266 FLY FISHING AND SPINNING 



quantities for its full development. In the abundant 

 larder at its disposal in the salt water the crustacean 

 figures largely, and there can be no doubt that it is from 

 such food that its body as well as its skeleton, is increased 

 so prodigiously.* 



THE QUESTION 



Is it the salmon which has successfully spawned once, 

 regained its condition, and developed a fresh batch of ova, 

 that is once again able to spawn ? or is it only the salmon 

 that has failed in its attempts to spawn in a natural 

 manner, which re-attempts in some following season, with 

 a new batch of ova, the difficult and dangerous ascent 

 to the spawning ground ? 



At present the signs of irregular decrepitation having 

 destroyed a certain number of the concentric markings on 

 the former edge of a scale, are considered by some of the 

 men to whom we owe most of our present knowledge, to 

 indicate that the salmon to which the scale belonged has 

 spawned. While fully recognizing the great value of their 

 patient investigations in this new study, as I said before, 

 I yet venture to think that such data fails to prove more 

 than the fact that the salmon has undergone genital changes, 

 entered fresh water, and approached a spawning condition, 

 but not that it has found a mate, and spawned under 

 favourable circumstances. 



The importance of determining this question must be 

 evident if scale reading is to form an exact datum on which 



* Calcium salts, i.e., lime salts, form a not inconsiderable portion of the 

 scales of a salmon. Miss Esdaile, who has devoted so much time to this 

 subject, has been kind enough to criticise some portion of this chapter, and 

 still further added to her kindness by writing to the author, on the gth 

 February, 1914, as follows : 



" When the calcium has been removed the scale appears to be 

 unchanged in shape and size, its markings are still clearly visible, and 

 the unevenness of the surface of the scale is still to be felt." 

 This indicates that while scale matter is composed partly of lime salts, 

 other materials go to form the base of its structure. 



