The brown trout (Salmo trutta) is the only nonnative fish species in Yellowstone that is not native to North America. This European species was introduced to Yellowstone in the later part of the 19th century, and was recorded as two different species—the Von Behr and the Loch Leven brown trout. These are now thought to be two varieties of the same species and most of the populations in Yellowstone are indistinguishable.
Bigelow, P.E. 2009. Predicting areas of lake trout spawning habitat within Yellowstone Lake, Wyoming. Doctoral dissertation, University of Wyoming, Laramie, WY.
Gresswell, R.E. 2009. Scientific review panel evaluation of the National Park Service lake trout suppression program in Yellowstone Lake, August 25–29, 2008: Final report, October 2009, Edited by USGS Northern Rocky Mountain Science Center. Bozeman, MT.
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. Mahony. 2006. Conserving Yellowstone cutthroat trout for the future of the Greater Yellowstone Ecosystem: Yellowstone’s Aquatic Sciences Program. Yellowstone Science 14(2).
Middleton, A.D., T.A. Morrison, J.K. Fortin, M.J. Kauffman, C.T. Robbins, K.M. Proffitt, P.J. White, D.E. McWhirter, T.M. Koel, D. Brimeyer, and W.S. Fairbanks. 2013. Grizzly bears link non-native trout to migratory elk in Yellowstone. Proceedings of the Royal Society B 280:20130870.
Munro, A.R., T.E. McMahon, and J.R. Ruzycki. 2006. Where did they come from?: Natural chemical markers identify source and date of lake trout introduction in Yellowstone Lake. Yellowstone Science 14(2).
Wyoming Water Project. 2014. Science supporting management of Yellowstone Lake fisheries: Responses to frequently asked questions. Trout Unlimited: Lander, WY.
Ruzycki, J.R., D.A. Beauchamp, and D.L. Yule. 2003. Effects of introduced lake trout on native cutthroat trout in Yellowstone Lake. Ecological Applications 13:23–37.
Native Fish Species
Native fish underpin natural food webs and have great local economic significance.
Native Fish Conservation Program
Learn how the Native Fish Conservation Program works to preserve Yellowstone Lake cutthroat trout and to restore fluvial trout populations.
Lake trout prey on Yellowstone cutthroat trout.
Rainbow trout are native to North America in waters which drain to the Pacific Ocean from northern Mexico to Alaska.
Eastern Brook Trout
Eastern brook trout was the first nonnative species introduced in Yellowstone—stocked in the (then fishless) Firehole River in 1889.
Native to the Missouri and Yellowstone river drainages in Montana and Wyoming, the lake chub is not native to Yellowstone National Park.
New Zealand Mud Snails
New Zealand mudsnails are invasive and have a significant detrimental effect on Yellowstone.
Whirling disease can infect some trout and salmon.
Red-rimmed melania, a small snail, was discovered in a warm swimming area.
Catch a Fish
Be a responsible angler and understand the regulations before you come.
Clean, Drain, and Dry
Protect park waters by preventing the spread of aquatic invasive species.
Lake trout and other invasive species pose many threats to Yellowstone's aquatic ecosystem.
Last updated: May 8, 2023