and
measuring these fish, some of the eyes would fall out. Some individuals
had evidently survived a considerable time after losing one or both
eyes, because the empty sockets had filled with scar tissue. The cause
of this popeye disease is not known, although the disease appears to be
associated with polluted water in the Upper Illinois River. The in-
cidence of popeye disease decreases in the downstream direction, away
from Chicago.
Carp (Cyprinus carpio)
Carp and gizzard shad were the only species that occurred abun-
dantly in the electrof ishing collections in all pools of the river.
Carp were introduced into the Illinois River in 1885. By 1898, carp
brought more money to commercial fishermen along the Illinois River than
all other fishes combined. The carp catch was 6 to 8 million pounds per
year and was worth more than $200,000 (Forbes and Richardson 1908). In
1908 the catch was over 15 million pounds, according to Thompson (1928).
At present, carp and bigmouth buffalo comprise the bulk of the commer-
cial catch in the Illinois River, although carp have decreased from
4,041,000 lbs in 1950 to 213,000 in 1973. Mills, et al., (1966) dis-
cussed the decline in the carp catch:
"Much of the decline in the commercial catch since 1950 has
resulted from the scarcity of carp of commercial size
(17 inches or more in total length) in the middle section
of the river. Small carp are often abundant in this section
but most of them disappear before attaining commercial size.
24
The commercial catch of carp in the Alton Pool has
changed little since 1950.... two factors — loss of
fingernail clams plus low dissolved oxygen — could
explain the dearth of commercial-size carp in the
middle and upper reaches of the Illinois River."
Mills, et al., (1966) also used carp as an indicator of the effects
of pollution:
"These are two noticeable effects of pollution on this
species. First, the length-depth ratio of individuals
goes up with increasing pollution. By dividing the
depth into the standard length, an index is obtained
which, if 3 or greater, indicates that the fish is too
thin for commercial uses. Any index under 3 would in-
dicate a satisfactory commercial fish. Second, carp
exhibit a rachitic bone malformation (an abnormality
characterized by malformed heads and gill covers)
known as a "knothead" condition. This becomes more
conspicuous with increased pollution."
The study suggested a relationship between the die-off of finger-
nail clams that occurred in the middle section of the Illinois River
in 1955, and the decline on carp, which like other bottom-feeding
fishes, find fingernail clams a nutritious food. Mills, et al. , (1966)
found that the length-depth ratios of carp in the 1963 electrof ishing
collection indicated a marked difference between fish taken above and
below Beardstown (mile 88.5). Carp caught below Beardstown had ratios
less than 3, while above Beardstown the ratios were 3 or more. The
difference appeared to be attributable to the loss of fingernail clams
above Beardstown. The Sangamon River enters the Illinois River at
Beardstown, and may dilute some type of pollution which is responsible
for the absence or paucity of fingernail clams in the middle and upper
sections of the river. In 1973 and 1974, the length-depth ratios of
carp appeared to show the same trend of relatively thinner fish above
Beardstown as in 1963. More will be said in Part IV about the impact
of the die-off of fingernail clams in 1955.
In 1973 and 1974, the incidence of knothead among carp was re-
markably reduced in the upper river compared to 1926-27 and 1963. In
the older collections, more than 50 percent of the carp taken above
2 5
Peoria Lock and Dam were knotheads, whereas in 1973 and 1974, the in-
cidence had dropped to about 10 percent. Thompson (1928) theorized that
knothead was a rachitic disease, possibly caused by lack of vitamin D,
like rickets in mammals.
At Sugar Creek Island (mile 94.3-95.2), carp with an abnormality in
coloration were frequently taken. The bronze color seemed to be missing
and the fish appeared predominantly pink, purple, and light yellow. The
pink muscles overlying the anterior and ventral edges of the operculum
could be seen through the skin and scales. The fish appeared to be in
good health. Hansen and Shoemaker (1943) found that color-deficient
carp comprised the following percentages of their total carp catch in
1942; 2 percent at Meredosia (mile 71.0), 5 percent at Browning (mile
97.0), and 2 percent at Havana (mile 120.0). Commercial fishermen re-
fer to these fish as "chicken carp." The cause of this color variation
is unknown.
Minnows, Family Cyprinidae
The electrof ishing survey was not designed to sample minnow popula-
tions, although some minnows were taken sporadically. The emerald
shiner, Notropis atherinoides, was abundant throughout the river —
hundreds would often be driven ahead of the electrof ishing boat until
they reached shallow water, where they would be stunned and lie strewn
over the bottom.
Carpsuckers (Carpoides, spp.)
Identification of the species is often difficult because they are
extremely variable in their morphological characters, and to compound
the difficulty, they probably hybridize (Trautman, 1957). The quillback
carpsucker, Carpiodes cyprinus, has no dentary nipple at the tip of the
lower jaw, and identifications of this species in the course of the
electrof ishing survey were probably accurate. Both the river carp-
sucker, Carpiodes carpio, and the highfin carpsucker, Carpiodes velifer,
possess dentary nipples. The anterior dorsal fin rays of the highfin
carpsucker are drawn out into a long point, in contrast to the shorter
dorsal fin of the river carpsucker, and if the long rays are present,
the fish can be positively identified as a highfin carpsucker.
26
However, the long point is easily and commonly broken or eroded, so that
positive identification is difficult. Also, young fish (less than 3 in.
long) of both species resemble each other. Therefore, carpsuckers with-
out high dorsal fins were divided into two classes: quillback carp-
suckers and Carpiodes spp . Most of the fish in the latter group were
probably river carpsuckers. Carpsuckers with dentary nipples and high
dorsal fins were identified as highfin carpsuckers.
The three species of the genus Carpoides were all found in the
Illinois River (Tables 13 and 14) . Most of the fish in the Carpiodes
spp. group were taken from the three lower pools of the river, Alton,
LaGrange, and Peoria, prior to 1973. For 1973 and 1974 combined, most
were taken in Starved Rock Pool, so their distribution in the river may
have changed after the high-water period of 1971-1973.
Carpiodes spp. populations do not appear to have changed greatly
since 1908. Forbes and Richardson (1908) reported that Carpiodes
carpio were found mainly in the Illinois and Mississippi Rivers and
were not anywhere abundant. At that time, most of the river carp-
suckers from the Illinois River were taken at Havana and Meredosia, in
what today are the LaGrange and Alton pools.
River carpsucker (Carpiodes carpio). River carpsuckers feed on
diatoms, desmids, filamentous algae, rotifers, microcrustaceans, and
midge larvae (Bucholz, 1957), so they were not noticeably affected by
the die-off of fingernail clams and rooted aquatic vegetation which oc-
curred in the middle section of the Illinois River in the mid-1950 's.
Quillback carpsucker (Carpiodes cyprinus) . In 1957, Trautman
listed two species of Carpiodes, C_. cyprinus and C. forbesi, and two
subspecies of C_. cyprinus, the eastern quillback carpsucker (C. c_.
cyprinus) and the central quillback carpsucker (C . c^. hinei) , but in-
dicated that environmental factors strongly influenced the morphological
characteristics of these fishes:
"Central quillbacks, living in large waters of
relatively low turbidity having an abundance of
food, such as at Buckeye Lake, grow very rapid-
ly, are excessively fat, deep-bodied and small-eyed.
27
and because of these characteristics they resemble
the eastern carpsucker, often to a remarkable degree.
On the other hand individuals from turbid waters con-
taining little food, and others heavily parasitized,
grow slowly, are terete and large-eyed and resemble
Carpiodes forbesi, a form inhabiting turbid streams
west of the Mississippi River." (Trautman, 1957:237)
The latest List of Common and Scientific Names of Fishes (American
Fisheries Society, 1970) does not list subspecies of C. cyprinus, and
_C. forbesi has been synonymized with C. cyprinus. There is a consider-
able range of variation in morphology of quillback taken in the Illinois
River electrof ishing survey, and some of the variation is undoubtedly
due to factors such as nutrition, mentioned by Trautman.
The greatest number of quillback carpsuckers (Carpiodes cyprinus)
was usually taken in three pools of the Illinois River: Marseilles,
Starved Rock, and Peoria, so the quillbacks apparently preferred the up-
stream portions of the Illinois River more so than did their close rela-
tive, the river carpsucker (Table 14) .
Highfin carpsucker (Carpiodes verlif er) . Two highfin carpsuckers
were taken in Starved Rock Pool in 1960 and one from the same pool in
1965. Highfin carpsuckers may have comprised a portion of the Carpiodes
spp. group mentioned above.
Smallmouth buffalo (Ictiobus bubalus)
Like the bigmouth buffalo, the smallmouth buffalo was most common
in the collections from Peoria and LaGrange Pools (Table 15) . An un-
usually large number of smallmouth buffalo were taken from Starved Rock
Pool in 1974. The smallmouth buffalo is a commercial species.
Bigmouth buffalo (Ictiobus cyprinellus)
The largest numbers of bigmouth buffalo were taken in Peoria and
LaGrange Pools (Table 16) . No bigmouth buffalo had ever been taken
from Dresden Pool by electrof ishing and none had been taken from
Marseilles Pool prior to 1974. Bigmouth buffalo had been taken in
Starved Rock Pool in only one year, 1966. In 1974, they were taken in
both Starved Rock and Marseilles Pools. It is surprising that few in-
dividuals of the three species of buffalo were ever taken in Alton Pool
28
and that none were taken in 1974. Several commercial fishermen at
Kampsville landing and Godar landing on the Alton Pool said that they
too were catching very few bigmouth buffalo in 1974. Bigmouth buffalo
rank second to carp in the commercial catch from the Illinois River.
Black buffalo (Ictiobus niger)
The black buffalo is a commercial species. It was not abundant in
the Illinois River electrof ishing collections and was taken only in the
lower three pools prior to 1974 (Table 17). In 1974, the few black
buffalo taken came from Starved Rock Pool.
Shorthead redhorse (Moxostoma macrolepidotum)
The shorthead redhorse occurred sporadically in the collections
throughout the river (Table 18).
White catfish (Ictalurus catus)
The white catfish is a native of brackish to fresh waters along the
East Coast from Pennsylvania to Florida. It has been introduced widely
in the Midwest, and several have been taken from the Illinois River by
commercial fishermen at Havana, including one on 13 May 1974. White
catfish have never been taken in our electrof ishing surveys. White
catfish seem to exist in the Illinois River at a stable, low density.
Black bullhead (Ictalurus melas)
The black bullhead is considered a commercial species, but most of
the bullheads in the electrof ishing collections were small. Most of
the black bullheads were taken from one station (Table 19), Ballard
Island Chute (river mile 247.8-248.2) in Marseilles Pool. As described
earlier this location is an unusually shallow, broad, marsh-fringed area
with very little current; the black bullhead prefers this type of
habitat.
Black bullhead were collected occasionally in the main navigation
channel, by means of an otter trawl. For example, On 26 August 1964,
51 black bullheads averaging 7 in. in total length were taken in
49 minutes of trawling at mile 193.
29
Yellow bullhead (Ictalurus natalls)
The yellow bullhead was uncommon in the collections and has been
taken only from the three lower pools: Alton, LaGrange, and Peoria
(Table 20).
Channel catfish (Ictalurus punctatus)
Prior to 1973, the numbers and pounds of channel catfish taken ap-
pear to be unrelated to water levels. Channel catfish were taken in
Marseilles Pool for the first time in 1974 (Table 21) . The largest
number and pounds of fish were also taken in the entire river in 1974.
Most channel catfish were taken below Beardstown (river mile 88.5).
Channel catfish were taken occasionally from the main channel by
trawling. On 13 November 1964, 68 young channel catfish averaging
3% in. in total length were taken in 53 minutes of trawling in the
channel at mile 156.
Channel catfish have declined in the Illinois River since 1899 as
evidenced by the following commercial fishing statistics for the entire
Illinois River: 241,000 lbs in 1899; 105,554 lbs in 1950; and about
98,000 lbs in 1964 (Mills, et al. , 1966), and 45,000 lbs in 1973
(Personal Communication, December 1974, Mr. Larry Dunham, Fishery
Biologist, Illinois State Department of Conservation, Aledo, Illinois).
At present, channel catfish bring the highest market price of all the
commercial species.
