102 THE LIFE OF THE SALMON 
as grilse but remain in the sea till the grilse stage 
is past are of course still maiden fish, and after 
entering such a river as the Tay as small spring 
salmon will spawn a year later than their fellows. 
They merge into the run of 10-16 lb. summer fish 
of the Tay which have completed their two annual 
rings. The summer class of fish are, however, apt 
to be mixed in a large river like the Tay, as we 
have now reached a stage in the salmon’s develop- 
ment when fish which have previously been in the 
river as grilse and which have spawned and de- 
scended for the short period of marine sojourn may 
be once more in the river. The proportion of such 
fish is, however, comparatively small, at least in the 
large rivers of Scotland. 
The study of the scales has prominently called 
attention to the infrequency of spawning amongst 
heavy fish. It comes as a surprise, for instance, to 
learn that very many of the large spring fish of the 
Tay—fish almost invariably about 20 lb. in weight 
—have never spawned. The scale shows the third 
annual ring in course of formation subsequent to 
the two-year-old smolt stage ; 7.¢., they are approxi- 
mately five years, yet their scales bear no spawning 
mark. They are entering fresh water for the first 
time, although many fish of smaller size have 
already propagated their species. Such information 
makes us realise with additional force the value of 
protecting fish when they do breed. 
Now let us deal with the records of adult salmon 
marked in fresh water as kelts and subsequently 
recaptured as clean fish. And first I will take the 
