May, 1945 



Bennett: Overfishing, Onized Lake 



393 



count ; great care was taken in sorting out 

 individuals of 6 or more inches in length. 

 The ratio of bluegills of desirable sizes to 

 those smaller was 1 :19; that is, the num- 

 ber of bluegills of desirable sizes repre- 

 sented about 5 per cent of the total num- 

 ber of bluegills. Because an accurate 

 count of the 1941 brood could not be made, 

 the calculated percentage of large fish was 

 much larger than the actual percentage. 



Tables 18, 19 and 20 show calculated 

 lengths of bluegills taken in the hoopnet 

 collections of 1938 and 1940, and in the 

 census of 1941. Growth curves based on 



these lengths, fig. 6, show some variation 

 in growth rates of bluegills represented by 

 each of these three collections. Unlike 

 the black crappies, bluegills spawned in 

 1939 apparently made no abnormal growth 

 increment during that year. Abnormal 

 growth in bluegills spawned early might 

 be obscured by the growth figures of those 

 spawned in July and August ; it also seems 

 that the growth of bluegills was less stim- 

 ulated by the results of heavy fishing than 

 was that of most other species. 



Other sources of information relative 

 to bluegill growth in Illinois are available. 



Table 18. — Average calculated total lengths in inches of 53 bluegills collected with hoopnets 

 from Onized Lake, August 29-31, 1938. 



Brood 



Number 



OF 



Fish 



Average Calculated Lengths 

 BY Years of Life 



1 



1934 2 



1935 10 



1936 30 



1937 11 



Total 53 



Average 



7.44 



1.37 



5.20 



6.56 



7.44 



Table 19. — Average calculated total lengths in inches of 99 bluegills collected with hoopnets 

 from Onized Lake, July 9-15, 1940. 



Brood 



Number 

 of 



Fish 



Average Calculated Lengths by 

 Years of Life 



1 



Average Total 



Length at Time 



OF Capture 