Flathead catfish (Pylodictis olivaris)
Flathead catfish are a desirable commercial species and often at-
tain weights of 20 to 40 lbs. Flathead catfish were never abundant in
the electrof ishing collections and were taken only in the lower two
pools (Table 22) . An 18-lb individual was taken in LaGrange Pool.
The following numbers of one- and two-year-old flatheads were taken
from the five stations in Alton Pool and the six stations in LaGrange
Pool: 0 (mile 18.7), 2 (mile 24.0), 1 (mile 26.0), 2 (mile 29.3),
0 (mile 57.5), 3 (mile 86.2), 1 (mile 94.3), 3 (mile 106.8),
0 (mile 112.8), 0 (mile 147.3), 0 (mile 154.5).
30
White bass (Morone chrysops)
The white bass is a game species. The largest number of white
bass was taken from the river in 1974, but the greatest catch in pounds
was in 1968 (Table 23) . White bass populations generally increase in the
downstream direction, with the largest number and most pounds usually
being taken in Alton Pool.
White bass spawn in shallow water where currents remove sediments
and expose a firm, clean bottom. Such spawning habitat is not now
generally available in the Illinois River.
Yellow bass (Morone mississippiensis)
Yellow bass were infrequently taken, and only from Peoria, LaGrange,
and Alton Pools. For example, only two were taken from the entire
Illinois River in 1973, and none in 1974. The largest number, 40, was
taken in 1964: 28 from Alton Pool and 12 from LaGrange Pool.
Yellow bass were once much more abundant in the Illinois River.
Forbes and Richardson (1908) reported that yellow bass were common in
the commercial catches at Havana, Meredosia, and Peoria, and that the
combined catch of yellow and white bass from the Illinois River in 1899
was 92,931 lbs, of which yellow bass comprised the greatest part.
Rock bass (Ambloplites rupestris)
The rock bass usually inhabits clear, rocky streams, and its oc-
currence in the Illinois River is probably accidental. One rock bass
was taken from LaGrange Pool in 1960, one from Marseilles Pool in 1966,
and one from Peoria Pool in 1969.
Green sunfish (Lepomis cyanellus)
Green sunfish are considered game fish by some people, although
they do not grow as large as their relative, the bluegill. The green
sunfish was taken in the Des Plaines River in two of the four years this
station was sampled; whereas the bluegill was never taken from this
station (Tables 24 and 25) . The largest number of green sunfish was
generally taken in Peoria Pool. The number of green sunfish taken did
not increase dramatically after the high-water period 1971-1973, as did
the bluegill.
11
Pumpkinseed (Lepomis gibbosus)
Forbes and Richardson (1908) reported that pumpkinseeds were most
abundant in the northern part of the state (Lake and McHenry Counties)
and were present along the Illinois River. Very few pumpkinseeds have
been taken by electrofishing: one from Peoria Pool in each year from
1960 to 1963, and two in 1962; one in 1967; one in 1968; and two in 1974,
from Marseilles Pool.
Warmouth (Lepomis gulosus)
A total of 126 warmouths were taken during the entire electrofishing
survey. Most of the fish were taken from Alton and LaGrange Pools. One
was taken from Peoria Pool in 1963 and another in 1974. Two were taken
from Marseilles Pool in 1974.
The warmouth' s principal habitat is ponded, often turbid water,
where bottoms are soft mud (Larimore, 1957). With a habitat preference
such as this, one might expect warmouths to be more abundant in the
Illinois River than they are. However, they also prefer dense weed beds
and feed on larval insects, including species which are associated with
weed beds, such as damselflies and dragonflies (Larimore, 1957). Since
weed beds and the associated weed fauna have been eliminated from most
of the middle and lower sections of the Illinois River, and since other
insect food organisms, such as mud-burrowing mayflies, are also less
abundant than they once were, the relative paucity of warmouths in the
electrofishing collections is not surprising.
Orangespotted sunfish (Lepomis humilis)
A total of 343 orangespotted sunfish were taken during the electro-
fishing survey, with the numbers taken per pool as follows: Dresden,
0; Marseilles, 38; Starved Rock, 4; Peoria, 240; LaGrange, 39; and
Alton, 22.
Forbes and Richardson (1908) reported that this species was often
taken along the shore of the Illinois River and in adjacent lakes and
sloughs. Orangespotted sunfish appear to tolerate turbid water, water
level fluctuations, and silt bottoms (Trautman, 1957; Cross, 1967).
32
Bluegill (Lepomis macrochirus)
The largest number and most pounds of bluegill per 30 minutes of
electrofishing were taken in 1974 (Table 25) . Bluegill populations
generally increased in the downstream direction, with either Alton or
LaGrange Pools having the greatest number and most pounds. However,
more were taken in Marseilles Pool than in the next pool downstream,
Starved Rock; only in 1969 were more bluegill obtained in Starved Rock
than in Marseilles.
Longear sunfish (Lepomis megalotis)
One species, the longear sunfish (Lepomis megalotis) , believed by
Starrett and Smith (Starrett, 1972) to have been extirpated from the
Illinois River and its bottomland lakes between 1908 and 1970, was taken
from LaGrange Pool, Turkey Island Chute (mile 147.3-148.2) on
September 5, 1973. Three adults, ranging in total length from 4.2 to
6.1 in., were taken.
One of these fish was preserved and later examined by Dr. Phillip W.
Smith, Taxonomist, Illinois Natural History Survey, who assigned it to
the subspecies known as the central longear sunfish (Lepomis megalotis
megalotis) . A subspecies known as the northern longear sunfish (Lepomis
megalotis peltastes) occurs in northern tributaries of the Illinois
River, but has not been taken from the Illinois.
Smallmouth bass (Micropterus dolomieui)
The few smallmouth bass (Micropterus dolomieui) were probably in-
troduced from tributary streams that are smaller and colder than the
Illinois River. Thirty-two smallmouth were taken from 1959 to 1974:
two from Marseilles Pool, one from Starved Rock Pool, and 29 from Peoria
Pool.
Largemouth bass (Micropterus salmoides)
The largemouth bass is a game species. Largemouth populations
generally increase in the river in a downstream direction. However,
fewer bass were taken at the two stations in Starved Rock Pool than
in the three stations in the next pool upstream, Marseilles Pool
(Table 26). Bass populations in the river were high in 1960 and 1961,
33
then showed a drastic decline during and following the drought years,
1962-1964. The recent increase in largemouth populations followed the
high-water years, 1971-1973. Largemouth bass were more numerous in
Marseilles Pool in 1973 and 1974 than they ever had been previously.
White crappie (Pomoxis annularis) and Black,
crappie (Pomoxis nigromaculatus)
The largest catch of both black and white crappie, in pounds and
numbers, was taken in the river in 1974, following the high-water years
1971-1973 (Tables 27 and 28) . Populations of both species showed a
steady decline in the years 1962-1965, during a drought period. Prior
to 1973, few crappies were taken in the upper three navigation pools,
but substantial numbers of both species were taken in the Starved Rock
and Marseilles Pools in 1974. In 1962, 1964, 1966-1969, and 1974, more
black crappies were taken in LaGrange Pool than Alton Pool, perhaps
because more backwater and side channel areas with brush piles (a
favorite habitat of crappie) were usually available in LaGrange Pool.
In 1974, a larger number of white crappie were taken in LaGrange Pool
than in Alton Pool, but a larger number of pounds of white crappie were
taken in Alton, showing that the white crappie in Alton were of larger
size. Both species are popular game fish.
Yellow perch (Perca flavescens)
Two yellow perch were taken during the electrofishing survey; one
from Peoria Pool in 1964, and one from Marseilles Pool in 1965. Yellow
perch were once common in the Illinois River. Forbes and Richardson
(1908) reported that yellow perch were taken in considerable numbers
from the Illinois River as far south as Meredosia (mile 71.2). Yellow
perch were commonly taken by pole-and-line fishing in backwaters and
lakes in the Havana area (mile 120), until 1943. In 1943 and 1944,
floods deposited a great deal of silt in the lakes and backwaters.
Following the floods, the once-abundant aquatic vegetation disappeared.
The yellow perch population declined drastically, probably as a result
of the loss of aquatic vegetation that perch use for spawning (Starrett
and McNeil, 1952).
34
Sauger (Stizostedion canadense) and Walleye (Stizostedion
vitreum vitreum)
Only two saugers were taken from the Illinois River by electro-
fishing. Both came from the Alton Pool, one in 1965 and one in 1974.
During a 10-year biological investigation of the fishes of Lake
Chautauqua (mile 124-130) from 1950-1959, Starrett and Fritz (1965)
obtained just three sauger, and the same authors reported that saugers
were caught occasionally in the river by commercial fishermen. Sauger
are reported to be more tolerant of turbid water and silted bottoms
than their close relative, the walleye (Trautman, 1957). In spite of
this tolerance, sauger are much less abundant in the Illinois River now
than prior to 1908.
Walleye were once common in the Illinois River, but not a single
specimen was taken during the electrof ishing survey or during the
10-year study of Lake Chautauqua mentioned above. By contrast, in
1899, 11,000 lbs of walleye were taken by commercial fishermen from the
Illinois River, and approximately 100 walleye could be taken per year
along each few miles of river (Forbes and Richardson, 1908) . Trautman
(1957) attributed reductions in walleye populations in Ohio to turbidity,
the silting over of hard bottoms, and dams which hindered the movements
of this highly migratory species.
Freshwater drum (Aplodinotus grunniens)
Freshwater drum is a commercial species. Every year, most were
taken in LaGrange and Alton Pools (Table 29). The largest number of
individuals and the second greatest number of pounds were taken in 1974,
following a high-water period.
Discussion of Electrof ishing Results
There are several patterns to the distribution of fishes in the
Illinois River in both space and time. Although one might think that
the total number or total weight of fish taken from the various naviga-
tion pools should provide a good summary of changes in fish populations
through time and space, such summaries tend to obscure, rather than
elucidate, patterns exhibited by particular species, because the total
abundance can remain constant while some species increase and others
decline.
Temporal distribution
Table 30 shows the average number of fish of all species taken per
30 minutes of electrof ishing in the years 1959 through 1974. The
greatest number of fish was taken in 1962 from Peoria Pool. This peak
in numbers is attributable to a peak in the abundance of one species,
gizzard shad, due to unknown causes. More fish were taken from
Marseilles Pool in the years 1960-1963, than in subsequent years. Again,
this peak is primarily attributable to the abundance of one species,
goldfish, although more largemouth bass, bluegills, green sunfish, and
white crappie occurred in Marseilles Pool in 1960, than in the years
immediately following.
Table 31 shows the average weight of fish of all species taken per
30 minutes of electrof ishing from 1959 through 1974. No consistent pat-
terns are evident, except that for five of the six years, 1960-1965,
more pounds of fish (primarily carp) were taken from Starved Rock Pool
than from the pools immediately above or below it, while just the re-
verse relationship has existed since 1965. Within memory of several
residents along the Fox River, fishing has gone from excellent to poor.
It is likely that the lower end of the Fox River may once have supplied
a haven for fishes, some of which found their way into the Illinois
and the electrof ishing collections. Now it appears that fish are no
longer recruited to Starved Rock Pool from the Fox River.
When one looks at the distribution of certain species of fish
through time (Table 32) a consistent and interpretable pattern is evi-
dent. Largemouth bass, black crappie, and white crappie populations
declined from 1962 through 1965, a drought period when water levels
were low. The maximum numbers of these three species were taken in the
fall of 1973, following a period of high-water levels from 1971 through
the spring of 1973. In addition, the lowest numbers of bluegill and
36
and flathead catfish were taken in 1965, and the maximum numbers of blue-
gill, flathead catfish, white bass, and bigmouth buffalo were taken in
1973 or 1974.
The list of species which benefited from high-water levels includes
desirable game fish, such as largemouth bass, bluegill, black crappie,
and white crappie, which are in the sunfish family (Centrarchidae) and
have similar life histories. All of these sunfishes lay their eggs in
nests which are constructed in shallow water. They prefer to construct
nests on firm, rather than muddy substrates. The fry feed first on
zooplankton, then largely on aquatic insects and fish. The sunfishes
are generally less tolerant of low dissolved oxygen levels than species
such as carp and black bullhead .
