900 
800 
—) 
uJ 
> 
uJ 
+ 700 
<q 
uJ 
?p) 
uJ 
Fig. 3. — Gradient profile 5 600 
of the Kaskaskia River with @ 
locations of four main collect- <x 
ing stations (modified from re 
3 Js 7/3). 
Luce 1933, p. 73) uj ©6500 
i 
400 
350 
350 300 
Taste 1.— Description of stations where the four Percina 
darter species were collected. Dates indicate when measure- 
ments were made. Where two years are shown, average values 
were used. 
Distance 
from 
Average Average River 
Station Number Length, Width, Depth, Mouth, 
and Location Feet Feet Feet Acres Miles 
2 ee ee ee 
1 Headwaters 
(1966) 182 39 0.8 0.16 
2 Arcola 
(1965-66) 197 43 AG 0.20 286 
3 Sullivan-Bruce 
(1965-66) 259 48 18 0.29 250 
4 Eagle Creek 
(1965-66) 238 60 255 0.33 232 
5 Moore’s Bridge 
(1965-66) 342 62 it 7 0.50 209 
6 Above Vandalia 
(1965-66) 453 73 2.6 0.78 172 
7 Below Vandalia 
(1966) 218 60 D3 0.30 136 
8 Above Carlyle 
(1965) 450 84 4.9 0.86 108 
9 Below Carlyle 
(1965-66) 380 85 BnO 0.74 105 
10 Below New Athens 
(1966) 527 106 BJ 1.28 47 
11 Above Evansville 
(1966) 300 120 21 0.68 13 
12 Below Evansville 
(1966) 300 125 3.8 0.86 6 
—CHAMPAIGN MORAINE 
USULLIVAN 
ABOVE 
VANDALIA : 
ABOVE 
CARLYLE 
NEW 
ATHENS 
250 200 150 100 50 
MILES ABOVE RIVER MOUTH 
comparisons to be made of certain life history featu 
over 350 miles of river. 
I am indebted to Drs. S. Charles Kendeigh, Ph 
W. Smith, George W. Bennett, and Edward Cia 
for helpful criticisms and suggestions in the preparat 
of this paper. I am particularly indebted to Dr. R.¥ 
don Larimore who made it possibe for me to use Illi 
Natural History Survey time, equipment, and person 
and who gave much helpful advice and encouragem 
throughout the study. I wish to thank Marvin Braa: 
Paul Fishman, John Holbrook, Henry Nilsen, War 
Brigham, and others who assisted in the collecting 
darters; Donald Webb of the Survey for identifica! 
of many insects during analysis of stomach conte 
Daryll Borst for identification of external parasites 
the darters; and Dr. William Childers of the Su 
and Dr. Horace Norton of the Department of Am 
Science at the University of Illinois for their help \ 
the computer program for analyzing age and gro 
data. I also wish to thank O. F. Glissendorf, Illi 
Natural History Survey technical editor, for editing 
manuscript, and Richard Sheets, Survey technical 
lustrator, and Wilmer Zehr, Survey photographer, 
their work on the figures presented in this paper. 
METHODS AND MATERIALS 
Specimens were collected from June 1965 to Jan 
1967. Additional material was examined from a ©0 
tion made at New Athens on August 13, 1964. 
Most collections were made from June thr 
