12 ESDAILK, Results of the Salmon Scale Research. 



tissue. Their weight, therefore, was becoming reduced, 

 and as the length could not become less, the ratio of 

 length and weight would naturally be higher, and hence 

 the maxima observed in the curves for 1911. 



After consultation with mathematicians, I find that the 

 records were not taken with sufficient accuracy to render 

 the second place of decimals absolutely reliable. However, 

 I have not left it out, as it would only mean a modification 

 of the curves and would not materially change their 

 direction. 



Coming next to the consideration of the scales of 

 those fish which are on their second visit to the river and 

 have spawned in a previous season, we are confronted 

 with, probably, the most difficult, but, at the same time, the 

 most interesting part of the whole question of the 

 life-history of the salmon. The first point which should 

 be noticed is the small proportion of fish that have 

 previously spawned. This is, however, a fact which is 

 by no means new, previous workers having commented 

 upon the infrequency of spawning in the salmon. 

 Calderwood (9), (10), (ll), Hutton (i2\ (13), Esdaile (i). 



It is now generally accepted tliat tlie salmon does not 

 take any regular nourishment during its sojourn in the 

 rivers previous to spawning, and this fact in itself may 

 afford one very good explanation for the infrequency o 

 spawning. As a general rule, when there are long periods 

 of fasting during the life of an animal there is hibernation, 

 or at any rate a prolonged sleep or state of quiescence. 

 But in the salmon the period of fasting is probably the 

 most strenuous time of its life. Every time this problem 

 is discussed new evidence is accumulated to prove that 

 the spawning salmon are of much more importance for 

 the fishery than was realised some little time ago. The 

 old idea that the salmon returned to the river year after 

 year and was the dutiful and self-sacrificing parent of 



