THE SALMON. 179 



year, and without smolt scales they will not migrate, and cannot exist in 

 salt water. 



"8. The length of the parr at six weeks old is about l|in. or 2in., 

 and the weight of the smolt before reaching the tidal wave from loz. 

 to 2oz. 



"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 21b. to 

 lOlb., the average being from 41b. to 61b., and these grilse spawn 

 about November 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 from 41b. to 121b. Thus a fish hatched in April, 1854, and marked 

 when migrating in May, 1855, was caught as a salmon of 221b. weight 

 in March, 1856. 



" 10. It appears certain, however, that smelts do not always return 

 during the same year a grilse, but frequently remain nine or ten months 

 in the sea, returning in the following spring as small-sized salmon. 



" Note. It will thus be seen that the fry of the salmon are called parrs 

 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 

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



"11. It has been clearly proved that in general salmon and grilse find 

 their way back to spawn to the rivers in which they are 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 of weight of from 71b. to lOlb. 



" Note. 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 their bodies. The females are darker in colour, 

 and are called black fish. After spawning the males are called kippers 

 and the females shedders or baggits." 



Before passing from the general subject of this fish's natural history 

 it becomes necessary to make some rather extended remarks on the 

 diseases to which it is liable. I shall not pretend to be exhaustive on 

 this branch of the subject, but rather suggestive, whilst at the same time 

 I desire to impress on my readers the importance of the subject which 

 the recent history of fish diseases seems fully to imply. In an earlier 

 chapter I have given some particulars of piscine diseases which, as the 

 reader will see, are chiefly parasitic. I did not then do more than hint 



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