b4 



The Salmon 



smolts until the\" return as grilse in May or June ot the iollowing 



year, or it may be two to six months 

 later. If, then, a smolt returns on 

 ist June, after being one year and 

 two months in the sea, how manv 



sho 



ulcl 



It 



ha\'e on its scales r 



^? 



On examining the scale we finci there 



o 



are titty-one rings on it : the same 

 result woukl ha\'e been got b)' multi- 

 plying the age of the fish — 3/;; years — 

 by 16, the number ot rings which are 

 added each year. I here take ist June, 

 because this was the date on which 

 our hrst wired grilse was caught from 

 those which were marked the year before. 

 I give enlarged photographs (Figs, ^j to 63) taken each 

 month from a scale from 



Fig. 57. 



i:J lbs. 4lh May 1907. 

 Xoilh Esk. 



one of these wired grilse, 

 which clearly show the 

 increase in the number 

 ot rings as the season 

 advances. I have also 

 made out a table show- 

 ingf the number of rino;s on 

 the scales at the different 

 ages. This table will be 

 found to be fairly accurate, 

 taking one month with 

 another. There may be a 

 difference of one or two 

 ring-s according; to the feed- 

 ing- in the sea being better 



5S. 



Uk. 41I1 Mav iQCHi. Nintli l-'„sk. 



in some months than others : but if more rings than usual are 

 added during any one month, the fewer are added in some of 



