FRESH-WATER TROUT. 191 



Variety. Estuary Trout.* 



Sahno estuarius, Knox, Lone Glens of Scotland, 1864, p. 29, and The Zoologist, 

 1855, xiii, p. 4662 ; Day, Brit, and Irish Pishes, ii, p. 99, pi. cix, f. 3. 



Salmo gallivensis, Giinther, Catal. vi, p. 88; Houghton, Brit. Freshwater 

 Fish, p. 105, c. fig. 



though now too much blocked up to allow the fish to pass." Their fin rays are similar to those 

 of burn trout ; a transverse row o£ teeth is present across the hind portion of the head of the 

 vomer, and a double row along its body. The preopercle has a distinct lower limb in some, indistinct 

 in others, while the shape of the subopercle varies. Fins — the pectoral is as long as the head 

 excluding the snout. Scales — 125 rows along the lateral-line, 15 from the base of the adipose 

 dorsal to the lateral-line, 25 from the lateral-Une to the base of the ventral fin. Gcecal appendages 

 — 46 in the one examined. Length of head 4| to 5 in the total length. Colours — silvery, with 

 the upper two-thirds of the body and head closely covered with X -shaped or round black spots, 

 and in two of the examples a few red spots, which were mostly confined to the lateral-line. Loch 

 Crasspuil has a pure white sandy bottom, which probably accounts for their silvery colour. When 

 fresh caught their backs are of a vivid green, varying to pale sea-green and dark olive, in 

 accordance with the depth of the water in which they live. Dorsal fin covered with black spots. 

 These fish have the sUvery appearance of auadromous forms, and attain to 3 lb. or 4 lb. weight. 

 The Eev. Mr. Coates, on September 16th, 1886, transmitted a specimen, 13 in. long, from 

 Loch Lomond, to The Field office, requesting information as to what sort of trout it was. He 

 observed that " similar fish are occasionally caught in Loch Lomond, and whether they are loch 

 trout or sea trout is a matter of dispute among local anglers. It has been suggested that loch 

 trout may go down to the salt water, and there assume the sUvery scales of the sea trout ; others 

 hold this to be impossible, and it is a matter of considerable interest to local anglers." 



The specimen from Loch Lomond, judging by the dentition, was unmistakably a fresh-water 

 trout. It had a double row of teeth along the whole extent of the body of the vomer, while its 

 other more distinctive characters were as follows : Forty-two oseoal appendages, fifteen rows of 

 scales between the lateral-line and the base of the dead fin, and its maxilla extended to behind a 

 level from the hind edge of the eye. The fish was of a silvery colour, with numerous black spots 

 on its head and body, and five red spots on the lateral-line in its posterior half, also a few 

 additional ones both above and below ; dorsal fin spotted, but without any white edge, but a 

 slight white edging existed in the front part of the anal fin. 



Mr. J. Harvie-Brown (Land and Water) observed that at a far inland locality in Sutherland- 

 shire, brown trout, dark and spotted, were caught in 1877, and introduced to a chain of lochs 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, is at a 

 lower level). These fish 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 of a lb. The 

 food in the loch is shell-fish and tadpoles, and the bottom granite, gravel and sand. Did this 

 species run up rivers, doubtless it would take on the colours of the brook trout, as it has its 

 dentition. 



Habitat. — ^Loch Crasspuill, in Sutherlandshire, the example being a female, 9"8 inches in length. 

 * Knox appears to be the first who elevated yellow trout found frequenting estuaries into the 

 rank of a species : in this Dr. Giinther appears to have coincided but omitted all reference to 

 Knox's statements and re-named the fish. The first author took his at the mouth of the Nith, 

 and also recorded it from the sea in the Kyle of Bute, Loch Fyne, the Forth, and the Esk in 

 Yorkshire. Although he found the dentition similar to other trout he counted 60 vertebras and 

 36 oaecal appendages, the longest measuring 1 in. (the fish appears to have measured 12-5 in. in 

 length). Dr. Giinther described his from Galway specimens, and recorded 59 vertebrce and 

 44 cseca, the young with 9 par bands. The osecal appendages he considered short, being 1 in. in 

 length in a fish 18 in. long. Some examples sent at the same time from the same place are 

 considered for the greater part to be hybrids. Couch, British Fishes, iv, p. 230, observed, "A well- 

 grown trout has been brought to me, that was caught at a considerable distance from a river or 

 fresh water. Under such circumstances a material alteration takes place in the colour of the 

 fish, which becomes of a rich dark brown with an aggravation of the other characteristic tints. 

 It is believed that these migratory examples in no long time return to their native river: at 

 which season again their appearance is so changed that they have been judged a distinct species, 

 and we believe that they are the same which Dr. Knox has denominated the Estuary Trout." 

 Day, British and Irish Fishes, figured one from Waterford where they are common. They have 

 been recorded from other localities. Mr. Ogilby, Boyal Dublin Society, 1885, p. 527, observed 

 that the estuary trout about Fortrush, in Ireland, is known as dolachan, and appears to be a large 

 brook trout residing the greater portion of the year in tidal reaches, ascending the streams about 

 October. Their colours are as follows: — "For about two-thirds of the length and one-third 

 above the lateral-line, the body is thickly studded with brick-coloured spots, about the size of a 

 threepenny piece, the upper part being covered with similarly sized brown spots, while from head 

 to tail there is a distinct lead-coloured longitudinal band, comprising about four rows of scales 

 below and two above the lateral-line. These fish, though living so long in salt or brackish water, 

 never assume a silvery appearance ; in fact, some of the most brilliantly coloured and spotted 

 trout that I have ever seen were taken in almost pure salt water, close to the mouth of the Bann." 



