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will be able to sustain itself in the face of increasing turbidities. The 

 largemouth bass population at Upper Spavinaw contrasted sharply with that of 

 Heyburno Young-of-the-year were extremely abundant both years. The population 

 of fingerling bass in the 10-acre cove rotenoned on June 21, 1955 was con- 

 servatively estimated at 21,780 individuals, ranging from 1,4 to 2.5 inches 

 total length. In 1954 yearling bass (1953 year class) in sizes of 5 to 11 

 inches could be seen throughout the lake on any day, with several schools often 

 simultaneously in view wildly thrashing the surface as they fed upon small fish. 

 This large year class dominated the angler catch throughout 1955. They con- 

 tinued to school throughout the second siimmer but were commonly seen only in the 

 early morning and almost always in the deep, open, central regions of the lake. 

 Here large numbers of boats converged each morning since the bass were easily 

 caught by placing amost any type of lure near the feeding, surfacing schools. 



White crappie 



Growth of Heyburn white crappies was also the poorest of any Oklahoma 

 reservoir of similar age and size (Table 11). Average second-year length was 

 5»0 inches, more than 3 inches less than the next slowest growth recorded from 

 other new Oklahoma reservoirs. First-year growth for four specimens of the 1954 

 year class collected at Upper Spavinaw was 7,7 inches, and for 8 individuals of 

 the 52 year class 7.9 inches; however, the collections were dominated by the 

 more abxindant 1953 year class which had an average first-year growth of only 3.4 

 inches. Again the results agree with investigations in Oklahoma (Hall, Jenkins 

 and Finnell, 1954) which found growth consistently slower in 31 turbid than in 

 45 clear Oklahoma lakes. 



In both 1954 and 1955 at Heyburn, the white crappie was the most abundant 

 fish (and very often the only fish) returned in hoop nets, gill nets, and wire 



