Turbidity readings were also made daily at each station. These 

 readings ranged from 22 to llU parts per million. There is no evidence 

 that turbidity within this range had any effect upon the movement and 

 catch of black crappies or any other species. 



U. Effect of Spawning Activities on the Catch . 



Direct observation of spawning activities was not possible because 

 of the turbidity of the water, but gonads of 3_^311 black crappies were 

 examined grossly and classified as to stage of development. The classi- 

 fication consisted of six categories: (1) undeveloped, (2) developing, 

 (3) ripe, (It) ripe and discharging when pressed, (5) partly spent and (6) 

 spent. A summary of the data on gonad examination i s shown in Table 3. 



It will be noted that spawning was in progress at the beginning of 

 netting and continued until late in July. During the last half of 

 August all the crappies examined had undeveloped gonads. Development of 

 the gonads for spawning the next year began in some fish in August and 

 was observed in more and more fish as the season progressed. The appear- 

 ance of the I9U6 year class and general mixing of the crappie population 

 was coincidental with the end of the spawning season. Although most of 

 the 2-year-old fish were apparently not with the older fish during the 

 spawning season, gonad examinations show that at least some of these 

 younger fish were capable of spawning and may have spawned elsewhere. 

 Gonad examination£ of 10 black crappies all under 7.6 inches long, which 

 were taken during Period III, showed six undeveloped, three partly spent 

 and one ripe. 



The present findings on age at sexual maturity of the black crappie 

 agree with the statement of Smith and Moe (19hh) that black crappies are 

 sexually mature at the age of two years. 



Except for the apparent separation of the older and younger crappies 

 during the spawning and the subsequent remixing of the population, spawn- 

 ing activities had no apparent effect on the catch. 



SUMIiiRY OF BLACK CRAPPIE CATCH TRENDS 



1. The means of black crappie trap net catches for each of the nine 

 netting periods fluctuated between 2,5 and 53.6 fish per net lift and be- 

 tween 1,2 and 21,5 pounds of fish per lift. There was? (1) a sharp drop 

 in catch during the first part of Jxine; (2) a gradual rise during which 

 catch was more than tripled during July; (3) a slight but general drop 

 during the first part of August; (h) a rise during which catch was about 

 doubled during the last half of August; and ($) an increase in the latter 

 half of September during which catch again was more than tripled. 



15 