Increased flow of water in the Illinois has several beneficial ef-
fects on fishes. Flooded areas often provide good spawning sites, with
firm bottoms, whereas the bottom in much of the river and its bottom-
land lakes is covered with flocculent mud. Several people reported that
sunfishes were spawning on flooded gravel roads and areas of firm mud or
sand in the spring of 1973. Flooded areas also provide good nursery
areas for juvenile fish, provided the water does not retreat too soon.
An increased current velocity in the river stimulates spawning migra-
tions of species such as white bass. An increased rate of water flow
(discharge) can dilute oxygen-demanding or toxic wastes. Butts, et al.
(1975) report that increased flows in the Upper Illinois River initially
result in reduced dissolved oxygen levels because combined storm and
sanitary sewers overflow to the river, but that during sustained high
flows, the oxygen levels are higher than during sustained low flows.
Carlson and Seifert (1974) have shown that oxygen levels at
35 percent saturation reduce the survival of larval largemouth bass by
13.7 percent, and oxygen levels at 70 percent saturation and below re-
tard the growth of larval largemouth bass. The tolerances of the other
members of the sunfish family to low dissolved oxygen are probably much
the same. The relationships among discharge, dissolved oxygen levels,
and largemouth bass populations in Chillicothe Island Chute are shown
37
in Figure 3. Chillicothe Island Chute is an area of prime largemouth
bass habitat in Peoria Pool. Midsummer oxygen levels were at 35 percent
saturation or below four years out of the eight-year period from 1963-
1970. Since the May-August water levels at Peoria did not fluctuate
greatly from 1963 through 1970, the decline in the largemouth bass popu-
lation is probably attributable to low oxygen levels, perhaps acting in
combination with other stresses, such as the presence of toxicants.
Spatial distribution
Tables 33 and 34 show the numbers and pounds of fish of selected
species taken in the various pools of the river during the period 1959-
1974.
The following species were more numerous in the two middle pools
of the river, LaGrange and Peoria Pools, which have the most connecting
lake acreage, than in the other pools: gizzard shad, carp, river carp-
sucker, smallmouth buffalo, bigmouth buffalo, black buffalo, yellow bull-
head, green sunfish, bluegill, largemouth bass, white crappie, black
crappie, and freshwater drum. The bottomland lakes and backwaters
provide fish habitat and an invertebrate fauna which supplies food for
many fish species. Fish produced in areas lateral to the river are
recruited to the river, where they show up in the electrof ishing col-
lections.
The following species showed a trend of increasing abundance in
the downstream direction, away from Chicago, with the largest number
occurring in Alton Pool: shortnose gar, bowfin, goldeye, mooneye,
channel catfish, flathead catfish, white bass (Table 33). Bowfin ap-
parently have always been more abundant in the southern part of Illinois
than in the northern part (Forbes and Richardson, 1908) . Goldeye and
mooneye both appear to be more common in the Mississippi than in the
Illinois, and both species probably enter the Illinois from the
Mississippi. In 1974, goldeye were taken only from Marseilles Pool and
mooneye only from Peoria Pool, so these fish may have run up the
Illinois during the high flows of 1971-1973. Other factors which may
influence the distribution of fishes whose populations increase in the
38
69 70
73 1974
Figure 3. Mean water levels, mean discharge, and mean dissolved oxygen
levels during July and August and the number of largemouth bass
taken per 30 minutes of electrof ishing in the fall at Chillicothe
Island Chute (mile 180) on the Illinois River.
Chillicothe Island Chute is in the Peoria Pool. Discharge was
measured at Marseilles (mile 247), water levels at Peoria
(mile 163), and oxygen levels in the chute. The oxygen reading
marked with an asterisk was taken on September 30. Water levels
were obtained from the "Missouri-Mississippi River Summary and
Forecasts," issued daily by the National Weather Service, River
Forecast Center, Kansas City, Missouri. Discharge was obtained
from an annual publication, "Water Resources Data for Illinois,"
by the U. S. Geological Survey District, Champaign, Illinois. The
other data were obtained by the Natural History Survey.
39
downstream direction are: the increased abundance of food organisms
such as mayflies, snails, and fingernail clams in the Lower Illinois as
compared to the Middle and Upper Illinois; the relatively higher oxygen
levels in the Alton Pool as compared to the upstream pools; and the
proximity to the relatively unpolluted Upper Mississippi River.
Black bullhead were abundant at one station, Ballard Island Chute,
Marseilles Pool (mile 247.8-248.2), which apparently provides preferred
habitat for this species.
Northern pike, yellow perch, and walleye were once abundant in the
river, but are now rare or limited in their distribution. Yellow perch
populations have declined probably as the result of the dissappearance
of beds of aquatic plants and disappearance of clean sand or pebble sub-
strates perch use for spawning.
Gizzard shad and carp were generally abundant throughout the river,
Goldfish showed a trend of increasing abundance in the upstream
direction, toward Chicago. Goldfish can tolerate the low dissolved
oxygen levels which are found in the Upper Illinois River. Moreover,
there is an absence of predators in the upper river, such as largemouth
bass, which are known to feed on goldfish. The fish populations of the
polluted Des Plaines River show the classic response of a community of
organisms to pollutional stress. The number of species is reduced as
pollution eliminates the intolerant organisms. Populations of the re-
maining tolerant species often expand, because of reduced competition
and predation.
The incidence of disease and deformities among all the fish, ob-
served to increase in the upstream direction, is probably related to
chemicals and pathogenic organisms in effluents from the Chicago area.
"Knothead" has been discussed earlier, under carp. Species other than
carp, such as bigmouth buffalo sometimes exhibit knothead, and the in-
cidence appears to increase upstream as for carp. Virtually all the
goldfish taken from the Des Plaines in 1973 had "popeye" (swollen, pro-
truding eyes) or missing eyes. The incidence of sores on the fins and
body, tumors, frayed fins, and abnormal spinal curvature was higher
40
among fishes from the Upper Illinois than from the middle and lower
sections.
The abundance of certain species in the electrof ishing collections
from Starved Rock Pool, in relation to other pools, indicates a localized
pollution problem of some sort, perhaps associated with the entry of the
Fox River into this pool. Carp, goldfish, and carp x goldfish hybrids
were more abundant here than in pools immediately above and below it.
All three of these fish can tolerate low oxygen levels. Members of the
sunfish family, including largemouth bass, bluegill, and white crappie,
require higher oxygen levels, and were generally less abundant in Starved
Rock Pool than in pools immediately above and below. Although dissolved
oxygen levels in the Fox River are generally close to saturation, the
entry of the Fox into the Illinois causes only a fraction of a milligram
per liter increase in dissolved oxygen (Butts, et al. , 1975). During
low flows, an oxygen sag develops in the next pool upstream from Starved
Rock Pool, Marseilles Pool, and continues into Starved Rock Pool, so
that Starved Rock Pool has lower oxygen levels during low flows than
Marseilles Pool or the upper end of Peoria Pool (Butts, et al . , 1975).
Reaeration of river water does not take place at Marseilles dam during
low flows, because the entire flow of the river is diverted through a
power plant (Butts, et al. , 1975).
Table 35 summarizes the commercial catch of fish from the Illinois
River and for comparison, the catch from the Mississippi River bordering
Illinois. In spite of the improvement in the electrof ishing catch in
1973 and 1974, apparently due to high-water levels in 1971-1973, the
commercial catch of fish in the Illinois River continued its historical
decline in the 1970' s. There was a slight increase in the catch in 1974,
probably due to fish spawned in 1971-1973, which were of large enough
size in 1974 to be taken commercially. Nevertheless, the general trend
since 1950 has been downward, and depending on whether the Illinois
Department of Conservation or the "Fisheries Statistics of the United
States (1950-1971)" are used, the catch dipped under one million pounds
for the first time in 1971 or 1972. The decline is not explained by a
decline in the number of commercial fishermen — there were 13 full-time
and 56 part-time Illinois River commercial fishermen in 1973, and
9 full-time and 47 part-time in 1971. Nor is it explained by a decline
in economic value of the catch. The catch from the Mississippi River
bordering Illinois has been relatively constant from 1950-1973. A
general decline in profits would be reflected in a general decline in
fishing effort in both the Illinois and Mississippi Rivers and a cor-
responding decline in catch.
Some of the reasons for the changing distribution patterns and
abundance of Illinois River fishes will be discussed in more detail in
the next section.
42
PART IV: IMPACTS ON THE FISH POPULATIONS OF THE ILLINOIS RIVER
Historical Impacts
The Illinois-Michigan Canal (1848)
The Illinois-Michigan Canal along the Upper Illinois River was com-
pleted in 1848, before any biological data were collected on the Illinois
River. It is unlikely that this canal had much of an impact on the mid-
dle and lower sections of the river, below Hennepin (river mile 208),
which are the sections most productive of fish and wildlife. The reason
they are the most productive is that the Illinois River below Hennepin
follows a large valley developed in the late Pleistocene epoch, and the
Illinois has developed lateral levee lakes, side channels, backwaters,
and marshes, which fill this ancient valley and provide excellent habitat
for fish and wildlife.
Chicago River reversal (1871)
In 1871, the flow of the Chicago River was reversed in order to
conduct sanitary wastes from the city of Chicago away from Lake Michigan,
which served as the drinking water supply for the city. The polluted
waters of the Chicago River were directed through the Illinois-Michigan
Canal into the Des Plaines River, thence into the Illinois River. Some
of the polluted water apparently backed up into the lower reaches of the
Kankakee. The effect of the polluted water on the fishes of the Kankakee
and Illinois Rivers was dramatic according to a report of the U. S. Com-
missioner of Fish and Fisheries (Nelson, 1878):*
"Previously to the opening of the Chicago River
into the canal in 1871, rockbass, (Ambloplites rupestris) ;
largemouth bass, (Micropterus salmoides) ; white bass,
(Morone chrysops) ; walleye, (Stizostedion vitreum vitreum)
mud-pike, (?) ; northern pike, (Esox lucius) ; mud eel,
(lamprey?); American eel, (Anguilla rostrata) ; buffalo,
Modern scientific and common names of fishes have been substituted
for older names in the following quotation, wherever possible.
43
(Ictiobus — ?); shorthead redhorse, (Moxostoma macrolepldotum) ;
suckers, (Catostomus — ?) ; bullheads (Ictalurus — ?); paddle-
fish, (Polyodon spathula) ; sunfish, (Lepomis — ?); catfish,
(Ictalurus — ?) ; bowfin, (Amia calva) ; longnose gar,
(Lepisosteus osseus) ; yellow perch, (Perca f lavescens) , were
caught in both these rivers, and also in the Du Page River,
which flows 6 miles east of Joliet, and empties into the
Des Plaines 8 miles south of that town; also in Hickory Creek
which rises about 14 miles east of Joliet, and empties into
the Des Plaines just south of the town, and in any of the
streams of sufficient size in this vicinity.
"When the current of Chicago River was first turned
through the canal and the rivers, it caused the fish in
them to bloat to a large size, and rising to the surface
they floated down the stream in large numbers. It was
estimated at the time that several tons of dead fish
passed through one of the canal locks just after the foul
water commenced running through the canal.
"When these bloated fish chanced to float into the
clear water at the mouth of some tributary of the river
they would revive and swim up the clear stream. Such
large numbers of the fish revived in this manner that
all the small streams flowing into the Des Plaines and
Kankakee rivers were filled with fish in such numbers
that many were taken with hook and line, one man taking
over 300 in a day in this manner at that time.
"When the spring freshets occur the current is so
rapid and the amount of pure water in the river is so
great, that the foul water does not have much effect upon
the fishes, and large numbers of the species mentioned
ascend the rivers and are caught with hook and line.
Later in the season as the water subsides, and the water
from Chicago River predominates , the fish which came up
in the spring die and are floated down the river. In
July and August when the water is the worst even the mud
turtles leave the river in disgust and seek less odorous
homes. "
Water from the Illinois-Michigan Canal also entered the Illinois
River at LaSalle, (mile 226) but the wastes were sufficiently decomposed
at that point that there was only a slight impact on the ecosystem of
the Illinois River below LaSalle (Starrett, 1972).
44
Low navigation dams (1871-1899)
Forbes, in describing the man-made changes which affected "the
biological system of the river" (in Richardson, 1928) does not mention
the construction of low navigation dams at Marseilles, Henry, Copperas
Creek, LaGrange, and Kampsville. He does mention the introduction of
the carp, Cyprinus carpio, the opening of the Chicago Sanitary and Ship
Canal, and draining and leveeing of bottomlands and bottomland lakes.
