THE SCALES OF THE SALMONID^E 271 



THE VARYING NUMBER OF RINGS ON A SCALE 



The consideration of this subject would not be complete 

 without a reference to the varying numbers of the annular 

 markings which occur on the scales of a salmon during each 

 summer and winter sojourn in salt water, and also as to the 

 number of bands added to the scale after each series of 

 so-called " spawning marks." 



It has been suggested by Mr. Malloch, that the number of 

 annular rings added to a salmon scale for each year of its 

 life is sixteen. This estimate seems approximately borne 

 out by the scales put forward as evidence by Mr. Malloch 

 in his excellently illustrated book " The Life History and 

 Habits of the Salmon/' 



But while any such particular estimate might perhaps be 

 true as regards the salmon of any one river, or indeed of any 

 one district, yet from the scales I have examined I feel 

 assured that such a thing cannot be accepted as having a 

 general application. 



This however is certain, that when once decrepitations 

 have destroyed the smooth and characteristic edges of the 

 scale of a virgin fish, it will be impossible to estimate 

 how many of such concentric markings have been destroyed. 

 Further, it will be impossible for a correct estimate of the 

 exact number of months which a salmon has spent in salt 

 water between any two succeeding conditions of spawning 

 to be made from scale markings that is, when once the 

 second series of decrepitations have been effected for it 

 will here again be impossible to tell how many or how 

 few of the latest added concentric markings have been 

 obliterated. 



The number of rings which are seen between the two 

 series of so-called "spawning marks" in Plate XXX., does 

 not definitely indicate the proportion of time which was spent 

 in salt water between the spawning seasons, because we 



