104 THE LIFE OF THE SALMON 



spring of 1906, and was caught on the date already 

 given. 



This Hehnsdale fish is typical, and the photo- 

 graphs show more plainly than any description can 

 do the characteristic appearance of the kelt and 

 adult clean fish scales. The magnification is in each 

 case 12 diameters. The additions G. and H. on 

 the later scale may appear slight in compari- 

 son with those seen in the kelt scale, but it is to 

 be recollected that as the age of a salmon increases 

 the rate of growth decreases. The first two summers 

 in the sea invariably show the greatest growth in 

 the fish. 



Evidence from scales of fish which have been 

 marked and recaptured is evidence of the most 

 reliable kind, and several instances might be cited 

 similar to the Helmsdale fish marked 1180. On 

 account of the nature of the evidence also, I consider 

 that there need be no hesitation in deducing evidence 

 from scales of fish for which no marking record is 

 available, provided always that the observer has a 

 competent knowledge of the subject and the scale 

 be taken from a suitable part of the fish, e.g., the 

 " shoulder." 



With regard to the number of lines which will be 

 found on the scales of fish of different ages, it may 

 be said that from marked kelts recaptured as clean 

 fi.sh, a scale having been obtained only at time of 

 recapture, Mr. Johnston has found that after the 

 smolt stage is passed a grilse may add 25 to 28 lines 

 the first year ; if then it enters the river to spawn 

 as a grilse the lines will vary according as it enters in 



