CONTENTS 



Page 



Area fished 1 



Gear used 3 



Methods 5 



Statistical considerations 5 



Season trends in catch of trap nets 6 



Black crappie catch trends 7 



Summary of black crappie catch trends 1$ 



White crappie catch trends 17 



Summary of white crappie catch trends 2k 



Blue gill catcfi trends 2U 



Summary of bluegill catch trends 30 



Catch trends for other species 32 



Summary and discussion 35 



Acknowledgements 3^ 



References cited 38 



ILLUSTRATIONS 

 Figure Page 



1. Pool 8 of the Mississippi River immediately below 



La Crosse, Wisconsin 2 



2. Mississippi River trap net used for test netting h 



3. Length-frequency distribution of black crappies for the 



nine netting peii.ods 9 



U. Fluctuation in black crappie catch showing effect of 



"recruitment" 12 



5. Fluctuation in water levels and mean water temperature in 



Pool 8 of the Mississippi River during summer of I9U8 ih 



6. Length-frequency distribution of white crappie for the 



nine netting periods 19 



7. Fluctuation in white crappie catch showing the effect of 



"recruitment" 21 



8. Length-frequency distribution of bluegills for the nine 



netting periods 27 



9. Fluctuation in bluegills catch showing effect of 



"recruitment" 29 



10. Percentage composition of total catch expressed as 



numbers of fish in netting Periods III, V, and VII 37 



