of the Fishery Board for Scotland. 



21 



APPENDIX II. 



THE SCALES OF SALMON. 

 By H. W. Johnston. 



[Fourth Paper. ~\ 



My three previous papers * on the scales of salmon may be supple- 

 mented by some notice of more recent developments. 



" Wired " Smolts and Maiden Salmon. 



In the Twenty-third Annual Report for the year 1904, it was pointed 

 out that the scales showed that some smolts returned as grilse in the year 

 following their migration, and that others prolonged their stay in the sea 

 and came back in later years as mature salmon of various ages. The two 

 papers afterwards published related how the recapture of smolts which 

 had been marked with a wire in 1905, confirmed the deductions from 

 scale examination as far as was possible up to the time of writing, viz., to 

 the stages of summer and autumn fish taken in 1907. Particulnrs of a few 

 additional recaptures of fish of the same marking, caught as spring salmon 

 in 1908 when also on their first return to the river after approximately 

 three years spent in the sea, have since been published, f 



One of these "wired" spring fish, caught in March, 1908, weighed 

 35 lbs., so that it had approximately gained one pound for each month 

 spent in the sea, thus maintaining the same rate of increase that was 

 shown in the case of the " wired " 27-pounder recaptured in the previous 

 August, one of whose scales was illustrated in the Twenty-sixth Report. 

 I regret I have been unable to obtain any scales of the 35 lb. spring fish 

 (though one is represented in Mr. Malloch's book); but to continue my 

 series a photograph of the scale of another spring salmon of similar weight, 

 age, and history is now given. 



It will be understood that there is no doubt that very nearly all the 

 " wired " recaptures hitherto mentioned (including the large spring fish of 

 1908) were on their first return, or were, as we may term them, maiden 

 salmon. Had they before been in fresh water for spawning purposes, 

 their great rate of growth would have been still more remarkable. 



As previously stated, the examination of the scales of still older salmon 

 led me to believe that they were in many cases revisiting fresh water for 

 the first time, and when it is considered that the number of smolts 

 " wired " in 1905 was limited, and that the proportion of the old and heavy 

 fish in the total annual catch is small, it will be apparent that there may 

 be some difficulty in securing a "wired" specimen of a maiden salmon of 

 six, seven, or eight years old. The present seems, therefore, a fitting 

 opportunity to judge how the lessons drawn from scales as stated in the 

 Report for 1904 have been actually borne out by recaptures of smolts 



* Twenty-third Annual Report for 1904 (Part II., App. II.). 



Twenty-fourth Annual Report for 1905 (Part II., App. II.). 



Twenty-sixth Annual Report for 1907 (Part II., App. III.), 

 t " The History and Habits of the Salmon, &c.," by P. D. Malloch. 1910. 



