Section V, 1919 [163] Trans. R.S.C. 



Growth Rate in the Pacific Salmon 

 By C. McLean Fraser, Ph.D., F.R.S.C, 



(Read May Meeting, 1919.) 



It is becoming more evident each year that the salmon question 

 on the Pacific coast, instead of being a single, comparatively simple 

 question, is a large series of problems more or less closely related, 

 since not only is it not safe to infer that what is true of one species is 

 true of any other species, but further it is not safe to infer that what is 

 true of one species, spawning in one river-system, is true of the same 

 species spawning in a different river-system. It follows, therefore, 

 that there is a separate problem for each species in each spawning 

 area along the coast. Fortunately, many of these problems are closely 

 related so that, when certain facts are brought to light in one case, 

 inferences may be verified in other instances with comparative ease 

 if suitable material can be obtained. 



Since it has been definitely established that scale and otolith 

 reading, within certain limits, can be depended upon in age determina- 

 tion and rate of growth calculation, it is now possible to fill in many 

 of the gaps in life-history that of necessity were left, in all accounts 

 where direct observation was the only basis on which conclusions 

 could be drawn, not that direct observation is now any the less im- 

 portant, because it is even more useful when the information obtained 

 by scale and otolith study is available to connect up the scattered data 

 thus obtained to make a complete life-history of the species in question. 



In previous papers the two methods have been combined in the 

 study of the spring salmon and the coho. During the season of 1916 

 advantage was taken of the opportunity to get material and data of 

 the whole five species of Pacific salmon, and this paper embodies 

 some of the results obtained by the examination of this materia. 

 In the case of three species, the sockeye, the humpback and dog, 

 material was obtained from different location and hence a comparison 

 was possible. In the case of the spring and the coho this was not so, 

 but here it was possible to compare with material of these species 

 from the same locality in the preceding year. The sockeye were ob- 

 tained from the Fraser river and from Rivers inlet, the spring and 

 coho from the strait of Georgia, the humpbacks from Rivers inlet, and 

 from the strait of Georgia near Comox, and the dog from the mouth 

 of the Little Qualicum river and from near Nanaimo. For the op- 



