358 



LAKES AND STREAMS 



salmon the hind border of the tail-tin is more notched than in the sea-trout, but this 

 difference tends to disappear with age. Differences between the two species are also 

 stated to occur in the form of the gill-cover, but these do not seem to be constant. 

 Often mistaken for salmon, sea-trout spend much of their time in the North 

 Sea and the Baltic, but, like the two foregoing species, spawn exclusively in rivers. 

 The lordly salmon (S. solar) is easily recognised by its size, the bluish grey back, 

 the silvery sides marked with few black spots (which may sometimes be wanting), 

 the silvery under-parts, and the dark grey fins. This noble fish is an inhabitant of 

 the northern parts of the Atlantic, but is unknown in the Mediterranean and the 

 Black Sea, and at the commencement of the spawning-season leaves the sea to 

 ascend the larger rivers, where, if salmon-ladders be not placed to assist its ascent, 



it often leaps appar- 

 ently impassable weirs 

 with comparative ease. 

 It has been stated 

 that salmon do not 

 feed while in fresh 

 water, being afflicted 

 during their sojourn 

 in rivers with a disease 

 of the lining mem- 

 brane of the aliment- 

 ary tract; but later 

 observations discredit 

 the correctness of this 

 view, evidence having 

 been adduced that 

 river-salmon catch and 

 digest minnows and 

 other fish. The pre- 

 sumed disease of the 

 lining of the stomach 

 is stated to be owing 

 to the fact that the fish examined were not sufficiently fresh. Still, the fact is not 

 disputed that, during the time spent in fresh water, salmon maintain themselves to 

 a very considerable extent on the store of fat accumulated in their tissues during 

 their marine life. During the spawning-season, which lasts from eight to ten days, 

 the female burrows with the flat part of her snout in the loose gravelly bed of the 

 river, to form a receptacle for the spawn ; and for some time after spawning, the 

 'fish are thin and unfit for table. The voracity of this fish corresponds with its 

 growth and the strength of its teeth. 



Very distinct is the charr (S. salvelinus), which inhabits the deep mountain- 

 lakes of central and northern Europe ; it is a small species, often brilliantly coloured 

 with orange beneath. The northern charr (S. alpinus) is confined to northern 

 Europe, including Iceland, and the north of Scotland ; S. u-illughbii is only known 

 in Windermere; S. killinensis in Loch Killin, Inverness-shire; and S. grayi in 



■ 



THE RIVER-TROUT. 



