ASIAN CARP IN THE ILLINOIS RIVER

Kevin S. Irons, John P. Wisher, T. Matthew O’Hara, Michael A. McClelland, and Thad 
R. Cook Illinois River Biological Station, Illinois Natural History Survey, 704 N. 
Schrader Ave, Havana, Illinois 62644

Non-native Asian carp (bighead carp Hypophthalmichthys nobilis, silver carp 
Hypophthalmichthys molitrix, and grass carp Ctenopharyngodon idella) have been 
present in the Illinois River since the early 1990’s.  Bighead carp have been collected by 
the Long Term Resource Monitoring Program (LTRMP) through routine monitoring of 
the La Grange Reach, Illinois River since 1995, silver carp since 1998, and grass carp 
since 1992.  The LTRMP fish data reveals significant spawn and recruitment of both 
bighead and silver carp in 2000, and variable spawning success since.  Length 
distributions from this data give insight into growth rates and cohort strength.  
Additionally, bighead and silver carp dietary overlap with two species, gizzard shad 
Dorosoma cepedianum and bigmouth buffalo Ictiobus cyprinellus, is suspected.  Over 
2,400 fish were measured and weighed in part to test for a change in fitness (weight at 
length) through time.  The long-term monitoring also gives a unique perspective into the 
invasion of these species by affording us the opportunity to capture and share some 
unique video events.  

Keywords: Asian carp, Illinios River, LTRMP, length distribution, cohort strength