1 70 Natural History of the River Trout, 



will lose his colour, and will assimilate to those 

 around him. May not, therefore, these so-called 

 varieties be attributed almost entirely to the effect 

 of light and food? The different kinds of food, 

 acting in a greater degree on the colour of the 

 flesh, and in a less degree on the colour of the 

 skin, whilst the effect of light acts in a greater 

 degree on the colour of the skin, and less on the 

 colour of the flesh/ 



In many of the Lochs in Scotland the trout vary 

 in colour. In three adjoining Lochs on Craig Muir 

 Arisaig, all stocked in 1864 from Loch Morar, se- 

 parated only by a few hundred yards, and at least 

 800 feet above the sea level, with no communication 

 with the sea, the trout are as different in colour as 

 it is possible to be. In one loch they are a beautiful 

 bronze, with yellow belly and dark spots ; in another, 

 dark backs, with red spots and silver bellies ; and 

 in the third, they appear to be a combination of 

 the other two. 



Yarrell, "British Fishes," says: "The trout 



^ I pointed out this effect on the river side to a well- 

 known and experienced fisherman. We had taken some 

 very fine fish — three pounds, two pounds and a-half, etc., in 

 a certain river where the water was deep, and rather sluggish, 

 and a muddy bottom. Every fish was beautifully silvery, 

 with black spots. On the shallows and gravelly streams 

 in the lower part of the river, every fish was red spotted — 

 some of these almost as large as those taken in the deep 

 water. 



