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 IT. 
