RESULTS OF SALMON MARKING 89 
second fish may have spawned in the interval of 
447 days, which is, of course, the interval between 
marking and recapture, not necessarily an indication 
of the length of time spent in the sea. Yet even 
without the second fish we have the first and third 
each with a precisely similar interval, yet one with 
twice the increase of the other. That these bull- 
trout do go to the sea may be inferred from the fact 
that sea lice are commonly found upon them, as well 
as gill maggots, when they come into the river. 
They are by no means confined to the Tay, but occur 
sparingly in other parts of the country. Personally 
I have noticed them also in the Ness, Helmsdale, 
and Dee. Giinther has described them from the 
Beauly, and Parnell.from the Forth. 
The last series of observations on the habits of the 
salmon to which reference may here be made has 
been obtained by the marking and recapture of clean 
run fish. Now the habits of clean run salmon, 
otherwise spring fish, have given rise to much dis- 
cussion, very largely because some rivers contain 
spring fish, while others, for no apparent reason, do 
not. It is proposed in another chapter to deal with 
early and late rivers, and in this rather to deal with 
the habits of the spring fish after it has entered its 
“spring river.” At the outset, however, it seems 
necessary to recollect that the habits of spring fish 
seem to be subject to considerable variation under 
the conditions which obtain in different countries. 
In Norway, Iceland, Lapland, and possibly elsewhere 
clean summer fish ascend freely in snow water. In 
Scotland “‘snaw bree” prevents fish running; by 
