The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Oncorhynchus clarkii utah
Oncorhynchus clarkii utah
(Bonneville cutthroat trout)
Native Transplant

Copyright Info
Oncorhynchus clarkii utah (Suckley, 1874)

Common name: Bonneville cutthroat trout

Synonyms and Other Names: Salmo clarki utah, Utah cutthroat trout. Species name sometimes given as "clarki". The lake-dwelling morph of O. c. utah found in Bear Lake, Idaho and Utah, is sometimes called Bear Lake cutthroat trout or bluenose trout.

Taxonomy: available through www.itis.govITIS logo

Identification: Stream-resident form: yellow-green to silvery grey body, with relatively large round spots sparsely scattered along body and dorsal, adipose, and caudal fins. Some individuals retain pale light-blue elliptical parr marks along sides through maturity. Similar to Yellowstone cutthroat trout (O. c. bouvieri), which lacks parr marks as adult and has spotting concentrated in caudal region (Behnke 2002; Page and Burr 2011).

Bear Lake resident form: silvery blue to green on dorsal surface fading to white ventrally, with fine irregular spots scattered along sides and dorsal and caudal fins (Behnke 2002; Page and Burr 2011).

Size: up to 46 cm TL; to 61 cm TL for Bear Lake morph (Behnke 2002).

Native Range: Bonneville basin of Idaho, Nevada, Utah, and Wyoming (Behnke 2002).

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

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 Oncorhynchus clarkii utah are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
ID198319945Blackfoot; North Fork Payette; Upper Henrys; Upper Snake; Weiser
NV187619533Hamlin-Snake Valleys; Long-Ruby Valleys; Spring-Steptoe Valleys

Table last updated 5/28/2024

† Populations may not be currently present.

Ecology: Bonneville cutthroat trout have similar habitat requirements to other cutthroat trout subspecies and western salmonids: generally found in cool, well-oxygenated waters of high elevation creeks, streams, rivers, and lake systems with clean gravel substrates, some submerged structure, and vegetated shorelines (Baker et al. 2008). Spawning primarily occurs in spring and early summer when water temperature reaches 4-10°C, with sexual maturity typically reached by 2 (males) to 3 (females) years of age (May et al. 1978). Fluvial populations primarily feed on terrestrial and aquatic invertebrates (Baker et al. 2008).

The Bear Lake morph differs slightly from fluvial populations of Bonneville cutthroat trout in both biology and ecology. The Bear Lake morph reaches a larger size, and has both a longer maximum life span (~10-11 years) and later age of maturity (typically > 5 years) than fluvial populations (Nielson and Lentsch 1988; Behnke 2002). The Bear Lake morph feeds primarily on terrestrial insects and zooplankton at small sizes, switching to piscivory at larger sizes. Fishes make up ~95% of the diet of adults in Bear Lake (Nielson and Lentsch 1988; Behnke 2002).

Means of Introduction: Stocked for sport.

Status: Extirpated in Idaho and Nevada. 

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: Bonneville cutthroat trout have been heavily impacted throughout their native range by the introduction of other salmonids such as brook trout Salvelinus fontinalis, brown trout Salmo trutta, and rainbow trout Oncorhynchus mykiss (Behnke 2002). Populations of Bonneville cutthroat trout have been reestablished in Great Basin National Park, Nevada (Baker et al. 2008). 

References: (click for full references)

Baker, G., N. Darby, T. Williams, and J. Wullschleger. 2008. Bonneville cutthroat trout restoration project—Great Basin National Park. Natural Resource Report NPS/NRPC/NRR—2008/055. National Park Service, Fort Collins, Colorado.

Behnke, R.J. 2002. Trout and salmon of North America. The Free Press, New York, NY.

Idaho Department of Fish and Game. 2012. Idaho Department of Fish and Game fish stocking database, 1967-2012. http://fishandgame.idaho.gov/public/fish/stocking/

La Rivers, I. 1962. Fishes and fisheries of Nevada. Nevada State Print Office, Carson City, Nevada.

May, B. E., J. D. Leppink, and R. S. Wydoski. 1978. Distribution, systematics, and biology of the Bonneville cutthroat trout, Salmo clarki utah. Utah Division of Wildlife Resources, Ogden. Publication 78-15.

Nielson, B.R., and L. Lentsch 1988. Bonneville cutthroat trout in Bear Lake: status and management. American Fisheries Society Symposium 4:128-133.

Page, L.M., and B.M. Burr. 2011. Field guide to freshwater fishes of North America north of Mexico. Peterson Field Guides series. Houghton Mifflin Harcourt, Boston, MA.

Other Resources:
FishBase Summary

Author: Neilson, M.E.

Revision Date: 6/29/2023

Peer Review Date: 6/6/2012

Citation Information:
Neilson, M.E., 2024, Oncorhynchus clarkii utah (Suckley, 1874): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=901, Revision Date: 6/29/2023, Peer Review Date: 6/6/2012, Access Date: 5/28/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [5/28/2024].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted.

For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.