Arctic Grayling

A submerged view of a fish in shallow water
Of the 11 native fish in Yellowstone, Arctic grayling is one of three considered a sport fish.

©Jay Fleming


Fluvial (entirely stream-dwelling) Arctic grayling (Thymallus arcticus montanus) were indigenous to the park in the headwaters of the Madison and Gallatin rivers and to the Gibbon and Firehole rivers below their first falls. Fluvial grayling were eliminated from their entire native range within the park by the introduction of competing nonnative fishes such as brown trout and brook trout, and the fragmentation of migration pathways by the construction of the Hebgen Dam outside the park. Grayling within the upper Gallatin River drainage disappeared around 1900, while grayling in the upper Madison River drainage disappeared by 1935. The only known populations left in the park are adfluvial (primarily lake-dwelling) descendants of fish that were stocked in Cascade and Grebe lakes.


  • Large sail-like dorsal fin.
  • Large scales.
  • Dark spots on the front half of its body.
  • Sometimes confused with mountain whitefish.


  • Spawning behavior of fluvial populations is unknown. Adfluvial populations migrate to streams in June. Spawn over many types of stream bed, from sand to course rubble.
  • Similar to trout, they eat true flies, caddisflies, and small crustaceans. Younger, smaller fish feed on zooplankton.


  • Present in Cascade, Grebe, and Wolf lakes.
  • Found in the Gibbon river. Sometimes found in Madison and Firehole rivers.


One of the goals of the park’s 2010 Native Fish Conservation Plan is to restore fluvial grayling to approximately 20% of their historical distribution. The upper reaches of Grayling Creek are considered the best site for immediate fluvial grayling restoration. Near the park boundary, a small waterfall exists in the creek (which flowed directly into the Madison River prior to the construction of Hebgen Dam in 1914). It is not known if grayling were ever present upstream of the waterfall, but they were abundant downstream.

The Grayling Creek restoration project aims to establish Arctic grayling and westslope cutthroat trout to 95 kilometers (59 miles) of connected stream habitat in one of the most remote drainages in the species historic range within Yellowstone.

In summer of 2013 a barrier was completed at the waterfall to prevent upstream movement of nonnative fish. During August 2013, a crew of 27 biologists from Yellowstone National Park, Montana Fish, Wildlife and Parks, Gallatin National Forest, Turner Enterprises, and US Fish and Wildlife Service treated the stream segment with piscicide to remove all fish. A second treatment took place in 2014. Restocking of the Grayling Creek watershed with native fluvial Arctic grayling and westslope cutthroat trout began in 2015 and continued in 2016. The effort included moving approximately 950 juvenile and adult westslope cutthrout trout to lower reaches of Grayling Creek, above the project barrier. In addition, 37,600 westslope cutthrout trout eggs and 150,000 fluvial grayling eggs were placed in remote-site incubators throughout the upper watershed.

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To maintain the natural biodiversity of the Yellowstone ecosystem, sometimes you have to start small. Fish biologist Todd Koel discusses efforts to restore native fish in Grayling Creek, a cup of eggs at a time.

An underwater view of a spotted fish with a red slash on its neck and side swims above pebbles

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Young cutthroat trout in a shallow creek

Fisheries & Aquatic Sciences Program

Explore the National Park Service science program for fish and aquatic species.

Three spotted fish with red jaws underwater

Yellowstone Cutthroat Trout

Yellowstone cutthroat trout are the most widespread native fish in the park.

A spotted fish with red belly laying on grass

Westslope Cutthroat Trout

Historically the most abundant and widely distributed subspecies of cutthroat trout throughout the West.

A silvery fish laying on a gray rock

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A gray fish with dark sports and striped fins underwater

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A longnose dace floating above the sandy river bottom


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A longnose sucker along the sandy river bottom


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2009. Yellowstone cutthroat trout: Conserving a heritage population in Yellowstone Lake. Mammoth Hot Springs, WY: National Park Service.

Baril, L.M., D.W. Smith, T. Drummer, and T.M. Koel. 2013. Implications of cutthroat trout declines for breeding opsreys and bald eagles at Yellowstone Lake. Journal of Raptor Research 47(3): 234–245.

