FRESH-WATER TROUT— HABITS. 205 



while others in the same water appreciate a different sustenance, and consequently 

 are not thus tinged ; if the gillaroo eats shells, occasioning thickening of the 

 middle coat of its stomach, while such diet, as a rule, is rejected by the common 

 variety of Salmo fario ; it appears to point out that the tastes of some difPer from 

 those of their companions, while it is a well-known fact that certain forms of food 

 promote fish-growth more rapidly than others. As already observed, those trout 

 which principally subsist upon fresh-water shrimps, Qammari, are generally of the 

 most brilliant tints, and the most pinky-coloured flesh, while vegetable diet 

 appears to mostly cause a silvery hue and sometimes a dull appearance.* 



and introduced to a chain of loohs in the same county, which have their sources in innumerable 

 springs of clear water from granite and limestone mountains — principally the former, as the 

 limestone for the most part lies at a lower level — became in a single year silvery and covered with 

 minute bright scales like sea trout, and grew to the size of 1 lb. weight in twelve months from at 

 most J lb. This experiment was made by our fishing party in 1877-78-79. The specimen first 

 caught after the introduction in 1878 is preserved in the collection of Dr. W. M. Mackintosh, of 

 Murthly. The food in this loch are shell-fish and tadpoles, and the bottom is granite, gravel, and 

 sand. On the other hand, trout are often caught in sandy lochs or bays at far inland localities 

 which present nothing of this silvery character at all. Thus those of the sandy or granitic pebbly 

 bays of Loch Erroehd, in Perthshire, are golden yellow trout. 



" But to return to North TJist. In most, if not in all, of the sandy-bottomed lochs of the west 

 coast the trout are more or less silvery. We do not with certainty know the favourite haunts of 

 the sea trout and other migratory fish whilst in the sea, but it is not, perhaps, unreasonable 

 to suppose that sandy bays, or patches of sand amongst the rooks, give them most harbourage 

 whence, perhaps, their silvery colour, which they rapidly lose upon entering peaty or rocky 

 streams and lochs, and never perfectly recover until they return to the sea. 



" In many of the larger lochs of North TJist — as, for instance, Loch Ghearn in the west and 

 Loch Scatavagh entering from the east, where the sea has regular or occasional access, sea trout 

 are known to ascend, but many, if not aU, fail to return to the sea. These fish, however, do not 

 easily succumb and die, but live, at all events for a considerable time, but are seldom caught in 

 good condition. Such fish are taken at all seasons of the year. In some lochs no doubt they do 

 finally succumb. Loch Soatavagh is a very large loch, and swarms with small iU-oonditioned 

 brown trout. All these lochs where the sea trout fail to return to the sea are rocky and intricate 

 in their shore-lines. The general behef amongst the natives is that the sea trout and bull trout 

 which ascend lose their way, and cannot again find the exit, or, in some oases, enter during high- 

 water tides, and cannot escape during the lower summer tides. 



" Now, in Loch Hosta and other lochs on the west coast, which either have regular or occasional 

 connection with the sea, or which, like Loch Hosta itself, had at one time communication, and 

 the banks and bottom being sandy or loamy, and having better feeding, it seems just possible that 

 sea trout ascending to these lochs in former times, or in exceptional and occasional times at 

 present, may have become acclimatized and have added to their stature, and even changed their 

 nature and appearance, and multiplied in number. It is evident from the sea levels at various 

 localities along this west coast of Uist, that one of two changes has taken place. Either the land 

 has actually risen, or, what appears more likely, the laud has gained upon the sea by reason of 

 the shifting sand upon the coast. Below Newton Farm the former sea level — ^remembered by 

 people still, or lately, living — ^is remarkably patent. 



" In the same way Loch Hosta has become sanded up at its exit, or at least sufficiently so to 

 prevent sea trout from ascending the shallow sand-stream which still unites it with the sea. 

 The present tides rise to within a hundred yards of Loch Hosta, but no sea trout enter it 

 now, though there is every reason to believe they must once have done so. At present, even 

 during a spate coming down the burn, sea trout could not get up, as the water debouches upon 

 the level sand and spreads all over it, having no defined channel. 



" Questions arise regarding these sandy lochs and their inhabitants which are curious, if not 

 also instructive. 



" At one time in the world's history possibly, indeed probably, not very remote — I speak in the 

 geological sense of remoteness — some of these lochs must have been bays of the sea. The 

 small, ditch-Uke burns now entering them show no appearance of ever having been any larger 

 than they now are, and in most cases are too insignificant to harbour the smallest adult brown 

 trout even at the present time. Hence comes the question, How came these lochs, once bays of 

 the sea, to be inhabited by Salmo fario ? 



" In the island of Barra, on the west coast, is a loch famous for the quality and beauty of its 

 trout, which are said by Wilson to resemble exactly the famed Lochleven variety. Mr. Wilson 

 says : — ' This loch, called, we believe, Tangtetal, has one side of its shores fiat, shallow, and 

 sandy, while the other is, at least in parts, more stony and abrupt.' Describing the trout further, 

 he calls them ' trouts of outward pearly lustre, and flesh of roseate hue.' 



" Another question is, have the sea trout (which at a remote date entered these sandy, loamy 

 lochs) all died out, or have the fittest survived their change of residence and confinement to 

 fresh water, reproduced, and in course of ages changed their nature and appearance to suit the 

 new conditions 1 " 



* T. Dougal, Fishing Gazette, May 29th, 1886, remarked that " I have frequently seen well- 



