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Cat fishes 



The clear and turbid reservoirs differed significantly in abundance of 

 channel and flathead catfishes. Both species are abundant at Heyburn, while 

 ^Kily a single adult flathead and only two adult channel catfish have been 

 recorded from Upper Spavinaw. The contrast is undoubtedly related to the 

 differences in turbidity. In the first years of clear reservoirs, bass, crappies, 

 and other scaled species apparently outproduce the catfishes and limit catfish 

 survival through predation on their young. While individual pairs of catfish 

 probably spawn as many yoxing in clear as in turbid waters, the protection 

 afforded by the turbid waters enables more to survive. The greater abilities 

 of the catfishes to find food in the turbid environment increases this ad- 

 vantage, and the bass and crappies lose ground in the competition for food. 



In spite of its tolerance for turbid waters, growth of channel catfish 

 at Jfeyburn was slower than growths recorded from any other Oklahoma reservoir 

 "Vf similar age and size (Table 12). These results agree with those of Finnell 

 and Jenkins (1954) who found turbidities to retard growth of channel catfish 

 uniformly in both small lakes and large lakes as well as in large reservoirs. 



On the whole, however, the channel catfish seemed well adapted to Heyburn 

 conditions. Growth rates compared more favorably with those from other waters 

 than the bass and crappie gr9wths, and the population structure was more normal 

 as evidenced by a more even distribution among the different age and size 

 groups . 



Growth of flathead catfish at Heyburn compared favorably with growths 

 in other Oklahoma reservoirs as recorded by McCoy (1955). However, McCoy's 

 lakes were mostly older waters, while Heyburn is comparatively new. Average 

 first-year growth at Heyburn was 4.9 inches, second year 11.0 inches, third- 



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