Nelson (1878) was of the opinion that a dam at Seneca (mile 252.5)
hindered the upstream movement of fishes.
European carp (1885)
The European carp was introduced to the Illinois River in 1885,
from stock brought to the United States a few years earlier (Forbes
and Richardson, 1908). By 1889, the carp catch exceeded the total
value of all other commercial fishes from the Illinois River (Thompson,
1928) . Forbes and Richardson (1908) reported fishery statistics in-
dicating that increased carp populations did not adversely affect the
populations of other species. Forbes and Richardson (1908) did feel
that carp might compete with the native drum and buffalo fishes, which
have the same food preferences as carp. Competition for food does not
appear to have markedly affected populations of bigmouth buffalo —
bigmouth buffalo and carp comprise the bulk of the commercial catch
from the Illinois River and both species are abundant in the electro-
fishing collections from Peoria and LaGrange Pools. Bigmouth buffalo
are not abundant in the other pools of the river, probably because of
poor water quality in the upper pools, and the relative paucity of back-
waters in the Alton Pool, rather than because of competition from carp.
Forbes and Richardson (1908) did not feel that carp, by their rooting
habit of bottom feeding, had increased the turbidity of the water in
the Illinois River. In contrast, Jackson and Starrett (1959) observed
local areas of heavy turbidity produced by schools of carp in Lake
Chautauqua, a bottomland lake along the middle section of the river.
They felt that some instances of carp activity may have been stimulated
by low oxygen levels. More recently, carp activities may have had a
greater effect on turbidity because of the increased presence of
45
flocculent bottom muds that have been carried into the bottomland lakes
by the river (Starrett and Fritz, 1965).
Sanitary and Ship Canal (1900)
On January 1, 1900, the Sanitary and Ship Canal was opened at
Chicago, connecting the Des Plaines and Illinois Rivers with Lake
Michigan. The canal was used to flush municipal and industrial wastes
into the Illinois River system and away from Chicago's municipal water
intakes in Lake Michigan.
The quantity and quality of water diverted through the canal had a
tremendous impact on the Illinois River. Water levels at Havana,
Illinois rose an average of 2.8 ft and, during the normal low-flow period
between June and September, rose 3.6 ft (Forbes and Richardson, 1919).
As a result the tree line along the river retreated and the loss
of mature pin oak and pecan trees meant a loss of food for mallard and
wood ducks (Mills, et al. , 1966). Populations of cavity-nesting tree
swallows and prothonotary warblers increased as a result of the increase
in nesting sites in zones of dead trees bordering the river and lakes.
When the last of the dead trees collapsed during the 1940' s, populations
of these species declined markedly. (Personal Communication, September
1974, Dr. Frank C. Bellrose, Waterfowl Biologist, Illinois Natural
History Survey, Havana, Illinois).
One beneficial effect of the diversion was to increase the surface
area of water in lakes and backwaters, which apparently improved the
fishery (Forbes and Richardson, 1919). It is also likely that stumps
and snags, left after the trees had died, temporarily provided cover
for certain species such as largemouth bass, sunfish, and crappie. The
increased shallow water areas and nutrient loading of the Illinois River
and its bottomland lakes initially may have increased the plankton popu-
lations and the biomass of bottom fauna in the middle and lower river
(Forbes and Richardson, 1913). In the river proper, populations of
molluscs, especially fingernail clams, probably increased the most, with
a beneficial effect on mollusc-consuming species of adult fish, such as
carp, catfish, buffalo, and drum.
46
Increased sewage pollution beginning c. 1910
After approximately 1910, as the pollution load increased, criti-
cally low dissolved oxygen levels in the water and putrescent conditions
in the bottom muds occurred farther and farther downstream with detri-
mental effect on food organisms and fish (Richardson, 192Lb) . Richardson
believed that in the 1915-1920 period the area in which the bottom fauna
was drastically reduced or obliterated was expanding downstream at the
rate of 16 miles per year. By 1920, the bottom fauna in the river and
bottomland lakes as far downstream as Browning (mile 97.0) had been
affected. The aquatic plants (Potamogeton, Ceratophyllum, Scirpus, and
Vallisneria) which once covered up to 50 percent of the total surface
acreage of bottomland lakes near Havana and several square miles of
Peoria Lake had practically disappeared. The weed fauna (aquatic insects
and snails which inhabit aquatic vegetation) had disappeared with the
aquatic plants. (Richardson 1921b) reported the following changes in the
bottom fauna of Peoria Lake:
"(1) Disappearance of most species and genera and of
several families of small Mollusca, along with important
average decrease in numbers of the more tolerant forms
still surviving; (2) enormous increase in larval midges
(Chironomidae) , with invasion of several more or less
distinctly pollutional species, and similar or even
greater increase in sludge-worms (Tubif icidae) ; and
(3) disappearance throughout Peoria Lake, except im-
mediately along shore or in the short, half-mile,
stretch of swifter water in Peoria Narrows, of all
"other insects" (Ephemeridae, Odonata, Phryganeidae,
Corixidae, etc.), as well as of planarians and leeches,
Amphipoda, Isopoda, sponges, and Bryozoa."
In the river channel upstream from Havana, he noted these changes
(Richardson, 1921b) :
"While the average weight of the channel haul here
was over 5,000 pounds per acre in 1915, in 1920 it
was less than 250 pounds — a net loss of 95.3 percent
In the 4 — 7ft. zone for the same five-year period
the average haul showed a shrinkage of 95.9 percent,
or from 2,122 pounds to only 87 pounds per acre.
•4 7
The change in the composition of the small bottom-
fauna, in turn, includes the disappearance since
1915 of five out of seven families of snails; of
more than half a dozen species of bottom-dwelling
larval midges; and of twelve out of thirteen or
fourteen families of "other insects," worms, small
Crustacea, and other small bottom-invertebrates."
Richardson (1921b) estimated that the midsummer standing crop of
bottom and weed fauna had been reduced by a total of 34,500,000 lbs
in the additional 103-mile section of the Illinois River affected by
Chicago effluents between 1915 and 1920. He estimated that this
drastic reduction in food organisms represented a loss of about
7,000,000 lbs of potential fish-yield.
Leveeing and draining (1903-1926)
One of the major impacts on the Illinois River below Hennepin was
the leveeing and draining of bottomland areas, primarily in the period
1903-1926. Of 400,000 bottomland acres subject to overflow by the
river, approximately 200,000 are now behind levees with a consequent
reduction in wildlife and fish habitat (Mills et al., 1966). The back-
waters and bottomland lakes of the Illinois River were, and are, criti-
cally important to fish and wildlife production. Richardson (1921a)
reported that the largest poundages of fish per acre were taken in
reaches of the river where the largest quotas of connecting lake acreage
existed:
"Taking the year 1908 as an illustration, and using
the figures for separate shipping points obtained by the
Illinois Fish Commission in that year, we find for the
59.3 miles of river and lakes between Copperas Creek dam
(river mile 136.9) and LaGrange dam (River mile 77.6),
with about 90% of its acreage consisting of lakes and ponds,
an average fish-yield per acre for water levels prevailing
half the year, of 178.4 pounds; for the 87 miles from LaSalle
(river mile 223.9) to Copperas Creek dam, with about 83% lakes,
130.4 pounds; and for the lower 77 miles, LaGrange to Grafton,
with around 63% lakes, only 69.8 pounds."
Richardson indicates that well over 80 percent of the total fish yield
came from the lakes and that much less than 20 percent came from the
river itself (Richardson, 1921a) . The bottomland lakes supported an
abundant aquatic weed-inhabiting invertebrate fauna, which supplied
food for sunfish, crappie, largemouth bass, northern pike, and yellow
perch.
Two important conclusions can be drawn from Richardson's work
(1921a) regarding the bottom fauna and fish production in the lower
80 miles of the Illinois River. First, this section of the river channel
had a less abundant bottom fauna than the section immediately upstream
because of a lack of soft mud substrate (Richardson, 1921a) relatively
more frequent dredging operations for channel maintenance (Richardson,
1921a), and because the absence of backwater areas (as a result of
leveeing) concentrated the feeding activities of the annual upstream
runs of large carp and buffalo in the spring (Richardson, 1921a).
Second, as a result of more extensive levees along the lower 80 miles
of river, there was a paucity of the connecting lake acreage necessary
to support an abundant weed fauna and consequently, a high level of
fish production was not possible.
High navigation dams (1930 's)
In the 1930' s, high navigation dams were constructed at Dresden
Heights (22 ft), Marseilles (24 ft), Starved Rock (19 ft), Peoria
(11 ft), and LaGrange (10 ft). The navigation dam on the Mississippi
at Alton raised water levels in the Illinois River as far north as
Hardin, mile 21.0 (Mills, et al., 1966). Timber and brush were cleared
from areas due to be inundated by the new dams. Clearing operations
probably did not markedly reduce the amount of mast available for water-
fowl because nut-bearing trees such as oaks, grow further from the
water's edge than softwood, according to Dr. Frank C. Bellrose, Water-
fowl Biologist, Illinois Natural History Survey, Havana, Illinois.
Starrett (1971) indicated that the reduction of diversion from Lake
Michigan after 1938 coupled with the higher dams on the river have re-
sulted in a decrease of average current velocity from about 1.25-
2.50 miles per hour prior to 1908 to 0.6 miles per hour in 1966.
Richardson (1921a) indicated that abundant populations of finger-
nail clams in the Illinois River were generally found in areas of
4"
reduced current and favorable conditions for sedimentation. Gale
(1971) reported that fingernail clams select mud substrates in preference
to sandy mud and sand. Abundant populations of fingernail clams over
soft mud bottoms in navigation pool number 19 on the Mississippi River
were reported by Gale (1969) and have been observed by the author.
If the high navigation dams constructed in the 1930's did reduce
the current and increase sedimentation in parts of the Illinois River,
then the habitat suitable for fingernail clams may have increased, with
a benefit to the mollusc-eating fish. It is puzzling that conditions
have been so dramatically different since 1955, when a die-off of finger-
nail clams and snails occurred in the middle section of the Illinois
River (Mills, et al., 1966). As late as 1973, the fingernail clams had
not returned to areas of the river where empty shells indicated they
had formerly been abundant.
The high navigation dams have a significant influence on dissolved
oxygen (DO) levels and waste assimilative capacity in the Illinois River,
according to Butts et al. (1975):
"The dams are significant reaeration sources for
waters overflowing them. The extent of the aeration
establishes the bases for the configurations of the DO
sag curves. However, the dams should not be considered
wholly beneficial. On the contrary, their existence
lessens the capability of the waterway to assimilate
organic waste by: 1) Increasing the time-of-travel
and thus lengthening incubation periods in each pool,
2) Increasing the depth of flow and decreasing stream
velocities thus lowering the reaeration capability of
the pooled water, 3) Encouraging deposition and ac-
cumulation of solids on the pool bottom thereby
creating benthic biochemical oxygen demands."
Changing agricultural practices beginning c. 1940
Starrett felt that the increased sluggishness of the river and the
increased planting of row crops in the Illinois basin in the last
30 years have made siltation an important factor adversely affecting
the survival of mussels and other organisms in the Illinois River and
its bottomland lakes (Starrett, 1971).
50
Sediment deposits in the Upper Illinois River are primarily of
urban origin (Butts, 1974), while agricultural sources probably make
the major sediment contribution in the middle and lower sections of the
river.
Many farmers have removed vegetation from fence rows and stream
borders in order to obtain additional space for row crops. Erosion
from fields planted in row crops such as corn and soybeans is greater
than from field planted in crops such as wheat or hay. More powerful
tractors and wider tillage equipment make it possible for individual
farmers to farm increasingly large acreages, but it becomes increasingly
inconvenient to leave fence rows, grass waterways, marshy areas, or
meandering streams. The common practice of fall plowing leaves the
ground bare and subject to erosion during rains and snowmelt. Wind
erosion is probably also significant in moving soil into ditches where
it is later washed into streams and rivers.
Sediment physically removes habitat by filling in areas; for
example, Lake Chautauqua, near Havana (river mile 124-130), lost
18.3 percent of its storage capacity in a period of 23.8 years (Stall
and Melsted, 1951). Areas in Quiver Lake, near Havana, where boats
could formerly be launched are now only a few inches deep during low-
water stages, and willows are encroaching on the lake.
