62 THE LIFE OF THE SALMON 
In dealing with the question of the short and the 
long periods of sojourn in the sea, only one class of 
particulars are reliable, the returns of fish marked 
when kelts after spawning and recaptured as clean 
fish in fresh waters or the mouths of rivers after the 
termination of their sojourn in the sea. It happens 
that in a combination of the Scottish and Irish 
returns there are 117 recaptures of this class which 
can be dealt with. In the following tables these 
are separated into groups according to the years of 
marking and recapture ; the records of fish marked 
in certain rivers are placed together, and all fish of 
short period are separated from fish of long period. 
The details extracted are the numbers of the marks, 
the intervals of time given in months, the increase 
in weight, and the weights of the kelt marked. 
Scottish and Irish results are given in parallel double 
columns. 
