GROWTH OF THE SALMON. 297 



ROYAL SOCIETY OF EDINBURGH. 



January 9th, 1843. — The following communications were 

 read : — 



1. " On the Growth of the Salmon," by Mi\ John Young, 

 Sutherlandshire. 



Mr. Young has hei'e taken up the subject of the salmon's 

 growth where it was necessarily left off by Mr. Shaw. So far 

 as the earliest or fresh- water state of the fish is concerned, he 

 entirely agrees with the observer just named. He then states 

 the various opinions which prevail regarding the more or less 

 rapid growth of smolts and grilse, and shows, by tabular lists 

 (the result of frequently repeated experiments), that the in- 

 crease in their dimensions is extraordinary, so soon as they 

 descend into the salt water. So far back as the months of 

 April and May, 1837, he marked a number of descending 

 smolts, by making a peculiar perforation in the caudal fin by 

 means of small nipping-irons constructed for the purpose. 

 He recaptured a considerable number of them ascending the 

 rivers as grilse, in the course of the ensuing months of June 

 and July, weighing several pounds each, more or less, ac- 

 cording to the diiference in the length of their sojourn in the 

 sea. Again in April and May, 1842, he marked a number of 

 descending smolts, by clipping off the little adipose fin upon 

 the back. In June and July he caught several of them re- 

 turning up the river, and bearing his peculiar mark, the adi- 

 pose fin being absent. Two or three specimens were exhibited 

 to the Society. One marked in April, and re-captured on the 

 30th of July, weighed three and a half pounds. 



As the season advances grilse increase in size, those being 

 the largest which abide the longest in the sea ; they spawn 

 in the rivers after their first ascent, and before they have 

 become adult salmon. 



]Mr. Young also described various experiments instituted 

 with the view of showing the transition of grilse into salmon. 



