CONTENTS 



Fishino; methods « ... o » ...... o. .... . 



Methods for conducting the experiment ........ 



Bullraking operations ............. 



Dredging operations .............. 



Underwater photography ............. 



Bottom samples ................. 



Analysis of results ................. 



Breakage of commercial-sized clams ....... 



Breakage of undersized clams .......... 



Smothering ... ............... . 



Effect of fishing upon setting and set survival 



Effect of fishing upon the physical characteristics of the 

 bottom .............. . 



Effect on other bottom forms ............. 



Size composition of catch .............. 



Size composition of clams left in plot .„.,,...... 



Disappearance of group "B" in control and in bullraked areas 



Conclusions ........................... 



Literature cited ................. . 



Page 

 3 



9 

 10 

 10 



12 

 12 

 13 

 13 

 13 



13 

 lU 



15 



15 



21 

 2U 

 26 



APPENDICES 



Appendix "A" ............................ 2? 



Size composition of population before and after fishing .... 27 



Appendix "B" ............................ 32 



Method for determining size composition of the catch in relation 



to available population for bullraking and dredging (Figure 7) • • 32 



Appendix "C" ............................ 33 



Population census using clamshell bucket ............ 33 



