CONTENTS. 



Page. 



Introduction 3 



History of the investigation 3 



Statement of the problems S 



Methods 6 



Presentation of data 7 



Fish from the Columbia River 7 



Fish from the Sacramento River 32 



Miscellaneous collections 42 



Conclusions 45 



Rate of growth 45 



Development of scales 51 



Migration 62 



Variations due to sex 65 



Sex proportions 65 



Relative sizes of males and females 66 



Precociously mature males 67 



Practical suggestions 68 



Summary ■,. 69 



Bibliography 71 



Explanation of plates 72 