Sediments can also cause undesirable habitat modification by
blanketing firm bottoms, increasing turbidity, and reducing dissolved
oxygen levels. As pointed out earlier, many gamefish prefer to spawn
on firm, rather than flocculent bottoms. Many bottomland lakes and
backwater areas along the Illinois River have filled with a flocculent
sediment that has been described by Starrett (1959) :
"The sediments in Lake Chautauqua are mostly
of a fine texture and form a loose, flocculent
'false bottom' (not similar to the type found in
bog lakes) over the original lake bottom. A slight
disturbance of the 'false bottom' causes particles
to become resuspended and so increases the turbidity
of the water ."
51
Jackson and Starrett (1959) found that an increase in wind velocity
from light to strong increased turbidity from 162 to 700 Jackson
turbidity units (JTU) and that a calm period of 7 to 12 days was
necessary for much of this sediment to settle from Lake Chautauqua.
As a consequence, this lake and other bottomland lakes remain highly
turbid most of the time.
The turbidity levels in bottomland lakes and backwaters along
the Illinois River are within the range that reduces fish production.
Buck (1956) studied fish production in farm ponds, hatchery ponds, and
reservoirs in Oklahoma which had a wide range of turbidities. The farm
ponds were rotenoned, then restocked with largemouth bass and bluegills
or largemouth bass and redear sunfish. A total of 12 farm ponds was
divided into 3 turbidity classes. After two growing seasons, the aver-
age total weights of fish were:
clear ponds (less than 25 JTU) 161.5 lb/acre
intermediate ponds (25-100 JTU) 94.0 lb/acre
muddy ponds (100 JTU) 29.3 lb/acre
The redear and bluegill sunfish reproduced more abundantly and grew
faster in clear water. Survival of bass was greater in intermediate
ponds than in clear ponds, perhaps due to competition with abundant
sunfish populations in the clear ponds. However, the surviving bass
grew faster in clear ponds:
average
length
increase
6.9 in.
5.1 in.
2.4 in.
The results from hatchery ponds, where turbidities were arti-
ficially controlled, and from the reservoirs, generally paralleled the
results from the farm ponds.
Ellis (1936) found that organic matter mixed with erosion silt
created an oxygen demand in water and that the oxygen demand was
52
average
weight
gain
clear ponds
14. Ox
intermediate ponds
7.1x
muddy ponds
2.5x
maintained 10 to 15 times as long as the oxygen demand created by the
same amount of organic material mixed with sand. The oxygen demand can
increase many-fold when sediment containing organic material and bacteria
is resuspended by waves or currents (Butts, 1974; Baumgartner and
Palotas, 1970). For example, Butts (1974) found that under quiescent
conditions the sediment oxygen demand in the Illinois River at mile 198.8
in Peoria Pool was 2.8 g/m2/day, while the demand was 20.7 g/m2/day
when the sediment was disturbed. At three sampling stations in Meredosia
Lake (mile 72-78) the sediment oxygen demand under quiescent conditions
ranged from 2.58 to 4.32 g/m2/day, and from 12.92 to 83.0 g/m2/day under
disturbed conditions (Personal Communication, 2 September 1975,
Mr. Thomas A. Butts, Associate Professional Scientist, Illinois State
Water Survey, Peoria, Illinois). The oxygen demand exerted by sediment
in some reaches of the river and in some bottomland lakes is great enough
to seriously diminish the oxygen supply in the water.
In August 1974, dissolved oxygen levels in Meredosia Lake were
3 mg/1, while oxygen levels in the river on the same date were 6 mg/1.
The readings were taken in the middle of the afternoon on an overcast
day, and waves produced by a strong wind were resuspending bottom sedi-
ments in the lake. In the lake, a die-off of gizzard shad was occur-
ring, and almost all the fingernail clams maintained in plastic cages
on the bottom of the lake had died since they had last been checked in
mid-July.
Fingernail clam die-off (1955)
Starrett (1972) documented the die-off of fingernail clams and
summarized the drastic effect on fish and waterfowl:
"Fingernail clams (Sphaeriidae) virtually dis-
appeared from the river above Beardstown in the mid-
1950' s (Paloumpis and Starrett, 1960 and unpublished)
These organisms were an important food item in the
river and its bottomland lakes for carp and diving
ducks (Aythyinae) , particularly the lesser scaup
duck (Ay thy a af finis) . Following the disappearance
of the fingernail clams, a sharp decline occurred
in the numbers of lesser scaups using the middle
53
section of the river and its lakes during migration
(Mills et al., 1966). In the 1960's fingernail clams
formed 50.2% (volume) of the food items taken by carp
collected in the river between Beardstown and its mouth
(Starrett and Paloumpis, unpublished). Only one finger-
nail clam was found in the food contents of the carp ex-
amined from the remainder of the river. Tubificidae
worms comprised only 4.3% (volume) of the food ingested
by carp taken from the section of the river between
Beardstown and the mouth, whereas in the upper river
(source to Starved Rock dam) , where there was a virtual
absence of fingernail clams, carp fed heavily upon
Tubificidae worms (30.5% volume). Carp collected during
the early 1960's from the lower section of the river,
where fingernail clams formed an important part of
their diet, were deeper bodied than those taken from
the remainder of the river (Mills et al. , 1966) ."
Paloumpis and Starrett (1960) reported that the population of
fingernail clams in lower Quiver Lake (mile 122) dropped from 1,115
individuals per square foot in 1952 to 54 per square foot in 1953 and
to 0 in 1954. Snail populations in lower Quiver Lake also declined
during this period.
As recently as the spring of 1973, no living fingernail clams were
collected at several stations in Quiver Lake (mile 122-124) where dead
shells indicated they had formerly been abundant.
Although the reason for the die-off is unknown, it appears that
the Sangamon River, which enters the Illinois at Beardstown, may be di-
luting some material in the river which is toxic to fingernail clams.
Fingernail clams may have died out in some bottomland lakes because of
low oxygen levels due to sediment oxygen demand (mentioned above) or
because flocculent sediments make it impossible for the clams to main-
tain themselves at the mud — water interface, or because the sediments
interfere with normal feeding activities.
Aquatic vegetation die-off s (1920 's and 1950 's)
The backwaters and bottomland lakes of the Illinois River were
once veritable aquatic gardens, as described by Kofoid (1903):
"The aquatic environment at Havana impresses the
visiting biologist who for the first time traverses
its river, lakes, and marshes, as one of exceedingly
54
abundant vegetation, indeed almost tropic in its
luxuriance. The aquatic flora of the ponds, lakes,
and streams of New England, of the Middle States,
and of the north central region is, as a rule, but
sparse in comparison with that which here constantly
meets his eyes .... he will find acres upon acres
of "moss", as the fishermen call it — a dense mat of
mingled Ceratophyllum and Elodea choking many of the
lakes from shore to shore, and rendering travel by
boat a tedious and laborious process . Beds of lotus
(Nelumbo lutea) and patches of Azolla will suggest
warmer climes, while the fields of rushes (Scirpus
f luviatilis) , and patches of water-lilies (Nymphaea
reniformis) , arrowleaf (Sagittaria variabilis) , and
pickerel-weed (Pontederia cordata) will recall
familiar scenes in northern waters . The carpets of
Lemnaceae will be surprising, and the gigantic growths
of the semiaquatic Polygonums will furnish evidence
of the fertility of their environment."
In the same report, Kofoid (1903) provided a list of "only the
most common and most important members of the aquatic flora" in and
along the Illinois River — 48 species of emergent and submergent plants
comprise the list. In wider parts of the river above both Peoria and
Havana, there were extensive areas that were permanently occupied by
aquatic plants (Kofoid, 1903). As mentioned earlier, the aquatic
vegetation disappeared from much of the middle and upper sections of the
Illinois River in the 1920's, as a result of increasing pollution orig-
inating from Chicago.
Improved waste treatment in Chicago apparently resulted in improved
conditions for aquatic plants, and between the late 1930 's and the mid-
1950' s, the growth was again luxuriant in Peoria Lake and elsewhere
along the middle section of the river (Mills, et al., 1966).
Since the mid-1950 's, aquatic plants have again disappeared from
the river proper and from most backwaters and bottomland lakes which
are overflowed by the river (Starrett, 1972). The plants may have dis-
appeared from the bottomland lakes because turbidity has reduced light
penetration or because flocculent bottoms make anchorage against wave
action impossible. Starrett (1972) and Mills, et al. (1966) were of the
5 5
opinion that some additional factors were responsible for the disap-
pearance of plants from the river proper. Coontail, longleaf and sago
pondweeds, and wild celery have disappeared from the Starved Rock Pool
since the 1940's, even though the transparency of the water has been
adequate for their growth in many years since then (Mills, et al. 1966).
Summary
In the early part of the 20th century, the bottomland lakes and
backwaters along the Illinois River produced most of the fish because
they contained most of the food, which in turn was associated with the
aquatic weeds that were abundant in the shallow, clear waters. Approxi-
mately half the bottomland acreage subject to overflow was drained or
leveed. The river became increasingly polluted, with low dissolved oxy-
gen levels occurring farther downstream, while some of the lakes, which
were fed by springs or tributaries, continued to offer havens for fish
and food organisms. More recently, some of the lakes have developed
periodic low dissolved oxygen levels during the summer, while the oxygen
levels in the middle and upper sections of the river have improved some-
what due to more and better waste treatment by industries and munici-
palities in the drainage basin.
The number of fish and duck food organisms in the lakes have de-
clined in recent years, probably because of low oxygen levels, absence
of aquatic plants, and presence of flocculent sediments. The once-
abundant rooted aquatic plants may have also served to lock up nutrients
that are now available to bacteria and plankton. Bacteria and plankton,
and the biochemical oxygen demand exerted by the sediments, are probably
responsible for low oxygen levels in the lakes during overcast days or
at night when photosynthesis does not occur.
Present Impacts
Many of the factors which have had a detrimental impact on the
biota of the Illinois River in the past continue to have an impact at
the present time. Two major factors are wastes from urban areas and
56
sediment originating from both agricultural and urban sources. Pesti-
cides may not be having a direct effect on fishes in the Illinois River,
but pesticides in some fish from the Illinois exceed levels allowed by
the Food and Drug Administration (FDA) in fish for human consumption.
Industrial and municipal wastes
Figure 4 shows the critically low dissolved oxygen levels in the
Illinois River during low flows in the summers of 1965 and 1966. Oxygen
levels were generally below saturation throughout the entire length of
the river; levels below 1.0 mg/1 occurred in Dresden, Peoria, and
LaGrange pools.
Increases in dissolved oxygen are apparent below the navigation
dams (due to reaeration by the dams) and in lower Peoria Lake (perhaps
due to plankton, reduction of oxygen demand, and reaeration by turbulence
of the river) . The decreases in dissolved oxygen occur because organisms
living in the water, in the sediments, and attached to substrates (such
as rocks or navigation locks) utilize oxygen as they feed on organic
wastes (Butts, et al., 1975).
The reduction in dissolved oxygen levels so far downstream of the
Chicago-Joliet and Peoria-Pekin metropolitan areas results from the
oxygen demand created as bacteria convert ammonia in sewage effluent to
nitrate. The rate at which populations of these nitrifying bacteria
develop is relatively slow, so that ammonia oxidation on the Upper
Illinois commences approximately three days time-of-travel below the
Lockport dam (mile 291.0): at mile 196 in the Peoria Pool during high
flows, and at mile 273 in the Dresden Pool during low flows (Butts,
et al., 1975).
Ammonia places aquatic organisms in double jeopardy: it not only
causes a reduction in oxygen levels, it is also toxic. It is only the
un-ionized form of ammonia which is toxic, approximately 5 percent of
the total ammonia concentration in the Illinois River. Lubinski, et al.
(1974) reported that un-ionized ammonia concentrations in the Upper
Illinois River and Des Plaines River on occasion reached 40 to 60 per-
cent of a lethal level for bluegills. Un-ionized ammonia is more toxic
-8 i
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58
to aquatic organisms when dissolved oxygen levels are low than when
oxygen levels are high. The combination of low dissolved oxygen and
high un-ionized ammonia levels in the Upper Illinois River is probably
stressful to fish.
