History of Fish Management

About 8,000-10,000 years ago, 12 species of native fish, including Arctic grayling, mountain whitefish, and cutthroat trout, dispersed to this region following glacier melt. These native fish species provided food for both wildlife and human inhabitants. The distribution of native fish species was originally constrained by natural waterfalls and watershed divides. These landscape features provided a natural variation of species distributed across the landscape and vast areas of fishless water. At the time Yellowstone National Park was established in 1872, approximately 40% of its waters were barren of fish—including Lewis Lake, Shoshone Lake, and the Firehole River above Firehole Falls.
historic photo ranger with fish in net
Early Run of blackspotted spawners. May 1936, Pelican Creek, Lanoue.

Early Fish Management

Created in 1872, Yellowstone National Park was, for several years, the only wildland under active federal management. Early visitors fished and hunted for subsistence, as there were almost no visitor services. At the time, fishes of the park were viewed as resources to be used by sport anglers and provide park visitors with fresh meals. Fish-eating wildlife, such as bears, ospreys, otters, and pelicans, were regarded as a nuisance, and many were destroyed as a result.
Ranger with three stock animals with fish packed on their back
Packing fish to a remote lake in Mammoth District. 1938, Barrows.
To supplement fishing and to counteract “destructive” consumption by wildlife, a fish “planting” program was established in Yellowstone. Early park superintendents noted the vast fishless waters of the park and asked the U.S. Fish Commission to “see that all waters are stocked so that the pleasure seeker can enjoy fine fishing within a few rods of any hotel or camp” (Boutelle 1889). The first fishes from outside the park were planted in 1889–1890 and included brook trout (Salvelinus fontinalis) in the upper Firehole River, rainbow trout (Oncorhynchus mykiss) in the upper Gibbon River, and brown trout (Salmo trutta) and lake trout (Salvelinus namaycush) in Lewis and Shoshone lakes. The harvest-oriented fish management program accounted for the planting of more than 310 million native and nonnative fish in Yellowstone between 1881 and 1955. In addition, from 1889 to 1956, some 818 million eggs were stripped from Yellowstone trout and shipped to locations throughout the United States.
Many rows of wooden boxes used to raise trout
Trout-rearing ponds in Mammoth. May 1929
Largely due to these activities and the popularity of Yellowstone’s fisheries, recreational angling became a long-term, accepted activity in national parks throughout the country. In Yellowstone, fisheries management, as the term is understood today, began with the U.S. Army, and was assumed by the National Park Service in 1916. Fish stocking, data gathering, and other monitoring activities began with the U.S. Fish Commission in 1889, were continued by the U.S. Fish and Wildlife Service until 1996, and have been the responsibility of the National Park Service since then.

The stocking of nonnative fishes by park managers has had profound ecological consequences. The more serious of these include displacement of intolerant natives such as westslope cutthroat trout (O. clarki lewisi) and Arctic grayling (Thymallus arcticus); hybridization of Yellowstone (O. c. bouvieri) and westslope cutthroat trout with each other and with nonnative rainbow trout; and, most recently, predation of Yellowstone cutthroat trout by nonnative lake trout. Over the years, management policies of the National Park Service have drastically changed to reflect new ecological insights. Subsistence use and harvest orientation once guided fisheries management. Now, maintenance of natural biotic associations or, where possible, restoration to pre-Euro-American conditions have emerged as primary goals. Eighteen fish species or subspecies are currently known to exist in Yellowstone National Park; 12 of these are considered native (they were known to exist in park waters prior to Euro-American settlement), and five are introduced (nonnative). Today, about 40 lakes have fish; others were either not stocked or have reverted to their original fishless condition.
newly constructed wooden building with construction debris piles
The newly constructed Yellowstone Lake Fish Hatchery, 1928

Yellowstone Lake Fish Hatchery

Hatchery operations at Yellowstone Lake became part of this undertaking when fish hatched from Yellowstone’s trout were used to stock waters in the park and elsewhere, sportfishing was promoted to encourage park visitation, and satisfying a recreational interest took precedence over protection of the park’s natural ecology. Built in 1930 by the National Park Service, the hatchery’s log-framed design is also an example of the period of rustic architectural design in national parks.

The hatchery was thought to be among the most modern in the West. The main room was outfitted with tanks and raceways for eggs, fingerlings, and brood fish taken from 11 streams that flowed into the lake. Small fry were fed in three rectangular rearing ponds in a nearby creek until they were ready for planting. Superintendent Horace Albright explained that the hatchery had also been designed with visitor education in mind, by making it possible “to take large crowds through the building under the guidance of a ranger naturalist without in any way impairing the operations of the Bureau of Fisheries."

