162 THE CHANGE INTO THE SMOLT 



only attempt approximate conclusions as to the times 

 at which the parr of any particular season's hatch 

 change into the smolt, or as to the sexes affected at 

 the various times of this change. It may be assumed 

 that the meteorological conditions affect the periods 

 over which the parr stage extends, and it is not im- 

 probable that the male parr is, as a rule, the first to 

 leave that state. 



One reason for this may be that the male parr is 

 physiologically more advanced than the female. 

 It has been proved that a 2-ounce male parr is 

 quite capable of fertilizing the ova of a full-grown 

 salmon of 30 pounds weight, but the female parr or 

 the female smolt does not spawn until its return 

 from the sea. I venture to suggest, therefore, that it 

 is not improbable that, under favourable conditions, 

 if it be assumed that the sexes are evenly divided in 

 each hatch, then about 80 per cent, of male parr 

 will undergo the smolt change and migrate during 

 the first succeeding spring that is, out of 100 

 male and female parr, 40 male parr will migrate 

 in one year ; that 80 per cent, of both sexes remain- 

 ing, or 48 fish in every original 100 fish, will migrate 

 as smolts during the autumn or in the second spring, 

 and the balance left behind, about 12 in every 100 of 

 each hatch, will migrate in the following autumn, 

 or in the third spring after being hatched. 



Smolts migrate during the autumn months, but 

 beyond this being known as a fact no absolute know- 

 ledge has so far been obtained as to the numbers, 



