two age) resembling that of spring chinook 

 scales. Moreover, these two groups of scales 

 are different in marine growth patterns. When 

 circulus spacing in the second year marine 

 growth is compared with that in the first year 

 marine growth, the ratio is far greater for the 

 sub-one group than for the sub-two group. 



4. Can fall chinook scales be separated from 

 spring chinook scales by objective means? 



The answer is positive. Fall and spring 

 chinooks can be differentiated by their scales. 

 Differentiation, however, is not made from 

 nuclear growth patterns as is usually done 

 visually, but is achieved objectively by compar- 

 ing marine growth circuli of the first 2 years, 

 the same technique as used for eai-ly-season 

 and late-season releases of fall chinook. In the 

 spring chinook, circuli in the second year of 

 marine growth are nearly 50 percent more wide- 

 ly spaced than those in the first year ; whereas 

 in the fall chinook, they are about the same. 



ACKNOWLEDGMENTS 



The most important ground work in con- 

 nection with the present paper had been done 

 before we started our studies, for marking 

 experiments on the Columbia River chinook 

 salmon and collecting scale samples and perti- 

 nent data had been performed by the Bureau 

 of Commercial Fisheries of the U.S. Fish and 

 Wildlife Service. Paul Zimmer, Harlan E. John- 

 son, and Roy Wahle of the Bureau provided the 

 study material and data. The Fish Commission 

 of Oregon and the Washington State Depart- 

 ment of Fisheries, which are also studying the 

 Columbia River chinook salmon, supplied addi- 

 tional material and information, and in this con- 

 nection, I was assisted by Sigurd J. Westrheim, 

 Raymond A. Willis, and Robert N. Thompson of 

 the former organization and Peter Bergman of 

 the latter agency. Charles E. Walker of the 

 Canadian Department of Fisheries in Van- 

 couver, British Columbia, sent us some dupli- 

 cate scale impressions of Big Qualicum chinook 

 salmon for our study, and Gei-ald J. Paulik of 

 the Fisheries Research Institute of the Univer- 

 sity of Washington advised us on the statistical 

 treatment of the data. 



LITERATURE CITED 



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FOERSTER, R. E. 



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1951. The eff"ect of fin removal on fingerling lake 

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SCALES OF CHINOOK SALMON 



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