CHINOOK SALMON MARKING, COLUMBIA RIVER 263 



tributary and continued up the main river. Six other experiments, which, Hke 

 experiment No. 7, involved spring chinooks that were liberated in tributaries other 

 than the one in which the eggs from which they developed were taken, have given 

 similar results. From these experiments only four returns to the place of liberation 

 have been reported. It may be concluded tentatively that, in part at least, some 

 element in the complex known as the homing instinct is hereditary, so that the 

 instinct does not function perfectly in the case of transplanted fish. It seems pos- 

 sible that this might be a determining factor in the establishment or rehabiHtation 

 of salmon runs by means of artificial propagation. 



The experiments with chinooks of the fall run have resulted in much greater 

 returns to the place of Hberation. Ninety-nine of the 504 recoveries recorded for 

 the experiments with salmon of this group were caught at the hatcheries at which 

 the fingerlings were reared and liberated. Five of these fish entered near-by tribu- 

 taries, but no others are definitely known to have strayed, the remainder having 

 been taken either in the ocean or in the Columbia River below the mouth of the 

 home tributary. The most striking instance of this return to the home stream is 

 that to Spring Creek. This stream is so extremely small that it is diflacult to see 

 how the salmon could find it at all, and yet 82 of the fish marked here were recaptured 

 here as adults, while only 4 were taken in other spawning tributaries. This is the 

 most definite evidence known to us of the validity of the home-stream theory as 

 applied to tributaries. 



The reason for this difference in the homing of the spring and fall chinooks is 

 not shown conclusively by the data at hand. It seems, however, that the homing 

 instinct is disturbed to some extent by transplanting the eggs from one tributary to 

 another, the disturbance being greatest when the eggs are transferred to tributaries 

 that offer least favorable conditions for the returning mature fish. The marked spring 

 chinooks in every experiment were transplanted in tributaries that could not support 

 a spring run. The fall chinooks, on the other hand, were liberated in either their 

 native stream or another that ofiered favorable conditions for a fall run. While by 

 no means conclusive, the evidence indicates that the transplanting of eggs from one 

 tributary to another has an unfavorable influence on the homing instinct of the 

 resulting fish. This is a matter of considerable importance in fish-cultural opera- 

 tions, particularly in cases where attempts are made to rehabilitate runs by trans- 

 plantation from other streams. So far as these experiments go, they indicate that a 

 better practice would be to stock each stream with eggs native to that stream. 



BIBLIOGRAPHY 



Chambehlain, Fked. M., and Ward T. Bower. 



1913. Fishery industries. In Fishery and fur industries of Alaska in 1912, by Barton Warren 

 Evermann. Report, U. S. Commissioner of Fisheries for 1912 (1914). Bureau of 

 Fisheries Document No. 780, 123 pp. Washington. [Marked salmon, pp. 29-31.] 

 Gilbert, Charles H. ■' 



1913. Age of maturity of the Pacific coast salmon of the genus Oncorhynchus. Bulletin, 

 U. S. Bureau "of Fisheries, Vol. XXXII, 1912 (1914), pp. 1-22, Pis. I-XVII. Wash- 

 ington. 



1919. Contributions to the life history of the soekeye salmon. No. 5. Appendix, Report of 

 the Commissioner of Fisheries, Province of British Columbia, 1918 (1919), pp. X26- 

 X52, pis. 1-34. Victoria. 