Yellowstone was the largest supplier of wild cutthroat trout eggs in the United States, and its waters received native and nonnative fish. A rift developed, however, between the federal fish agencies and the National Park Service, which began moving away from policies that allowed manipulation of Yellowstone’s natural conditions. In 1936 Yellowstone managers prohibited the distribution of nonnative fish in waters that did not yet have them and opposed further hatchery constructions in the park’s lakes and streams. After research showed that it impaired fish reproduction, egg collection was curtailed in 1953. Four years later, the fish hatchery ceased operations and the US Fish and Wildlife Service transferred ownership of the building to the National Park Service. Official stocking of park waters ended by 1959.

Today, vegetation and stream flow have largely reclaimed the rearing ponds on Hatchery Creek, but their outlines can still be detected, and the most serious results of fish planting are irreversible. Nonnative fish can alter aquatic ecology through interbreeding or competition with native species. Although its condition has deteriorated, the hatchery building has changed relatively little. Nearly all of the exterior and interior materials are original to the building or have been repaired in kind. Now used as a storage facility, it is the primary structure of the nine buildings in the Lake Fish Hatchery Historic District, which was listed on the National Register in 1985.

Native Fish Restoration Efforts



Gillnetting Lake Trout

In 1995, after confirming lake trout were successfully reproducing in Yellowstone Lake, the NPS convened a panel of expert scientists to determine the likely extent of the problem, recommend actions, and identify research needs. The panel recommended that the park suppress lake trout to protect and restore native cutthroat trout. The panel also indicated that direct removal efforts such as gillnetting or trapnetting would be most effective but would require a long-term, possibly perpetual, commitment.

As initial gillnetting efforts expanded, the number of lake trout removed from the population also increased. This suggested the lake trout population was continuing to grow. In 2008 and 2011, scientific panels were convened to re-evaluate the program and goals. The panel concluded netting is still the most viable option for suppressing lake trout. Both reviews also indicated a considerable increase in suppression effort would be needed over many years to collapse the lake trout population.

Starting in 2009, the park contracted a commercial fishing company, to increase the take of lake trout through gillnetting. From 2011 to 2013, they also used large, live-entrapment nets that allow removal of large lake trout from shallow water while returning cutthroat trout to the lake with little mortality.

Discovery of New Species in Yellowstone Lake

On August 22, 2019, a gill net set in 158 feet of water northeast of Stevenson Island captured one fish of a new species not previously known to exist in Yellowstone Lake. This was a 3-year-old immature female cisco (Coregonus artedi). Based on otolith microchemistry, it likely hatched in Yellowstone Lake. Undoubtedly this species was illegally introduced to Yellowstone Lake, as the nearest source populations are in northern Montana and Minnesota. There are no existing waterways between Yellowstone Lake and any known cisco populations.In its native range, cisco are a preferred prey item for lake trout where the two species overlap. They prey mostly on aquatic invertebrates and tend to reside at mid-water depths. Fortunately, despite miles of gill nets, some specifically targeting cisco habitat, surface tows for larvae, eDNA sampling at 24 sites around the lake, and examination of thousands of lake trout stomachs, no other cisco have been found in Yellowstone Lake.

Fish Management Research

In 2010, Yellowstone developed the Native Fish Conservation Plan. This adaptive management plan guides efforts to recover native fish and restore natural ecosystem functions based on scientific assessment.

In 2011, the National Park Service and the US Geological Survey launched a movement study to target lake trout embryos in spawning beds and identify general and seasonal movement patterns. The results helped gillnet operators to target lake trout more efficiently.

In 2013, NPS and Montana State University conducted a mark-recapture study of lake trout in Yellowstone Lake. To estimate population size, 2,400 lake trout were tagged and released back into the lake. More than 5% of tagged fish were recaptured within the same fishing season. Results produced an estimate of the number of lake trout present in the lake: 367,650 fish greater than 210 millimeters (8.3 in.) long.

The mark-recapture study also helped estimate rates of capture for four size classes. This effort removed 72% of lake trout 210–451 millimeters (8.3–17.8 in.) in length, 56% for fish 451–541 millimeters (17.8–21.3 in.) long, 48% for fish 541–610 millimeters (21.3–24.0 in.) long, and 45% for fish more than 610 millimeters (>24.0 in.) long. These results supported previous estimates and highlighted the difficultly in catching older, mature lake trout, which eat the most native cutthroat trout and have the highest reproductive success. In 2022, we caught three lake trout which had originally been tagged in 2013 as part of this study.

More Information

A biologist holds a net full of Yellowstone cutthroat trout
Fish Management

Learn how the Native Fish Conservation Program works to preserve Yellowstone Lake cutthroat trout and to restore fluvial trout populations.

Yellowstone cutthroat trout
Fish Ecology

Yellowstone is home to 12 native species of fish.

two park rangers inspecting the wing of a small bird
Science Publications & Reports

View science publications and reports created by Yellowstone's Center for Resources on a variety of park topics.

Angler fishing in Yellowstone during a golden morning.
Catch a Fish

Be a responsible angler and understand the regulations before you come.

Last updated: March 15, 2024

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Yellowstone National Park, WY 82190-0168



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