86 
there lies that beautiful silvery membrane, or skin, which makes 
its appearance so attractive as it is exposed on the slab. I his 
silvery membrane has the power of reflection, as a looking-glass, 
which is very valuable to the fish as it lies on the bottom of a 
pool in the river, for it reflects the colour of the surroundings, 
such as rocks, etc., and so disguises the appearance of the fish 
from its enemies. Speaking from my own experience, it is by 
no means easy to detect a salmon lying at the bottom of a river, 
unless it turns its silvery side up towards the rays of light. 
Now in order to understand the history of the fish as stamped, 
so to speak, upon its scale, it is necessary that the student should 
have some knowledge of the habits of that fish, for in the case 
of the salmon, which passes part of its life in fresh water and 
part in salt water, these changes of condition are so well marked 
on the scale, as to enable anyone who has had some little 
experience in the study of fish-scales, to tell with accuracy how 
many years the fish has passed in fresh, and how many 
vears it has passed in salt water—how many winters it has passed 
in the sea—and, more important than all, whether it has spawned 
and how many times. 
For the benefit of those who have no intimate ideas as to 
the average life and habits of a salmon let me briefly give a 
short description. 
Salmon, as most people know, are anadromous. They 
approach, our coasts from the sea at certain times of the year 
to go up our rivers for the purpose of propagating their species, 
-and it is a remarkable thing that whereas the salmon has to 
seek the fresh water for depositing and hatching its 
ova, for the reason that salt water would destroy the vitality of 
the eggs of this fish, so the ordinary freshwater eel, found in 
our rivers, is obliged to go down to the sea to deposit its spawn 
in the deepest portions of the ocean. 
To return to salmon, the ova are deposited in the beds of 
rivers Avhere water flows with rapidity, and these spawning beds 
are called “ redds.” After some weeks, hatching commences, and 
for a period of two years the young fish so hatched remain in the 
fresh water of the river, at the end of which term they are called 
“ smolts.” This portion of the fish’s life is well marked upon 
the scales. 
At the end of the two years the smolt by natural instinct pro¬ 
ceeds down the estuary of the river, and goes straight out to sea. 
This is called the migration of the smolt, and by experiments on 
the River Tay it is found that these smolts congregate like a 
flock of sheep, and make their migration to salt water in big shoals. 
Some return the following year, in most cases to the river where 
they were hatched. Others come back in the second year after 
migration, whilst others remain in the sea for a still further 
period, until the spawning instinct compels them to visit our 
shores and ascend our rivers for the purpose of propagation. 
