1 68 Natural History of the River Trout, 



Colour of Trout : how produced. 



All fly-fishers know well how trout vary in 

 external colour, and in their flesh, and often in the 

 same river. Some, with dark backs, silver sides, 

 and black spots ; others, splendid fellows, with 

 yellow sides, with red spots predominating. In 

 the Chess, for instance, the fish in the mill-head and 

 still water above are, for the most part, of the 

 former type. Below the mill, they are of the 

 latter. The first have pink flesh ; the second, 

 yellow. In the Kennet — near Marlborough, in the 

 Savernake water — the trout appear to be of the 

 two varieties. Lower down, at Ramsbury, equally 

 fine, but more red spotted. The same at Littlecote. 

 Also in many other rivers the same difference is 

 found. Sir Humphry Davy, in " Salmonia," p. 30, 

 attributes the silvery colour to the nearer approach 

 to perfection : — " The colour of the body becomes 

 more uniform — pale olive above and bright silver 

 below — and these qualities are always connected 

 with a small head, oval body, and deep red flesh." 

 He thinks this condition very much depends on the 

 food. At p. 36 he says : ** I think it possible when 

 trout feed much on hard substances, such as larvae 

 and their cases, and the ova of other fish, they have 

 more red spots and redder fins. This is the case with 



