FRESH-WATER TROUT-GREAT LAKE TROUT. 193 



Vm^ctij. Great Lake Trout.* riato VIII, fig. 1. 



Salmn lacustri's, Bcrkenliout's Syn. Ed. 1795, i, p. 79, sp. 3. 

 Sahno fcrox, Jardinc, Ency. Brit. (ed. 7) Art. Anglino-, p. 142, and Edin. New 

 Phil. Journal, xviii, p. 55, and Saliu. pi. iv ; Jenyns, Manual, p. 425; Yarrcll 



by means of a minnow. Small ones removed to a pond attain in about three years to 3 lb. or 

 3h lb. in size, their desh is pinkish, and their flavour said to be excellent. Out of 8 examples, 

 G had no red spots, 1 had them along the lateral-line, and the last had them both on the lateral- 

 line and in one or two rows below it. . , i i i i 



If a trout, normally belonging to a small race, as S. cornuhiensii^, is transferred to a lake or 

 reservoir, as in the one near Penzance, where food is plentiful, it attains a size to which it never 

 reaches in its ancestral stream, showing capacity for growth to be inherent, and called into action 

 by luxuriant living. 



* The great lake trout, or Sahno ferox, appears to be simply a large fish, probably an old one, 

 which prefers to live in lakes at great depths, and, consequently, when residing there is usually ot 

 a dark colour. Eichardson alluded to a variety occurring in Loch Loyal, in Sutherland, of a 

 purplish brown above, blackish gray beneath, and the entire body covered with dark scpia- 

 coloured spots, smallest below the latcral-hne ; being very similar in colour to the exaniple, 

 Plate viii, fig. 1, from Otago, and likewise to a fish from Mulach Corrie, in Sutherlandshirc, 

 where it is termed a gillaroo {see pi. x, fig. 2), but its stomach is hardly so thickened as in Irish 

 examples. It is known as buddagh, or " big fat fellow," in Lough Neagh and some parts of 

 Ireland (Harris, Hist. Co. Down, 1744, p. 236), and as fiadh-hhreac in Gaelic, in the Highlands of 

 Scotland, and is said to be a deep-water form confined to lakes, seldom wandering to rivers or to 

 the sea, mostly taken by trolling though sometimes with a fly. It has been known to return a 

 second or third time to the bait, even after it has been previously hooked and dragged forty or fifty 

 yards. Thompson found one from 10 to 12 lb. weight contained 4620 ova. Its flesh is of a dull 

 orange colour and generally coarse. „ i •. .i. ,, i i i 



Among our earlier British ichthyologists we find that Berkenhout called it the "great lake- 

 trout," 5'. lacustris (under which name it appears in Sampson's Londonderry and Dubourdieu s 

 Co. Down), supposing it to be identical with the continental variety. Jardine and Selby termed 

 ours S. fero.v, the specific name having been chosen to characterize its size and voracious habits. 

 Moreau"(vol. iii, p. 534) placed among the synonyms of Triitta (or Sahno) fario, "La Forelle du 

 Lac Leman, Fario Lemanus •;' and at p. 536 observed, " La Tndte feroce, Trutta Jerox,^ Valenc., 

 des eaux du Foretz est une simple vari6t6 de la Truite vnlgaire, et nullement une espece parti- 

 culiere." In fact, the great lake trout of Geneva is the Sahno ferox of lakes in Wales, the north 

 of England, Scotland and Ireland, and merely a form of our fresh-water trout. It has been 

 recorded as attaining to 60 lb. in weight. i i i • i a 



Dr. Giinther laid great stress on the " preoperculum being crescent-shaped, the hinder ana 

 lower margins passing into each other without forming an angle ;" but this form is not rare in 

 undoubted brook trout. The example figured from Otago, raised from eggs of our own brook 

 trout, was 20f in. long and 16 lb. weight {see fig. 44, p. 197). _ ^ ^x , ^ , . 



Dr Giinther likewise asserted that structural difference between it and the brook trout 

 existed among the specimens in the British Museum, showing that .S'. Jerox possessed 

 56 to 57 vertebrffi and 43 to 49 casca, while S. fario had 57 to 60 vertebrte and 33 to 

 47 casca. Thompson found 56 vertebrae in a gillaroo. I have, however, now shown (p. 1»J) 

 that examples of S. fario may have from 56 to 60 vertebras, and likewise from 33 to bl 

 cffica; thus overlapping the entire amount of variations ascribed to British forms Sir William 

 Jardine stated that "the dorsal fin in S. ferox contains 15 rays, and appears to be constant in 

 that number;" and that "in form it is generally shorter proportionally and deeper than large 

 specimens of S. fario." Sir J. Eichardson distinguished between the great lake trout and brook 

 trout by the size attained. The tail " in adults is perfectly square, or might even be described 

 as slightly rounded at its extremity ; in the young it is slightly forked, and appears to fill up 

 gradually as the fish advances in age." The relative position of the fins and the number ot rays 

 in the dorsal, were said to vary from 2-4/11 or a total of from 13 to 15. Thompson observed that 

 he found from 33 to 49 Cffica in six examples of S. ferox from 12 to 17 inches in length. 



Undoubted examples of our common brook trout have from 13 to 15 dorsal rays : Moreau 

 likewise, in French specimens of the brook trout, found 3 or 4 undivided and 9 to 11 divided rays 

 in the dorsal fin, also 3 undivided and 7 to 9 divided anal rays : while as to the caudal fin 

 being square in adults, so it also is in large examples of the brook trout {see p. 199). iarrefl 

 (ed 3, i, p. 281) gave an illustration of a large Thames trout (a locality not frequented by S. ferox 

 according to authors), in which the caudal fin was as rounded as in any examples of great lake 

 trout of similar size. It was a male, 28 in. long, having a hooked lower jaw while it weighed 

 11 lb. The comparative length of the head and height of the body are almost identical with wfiat 

 obtains in an example of .S'. ferox, 20 in. long, from Llanberris, and which is in the Britisn 

 Museum. I examined, a few years since, a specimen (which is still preserved) of trout, weighing 

 upwards of 13 lb., taken from a large sheet of water at Alresford in Hampshire, which is well 

 stocked with coarse fish. This was one of about a dozen that some years previously had been 

 transferred from the contiguous stream, to which they could not_ subsequent y obtain access. 

 Without a history of from whence the fish came, I maintain that no ichthyologist could be certain 

 whether any given specimen is or is not a "great lake trout." The New Zealand specimen 



13 



