128 SALMON AND TROUT. 



9. In at least many cases, smolts thus migrating to the sea 

 in May and June return as grilse, sometimes within five, 

 generally 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 November or 

 December — go back to the sea — and (in many cases) reascend 

 the rivers the next spring as salmon, with a further increase of 

 from 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. 



10. It appears certain, however, that 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. 



\Note. — It will tlius be seen that the fry of salmon are called /arrj until 

 they put on their migratory dress, when they become smolts and 

 go down to the salt water ; grilse if they return from the sea during 

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



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

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

 they were bred — sometimes to the identical spots — spawn 

 about November or December — and go down again 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 from seven to 

 ten pounds. 



[^A't;/*. —Shortly before spawning, and whilst returning to the sea as 

 kelts, or spent fish, salmon are unfit for food, and their capture is 

 then illegal. ' Foul fish ' before spawning are, if males, termed red 

 fish, from the orange-coloured stripes with which their cheeks are 

 marked and the golden orange tint of the body ; the females are 

 darker in colour, and are called black fish.] 



The foregoing still represents, in a condensed form, our 

 positive knowledge as regards the leading facts of salmon 

 history. 



The irregular return of salmon from the sea, referred to in 



