ARCTIC GRAYLING Thymallus arcticus (Pallas, 1776) 



Order: SALMONIFORMES Family: SALMONIDAE 



The grayling, now considered one species, was formerly in a separate family, the 

 THYMALLIDAE, and contained three species: 



Thymallus signifer Richardson, 1823, Arctic grayling 

 Thymallus tricolor Cope, 1865, Michigan grayling (extinct) 

 Thymallus montanus Milner, 1874, Montana grayling 



The Arctic grayling is neither rare nor endangered in Alaska 



The paper is primarily concerned with the Montana form of the grayling and the following 

 remarks apply to the Montana form . 



Distinguishing characteristics : Huge dorsal fin, particularly in the spawning male, 

 which is bluish-green with bright pink or red spots. The back is olive, shading into 

 a light purple on the sides and a bluish-white on the belly. Sides of body above pectorals 

 with irregular black spots . With adipose fin and large scales . Usual weight in Montana 

 is less than a pound . 



Present distribution : Relict and transplanted populations exist in 20 lakes and 25 streams 

 in Montana, however substantial populations occur in only a few of these; 20 lakes in Utah; 

 3 lakes in Wyoming; 2 lakes in Washington, 1 lake in Colorado; and in Glacier and 

 Yellowstone National Parks . 



Former distribution : The Arctic grayling was common in the Missouri River drainage 

 above Great Falls, mostly in Montana. The Michigan form was found in the upper part 

 of the Lower Peninsula of Michigan and the Otter River drainage in the Upper Peninsula. 



Status : Very uncommon. 



Estimated numbers : No data . 



Fecundity : Grebe Lake, Yellowstone National Park--average 1,650 eggs per adult female; 

 Rogers Lake, Montana--range 1,000 to 15,000 eggs per female; averages 5,828 eggs per 

 female, 750-840 eggs per ounce and 2,737 eggs per female, 627 eggs per ounce. 



Reasons for decline : Change of habitat resulting from timber removal; surface mining 

 and overgrazing; streams became warmer, gravel spawning areas became covered with silt 

 and sand . Beaver dams block spawning migrations . Water of some streams is used for 

 irrigation. Competition from other species, including brook trout, rainbow trout, and 

 suckers . 



Protective measures already taken : Limited fishing permitted in grayling habitat on 

 Red Rock Lakes National Wildlife Refuge . A counting weir was installed on Red Rock 

 Creek . Length of fishing season was reduced in other Montana waters . Hatchery 

 production varies considerably at State and National fish hatcheries. About a million fry, 

 10,000-20,000 fingerlings and 10,000-30,000 six-inch fish are reared annually. 



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