EXPERIMENTS IN MARKING YOUNG CHINOOK SALMON ON 

 THE COLUMBIA RIVER, 1916 TO 1927 



By 

 WILLIS H. RICH, Ph. D., Chief Investigator, Salmon Fisherie:s 



and 

 HARLAN B. HOLMES, A. B., Assistant Aquatic Biologist, United States Bureau of Fisheries 



CONTENTS 



Page 



Introduction . 215 



Experiments 220 



No. 1. — Bonneville hatchery, Februarj'- April, 1916 220 



No. 2. — Klaskanine hatchery, July and August, 1916 223 



No. 3. — Little White Sahnon River hatchery, July and August, 1916 224 



No. 4. — Bonneville hatchery, September, 1918 225 



No. 5.^Little White Salmon River hatchery, June and July, 1917 228 



No. 6.— Herman Creek hatchery, March, 1920 230 



No. 7.— BonneviUe hatchery, October, 1920 233 



No. S. — Little White Salmon River hatchery, July and August, 1920 237 



No. 9. — BonneviUe hatchery, September and October, 1921 242 



No. 10. — Bonneville hatchery, August and September, 1922 244 



No. 11. — Klaskanine hatchery, August, 1922 248 



No. 12.— Big \\Tiite Salmon River hatchery. May and June, 1923 249 



No. 13. — Salmon, Idaho, hatchery, August, 1924 256 



Conclusions 257 



Percentage of return 257 



Success of long and short periods of rearing 258 



Interpretation of scales 259 



Time of entering fresh water 260 



Age at maturity 261 



Homing instinct 262 



Bibliography 263 



INTRODUCTION 



As one of the most important means of studying the life histories of sahnon, the 

 Bureau of Fisheries, in cooperation with the Oregon Fish Commission, has conducted 

 an extensive series of marking experiments during the past 11 years. In these experi- 

 ments young, artificially reared salmon were marked by removing certain of the fins 

 and then were liberated in the streams on which the various hatcheries are situated. 

 The experiments that were begun during 1916 and 1917 were described in United 

 States Bureau of Fisheries Economic Circular No. 45. Other experiments have been 

 initiated since then and are described here for the first time. 



215 



