72 UNIVERSITY OF COLORADO STUDIES 



Thymallus montanus Milner 

 Montana Grayling 

 Thymallus montanus Milner, Repl. U.S. Fish Com., Vol. II for 1872-73, p. 741, 1874 (tributaries 

 of the Missouri at Camp Baker). 



Body somewhat elongate and compressed, not much elevated; depth 4.5 to 

 5 or a little more in the length; head rather short, its length about equal to the 

 greatest depth of the body; diameter of the eye equalling the length of the snout, 

 3. 5 to 4 in the head; dorsal fin long and rather high, length of its base equalling 

 or slightly exceeding the length of the head, length of the longest dorsal ray 

 barely equal to or usually a little less than the length of the base of the dorsal, 

 dorsal rays 19 to 22; pectorals small, tip of the pectorals not reaching the base 

 of the ventrals by the length of the pectorals; ventrals about the same size as 

 the pectorals, base of the first rays of the ventrals on or slightly in front of the 

 level of the last dorsal ray; anal rays 10 or 11; scales small and loose, 8 or 9, 

 80-90, 9 or 10; reaching the weight of 2 pounds or more. 



General color grayish to silvery, shading dorsally into rather dark grayish 

 blue or purple, below the lateral line pinkish shading into silvery white ventrally; 

 sides with a lilac or purplish reflection; sides of the body above the pectoral fins 

 with several small irregular black spots, each covering portions of from one to 

 four scales; dorsal fin rather dark greenish gray, margined with rose-pink, crossed 

 by five or more rows of orange-red or pinkish spots some of which are distinctly 

 ocellated with white, upper posterior portion of the dorsal with a few reddish 

 blotches; ventral fins with three rose-red stripes; pectoral and anal fins white 

 with a pinkish or brownish cast. 



The Montana Grayling is a native to the Missouri and its tributaries above 

 the Great Falls, inhabiting the clear streams with rock or gravel bottoms. As this 

 region was traversed by the Lewis and Clark expedition, the earliest record of 

 this species occurs in their journal,' although the fish was not named at that time. 

 It has been introduced in various parts of the country with but fair success. 



Thymallus montanus spawns in April and May, the eggs being much like those 

 of the trout except that they are smaller. 



In Colorado the Grayling has been introduced on both sides of the Continental 

 Divide by the United States Fish Commission, the State Fish Commission and 

 by local fishing clubs.^ In 1901,3 100,000 fry and fingerlings were liberated in 

 Colorado by the United States Fish Commission alone, yet the Grayling is not 

 well established in the state at present. 



Many of the reports of Grayling in Colorado which have been received by 



' Bass, Pike, Perch and Others, p. 182, 1903, New York. 



' See Reports of the United States Fish Commission; of the Colorado Commissioner of Game and Fish; 

 and reports of American Fisheries Society. 



1 Rept. U.S. Fish Com. for iQOi-igoz, p. loi. 



