8- 



u 



X 



u 



z 



X 



I- 

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z 



UJ 



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_l 

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I- 

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7- 



6- 



5- 



4- 



3- 



ORIGINAL 



STOCK 



"T I I I I I I I 1 1- 



MAR APR MAY JUN JUL AUG SEP OCT NOV 



1939 



FIG. 1. — ^Average total lengths of bluegills taken each month from Fork Lake, 1939, 



INDEX OF CONDITION 



The Index of condition, suggested as a practical measure of the relative plumpness of 

 fish (Thompson & Bennett 1939b), was applied to the fish collected from Fork Lake. In 

 general, the bluegills were in exceptionally good condition, with much fat around the 

 digestive organs. On the other hand, the condition of the bass was near the average for 

 this fish in other Illinois waters. 



The largemouth bass and the bluegill, as well as most other members of the sunfish 

 family, tend to grow in width and thickness faster than they grow in length. This means 

 that the index of condition increases with length. In the bluegills, the males had a 

 greater index than the females because of their greater length. Table 5 shows the average 

 index of condition of the fish taken from Fork Lake. 



TABLE 5. —AVERAGE INDEX OF CONDITION, "C," OF LARGEMOUTH BASS AND 

 BLUEGILLS TAKEN FROM FORK LAKE, MARCH THROUGH NOVEMBER, 1939. 