Low dissolved oxygen levels are also partially attributable to oxy-
gen utilization by microorganisms, tubificid worms, and midge larvae
living in sediment deposits on the bottom of river. Sediments in many
parts of the river are high in organic content and resemble primary
sewage sludge (Butts, 1974; Butts, et al . , 1975).
Stormwater probably contributes considerable oxygen-demanding waste
and sediment to the river. This waste is washed from streets, gutters,
parking lots, etc., during storms. In addition, stormwater overloads
sewage systems, so that raw sewage mixed with stormwater is discharged
directly to the river. The lowest dissolved oxygen levels (1.1 mg/1)
observed in the Upper Illinois River during a 1971-1972 study by the
Illinois Water Survey occurred in Peoria Pool while water levels were
rising to a flood crest (Butts, et al . , 1975). During persistently high
flows, the oxygen levels recover, because streets, gutters, and sewers
are swept clean by the initial rainfall and there is a dilution effect.
Industrial effluents presently enter the river directly, or in-
directly, through municipal sewage systems. Domestic wastes contain
materials such as LAS detergents and fluoride (added to drinking water) ,
which can be toxic to aquatic organisms at certain concentrations.
Lubinski, et al . (1974) expressed the concentrations of individual
toxicants in the Illinois River as fractions of the lethal concentra-
tions (96-hr LC50's) to bluegills. To do this, Lubinski, et al. (1974)
used chemical monitoring data, gathered by the Illinois Environmental
Protection Agency (EPA) , for 17 stations on the Illinois River and bio-
assay information available in the literature or from their (Lubinski,
et al.) own experiments. They used the bluegill as a reference organism
because it is found in the Illinois River and a great deal of informa-
tion is available on the toxicity of chemicals to bluegills. Certain
assumptions and calculations were made (as detailed in Lubinski, et al.,
1974 and in Lubinski, 1975), in order to estimate what proportion of
certain chemical concentrations reported by the Illinois EPA actually
existed in a toxic form. Seven chemicals were estimated to have made
the following average contributions to the toxicity of the Illinois
River in 1972 and 1975: hydrogen cyanide, 3.0 percent of a lethal con-
centration (96-hr LC50) ; un-ionized ammonia, 2.4 percent of a lethal
concentration; LAS detergent, 1.9 percent; fluoride, 1.0 percent; copper,
0.6 percent; zinc, 0.3 percent; and phenol 0.2 percent. When the average
toxicities contributed by each toxicant were added together, the esti-
mated total toxicity ranged from a low of 4.5 percent of a lethal level
at mile 56.0 to 16.8 percent of a lethal level at mile 119.7.
Lubinski, et al. (1974) concluded that the toxicants normally do
not occur at levels high enough to cause fish in the Illinois River to
die. This was partially verified by field tests using caged bluegills.
However, hydrogen cyanide and un-ionized ammonia periodically occurred
at high enough concentrations (63 percent of a lethal level of un-ionized
ammonia, at mile 277.8; an estimated 47 percent of a lethal level of
hydrogen cyanide, at mile 119.7) to stress fish, although the lengths of
time fish were exposed to these toxicants, and hence their possible
lethal effects, could not be determined (Lubinski, et al. , 1974).
Brown, et al. (1973) found that 4.38 percent of 2121 fish taken
from the Fox River (a tributary of the Illinois) had tumors compared to
1.03 percent of 4639 fish taken from an unpolluted watershed in Canada.
Brown, et al. (1973) felt that various organic and inorganic chemicals
and viruses were responsible for the greater frequency of tumors in Fox
River fish.
Pesticides
Starrett (1971) had 14 mussels representing 7 species collected
from 5 locations in the Illinois River in 1966 analyzed for the presence
of organochlorine pesticides. In no instance did the total concentra-
tion of organochlorine pesticides exceed 0.0585 ppm, and the average
content was 0.0331 ppm. Since freshwater mussels can concentrate or-
ganochlorine pesticides several thousandfold from water (Bedford and
60
Zabik, 1973), Starrett's results indicate that organochlorine pesticide
levels in the Illinois River were fairly low in 1966.
The U. S. Fish and Wildlife Service has analyzed fish taken from
the Illinois River at Beardstown (mile 88.0) for pesticides, as part of
the Nationwide fish monitoring program. Fish have been collected for
analysis once or twice a year since 1967. Whole fish are analyzed, and
the results are expressed as milligrams of pesticide per kilograms wet
weight of the whole fish. The results for the years 1967 through 1969
are summarized in Table 36. Inconsistencies were apparent in the results
reported by five different laboratories on subsamples of the same fish
homogenate in 1967 and 1968 (Henderson, et al., 1969). For example, the
analyses of DDT and its metabolities in bigmouth buffalo from the
Illinois River ranged from .05 to .54 ppm — an order of magnitude dif-
ference (Henderson, et al . , 1969). Nevertheless, Henderson, et al.
(1971) felt that the 1969 values for DDT and dieldrin were reliable.
Henderson, et al. (1971) did not place much significance on the results
of heptachlor and heptachlor epoxide and the results from these com-
pounds are not reported in Table 36. Food and Drug Administration
limits for dieldrin in fish were exceeded in carp, bigmouth buffalo, and
channel catfish from the Illinois River.
The possible adverse effects on fish and wildlife of the pesticide
and mercury levels reported in Table 36 are largely unknown. Lubinski,
et al. (1974) reported that aldrin was present in the Kankakee River
(a tributary of the Illinois) at concentrations ranging from 0.34 to
3.00 micrograms per liter, and that this represented approximately
13 percent of a lethal concentration for bluegills . Pesticide levels
which are too low to have a direct effect on fish may affect fish-eating
birds or other animals.
Snails (Physa sp.) which were reared in the laboratory under con-
ditions designed to reduce their exposure to pesticides as much as
possible, rapidly accumulated dieldrin when exposed in cages to Illinois
River water at mile 87 and mile 120 for a period of 8 days in August
1974. The snails at mile 87 increased in dieldrin content from
61
0.1797 ppm wet weight-whole organism to 0.8156 ppm; those at mile 120
increased from 0.1797 to 0.5408 ppm (Sparks and Walter, unpublished
data) .
Sediment
The past detrimental impacts of sediment on aquatic vegetation,
fish habitat, fish food organisms, and the fishes of the Illinois River
were described in a previous section. At the present time, sediment
continues to enter the river and to fill bottomland lakes and backwaters
with each influx of sediment-laden water from the river.
Sediment affects many uses of the river, in addition to fishing.
Many residents of Quiver and Baldwin beaches near Havana bought lake-
front property because they enjoy water-based recreation. During the
prime months for water recreation, the summer months, the water levels
are low and Quiver Lake is now so filled with sediment that it is im-
possible to launch a boat in the upper two- thirds of the lake. The an-
nual speedboat races at De Pue Lake (mile 211-213) were cancelled in
1974 because the water had become too shallow. Mr. Bruce Hillemeyer,
co-owner of the Tall Timbers Marina at Havana (mile 120.5), reported in
1974 that it cost approximately $50,000 to dredge the channel to the
marina every 2 to 3 years, and that this increasing expense, added to
other expenses, was forcing him to sell his business. The navigation
channel in the vicinity of Kingston Mines (mile 146) was closed to
two-way barge traffic for several weeks in 1974 because extensive
dredging operations were necessary.
Once the sediment is in the river and lakes, it can be resuspended
by boat traffic or waves produced by wind. The increased barge traffic
(Starrett, 1972) associated with the improved navigation channel in-
creases the turbidity of the river. The turbulence produced in mid-
channel, as well as the washing action along shore, resuspends sediment
and thereby increases the turbidity. Starrett (1971) made numerous ob-
servations of the effect of barges on turbidity of the river:
"A towboat underway causes a strong current and
washing action on the silt bottom ("false bottom")
in shore, which resuspends the silt particles, there-
62
by increasing the turbidity. The increase in turbid-
ity is more noticeable in the lower three pools, par-
ticularly in the Alton Pool, than it is upstream be-
cause of differences in bottom types.... The outrush
of water from shore toward the channel caused by a
towboat also temporarily exposes the shallow areas.
On November 18, 1964, in the Alton Pool at river
mile 65.1, the turbidity just prior to the passing
of two towboats was 108 units (Jackson turbidity
units), and within 6 minutes after the tows had passed,
the turbidity was 320 units. Sixteen minutes later
the turbidity had dropped to 240 units."
Figure 5 shows that the turbidity in mid-channel at mile 25.9 was in-
creased by approximately 100 Jackson turbidity units (JTU) as towboats
passed on three occasions. It took approximately 2% hours for the tur-
bidity to return to background levels following passage of towboats.
In addition to increasing turbidity, the resuspended sediment ex-
erts an oxygen demand. Butts (1974) reported that the oxygen demand
of sediment in the Upper Illinois River increased several-fold when the
sediment was disturbed. The oxygen measurements plotted in Figure 5
suggest that resuspension of sediment by barge traffic significantly
depresses oxygen levels. The oxygen levels at the bottom and surface
declined following passage of a towboat. The oxygen levels at mid-depth
increased slightly. The decline of 0.4 mg/1 oxygen at the bottom is
significant, because the standard deviation of the method used to meas-
ure dissolved oxygen (azide modification of the Winkler method) is
0.1 mg/1. The present impact of boat traffic and the potential impact
of increased traffic on dissolved oxygen levels and turbidity in the
river should be investigated further.
Future Impacts
Improvements in waste treatment
The Illinois State Water Survey has developed a model to predict
dissolved oxygen levels in the middle and upper sections of the Illinois
River under various waste loads during low-flow conditions (Butts,
et al. 1975). Under extreme low-flow conditions likely to occur once
63
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every 10 years and to persist for at least 7 days, the dissolved oxygen
levels under existing waste loads would be below the Illinois standard
of 5 mg/1 in Marseilles, Starved Rock, and Peoria Pools (Butts, et al.,
1975). Moreover, the oxygen levels would be between 0 and 1 mg/1 in
substantial portions of these pools. Such low oxygen levels would dras-
tically reduce the fish populations in the river. In order to meet the
State dissolved oxygen standard in the Upper Illinois River during 7-day
10-year low-flow conditions, Butts et al. (1975) estimate that 97.5 per-
cent of the carbonaceous biochemical oxygen demand must be removed from
waste at the West Southwest treatment plant of the Metropolitan Sanitary
District of Greater Chicago. Moreover, all other carbonaceous dis-
charges between the Lockport Dam and the Kankakee River must be reduced
50 percent, and 98 percent of the nitrogenous waste load above mile 273
must be removed.
Some steps are planned, or have already been taken, to reduce waste
loads in the upper river. In 1971, the Chicago Metropolitan Sanitary
District began a large-scale sludge recycling project near the Illinois
River at St. David. In 1974, the district began aerating a section of
the Chicago Sanitary and Ship Canal, and more of the canal will be
aerated in succeeding years. In the future, all Chicago storm waters
probably will be captured and stored in a deep tunnel under Chicago,
instead of discharged to the canal, and will be treated before being
released to the canal. Advanced waste treatment plants should be cap-
able of removing the ammonia that now exerts an oxygen demand as far as
140 miles down river. All of these improvements in waste treatment will
certainly have a beneficial impact on the aquatic life in the river by
reducing the oxygen demand on the river and by improving oxygen levels
during critical low-flow periods. Waste treatment probably will also be
improved in the Pekin-Peoria metropolitan area.
Proposed channel improvements
After measuring sediment oxygen demand in the Upper Illinois River
under both disturbed and quiescent conditions, Butts (1974) concluded
that improved waste treatment alone would not greatly restore the
aquatic ecology of the upper river:
hS
"Because of the areal extent and depths of bottom
sediments, particularly in the Brandon Road and Dresden
Island pools, coupled with the periodic resuspension of
the sediments by barge tows, it is doubtful that the
aquatic ecology of the waterway can be measurably en-
hanced solely by achieving current water quality standards.
A program for the removal of undesirable sediments in crit-
ical zones probably will have to be devised and implemented.
However, any such program should be preceded by a study de-
signed to predict the impact of resuspended sediments on
downstream DO (dissolved oxygen) resources that would re-
sult from sediment removal operations."
