Identification: Scott and Crossman (1973); Morrow (1980); Page and Burr (1991). Grayling can be distinguished from all other salmonids by the presence of a large, sail-like dorsal fin. At one time T. arcticus was divided into four separate species: T. signifer, T. montanus, T. tricolor, and T. ontariensis. Thymallus signifer is now treated as synonymous with T. arcticus, and the others are considered subspecies of T. arcticus (Lee et al. 1980 et seq.).
Native Range: Widespread in Arctic drainages from Hudson Bay to Alaska and in Arctic and Pacific drainages to central Alberta and British Columbia; upper Missouri River drainage, Montana. Formerly in Great Lakes basin, Michigan. Also in Asia (Page and Burr 1991).
The only remaining natural, native remnant population in the continental United States is in Big Hole River, Montana (Wydoski and Whitney 2003). All other populations are the result of introductions or re-introductions.
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Thymallus arcticus are found here.
Ecology: Grayling generally inhabit clear, cold, high-altitude lakes and rivers (Behnke 2002; Wydoski and Whitney 2003). Spawning occurs in the spring, when water temperatures reach 45-50° F. Unlike most salmonids, grayling do not construct any sort of nest but spawn directly over gravel or rocky areas of smaller streams and tributaries (Behnke 2002). Diet primarily consists of aquatic and terrestrial invertebrates, zooplankton, small fishes, and occasionally fish eggs (Behnke 2002; Wydoski and Whitney 2003).
Means of Introduction: Authorized stocking for sportfishing. First stocked in Arizona in 1943 (Rinne 1995). First stocked in Connecticut in the 1870s (Whitworth 1996). Stocked in Nebraska in 1939 (Jones 1963). First stocked in southern Michigan in 1877 (Fukano et al. 1964).
Status: Established in several states, including Arizona (Rinne 1995). Reported from Colorado, Montana, Nevada, Oregon, and Vermont. Failed in Connecticut, Maine, Missouri, Nebraska, New Mexico, and Virginia. Extirpated from Pennsylvania. Although largely extirpated from its native range within the Great Lakes basin, it is found in some inland lakes in the region that were not part of its original range.
Remarks: Native populations are considered extinct in Montana (Holton 1990) except for a remnant population in the Big Hole River (Wydoski and Whitney 2003). The species has be re-stocked in the Red Rock, Madison, Gallatin and Sun drainages, as well as other locations. A relict population was present in the Great Lakes up until the 1930s, when it was extirpated due to competition with other introduced salmonids, habitat degradation, and fishing pressure (Hubbs and Lagler 1958). The Upper Missouri River population has been proposed to be classified as threatened or endangered under the Endangered Species Act (USFWS 2010).
Baxter, G.T., and J.R. Simon. 1970. Wyoming fishes. Wyoming Game and Fish Department Bulletin 4, Cheyenne, WY.
Bean, T.H. 1892. The fishes of Pennsylvania, with descriptions of the species and notes on their common names, distribution, habits, reproduction, rate of growth and mode of capture. Report of the State Commissioners of Fisheries for the years 1889-90-91. Edwin K. Meyers, State Printer, Harrisburg, PA.
Beckman, W.C. 1952. Guide to the fishes of Colorado. University of Colorado Museum, Boulder, CO.
Bickford, W.M. 1914. Notes on the Montana grayling. Transactions of the American Fisheries Society 43:153-155.
Bowers, G. M. 1901. Report of the commissioner of fish and fisheries for the year ending June 30, 1900. Part XXVI. U.S. Commission of Fish and Fisheries, Washington, D.C.
DeLorme Mapping. 1992. Wyoming Atlas and Gazetteer. DeLorme Mapping, Freeport, ME.
Ellis, M.M. 1974. Fishes of Colorado. University of Colorado Studies, Boulder, CO 11(1):1-136.
Everhart, W.H., and W.R. Seaman. 1971. Fishes of Colorado. Colorado Game, Fish and Parks Division, Denver, CO.
Fukano, K.G., H. Gowing, M.J. Hansen, and L.N. Allison. 1964. Introduction of exotic fish into Michigan. Michigan Department of Conservation, Institute of Fisheries Research, Ann Arbor, MI.
Gorges, M. 1994. Resident fish habitat management strategy for Wyoming. Bureau of Land Management, Wyoming State Office.
Hubert, W. 1994. Exotic fish. 158-174 in T.L. Parrish, and S.H. Anderson, eds. Exotic species manual. Wyoming Game and Fish Department, Laramie, WY.
Idaho Department of Fish and Game. 1990. Fisheries Management Plan 1991-1995. Appendix I - A list of Idaho fishes and their distribution by drainage. Idaho Department of Fish and Game.
Idaho Department of Fish and Game. 1996. Fisheries Management Plan 1996-2000. Idaho Department of Fish and Game.
Johnson, H.E. 1937. Feeding Montana grayling fry. Progressive Fish Culturist 30:35-36.
Jones, D.J. 1963. A history of Nebraska's fisheries resources. Dingell-Johnson Federal Aid in Fish Restoration Project F-4-R Publication. Nebraska Game, Forestation and Parks Commission.
Koster, W.J. 1957. Guide to the fishes of New Mexico. University of New Mexico Press, Albuquerque, NM.
Pflieger, W.L. 1971. A distributional study of Missouri fishes. University of Kansas Museum of Natural History 20(3):225-570.
Rinne, J.N. 1995. The effects of introduced fishes on native fishes: Arizona, Southwestern United States. 149-159 in D.P. Philipp, J.M. Epifano, J.E. Marsden, J.E. Claassen, and R.J. Wolotina, Jr., eds. Protection of aquatic diversity. Proceedings of the World Fisheries Congress, Theme 3. Oxford & IBH Publishing Company, New Delhi.
Shebley, W. H. 1917. History of the introduction of food and game fishes into the waters of California. California Fish and Game 3(1):3-10.
Sigler, W.F., and J.W. Sigler. 1996. Fishes of Utah. University of Utah Press, Salt Lake City, UT.
U.S. Fish and Wildlife Service. 2010. Endangered and threatened wildlife and plants; revised 12-month finding to list the upper Missouri River distinct population segment of Arctic Grayling as endangered or threatened; proposed rule. Federal Register 50 CFR Part 17:54708-54753.
Wydoski, R.S. and R.R. Whitney. 2003. Inland fishes of Washington. Second edition. University of Washington Press, Seattle, Washington.