Further Studies on the Growth Rate in Pacific Salmon. 



C. McLean Fr.\ser, Ph.D., F.R.S.C, etc. 

 Curator of the Pacific Biological Station, Departure Bay. B.C. 



IXTRODUCTIOX. 



Having completed and submitted my reix)rt on salmon material collected in 1916, 

 I secured further material in 1917 and the present report is therefore a continuation 

 of the preceding reeearches. All of the Pacific salmon again receive attention. In some 

 respects the material was better for examination than that from the preceding year. 

 Practically all of the scales were in good condition and as the material was obtained 

 from a greater num'ber of localities it gave a better chance for comparison. For this 

 diversity of material I am indebted to the ma-nagers and employees of the canneries at 

 Q'uathiaski, Lasqueti island and Nanaimo. The weight of the fish was taken in each 

 tease 'and that permitted the working o\\<t of a length-weight ratio for each species in 

 each locality. The methods used were the same throughout as with the 1916 material. 



On March 24 and 25, 1915, one thousand spring salmon fry and one thousand coho 

 fry were marked at the Cowichan Lake hatchery. The information gained from these, 

 although not very extensive, was quite satisfactory. On October 11, 19*17, one of the 

 cohos was caught in Cowichan hay, near the mouth of the river up which evidently it 

 would have gone to spawn if it had not been caught. It weighed 9| pounds. The 

 •scale corresponded perfectly with the scales of those that have all along been taken as 

 three-year fish. It must have gone down the Cowichan river as a yearling and evidently 

 it was on its way to ascend the same river to spawn. 



On January 9, 1918, one of the marked spring salmon", 26 inches long, weighing 

 8^ pounds, was caught in Departure bay, near the north shore, not far from the Biolo- 

 gical Station. Its scalee' indicated a three-year spring of the sea type. It was in no 

 sense mature and hence there was nothing to indicate the river it would have ascended. 

 The fact that is was caught in Departure hay corroborates, as far as it goes, the opinion 

 expressed previously that some spring salmon that have passed into the strait of Georgia 

 from the rivers that empty into it do not go out to the open sea but instead wa-nder 

 aboiut in the inner waters in search of food. 



The five species are considered in much the same way as in the previous paper 

 although the same amount of detail was not considered necessary. On the other hand, 

 the po'ssihility of comparing each species in the two years has somewhat enlarged the 

 field. 



Spring Salmon. 



As in previous years, it was not possible to get many spring salmon that could be 

 definitely assigned to any particular river-system. Some Fraser river fish were 

 obtained but as, in general, these were on the cannery floor with others caught 

 elsewhere, they could not be separated with certainty. Specimens obtained at 

 Quathiaski cannery and from the Lasqueti island cannery are included, but as they 

 were few in number and as the areas from which they were received, approach or 

 overlap the Nanaimo cannery area, it was scarcely worth while to consider them 



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