Butts (1974) felt that, "The resuspension of sediments by barge
traffic may increase short-term localized oxygen demand loads by seven
or eight fold." If the depth of the navigation channel of the Illinois
River is increased from 9 to 12 ft, as has been proposed, the increased
size of the towboats using the improved navigation channel and the in-
creased number of tows would keep more sediment in suspension, with a
consequent increase in oxygen demand and turbidity. Figure 5 shows that
if towboats pass a point on the river more frequently than once every
2% hours, the resuspended sediment will not have a chance to settle out,
and the mean amount of suspended sediment in the river will increase.
It is likely that river traffic will increase to some extent in the
future, whether or not the channel is improved, but it is certain that
traffic will increase to a much greater extent if the proposed improve-
ments are undertaken.
The proposed increase in channel depth would be accomplished by
a combination of raising low-flow water levels and dredging. Depending
on local topography, the water surface area might be increased. Judging
by the increased fishery in the Illinois River following a rise in water
levels in 1900 as a result of water diversion from Lake Michigan, one
might expect a beneficial effect. However, bottomland lakes that now
have a chance to clear during periods when they are cut off from the
river might then become permanently connected to the river and receive
a continuous, rather than intermittent, input of oxygen-demanding silt.
Some of the bottomland lakes on the east side of the Illinois River
between Kingston Mines (mile 145.3) and Meredosia (mile 71.1) recover
66
from turbidity and the blanketing effects of sediment when they are cut
off from the river during low flows. An influx of groundwater from the
sandy eastern bluffs and sandy lake bottoms flushes away sediment de-
posited by the river. According to an Illinois Water Survey report
(Singh and Stall, 1973), this influx amounts to 309 cu ft/sec, or about
one-twelfth of the total input to this 73-mile section of the river,
during the lowest flow expected for a 7-day period at a recurrence in-
terval of 10 years. Matanzas Lake (mile 114.5-117.0) still exhibits a
recovery pattern, but mud now blankets the sandy bottoms in other lakes
such as Quiver Lake (mile 121.0-124.0), which once received spring water
(Richardson, 1921a). The influx of groundwater to these latter lakes
might still be sufficient to provide clear water if the bottoms could be
stabilized against wave action and the influx of sediment from the river
reduced or prevented.
Another detrimental impact of the proposed increase in the depth
of the navigation channel would be the reduction in the capability of
the river to assimilate organic waste, due to increased time-of-travel,
reduced reaeration, and increased sedimentation (Butts, et al., 1975).
Land use in the drainage basin
If predictive studies indicate that a reduction of sediment input
would actually reduce sedimentation in the river and the lakes and back-
waters, the most practicable solution to the sediment problem in the
future may be to reduce the amount entering the river. It is possible
that once sediment is in the river and lakes, it is recycled and re-
suspended there, and no reduction in turbidity or oxygen demand would
be achieved by reduction of sediment input, without the physical re-
moval of sediment or the use of restoration techniques, such as drying
out lakes. However, it is possible that reduced sediment input to the
river may cause the river to flush out backwater areas and lakes during
periods of high flow, thus bringing about a natural restoration of these
areas. Once the turbidity was reduced, fringing marshes and beds of
aquatic plants might appear again, further accelerating restoration by
acting as sediment filters and nutrient traps.
67
The sediment input to the river could be reduced in the future by
wide adoption of soil conservation practices in the Illinois basin,
including such new practices as no-till farming, where row crops are
planted directly in stubble or some other ground cover, without greatly
disturbing the soil. The ground cover breaks the impact of raindrops,
and holds water, soil, and nutrients, rather than allowing all three to
run rapidly into tributary streams, thence into the river.
Before no-tillage or minimum tillage is practiced on a wide scale,
the total energy requirements (including the energy for the manufacture
of agricultural chemicals) of various alternative farming methods need
to be determined, and the environmental impact of the herbicides that
must be used with present no-till farming methods needs to be assessed.
In the future, it may be possible to reduce the amount of herbicide used
in no-till farming by choosing the proper sequence of crops and by
breeding varieties of row crops that can compete with weed species. No-
till farming does reduce the energy required by farm machinery, since
there is little or no plowing, harrowing, or cultivating. No-till
farming also enables farmers to get on their land earlier in the spring
for planting, because sod is not as slippery or soft as bare ground.
Proposed increase in diversion
The city of Chicago and lakefront residents whose property has been
damaged as a result of recent high-water levels in Lake Michigan have
requested an increased diversion of Lake Michigan water into the
Illinois River. Since Lake Michigan water is good quality water, it
probably would improve the quality of the upper river by simple dilu-
tion, if diversion occurred during the summer months.
Hovrever, increased diversion would probably raise water levels,
with some of the detrimental effects discussed earlier. In addition,
if ammonia removal is not achieved by the Chicago Metropolitan Sanitary
District, the effect of increased diversion would be to push this ox-
ygen- demanding waste further downstream before its oxygen demand could
be. satisfied.
68
Introduced species
Two introduced species have entered the Illinois River recently
and will probably become more abundant, just as the introduced carp,
goldfish, and white catfish have. It is difficult to predict whether
the latest arrivals will increase explosively, as carp and goldfish
did, or whether they will barely maintain themselves, as white catfish
have. White catfish are only occasionally taken from the Illinois River
and do not seem to reproduce abundantly in the river.
The white amur (Ctenopharyngodon idella) , a plant-eating fish in-
troduced from Asia, is now being taken regularly by commercial fishermen
from the Mississippi River at Crystal City, Missouri, and from the
Missouri River (Personal Communication, October 1974, William L.
Pflieger, Fishery Biologist, Missouri Department of Conservation,
Jefferson City, Missouri; and Peter Paladino, District Fishery Biologist,
Illinois Department of Conservation, Aledo, Illinois) , and has probably
entered the Lower Illinois River. If rooted aquatic vegetation could be
restored to the Illinois River and its bottomland lakes by the lake
restoration techniques discussed above, or by a reduction of silt loads
in the river as a result of improved soil conservation practices in the
basin, the white amur might have a detrimental impact. On the other
hand, white amur from the Mississippi are being marketed in small quan-
tities commercially and their flavor is reported to be excellent. White
amur in the Mississippi grow to a large size (10 to 14 lb) in 2 years
(Personal Communications, October 1974, Pflieger and Paladino). They
might become useful commercial species in the Illinois River.
Another exotic species, the Asiatic clam (Corbicula manilensis) was
found at three locations on the Illinois in the course of the 1974
electrofishing survey: at Kampsville (river mile 32.0), Bath Chute
(mile 106.7), and Turkey Island Chute (mile 148.4). Judging by the
size of the shells, the oldest clams were four years old. Asiatic clams
probably first occurred in the Illinois River in 1970-1971 (Thompson
and Sparks, in press). The Asiatic clam is a serious nuisance, because
69
it has blocked condensor tubes of power plants in Illinois and else-
where. In addition, it may possibly displace the native fingernail
clams .
Recommendations
Restore lakes
Past surveys of fish populations in the Illinois River and the
present electrofishing survey demonstrate that the most fish and the
most desirable kinds of fish are generally produced in the reaches of
the river with the most lateral lakes and backwaters. Marshes, lakes,
and backwaters are essential for fish production in the Illinois River,
because they serve as fish nurseries. The lakes have been degraded by
sediment, and fish and wildlife production has declined.
The Illinois Department of Conservation has taken two approaches to
restoration of lakes along the Illinois River. One approach is to keep
the Illinois River from entering and degrading the lakes, and to rely
on groundwater and rainfall to maintain the water level. This is the
approach that will be taken in Banner Marsh. The Department of
Conservation is currently purchasing the Banner Special Drainage and
Levee District (mile 138-145.5), a former strip mine on the flood plain
of the river. The Department plans to restore the natural lake and
marsh habitat within the Banner district. The existing high levees
which surround the district will be maintained in order to keep the
river out of the restored area.
The other approach to lake restoration is exemplified by Rice Lake
(mile 133-137) and Stump Lake (approximately mile 5). The Department of
Conservation has been able to restore aquatic vegetation in these lakes
by pumping water out of the lakes or allowing them to dry out naturally
(Personal Communication, September 1973, Mr. Robert L. Glesenkamp, Area
Wildlife Manager, Illinois Department of Conservation, Havana, Illinois).
Midsummer drying was a natural occurrence in this type of shallow lake,
during low-flow years, prior to Lake Michigan diversion and construction
70
of navigation dams (Richardson, 1921a). On drying, the bottom muds com-
pact, and when the lakes are reflooded, the turbid water generally
clears, and the plants can gain roothold in the firm bottom. This ap-
proach represents a temporary restoration only. The sediment storage
capacity of a lake is limited and the river deposits more sediment during
each period of overbank flow.
Private duck clubs and Federal wildlife refuges along the Illinois
River also attempt to reduce water levels in the summer in order to ex-
pose mud flats and encourage the growth of moist soil food plants for
waterfowl. Once again, a natural drying cycle has had to be replaced or
supplemented by pumping, because water levels do not attain the low
levels they once did. Such management techniques require energy, equip-
ment, and manpower, but are necessary if fish and wildlife populations
are to be maintained at existing levels, or if they are to recover to
some proportion of the population levels which once existed in the
Illinois valley.
Refuges, unpolluted lakes, and unpolluted tributary streams must
be maintained or restored if the river is to be capable of the recovery
pattern in the future that it exhibited in 1973-1974, following the
high-water period and improved oxygen levels from 1971-1973. When
formerly degraded areas are restored, they can be recolonized rapidly
by species that are desirable to man, if reservoirs of such species and
reservoirs of food organisms for desirable species are available in
undegraded pockets here and there in the ecosystem. The refuges main-
tained by man have precisely this function.
Predict impacts
Information and methodologies need to be developed to predict the
impact of man's future activities on the Illinois River system, so that
a rational choice of alternatives can be made. For example, the effects
of various future channel improvement schemes and various levels of
barge traffic on oxygen levels and turbidity in the main channel and
backwaters needs to be predicted. The expected life span and probable
future condition of bottomland lakes and marshes should be predicted so
that conservation agencies can make a wise selection of new refuge
areas, and develop scientific restoration and management methods
for existing areas.
The impact of present and future waste loads on the river system
must be estimated so that a rational method of utilizing the waste as-
similative capacity of the river, without further degrading the river
can be developed. The relative impact on aquatic life of pollutants
from both nonpoint and point sources needs to be assessed, so that
pollution abatement measures can be directed, on a priority basis,
toward those pollutants which are actually doing the most damage to the
Illinois River system. Such a priority system would assure the greatest
tangible return possible, in terms of improved fishery and wildlife
values, per dollar spent on pollution control.
Coordinate management for multiple use
Once the capability is developed for assessing and predicting the
impacts of man's activities on the Illinois River system, it will be
possible to manage the system in a more coordinated fashion than now
occurs. For example, it is possible at present for one arm of the
Federal Government and for State governments to spend resources in im-
proving and restoring refuge areas while another arm of Government en-
gages in practices which degrade such areas. There is little point in
the Metropolitan Sanitary District of Greater Chicago and other munic-
ipalities and industries expending millions of dollars in improved
waste treatment if the river and its bottomland lakes are degraded
largely by sediment from nonpoint sources.
The river and its bottomland lakes, backwaters, marshes, and
tributaries need to be managed as a system rather than piecemeal. The
river system has been managed as a series of arbitrary administrative
and jurisdictional units. Upstream users of the entire river's as-
similative capacity, such as the Metropolitan Sanitary District of
Greater Chicago (MSDGC) are responsible only for impacts which occur
within their jurisdiction. Agencies develop plans independently of
each other, although it is clear that their activities will interact
and perhaps conflict. For example, it is possible that the proposed
increase in diversion of Lake Michigan water at Chicago may have a
positive impact on navigation, making it possible for the present navi-
gation channel to accommodate deeper-draft barges in certain areas,
without additional dredging or higher dams, yet plans for a greater
channel depth and for increased diversion are pursued independently.
Increased diversion would conflict with attempts to manage and restore
bottomland lakes by dewatering, yet downstream effects do not seem to
weigh heavily in the controversy over diversion.
It is likely that some of the conflicts existing in the present
piecemeal management of the Illinois River system could be resolved or
ameliorated by interagency cooperation and coordination. If management
of the river can be coordinated, and if methodologies and information
can be developed to predict the future of the Illinois River system
under a variety of development, restoration, and pollution abatement
programs, it should be possible to determine what portion of the fish
and wildlife production of the past could be bought back in the future.
