112 THE SEA-TROUT 



descent " of the salmon smolt, though not absolutely constant, is, in 

 Scotland, in the great majority of instances in the spring months after 

 two full years' residence in fresh water. But if the young sea-trout 

 voluntarily remains in fresh water, as the scales seem to indicate, for 

 three, four, five, or (in Norway) actually six years, how much more will 

 it be likely to retain a " trout-like appearance "? To all seeming it is 

 quite content to remain a trout for an indefinite period, or, to put it 

 another way, the migratory habit takes a somewhat indefinite number of 

 years to declare itself. While this instinct or habit remains dormant, 

 the sea-trout is to all intents and purposes rather a miserable specimen 

 of a trout which will not develop generous proportions till it gains the 

 richer feeding grounds and more extended range of the sea or estuary, 

 just as the puny occupant of a mountain tarn will never develop in such 

 a habitat, but will, if removed to richer feeding grounds in a wider 

 range of water, at once begin to gain in bulk and appearance. Most 

 readers will be aware of some instance where such a result has followed 

 upon the transplanting of trout. For a curious example noted by Mr. 

 Knut Dahl I may refer the reader to pp. ']'] and 78 and Fig. 33 

 (Plate X) of his work already noticed. 



In this connection I think that the Howietoun experiments described 

 in my introductory chapter have some relevancy, and I would ask the 

 reader again to study the account given of them with some care. The 

 points material to the history of the sea-trout — and to Mr. Regan's 

 theory — may for convenience be here again noted : — 



1. That the Howietoun sea-trout parr lived in fresh-water quarters 

 for four years without any apparent discomfort; 



2. That in their third year critical observers could not distinguish 

 them from common trout; 



3. That in their fourth year the females inter-bred with Loch Leven 

 males; 



