AN ECOLOGICAL STUDY OF FOUR DARTERS OF THE GENUS 
29ERCINA (PERCIDAE) IN THE KASKASKIA RIVER, ILLINOIS 
REPRODUCTION OF DARTERS of the genus 
ercina has been studied and reported on by Reighard 
1913), Petravicz (1938), Winn (1953, 1958a, 1958b) , 
ew (1966), Page & Smith (1970), and others. These 
nd other studies, such as those of Karr (1963), were 
stricted to small geographic areas and do not demon- 
rate geographic variation in aspects of the life history. 
The logperch, P. caprodes (Rafinesque)!; blackside 
arter, P. maculata (Girard); slenderhead darter, P. 
hoxocephala (Nelson); and the river darter, P. shu- 
ardi (Girard) were studied in the Kaskaskia River 
uring the period from June 1965 to January 1967. This 
ver arises 4 miles northwest of Champaign-Urbana in 
hampaign County, Illinois, flows in a southwesterly 
rection for about 350 miles, and empties into the Mis- 
opi River approximately 7 miles above Chester (Fig. 
. In its upper basin the Kaskaskia River flows over 
isconsin till. For a number of miles below the Shelby- 
lle Moraine, sand outwash predominates, but below 
andalia the river bottom is mainly Illinoian drift of 
nd, silts, and loams over a subsoil of compact clay. 
‘The population of logperch in the Kaskaskia River consists of P. 
orodes carbonaria x caprodes intergrades. 
‘ig. 2. — Percent of bottom materials 
each station in 1965 and 1966. 
PERCENTAGE OF BOTTOM MATERIALS 
By David L. Thomas 
Fig. 2 shows the types of bottom materials along the 
river. 
The descent of the river is gradual (Fig. 3), with a 
total fall of about 450 feet between source and mouth. 
The most rapid descent is through Moultrie County, 
where the river drops 3 feet per mile (University of 
Illinois 1937). 
Information on the distribution and abundance of 
the four darters was collected from 12 stations (Fig. 1 
and Table 1). Because of their distinctiveness, four main 
areas were selected for further study: New Athens- 
Evansville (Stations 10 and 11), Carlyle (8, 9), Van- 
dalia (6, 7), and Sullivan (3). 
Much of the research was aimed at determining the 
relationships between the populations of these darters 
and the changing physical and biotic factors of the river. 
Information was gathered on habitat preference, popu- 
lation structure, growth, and food habits, which allowed 
irhetoare: is published by authority of the State of Illinois, IRS 
Ch. 127, Par. 58.12, and is a contribution from the Section of Aquatic 
Biology of the Illinois Natural History Survey. It was submitted in its 
original form by David L. Thomas in partial fulfillment of the require- 
ments for the degree of Master of Science in the Graduate College of 
the University of Illinois. Mr. Thomas, a former technical assistant 
at the Illinois Natural History Survey, is presently a research biologist 
for Ichthyological Associates, Middletown, Delaware. 
3 4 5) Cre 7. 8 Cie Ogee | l2 
STATIONS (HEADWATERS TO MOUTH) 
