EFFECTS OF ABIOTIC FACTORS ON CHANNEL CATFISH  ICTALURUS  PUNCTATUS
POPULATIONS IN THE ILLINOIS RIVER

Kathryn A. Emme 1, Dr. Kenneth Cramer 1, and Kevin S. Irons 2.
1 Department of Biology, Monmouth College, 700 East Broadway, Monmouth, IL 
61462; and 2 Illinois Natural History Survey, Long Term Resource Monitoring Program, 
Havana Field Station, 704 North Schrader Avenue, Havana, IL 62644.

Beginning in 1990 the Illinois Natural History Survey's Havana Field Station has 
monitored fish populations in the La Grange Reach of the Illinois River as part of the 
Long Term Resource Monitoring Program (LTRMP).  The LTRMP uses a multiple gear 
approach in sampling fish communities from 6 key reaches of the Upper Mississippi 
River System (UMRS).  This study focuses on channel catfish, Ictalurus punctatus, 
sampled by day electrofishing in La Grange Reach of the Illinois River.  Seven abiotic 
factors including turbidity, temperature, conductivity, dissolved oxygen, depth class, 
velocity, and river stage were analyzed to see if they had any effect on the location 
and number of channel catfish.  Abiotic data from 1999 day electrofishing sites were 
compared to the same type of data measured from 1995-1998.  Conductivity and 
dissolved oxygen levels were on average higher in 1999 while turbidity, depth 
classes, velocity, and river stage averages were greater from 1995-1998.  Pearson 
correlations analyzed each abiotic factor versus total channel catfish caught.  Except 
for 1999, velocity and dissolved oxygen showed mostly weak negative correlations 
with the largest being -.275 from 1995-1998 river stages.  Velocity and dissolved 
oxygen values (.064 and .099 respectively) showed positive but weak relationships. 
River stage negatively affected catfish catches more than any of the other abiotic 
factors, possibly a result of gear efficiency more than biologic response of the catfish. 
The abiotic factors acting alone, however, did not how any significant correlation with 
location of large catches of catfish.

Keywords:  channel catfish, Illinois River, abiotic factors, correlation, Long Term 
Resource Monitoring Program
_________________________________________________________________________________




































                           1