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Larqemouth bass 



Growth of largemouth bass in Heyburn Reservoir was slower than in Upper 

 SpavinaWj, as well as in all other Oklahoma reservoirs of similar age and size 

 for which data were available (Table 10). While average first-year growth was 

 greater at Heyburn than at Canton Reservoir, this advantage was lost during 

 the second and third growing seasons „ The comparisons in Table 10 are re- 

 stricted to new (impounded five years or less) Oklahoma reservoirs of over 

 500 surface acres. Here, as in subsequent comparisons, the growth figures 

 represent weighted averages for the various years of growth. For example, 

 the figure presented in Table 10 as first-year growth for Heyburn represents 

 a weighted average of first-year growths made during five different growing 

 seasons. This growth was remarkably uniform at Heyburn, averaging 5.2 inches 

 for the four years 1950 through 1953, dropping to 4.1 in 1954. First-year 

 growth in Upper Spavinaw averaged 6,4 inches. These results agree with those 

 of Jenkins and Hall (1953) who found growths of bass to be consistently faster 

 in Oklahoma lakes known to be usually clear than in those known to be con- 

 sistently turbid. 



The history of the Heyburn largemouth bass population is unique. Out- 

 standing characteristics have been the preponderance of relatively old bass 

 and the scarcity of young bass — an extremely unusual condition in new res- 

 ervoirs. In 1952 and 1953 Orr (personal correspondence) collected 93 bass 

 of which 72 percent were of the 1950 year class, and 20 percent were of the 

 1951 year class. When collected, 92 percent of Orr's fish were in their 

 third year or older, and yearling bass were completely absent from the 1953 

 collections at a time when, in a normal population structure, they should 

 have been dominant. The results in 1954 and 1955 were very similar. 



