68 Carrying Capacity, Productivity, and Growth 



mouths were stocked in 1949 and channel catfish, in small numbers in 

 1951 and 1955. Neither were numerically very abundant because of low 

 success in reproduction; in fact, only a few young catfish were ever 

 observed in the last three censuses. Other fish entered from the small 

 feeder stream or came upstream over the spillway during floods. 



Table 4.2 Numbers and weights of fish per acre taken in 8 draining 



CENSUSES OF RIDGE LAKE, COLES COUNTY, ILLINOIS. By 1951 AN 

 accumulation of silt in THE UPPER LAKE BASIN HAD REDUCED 

 THE LAKE SURFACE AREA FROM 18 TO 17 ACRES. 



* Population influenced by September drawdowns. 

 t Data for 1953 and 1956 not included in average. 

 t Not included because bluegill population newly introduced. 



Table 4.2 shows that no two censuses were very similar, either in 

 numbers, or pounds of fish per acre. The poundage of bass in 1943 when 

 almost no other fish were present was exceeded by only two subsequent 

 censuses. Exclusive of the drawdown period, the lowest poundages of 

 bass appeared in the 1947 and 1959 censuses when the bluegills were most 

 abundant, both in numbers and in pounds per acre. Bluegills larger than 

 about 2.5 inches ranged in number from 440 to 5400 per acre and in 

 weight from 58 to 193 pounds per acre. 



