io8 THE SEA-TROUT 



which I have seen measuring lo^ inches in length. In the same way 

 some of the Loch Lomond whithng appeared to me to attain excep- 

 tional growth. It had occurred to me that the question of age, as well 

 as questions of diet, might have some bearing upon the matter, but it 

 was not till the autumn of 1914 that the matter was made fairly clear. 



Early in 19 14 Mr. J. Arthur Hutton was kind enough to say that if 

 1 would collect for him a series of scales taken from Loch Lomond 

 sea-trout he would devote some of his leisure to making a special study 

 of them, as the facts derived from such a study might help to throw 

 some light upon the various problems which would certainly arise in 

 course of the inquiry which I was undertaking. I need hardly say 

 how valuable such an offer in the circumstances appeared to me to be 

 and I gratefully availed myself of it, collecting as I did for Mr. Hutton 

 during the season of 1914 a series of scales taken from 45 sea-trout in 

 various stages of growth and in different states of physical condition. 

 Mr. Hutton was further so kind as to place at my disposal such data 

 on this subject as could be gleaned from other sets of sea-trout scales 

 in his possession. Notwithstanding that he has cautioned me against 

 rating his experience of the reading of sea-trout scales too highly, I 

 myself have no real doubts as to the substantial accuracy of his scale 

 interpretations, more especially as these are borne out by the results 

 obtained by Mr. Knut Dahl with respect to Norwegian fish. 



On the particular point, then, as to the time of descent of the sea- 

 trout smolts as indicated by the scales, Mr. Hutton finds — and in his 

 company I have confirmed his "readings" — that of the 45 Loch Lomond 

 fish none descended after only one winter spent in fresh water. Mr. 

 Hutton further informs me that of all the sea-trout scales he has 

 examined, including scales of fish from several rivers in Norway, from 

 the Wye, and from South Uist, he has not come upon a single instance 

 of a sea-trout having migrated to the sea after only one year's fresh- 

 water life. The periods of actual descent, following Mr. Knut Dahl's 

 method of tabulating the facts, may be shown thus : — 