Bigelow, P.E., T.M. Koel, D. Mahony, B. Ertel, B. Rowdon, and S.T. Olliff. 2003. Protection of native Yellowstone cutthroat trout in Yellowstone Lake, Yellowstone National Park, Wyoming, Edited by US Department of the Interior, National Park Service. Fort Collins, CO: National Park Service, Water Resources Division.

Gresswell, R.E. and J.D. Varley. 1988. Effects of a century of human influence on the cutthroat trout of Yellowstone Lake. In R.E. Gresswell, ed., Status and management of interior stocks of cutthroat trout, 45–52. Vol. Symposium 4. American Fisheries Society.

Gresswell, R.E., W.J. Liss, and G.L. Larson. 1994. Lifehistory organization of Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) in Yellowstone Lake. Canadian Journal of Fisheries and Aquatic Sciences 51(S1):298–309.

Gresswell, R.E. 1995. Yellowstone cutthroat trout. In M. K. Young, ed., Conservation assessment for inland cutthroat trout, 36–54. Fort Collins, CO: US Forest Service, Rocky Mountain Forest and Range Experiment Station.

Heckmann, R. 1994. Cutthroats and parasites: Yellowstone Lake’s complex community of fish and companion organisms. Yellowstone Science 2(3).

Kaya, C. 2000. Arctic grayling in Yellowstone: Status, management, and recent restoration efforts. Yellowstone Science 8(3).

Kerkvliet, J., C. Nowell, and S. Lowe. The economic value of a predator: Yellowstone trout. In A. P. Curlee, A. Gillesberg and D. Casey, ed., Greater Yellowstone predators: Ecology and conservation in a changing landscape: Proceedings of the third biennial conference on the Greater Yellowstone Ecosystem, 143–150. Yellowstone National Park, WY: Northern Rockies Conservation Cooperative and Yellowstone National Park.

Koel, T.M., P.E. Bigelow, P.D. Doepke, B.D. Ertel, and D.L. Mahony. 2005. Nonnative lake trout result in Yellowstone cutthroat trout decline and impacts to bears and anglers. Fisheries 30(11):10–19.

Koel, T.M., P.E. Bigelow, P.D. Doepke, B.D. Ertel, and D.L. Mahoney. 2006. Conserving Yellowstone cutthroat trout for the future of the Greater Yellowstone Ecosystem: Yellowstone’s Aquatic Sciences Program. Yellowstone Science 14(2).

Koel, T.M., D.L. Mahony, K.L. Kinnan, C. Rasmussen, C.J. Hudson, S. Murcia, and B.L. Kerans. 2006. Myxobolus cerebralis in native cutthroat trout of the Yellowstone Lake ecosystem. Journal of Aquatic Animal Health 18(3):157–175.

May, B.E., W. Urie, and B.B. Shepard. 2003. Range-wide status of Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri): 2001, Edited by US Forest Service, Montana Fish, Wildlife and Parks, Montana Cooperative Fishery Research Unit. Bozeman, MT.

National Park Service, Yellowstone National Park. 2010. Native Fish Conservation Plan / Environmental Assessment, Edited by Department of the Interior. Yellowstone Center for Resources.

Reinhart, D.P., S.T. Olliff, and K.A. Gunther. Managing bears and developments on cutthroat spawning streams in Yellowstone National Park. In A.P. Curlee, A. Gillesberg and D. Casey, ed., Greater Yellowstone predators: Ecology and conservation in a changing landscape: Proceedings of the third biennial conference on the Greater Yellowstone Ecosystem, 161–169. Yellowstone National Park, WY: Northern Rockies Conservation Cooperative and Yellowstone National Park.

Steed, A.C., A.V. Zale, T.M. Koel, and S.T. Kalinowski. 2011. Population viability of Arctic grayling in the Gibbon River, Yellowstone National Park. North American Journal of Fisheries Management 30:1582-1590

Varley, J.D. and P. Schullery. 1995. The Yellowstone Lake crisis: Confronting a lake trout invasion: a report to the director of the National Park Service. Yellowstone National Park, WY: National Park Service, Yellowstone Center for Resources.

Last updated: April 19, 2017

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