Nonnative Fish Species

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Nonnative Fish Species

Nonnative fish distribution and their influence on native fish are not static. While they have not been intentionally stocked since the 1930s, nonnative fish continue to advance into new habitats and hybridize with or displace native fish that previously persisted in the face of extreme environmental change for thousands of years.

Hybridization of cutthroat trout resulting from rainbow trout range expansion continues to be the greatest threat to the park’s remaining native fish populations in waters outside the Yellowstone River headwaters, Yellowstone Lake, and the Snake River headwaters.

Not all of the movement by nonnative fish in Yellowstone has occurred naturally. Nonnative lake trout, intentionally introduced by managers in 1890 to Lewis and Shoshone lakes, and illegally introduced (possibly intentionally) to Yellowstone Lake in the mid-1980s, first appeared in angler catches in 1994. The lake trout population expanded and, over the following decade, caused a rapid decline in the Yellowstone cutthroat trout population in Yellowstone Lake.

 

 

History At a Glance

• When the park was established, many of its waters were fishless.
• Park waters were stocked with native and nonnative fish until the mid-1950s.
• Stocking changed the ecology of many Yellowstone waters as nonnative fish displaced or interbred with native species.
• By the 1960s, native trout populations were in poor condition and the angling experience had declined.
• By the late 1980s, native trout had recovered in some areas due to restrictions in fish harvest.
• In 2001, fishing regulations changed to require the release of all native fishes caught in park waters.

 

 

Resources

The Yellowstone Resources and Issues Handbook, updated annually, is the book our rangers use to answer many basic park questions.

100th Meridian Initiative

Bartholomew, J.L. and P.W. Reno. 2002. The history and dissemination of whirling disease. In J.L. Bartholomew and J. C. Wilson, ed., Whirling disease: Reviews and current topics. Vol. Symposium 29. Bethesda, MD: American Fisheries Society.

Franke, M.A. 1997. A grand experiment: The tide turns in the 1950s: Part II. Yellowstone Science 5(1).

Franke, M.A. 1996. A grand experiment: 100 years of fisheries management in Yellowstone: Part I. Yellowstone Science 4(4).

Kerans, B.L. and A.V. Zale. 2002. The ecology of Myxobolus cerebralis. In J.L. Bartholomew and J.C. Wilson, ed., Whirling disease: Reviews and current topics, 145–166. Vol. Symposium 29. Bethesda, MD: American Fisheries Society.

Koel, T.M., D.L. Mahony, K.L. Kinnan, C. Rasmussen, C.J. Hudson, S. Murcia, and B.L. Kerans. 2007. Whirling disease and native cutthroat trout of the Yellowstone Lake ecosystem. Yellowstone Science 15(2).

Koel, T. et al. 2014. Yellowstone Fisheries and Aquatic Sciences Report 2012–2013. National Park Service: Yellowstone National Park.

MacConnell, E. et al. 1997. Susceptibility of grayling, rainbow, and cutthroat trout to whirling disease by natural exposure to Myxobolus cerebralis. Whirling Disease Symposium, Logan, UT.

Murcia, S., B.L. Kerans, E. MacConnell, and T.M. Koel. 2006. Myxobolus cerebralis infection patterns in Yellowstone cutthroat trout after natural exposure. Diseases of Aquatic Organisms 71(3):191–199.

National Exotic Marine and Estuarine Species Information System

National Park Service. 2011. Native Fish Conservation Plan /Environmental Assessment for Yellowstone National Park. Yellowstone Center for Resources.

Varley, J.D. and P. Schullery. 1998. Yellowstone fishes: Ecology, history, and angling in the park. Mechanicsburg, PA: Stackpole Books.