[mcmurrich] pacific COAST SALMON 27 



Oncorhynchi there is, however, no such winter check visible in the 

 narrow-lined zone and so long as Professor Gilbert's interpretation fails 

 to explain not only its absence, but also the existence of the entire zone, 

 this interpretation must be regarded with suspicion. Since the lines of 

 similar quality and position in the scales of the Atlantic Salmon are 

 definitely known to represent the period spent in fresh water, it is but 

 natural to assume that they have the same significance in the closely 

 allied Oncorhynchi. 



In at least two important points, then, I believe Professor Gilbert's 

 position to be untenable, namely, in that his interpretation of the scale 

 markings fails to harmonize with the known periodicity of the Fraser 

 River Sockeye and in that he fails to explain the marked difference 

 in quality of the narrow-lined zone immediately surrounding the nucleus. 

 I am pleased, however, to note that in another point, which, it seems 

 to me, is the most interesting result yet obtained from the study of the 

 scales of these fish, we are in essential agreement, namely, that the 

 Coho and Humpback salmon never pass beyond what may appropriately 

 be termed the grilse stage. 



The Steelhead (Salmo Gairdneri Richardson) . 



The life-histories of the various species of Oncorhynchus differing 

 so markedly in several respects from what has been worked out for 

 the Atlantic Salmon, it became a matter of considerable interest to 

 determine whether the Steelhead salmon of the Pacific coast shared 

 in the peculiarities of the Oncorhynchi or resembled more closely its 

 Atlantic congener. The Steelhead and the Atlantic salmon are both 

 representatives of the genus Salmo and in the streams of the Pacific 

 coast two other forms, generally recognized as distinct species of Salmo, 

 also occur, namely the Cutthroat trout {S. mykiss) and the Rainbow 

 trout (S. irideus). So far as I have been able to discover very little is 

 definitely known as to the life-histories of any of these Pacific coast 

 Salmo and this was a further reason for the study of the scale markings 

 of at least one of them. 



The SteC'liead Salmon does not run in anything like the numbers 

 characteristic of the various species of Oncorhynchi, and at present, 

 where the facilities exist, they are generally preserved in cold storage 

 instead of being canned. To this practice I am indebted for most of 

 the material I studied, the great majority of the fish from which I 

 obtained scales having been those in the cold storage plants of the 

 Claxton Cannery and the St. Mungo Cannery of New Westminster. 

 To the managers of these canneries I am under great obligations for 

 many courtesies. I have examined the scales from twenty-two fish 



Sec. IV, 1913—2 



