96 THE LIFE OF THE SALMON 



closely associated with the under skin in the skin 

 pockets in which all scales lie. In all subsequent 

 appearances it is this covered up portion of the scale 

 which chiefly supplies the records of growth, of 

 migration, and of spawning. The exposed or posterior 

 area of the scale — which is a small portion of the 

 whole — becomes, as life goes on, a mere irregular half- 

 moon shaped area of comparatively featureless surface. 



For our information respecting the scales of the 

 salmon and their interpretation we are indebted to 

 Mr. H. W. Johnston, who in two papers to the 

 Reports of the Fishery Board for Scotland * has dealt 

 with the subject exhaustively. 



The experiments made at Fochabers on the rear- 

 ing of smolts have constantly shown that, even 

 amongst those young fish, food is freely taken during 

 spring and summer, but much less freely taken at 

 other times of the year. Dr. Hoffbauer, who studied 

 the scales of a German carp in 1899, and Mr. Stuart 

 Thomson, who wrote on the periodic growth of 

 cod scales in 1902 and 1904, have each shown that 

 this habit is common to other fishes, and that there 

 is a distinct result in the appearance of the scales : 

 that while summer feeding and growth is in progress 

 the lines or ridges on the scales are added in greater 

 numbers than at other times, and that between the 

 ridges the spaces are greater, and that while the 

 more moderate feeding of winter is in progress the 



* H. W. Johnston, " The Scales of Tay Salmon as Indicative of 

 Age, Growth, and Spawning Habit." Twenty-third Annual Report, 

 Fishery Board for Scotland, Part II. Appendix II. Ibid. "The 

 Scales of Salmon." Twenty-fifth Annual Report, Fishery Board 

 for Scotland, Part II. Appendix II. 



