Pekin (RM 155.1), and Turkey Island (RM 148.0) the average has been 11 species 

 (Appendix F). It also should be noted from Appendix F that low numbers of species 

 typically occurred at sites following the drought years of the late 1980s (1989 and 

 1990), while high species richness at sites typically occurred following a high water 

 year (1995). In 1998, the greatest number of species (39) was collected from Peoria 

 Reach and the fewest species (14) were collected from Starved Rock Reach 

 (Appendices D and E). The high richness of Peoria Reach is likely due, in part, to its 

 position along the waterway which includes the Great Bend (above Hennepin) of the 

 Illinois River. This reach represents a transition from a river which is constricted, 

 lacks contiguous backwaters, and is high in gradient (upper river) to a large river 

 floodplain system with low gradient (lower river) (Sparks 1977); species typical of 

 both the upper and lower waterway have been collected and are common in Peoria 

 Reach. 



The total weight of fishes collected 1994-1998 was also highest in Peoria 

 Reach, where CPUEw was 1 14.14 (Table 8). Species accounting for this high catch 

 in weight were bigmouth buffalo, common carp, smallmouth buffalo, and white bass. 

 Catch in weight was also high in La Grange and Alton Reaches. For example, of 

 1,860 pounds offish collected during our 1997 survey, 1,732 pounds (93%) were 

 collected from the lower and middle river, and only 128 pounds (7%) were collected 

 from the upper river. These catches reflect the high productivity of the lower and 

 middle Illinois River floodplain ecosystem. 



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