Black crappies, white crappies and bluegills were taken in much 

 greater numbers than the other species and allow more thorough analysis 

 of catch fluctuation than is possible for the other species. A summary 

 of the findings for each of these three species \-n.ll conclude the dis- 

 cussion of each. A general summary and discussion of catch fluctuations 

 for all species will be found at the end of the paper. 



BLACK CRAPPIE CATCH TRENDS 



During the nine netting periods U,10ii black crappies weighing 1,85U 

 pounds were taken in the trapnets. Fluctuations and trends in the catch 

 of the black crappie are shown in Table 1 in terms of mean number and 

 mean weight per net lift for each netting period. The mean catch pei 

 net lift for each period is also expressed as a percentage of the mean 

 catch per net lift for the entire netting season - all nine periods. 

 This latter method of presentation places all catches whether expressed 

 as numbers or pounds on a comparative scale. 



Table 1 shows that the catch of black crappies declined during the 

 first part of Junej remained at a low catch level for a few weeks, and 

 then began to rise. This rise was interrupted during the first part of 

 August (Period VI) by a slight drop in the catch at all but one station. 

 After August l8 the catch increased in a more or less rapid and regular 

 fashion and reached a high point for the season in the last fishing 

 period (September l6 to 25) . 



The effect of four main factors on the catch of black crappies will 

 be considered. They are (l) recruitment to the catch; (2) losses from 

 the fish population; (3) activity and movement of the fish; and (h) 

 spairming activities. 



1. Recruitment to the Black Crappie Catch . 



Recruitment to the catch of the black crappie was studied by (1) 

 analysis of the c hanges in length-frequency of the catch during the 

 netting, and (2) age and growth determinations from scales collected 

 during the netting. 



Length-frequency distributions of the catch during each of the nine 

 netting periods are shown in Figure 3. It will be noted that all black 

 crappies caught during Period I (May l5 to 2h) were 7 inches long or 

 longer. Age determinations from scales collected indicate that these 

 fish were of the 19l;5, 19l;U and 19U3 year classes. These 3, h and 5- 

 year old fish may be termed the "residual" fish for they were both (1) 

 large enough to be taken in the nets during Period I, and (2) present 

 in the area being netted during Period I, 



