FISHES OF COLORADO 83 



weight. Specimens caught in Boulder Creek which weighed almost a pound have 

 been examined. This species spawns in early spring and according to Jordan' 

 prefers the water from melting snow to that of springs when running to spawn. 



Salmo clarkii macdonaldi (Jordan and Evermann) 

 Yellow-finned Trout of Twin Lakes 



Salmo mykiss macdonaldi Jordan and Evermann, Proc. U.S. Nat. Mus. for i88g, p. 453, 1890 

 (Twin Lakes); Jordan, Bull. U.S. Fish Com., Vol. IX, p. 11, 1889 (Twin Lakes). 



Salmo macdonaldi (Jordan and Evermann) — Juday, Bull. U.S. Fish Com., Vol. XXVI, 

 p. 162, 1906 (no specimens). 



This trout is a large form known only from Twin Lakes, where it inhabits the 

 deep water, running into the adjoining streams to spawn in the early spring when 

 the water begins to rise from the melting snows. The largest specimen of this 

 form recorded weighed 8 pounds ii§ ounces. Although it was reported abundant 

 in i88g it is apparently very rare in these lakes at present. No specimens were 

 obtained by Juday during the summers of 1902 and 1903 and Mr. Irwin Simonson, 

 who made inquiry of several persons who fish regularly in Twin Lakes, reports 

 that no Yellow-finned Trout have been caught for several years. 



Salmo fario Linnaeus 

 Brown Trout, Von Behr Trout 

 The Brown Trout or Von Behr Trout is the trout of England concerning 

 which much has been written both by anglers and by others. It has been intro- 

 duced into many parts of the United States. Plantings of this species and its 

 variety, the Loch Leven Trout, were made in Colorado in 1894 and 1901 by the 

 United States Fish Commission.^ This trout is easily distinguished from the 

 other species of the genus Salmo found in Colorado by the bright red spots which 

 are more or less ocellated with white or pale pink, together with the bright orange 

 tip of the adipose fin and the general brown color. The red spots might cause this 

 species to be mistaken for the Eastern Brook Trout, Salvelinus fontinalis, which 

 may be recognized by the broad white edging of the anterior margins of the 

 pectoral, ventral and anal fins. No specimens of this trout collected in Colorado 

 have been examined in the present study, although it has been reported to the 

 writer from the Gunnison River. 



Salmo fario levenensis (Walker) 



Loch Leven Trout 



This variety of the preceding species is a native of Loch Leven, Scotland. It 



was introduced into Colorado in 1894. This fish differs from the Brown Trout 



in having fewer spots, the red spots being entirely absent in some specimens, and 



■Bm//. U.S. Fish Com., Vol. IX, p. 13, 1889. 



' See Repts. U.S. Fish Com. for 1894-95 and 1901-02. 



