History and Habits 7 



IX. In at least many cases smolts thus migrating to the 

 sea in May or June return as grilse sometimes within five, gen- 

 erally within ten weeks, the increase in weight during that 

 period varying from two to ten pounds, the average being 

 from four to six pounds, and these grilse spawn about Novem- 

 ber or December, go back to the sea, and (in many cases) re- 

 ascend the rivers the next spring as salmon with a further 

 increase of four to twelve pounds. Thus a fish hatched in 

 April, 1854, and marked when migrating in May, 1855, was 

 caught as a salmon of twenty-two pounds' weight in March, 

 1856. 



X. It appears certain, however, that the smolts do not 

 always return during the same year as grilse, but frequently 

 remain nine or ten months in the sea, returning in the following 

 spring as small-sized salmon. 1 



XI. It has also been clearly proved that, in general, salmon 

 and grilse find their way back to spawn in the rivers in which 

 they were bred, sometimes to the identical spots, spawn 

 about November or December, and go down to the sea as 

 " spent fish " or " kelts " in February or March, returning, in 

 at least many cases, during the following four or five months as 

 " clean fish " and with an increase in weight of seven to ten 

 pounds. 



These " facts " have to be modified to fit the 

 conditions of salmon existence in this country, 

 where the lives of the fish are subject to quite 



1 It will thus be seen that the fry of the salmon are called parrs 

 or parr until they put on their migratory dress, when they become 

 smolts and go down to the salt water ; grilse, if they return during 

 the first year of their migration ; and at all other periods, salmon. 



