collected at Crater-Willow Islands and Big Blue Island than in 1995, when 16 and 19 

 species were found, respectively. 



On the middle Illinois River, we collected 3,731 fish representing 38 species 

 plus one hybrid (one bluegill x green sunfish) (Tables 3 and 4) From six sites on La 

 Grange Reach (RM 80-158), 1732 fish representing 28 species were collected 

 From eight sites on Peoria Reach (RM 1 58-231 ), 1 999 fish representing 34 species 

 and the bluegill x green sunfish hybrid were collected. Species richness ranged 

 from 9 at Hennepin Island (RM 207.9) to 20 at Lambie's Boat Harbor (RM 170 7); 

 habitat diversity was low at Hennepin Island and sampling time was only 0.5 h. In 

 1995, 15 species were collected at Hennepin Island during 0.5 h (Lerczak et al 

 1996:10). A substantial reduction in species richness was also observed at Clark 

 Island (RM 215.3); 14 species were collected in 1996, whereas 21 and 19 species 

 were collected in 1994 and 1995, respectively. However, even though species 

 richness was lower at Clark Island in 1 996, the total abundance of fishes collected 

 was higher than in recent years In 1996, 347 individuals v/ere collected compared 

 to 325 in 1995 and 165 in 1994. A species never before collected during Long-term 

 Illinois River Fish Population Monitoring, the mud darter, v/as taken at Henry Island 

 (RM 193.9) of Peoria Reach. 



. On the upper waterway in 1996 we collected 700 fish representing 23 species 

 plus one hybrid (three carp x goldfish) (Table 5). This is substantially fewer fish 

 than collected in 1995, when 3,827 individuals representing 34 species and two 

 hybrids were collected (Lerczak et al. 1996:1 1). Large declines in cypnnids were 



