82 UNIVERSITY OF COLORADO STUDIES 



lower jaw. Four of these forms are found in Colorado as Native Trout. They 

 were originally restricted to particular drainages until transported by man, but 

 are now scattered over the state regardless of drainage boundaries. These Native 

 Trout spawn in the early spring. 



Salmo clarkii spilurus (Cope) 

 Rio Grande Trout 



Salmo spilurus Cope, Hayden Geological Survey of Montana for 1871, p. 470, 1872 (Sangre de 

 Cristo Pass) . 



Salmo mykiss spilurus (Cope) — Jordan, Bull. U.S. Fish Com., Vol. IX, p. 14, 1889 (Rio 

 Grande) . 



This species is native only in the Rio Grande drainage. In general coloration 

 it is the lightest of the native species, although individuals vary greatly. Some 

 specimens of this form taken from the Rio Grande at Creede in 191 2 were quite 

 silvery and had very small black spots; the lateral band was of a pale rose-red 

 color. An individual caught in Boulder Creek where it has been introduced was, 

 on the other hand, quite dusky. The Rio Grande Trout reaches a length of over 

 26 inches. 



Salmo clarkii pleuriticus (Cope) 



Colorado River Trout 



Salmo pleuriticus Cope, Hayden Geological Survey of Montana for 1871, p. 471, 1872 (head- 

 waters of Green River in Wyoming); Cope and Yarrow, Wheeler Survey, Vol. V, p. 693, 1875 (Ft. 

 Garland, Rio Grande; Pagosa). 



Salmo mykiss pleuriticus (Cope) — Jordan, Bull. U.S. Fish Com., Vol. IX, pp. 14, 28, 1889 

 (Trappers Lake; Eagle River; Canyon Creek; Sweetwater Lakes; Gunnison River; Rio Florida); 

 Jordan and Evermann, Bull. 47, U.S. Nat. Mus., p. 496, 1896 (Eagle and Gunnison rivers). 



The Colorado River Trout is a native of the headwaters of the Colorado River, 

 being quite abundant in Grand Lake, Trappers Lake, and the upper Grand River. 

 Average specimens are quite dark with numerous rather large black spots which 

 are rather uniformly distributed over the body. The red lateral band is usually 

 very prominent in this form. Size moderately large, reaching a weight of 3 

 pounds or more. This trout and the Rio Grande trout have been considered 

 almost if not quite identical by some writers. 



Salmo clarkii stomias (Cope) 

 Green-backed trout 



Salmo stomias Cope, Hayden Geological Survey of Wyoming for 1S70, p. 433, 1871 (South Platte 

 River); Juday, Bull. U.S. Fish Com., Vol. XXVI, p. 162, 1906 (Twin Lakes); Cockerell, Univ. 

 Colo. Studies, Vol. X, p. 174, 1908 (Boulder Creek, Boulder). 



Salmo mykiss stomias (Cope) — Jordan, Bull. U.S. Fish Com., Vol. IX, p. 8, 1889 (Bear Creek 

 above Morrison) . 



The Green-backed Trout is the native trout of the Arkansas and Platte 

 drainages. It is a small species, average individuals rarely exceeding a pound in 



