THE LIFE-HISTORY OF THE SALMON. 283 



It is noteworthy that within the last thirty years, probably 

 less, our notions of the life-history of this fish have been greatly 

 modified, especially as to its sojourn in the sea. Thus during 

 the twenty-three years — from 1860 to 1882 — the prevailing 

 opinion was that some of the young (called Parr) became 

 silvery fishes (Smolts) at the end of the first year, which Dahl 

 still holds is the rule for Norway, and that all became so at the 

 end of the second year, and migrated to the sea. Further, that 

 after a sojourn in the sea of a few months they returned as 

 Grilse of some pounds weight (1|- to 5) to their native rivers. 

 This view (as to the speedy return from the sea) was held to be 

 proved by the capture of those from which the " fatty " fin had 

 been removed on their issue from Stormontfield ponds. There 

 can be no doubt that my old friends, Mr. Eobert Buist and Mr. 

 William Brown, were quite right in holding that the "fatty " fin 

 is not reproduced ; but, on the other hand, it may be asserted 

 that other agencies than scissors might have bereft a few of this 

 organ. The modern method of placing a loop of silver wire in 

 the dorsal fin admits of no doubt, and it has now been shown 

 that the young Smolts remain a year or more (three) in the sea 

 before returning to their early haunts to spawn. It is held, 

 indeed, that some are fishes of considerable size before leaving 

 the sea— where, of course, it is impossible for them to spawn, 

 and these constitute the various runs of Salmon so well-known 

 to tacksmen and to careful observers like Mr. Calderwood, 

 Mr. Moreton Frewer, Mr. Malloch, the late Mr. John Dickson, 

 of Perth, and others. 



Quite recently, also, the intimate structure of the scales of 

 the Salmon at various ages has facilitated more accurate know- 

 ledge of its age and habits. When dealing more than fifty years 

 ago with the Salmon of the Tay and figuring the scales of 

 Salmon and of Smolt, it was pointed out and figured that the 

 concentric rings in the latter were few, and that there was 

 scarcely a blank at the free end ; whereas in the former the 

 rings greatly increased in number, and the smooth portion at 

 the free edge was of considerable size. The question of grouping 

 the rings into annual series had not then been inquired into, 

 and the spawning mark was unknown. (Figs. 1 and 2.) 



Becently many writers have devoted special attention to 



z 2 



