Section IV, 1912 [9] Trans. R.S.C. 
The Life Cycles of the Pacific Coast Salmon Belonging to the Genus 
Oncorhynchus, as Revealed by Their Scale and 
Otolith Markings. 
By J. Puayrarr McMurricn, M.A., Px.D. 
In a former paper’, in which I endeavoured to present an account 
of what was known concerning the life history of the Sockeye salmon 
(Oncorhynchus nerka) of the Pacific coast, I made mention of an obser- 
vation upon the otoliths of some four individuals, which seemed to 
indicate that the fish from which they were taken were four years old.? 
This formed an interesting confirmation of the conclusions derived from 
the cannery statistics, these pointing very clearly to a four-year cycle 
in the life-history, and it seemed advisable to make a more thorough 
study both of the otoliths and scales of this salmon and also to compare 
with the results thus obtained, observations on the same structures in 
the other four species of Oncorhynchus. 
During the past summer, aided by a grant from the Board of 
Directors of the Marine Biological Stations of Canada, I was enabled to 
obtain the material necessary for this purpose. I would take this 
opportunity for expressing my thanks, not only to the Board by whose 
generosity this investigation was made possible, but also to those who 
most courteously and in various ways aided me in obtaining the material 
I desired. Among these I would mention especially Rear-Admiral 
Kingsmill and Captain Holmes Newcomb, Mr. Bell-Irving, President of 
the A.B.C. Packing Company, Mr. Barker of the B.C. Packers’ Asso- 
ciation and the managers of the Phoenix Cannery, Steveston, and the 
Esquimalt and Claxton Canneries. 
The idea that it is possible to determine the age of a fish by the 
markings on its scales dates back to Leeuwenhoek (1696); but it was 
not until 1899 that the systematic study of the question was inaugurated 
in a paper by Hoffbauer,’ who had found that in the case of individual 
fish belonging to certain varieties of carp, whose age and life-history 

‘MecMurrich, J. P., The Life History of the Pacific Salmon, Transactions of the 
Canadian Institute, IX. 1909. 
As a matter of fact my interpretation of the markings on these otoliths was 
incorrect in detail, although the conclusions as to the age of the fish were correct. 
SHoffbauer, Die Alterbestimmung des Karpfen an seiner Schuppe. Jahresber. 
Schlesischen Fischerie Vereins, 1899. 
