Table 17: — Age-class distribution of bluegill in percent of sanple aged, 

 Lewis and Clark Lake, 1956-62 



Age group 



Year o£ collection 



1956 



1957 



1958 



1959 



1960 



1961 



1962 



I 



II 



III 



IV 



V 



VI 



100 



84 



15 



1 



16 



78 



5 



1 



3 

 3 



83 

 11 



23 



75 



2 



10 



89 



1 



30 

 10 

 30 

 20 

 10 



Number of fish aged 



12 



46 



112 



70 



35 



41 



10 



1957, but more were collected in 1958 and 1959 

 than any other species . Abundance was reduced 

 in 1960, and it remained relatively constant 

 through 1962 (table 6). Number of white crappie 

 was strongly influenced by the large 1956 year- 

 class which dominated the population through 

 1962 (table 18). Reproduction from 1957 to 1962 

 was comparatively poor. The age-class distri- 

 bution of the catch (table 18) suggests that fair 

 reproduction occurred in 1957 and 1958, but this 

 was not indicated by shore seining in those years 

 (table 7). Results of shore seining suggest that 

 reproduction in 1962 was the best since 1956. 



Spawning and annulus formation for most 

 fish was completed by July 1 . Average length 

 in inches by age group for fish collected in 1962 

 was as follows: I, 2.7; II, 4.0; HI, 5.8; IV, 7.1; 

 V, 8.2; VI, 9.6; VII, 10.6; and VIH, 12.2. 

 Growth was poor compared to that attained by 

 this species in other areas of the United States 

 (Gar lander, 1953), and much less than in Fort 

 Randall Reservoir (Sprague, 1961, op. cit.), 

 where lengths of 4 -year -old fish were compara - 

 ble to that of the 7-year-olds taken from Lewis 

 and ClarK Lake. Although growth was poor and 

 reproduction erratic, the white crappie will 

 probably continue to be one of the dominant 

 fishes in the reservoir. 



Black crappie 



The black crappie is now a minor species 

 in the reservoir, although it was important in 

 1957 and 1958 (table 2). A large year-class 

 produced in 1956 dominated the catch for the 

 following 2 years (table 19). Reproduction as 

 indicated by shore seining was poor after 1956, 

 and with the demise of this year-class the abun- 

 dance of this species declined to a minor role 

 (table 6) . According to Harlan and Speaker 

 (1951) and Trautman (1957), white crappie often 

 is dominant over the black crappie in turbid 

 waters, as is the condition in Lewis and Clark 

 Lake. 



Spawning and annulus formation were 

 usually completed by July 1 . Average length 

 in inches by age group for fish collected in 1962 

 was as follows: I, 2.3; U, 4.5; III, 5.9; IV, 7.5; 

 V, 9.0; and VI, 9.7. Like that of the white 

 crappie, growth of the black crappie was poor 

 compared with that in other areas of the United 

 States (Carlander, 1953) and much poorer than 

 in Fort Randall Reservoir (Sprague, 1961, op. 

 cit.). All age groups of black crappie were 

 found in the reservoir in 1962, suggesting limited 

 successful spawning in each year . The decline in 



18 



