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 × mykiss
Oncorhynchus clarkii × mykiss
(cutbow trout)
Native Hybrid

Copyright Info
Oncorhynchus clarkii × mykiss

Common name: cutbow trout

Identification: Rourke and Wallace (1978); Behnke (1992).

Size: 2.46 kg.

Native Range: Not applicable; artificial hybrid. Can occur "naturally" where both species come in contact through stocking.

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 × mykiss are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AZ199719972Lower Colorado Region; Lower Colorado-Lake Mead
CA199719971California Region
CO1993200915Cache La Poudre; Colorado Headwaters; Fountain; Huerfano; Middle South Platte-Cherry Creek; Middle South Platte-Sterling; North Platte; North Platte Headwaters; Purgatoire; Rio Grande Headwaters; South Platte; South Platte Headwaters; Upper Arkansas; Upper Arkansas-Lake Meredith; Upper San Juan
ID1968201148American Falls; Bear Lake; Beaver-Camas; Big Lost; Big Wood; Blackfoot; Boise-Mores; Brownlee Reservoir; C.J. Strike Reservoir; Camas; Clearwater; Idaho Falls; Lake Walcott; Lemhi; Little Salmon; Lochsa; Lower Bear; Lower Bear-Malad; Lower Boise; Lower Henrys; Lower Middle Fork Salmon; Lower North Fork Clearwater; Lower Salmon; Lower Selway; Middle Bear; Middle Salmon-Chamberlain; Middle Salmon-Panther; Middle Snake-Succor; North and Middle Forks Boise; North Fork Payette; Payette; Pend Oreille Lake; Portneuf; Salmon Falls; Salt; South Fork Clearwater; South Fork Payette; South Fork Salmon; Teton; Upper Henrys; Upper Middle Fork Salmon; Upper North Fork Clearwater; Upper Salmon; Upper Selway; Upper Snake; Upper Snake-Rock; Upper Spokane; Weiser
MT199720003Middle Kootenai; Missouri-Poplar; Upper Yellowstone
NV196719975Lake Tahoe; Pyramid-Winnemucca Lakes; Smoke Creek Desert; Thousand-Virgin; Truckee
NM199519975Rio Grande-Elephant Butte; Upper Pecos; Upper Rio Grande; Upper Rio Grande; Upper San Juan
OR199019974Brownlee Reservoir; Lower Columbia-Clatskanie; Pacific Northwest Region; Willamette
WA199719973Hoh-Quillayute; Pacific Northwest Region; Puget Sound
WY199719973Big Horn; Snake Headwaters; Upper Green

Table last updated 6/14/2024

† Populations may not be currently present.

* HUCs are not listed for states where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: Intentionally stocked as sport fish.

Status: Maintained by stocking either the hybrid or a parent species where the other parent species naturally occurs (usually stocking the rainbow in cutthroat native range).

Impact of Introduction: Native cutthroat are being replaced by introduced rainbow trout through hybridization and competition. Where the two species naturally co-occur, they rarely hybridize (Sigler and Miller 1963; Behnke, personal communication). Seiler and Keeley (2009) showed that cutthroat trout had reduced growth rates in the presence of cutthroat-rainbow hybrids in laboratory experiments.

Remarks: Recorded from the Southwest as early as 1918 (Sigler and Miller 1963). Private hatcheries sell hybrids between rainbows and Snake River cutthroats (Behnke, personal communication). These two species do not hybridize in areas where both are native (Sigler and Miller 1963). Hybrid trout have not been stocked in Oklahoma (Pigg, personal communication).

References: (click for full references)

Insider Viewpoint. 2001. Fishing Records – Nevada. Insider Viewpoint Magazine. 3 pp.

Rasmussen, J.L. 1998. Aquatic nuisance species of the Mississippi River basin. 60th Midwest Fish and Wildlife Conference, Aquatic Nuisance Species Symposium, Dec. 7, 1998, Cincinnati, OH.

Seiler, S.M., and E.R. Keeley. 2009. Competition between native and introduced salmonid fishes: cutthroat trout have lower growth rate in the presence of cutthroat-rainbow trout hybrids. Canadian Journal of Fisheries and Aquatic Sciences 66:133-141.

Sigler, W.F., and R.R. Miller. 1963. Fishes of Utah. Utah Department of Fish and Game, Salt Lake City, UT.

Other Resources:
Fact Sheet for Oncorhynchus clarkii - USGS Nonindigenous Aquatic Species Database

Fact Sheet for Oncorhynchus mykiss - USGS Nonindigenous Aquatic Species Database

Author: Fuller, P.

Revision Date: 5/20/2013

Peer Review Date: 5/20/2013

Citation Information:
Fuller, P., 2024, Oncorhynchus clarkii × mykiss: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=904, Revision Date: 5/20/2013, Peer Review Date: 5/20/2013, Access Date: 6/14/2024

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 [6/14/2024].

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