then showed a drastic decline during and following the drought years, 



1962-1964. The recent increase in largemouth populations followed the 



high-water years, 1971-1973. Largemouth bass were more numerous in 



Marseilles Pool in 1973 and 1974 than they ever had been previously. 



White crappie (Pomoxis annularis) and Black, 

 crappie (Pomoxis nigromaculatus) 



The largest catch of both black and white crappie, in pounds and 

 numbers, was taken in the river in 1974, following the high-water years 

 1971-1973 (Tables 27 and 28) . Populations of both species showed a 

 steady decline in the years 1962-1965, during a drought period. Prior 

 to 1973, few crappies were taken in the upper three navigation pools, 

 but substantial numbers of both species were taken in the Starved Rock 

 and Marseilles Pools in 1974. In 1962, 1964, 1966-1969, and 1974, more 

 black crappies were taken in LaGrange Pool than Alton Pool, perhaps 

 because more backwater and side channel areas with brush piles (a 

 favorite habitat of crappie) were usually available in LaGrange Pool. 

 In 1974, a larger number of white crappie were taken in LaGrange Pool 

 than in Alton Pool, but a larger number of pounds of white crappie were 

 taken in Alton, showing that the white crappie in Alton were of larger 

 size. Both species are popular game fish. 

 Yellow perch (Perca flavescens) 



Two yellow perch were taken during the electrofishing survey; one 

 from Peoria Pool in 1964, and one from Marseilles Pool in 1965. Yellow 

 perch were once common in the Illinois River. Forbes and Richardson 

 (1908) reported that yellow perch were taken in considerable numbers 

 from the Illinois River as far south as Meredosia (mile 71.2). Yellow 

 perch were commonly taken by pole-and-line fishing in backwaters and 

 lakes in the Havana area (mile 120), until 1943. In 1943 and 1944, 

 floods deposited a great deal of silt in the lakes and backwaters. 

 Following the floods, the once-abundant aquatic vegetation disappeared. 

 The yellow perch population declined drastically, probably as a result 

 of the loss of aquatic vegetation that perch use for spawning (Starrett 

 and McNeil, 1952). 



34 