The 1973-1974 recovery in the game fish populations of the Illinois
River, in response to temporarily improved conditions in the river,
demonstrates that the past can be redeemed — to what extent depends upon
man's willingness to spend resources in restoring habitat and improving
water quality.
73
The Upper Illinois River is warmer than the lower river, as a
result of warm municipal and industrial effluents.
The upper river is less turbid because the bottom is generally
rocky, whereas the lower portion, including Peoria, La Grange, and Alton
Pools contains flocculent muds that have entered the river and are kept
in suspension by the river current and by wave action resulting from
wind, towboats, and pleasurecraf t .
Dissolved oxygen levels at the surface and the bottom of the river
were virtually the same in the fall of 1974, and dissolved oxygen levels
were 77-97 percent of saturation in Alton Pool, 56-122 percent of satura-
tion in la Grange and Peoria Pools, and 47-104 percent of saturation in
the upper pools of Starved Rock, Marseilles, and Dresden. Local areas
of super-saturation occurred where plankton blooms appeared to be in
progress. In an area that provided good physical habitat for largemouth
bass, Chillicothe Island Chute, Peoria Pool (mile 180), midsummer oxy-
gen levels were at 35-percent saturation or below for 4 years out of the
8-year period 1963-1970. During this period, the number of largemouth
bass taken by electrof ishing in Chillicothe Island Chute decreased con-
siderably. Laboratory experiments have shown that oxygen levels below
35-percent saturation reduce the survival of larval largemouth bass and
that levels below 70 percent retard their growth.
The number of fish species taken by electrof ishing in the Dresden
Pool, Des Plaines River portion of the Illinois Waterway during the
period 1959-1974 was consistently low. Only carp and goldfish and hy-
brids of these two pollution- tolerant species were commonly taken.
The following species showed a trend of increasing abundance in the
downstream direction, away from Chicago, with the largest number occur-
ring in Alton Pool: shortnose gar, bowfin, goldeye, mooneye, channel
catfish, flathead catfish, and white bass.
Goldfish showed a trend of increasing abundance in the upstream
direction, toward Chicago.
74
The following species were most abundant in one or both of the two
middle pools of the river, La Grange and Peoria Pools, which have the
most connecting lake area: gizzard shad, carp, river carpsucker, small-
mouth buffalo, bigmouth buffalo, black buffalo, yellow bullhead, green
sunfish, bluegill, largemouth bass, white crappie, black crappie, and
freshwater drum.
Gizzard shad and carp were generally abundant throughout the river.
Black bullheads were abundant at one station, Ballard Island Chute,
Marseilles Pool (mile 247.8-248.2), which apparently provides preferred
habitat for this species.
Gamefish populations declined during the low water years 1962-1964,
and recovered following the high water years 1971-1973. Largemouth bass
populations in La Grange and Peoria pools did not recover to 1959-1962
levels. The recovery appears attributable to improved oxygen levels in
the river, and perhaps to increased dilution of toxic materials, and
demonstrates how rapidly fish populations respond to improved conditions
in the river.
The commercial and sport fisheries in the Illinois River have
generally declined from levels around the turn of the century. The
decline is attributable to a loss of habitat and increasing pollution.
Habitat was lost due to leveeing and draining of bottomland areas in the
period 1903-1926 and due to sedimentation in the remaining areas. Sedi-
mentation has resulted in undesirable habitat modification, as well as
habitat reduction.
Northern pike, yellow perch, and walleye (Stizostedion vitreum
vitreum) were once abundant in the river but are now rare or limited in
their distribution. Yellow perch populations have declined probably as
the result of the disappearance of beds of aquatic plants and disap-
pearance of clean sand or pebble substrates perch use for spawning.
In the past, the bottomland lakes and backwater areas offered
havens for fish and fish food organisms, as the river became increasingly
polluted. Now dissolved oxygen levels in the upper river seem to have
improved somewhat, while the lakes have filled with sediment that
75
apparently exerts an oxygen demand, keeps aquatic plants from growing,
and does not support an abundance of food organisms .
More and better waste treatment facilities are being constructed
by industries and municipalities in the drainage basin of the Illinois
River. However, the production of fish and wildlife in the Illinois
River and its bottomland lakes is not likely to improve unless sediment
pollution is also brought under control.
The consequences of future uses of land in the drainage basin and
the consequences of future uses of the river must be predicted, so that
a wise selection of alternatives can be made. If the river is to be
managed in the future for a variety of beneficial uses, then the various
State, Federal, and private agencies charged with managing land and
water within the drainage basin must work in a coordinated fashion,
rather than at cross purposes.
76
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United States, 1960. Statistical digest no. 53. U.S.
Government Printing Office, Washington, D.C. 529 p.
. 1963. Fishery statistics of the
United States, 1961. Statistical digest no. 54. U.S.
Government Printing Office, Washington, D.C. 460 p.
. 1964. Fishery statistics of the
United States, 1962. Statistical digest no. 56. U.S.
Government Printing Office, Washington, D.C. 466 p.
. 1965. Fishery statistics of the
United States, 1963. Statistical digest no. 57. U.S.
Government Printing Office, Washington, D.C. 522 p.
. 1966. Fishery statistics of the
United States, 1964. Statistical digest no. 58. U.S.
Government Printing Office, Washington, D.C. 541 p.
. 1967. Fishery statistics of the
United States, 1965. Statistical digest no. 59. U.S.
Government Printing Office, Washington, D.C. 756 p.
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Phylogenetic Listing of Fish Species Taken by Elec trof lshlng
1959-1974
Common Name
Longnose gar*
Shortnose gar
Bowf in
American eel*
Skipjack herrinj
Gizzard shad
Goldeye*
Mooneye*
Grass pickerel*
Northern pike*
Goldfish
Carp
Scientific Name
Category*
Lepisosteus osseus
Lepisosteus platostomus
Amia calva
Anguilla rostrata
Alosa chrysochloris
Dorosoma cepedianum
Hiodon alosoides
Hiodon tergisus
Esox americanus vermiculatus
Esox lucius
Carassius auratus
Cyprinus carpio
Commercial Sport Other
X
X
X
X
Carp x goldfish hydrid C. carpio x C. auratus
Silverjaw minnow*
Silvery minnow*
Silver chub*
Golden shiner*
Emerald shiner*
Ghost shiner*
Striped shiner*
Pugnose minnow*
Spottail shiner*
Ericymba buccata
Hybognathus nuchalis
Hybopis storeriana
Notemigonus crysoleucas
Notropis atherinoides
Notropis buchanani
Notropis chrysocephalus
Notropis emiliae
Notropis hudsonius
: Denotes species which were infrequently taken, due to sampling technique
or to low population size.
' Based upon 1974-1975 Illinois Fishing Information, published by the
Illinois Department of Conservation. "Other" includes forage and bait
species.
Sheet 1 of 3
Table 3 (continued)
Category*
Common Name Scientific Name Commercial Sport Other
Red shiner* Notropis lutrensis X
Spotfin shiner* Notropis spilopterus X
Sand shiner* Notropis stramineus X
Suckermouth minnow* Phenacobius mirabills X
Bluntnose minnow* Pimephales notatus X
Fathead minnow* Pimephales promelas X
Bullhead minnow* Pimephales vigilax X
Creek chub* Semotilus a t romacula tus X
River carpsucker Carpiodes carpio X
Quillback carpsucker Carpiodes cyprinus X
Highfin carpsucker* Carpiodes velifer X
White sucker* Catostomus commersoni X
Smallmouth buffalo Ictiobus bubalus X
Bigmouth buffalo Ictiobus cyprinellus X
Black buffalo Ictiobus niger X
Silver redhorse Moxostoma anisurum X
Golden redhorse* Moxostoma erythrurum X
Shorthead redhorse* Moxostoma macr olepido turn X
Blue catfish* Ictalurus furcatus X X
Black bullhead Ictalurus melas X X
Yellow bullhead Ictalurus natalis X X
Brown bullhead* Ictalurus nebulosus X X
Channel catfish Ictalurus punctatus X X
Tadpole madtom* Noturus gyrinus X
Flathead catfish Pylodictis olivaris X X
Trout-perch* Percopsis omiscomay cus X
Mosqui tof ish* Gambusia affinis X
Sheet 2 of 3
Table 3 (concluded)
Category*
Common Name Scientific Name Commercial Sport Other
Brook silverside* Labidesthes slcculus X
White bass Morone chrysops X
Yellow bass* Morone miss lsslpplensia X
Rock bass* Ambloplites rupestris X
Green sunfish Lepomls cyanellus X
Pumpkinseed* Lepomis gibbosus X
Warmouth* Lepomis gulosus X
Orangespotted sunfish* Lepomis humilis X
Bluegill Lepomis macrochirus X
Longear sunfish* Lepomis megalotis X
Smallmouth bass* Micropterus dolomieui X
Largemouth bass Micropterus salmoides X
White crappie Pomoxis annularis X
Black crappie Pomoxis nigromacula tus X
Yellow perch* Perca flavescens X X
Logperch* Percina caprodes X
Sauger* Stizostedion canadense X
Freshwater drum Aplodinotus grunniens X
Sheet 3 of 3
Table 4
Fish Species Extirpated from the Illinois River
and its Bottomland Lakes Between 1908 and 1970*
Common Name
American brook lamprey
Alligator gar
Cisco
Ozark minnow
Pugnose shiner
Common shiner
Blackchin shiner
Blacknose shiner
Rosyface shiner
Weed shiner
Blacknose dace
Creek chubsucker
Spotted sucker
River redhorse
Black redhorse
Freckled madtom
Bantam sunfish
Iowa darter
Fantail darter
Scientific Name
Lampet ra lamot tei
Lepisos teus spatula
Cor egonus ar t ed ii
Dionda nubila
No tropis anogenus
N . cornutus
N . heterodon
N . heterolepis
N . rubellus
N . texanus
Rhinichy thys atratulus
Er imy zon oblongus
Miny tr ema melanops
Moxos toma car inatum
M. duquesnei
Noturus nocturnus
Lepomis symmetr icus
Etheos toma exile
E. flabellare
* Taken from Starrett, 1972
Notes for Tables of Electrof ishing Results
(Tables 5-29)
1. Fish species are listed in phylogenetic order. All common and
scientific names are taken from A List of Common and Scientific
Names of Fishes from the United States and Canada, 3rd edition,
1970, American Fisheries Society Special Publication No. 6.
Species that were rarely taken by electrof ishing are not shown in
the Tables, but are discussed in the text. The values in the body
of each Table are determined by summing the number of fish or weight
of fish obtained at all stations in the navigation pool and dividing
the sum by the total number of half-hour intervals fished in that
pool. Thus the values are average catches per unit effort for each
pool. The number of electrof ishing stations in each pool are as
follows: Alton Pool (4-5), LaGrange Pool (6), Peoria Pool (8),
Starved Rock Pool (2), Marseilles Pool (3), and Dresden Pool (1).
2. Values in the last two columns are the total number of fish or total
weight of fish taken during the designated year in the Illinois
River divided by the total number of half-hour intervals fished.
The Dresden Pool, Des Plaines River, is excluded from this tabula-
tion.
3. An asterisk denotes that less than 0.01 fish were taken per 30 min-
utes fished.
4. Zeros indicate that electrof ishing was conducted, but no fish of
the designated species were taken.
5. Dashes indicate that no electrof ishing was conducted.
6. NWT indicates that no weights were taken.
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STATE OF ILLINOIS
DEPARTMENT OF
REGISTRATION AND EDUCATION
Ronald E. Stackler, Director
Springfield
"EH™ ILLINOIS NATURAL HISTORY SURVEY
GEOLOGY L. L. Sloss
chemistry .... Herberts, gutowskv Natural Resources Building Telephone: 333-6880
ENGINEERING ... Robert H. Anderson
biology Thomas park Urbana, Illinois 61801 Area Code 217
FORESTRY Stanley K. Shapiro
UNIVERSITY OF ILLINOIS
Dean William L. Everitt
SOUTHERN ILLINOIS UNIVERSITY
Dean John C. Guyon GEORGE SpRUGEL, Jr., Chief
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