EXECUTIVE SUMMARY 



During late August and September each year 1994-1998, we sampled 26 sites on 

 the Illinois River WatenA/ay and one site on Reach 26 of the Mississippi River by 

 electrofishing to monitor fish communities. From 1994-1998, we collected a total of 

 25,921 fish representing 62 species (plus five hybrids) from fourteen families during 

 125.70 hours of sampling at 26 sites on the Illinois Watenway and a single site on the 

 Mississippi River. Of these fishes, 25,278 individuals were collected from the Illinois 

 Waterway sites, and 643 were collected from Brickhouse Slough of the Mississippi 

 River. The year with the greatest overall catch of fishes was 1995 (7941 individuals, 

 CPUEn = 325 fish per hour) and the year with the lowest overall catch of fishes was 

 1994 (3421 individuals, CPUEn = 131 fish per hour). For all stations combined, the 

 greatest number of species were collected in 1995 (48 species plus 3 hybrids) and 

 the least were in 1997 (38 species plus 4 hybrids). The number of species collected 

 from upper waterway reaches ranged from 12 for Starved Rock in 1996 to 24 for 

 Marseilles in 1995. The number of species collected from middle river reaches 

 ranged from 23 for La Grange Reach in 1997 to 34 for Peoria Reach in 1996. The 

 number of species collected from the lower river (Alton Reach) ranged from 18 in 

 1994 to 25 in 1995. The Peoria Reach consistently had highest species richness 

 during all years (1 994-1 998) of sampling for this project. 



