lOO THE SEA-TROUT 



It is probable that some one or other of the distinctions thus 

 tabulated will help the reader to discriminate in most waters between 

 salmon, sea-trout and trout when in the " parr "" stage of growth. It 

 remains to point out the special characteristics of the smolts of salmon 

 and sea-trout. 



One cannot well speak of the .smolt of the common trout because, 

 while individuals of the type known as Saliiio fario seek the sea 

 and in doing so assume a silveriness of scale beyond the normal, 

 their migration is never so marked or so periodic as to constitute a 

 feature of their career. But it is curious to note that trout are commonly 

 more silvery in spring than at other seasons of the year. How far this 

 may suggest preparation for a possible migration, and how often that 

 migration may actually be effected it is not very easy to decide. In 

 circumstances where environment specially favours migration it may, 

 as we shall see, very commonly occur. I apprehend that if and when 

 such a descent does occur the descending trout will be indistinguishable 

 from descending sea-trout smolts. In this connection I submit a plate 

 of a Loch Lomond trout (Plate VI) in which the first figure shows the 

 complete silvery dress while the second figure (of the same fish) shows 

 the silvery scales partially removed. The scales of this fish, which was 

 caught towards the end of May 19 15, showed that it had just commenced 

 feeding freely in its third year. Assuming my drawing to be approxi- 

 mately accurate it may readily be conceived that the difficulty of 

 distinguishing a Loch Lomond trout from a sea-trout is extreme, but 

 my own opinion, based very much upon the appearance of the exposed 

 skin surface that this fish was actually a trout, was confirmed at the time 

 by the opinion of several of the most experienced Luss boatmen, and 

 of the manager of Luss Hatchery. 



The salmon smolt can hardly be mistaken. It is seldom less than 

 six and a half-inches in length and seldom more than seven and a half 

 inches. It is of the most brilliant silvery sheen, the general body colour 



