Disclaimer:

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.

---

Common name: Rainbow Trout

Synonyms and Other Names: steelhead [anadromous form], coastal rainbow

Taxonomy: available through www.itis.gov

Identification: Rainbow trout are a deep-bodied, compressed species with a typical trout body shape, a moderately large head, and a mouth that extends back behind the eyes. Rainbow trout have highly variable coloration: those that live in lakes are silvery with a dark olive-green colour on the back, though the dorsal coloration is sometimes a deep steely blue, mostly in fish that live offshore in deep lakes or in small fish that have not yet spawned. Numerous spots are present on the back and extend about two-thirds of the way to the lateral line down the sides. The sides are silvery and largely free of spots, the belly and ventral surface of the head are whitish, and sometimes a soft metallic-pink color is present along the sides of the body and the head (GISD, 2019).

When rainbow trout leave lakes to spawn, their coloration becomes more intense: the pinkish stripe that is present on the sides of lake fish, along with the fins, turn a rich crimson color, and there is sometimes a red slash in the folds below the lower jaw. The belly and the lower sides turn gray, and spots on the sides and upper fins become bolder and more clearly delineated. Juvenile trout are olive-green along their back and silvery olive high on their sides. There are 8-13 oval-shaped marks along the sides, which may also have smaller dark spots along them. Blush-pink to yellowish markings occur along the lateral lines between the oval marks (McDowall, 1990).

For further identification guides, see Moyle (1976a); Scott and Crossman (1973); Wydoski and Whitney (1979); Morrow (1980); Eschmeyer et al. (1983); Page and Burr (1991); Behnke (1992). Behnke (1992) gave accounts and drawings for several subspecies. A commonly used named for this species is Salmo gairdnerii, sometimes given as S. gairdneri.

Size: 114 cm

Native Range: Pacific Slope from Kuskokwim River, Alaska, to (at least) Rio Santa Domingo, Baja California; upper Mackenzie River drainage (Arctic basin), Alberta and British Columbia; endorheic basins of southern Oregon (Page and Burr 1991).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Native range data for this species provided in part by NatureServe

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

Ecology: Lake fish usually spawn in lake tributaries, where the young trout feed and grow before migrating downstream after about a year. Growing to maturity in the lake takes between 2-4 years, at which time they migrate back to the tributaries to spawn. Most fish will return to the tributary in which they hatched (McDowall, 1990). Some lake populations may spawn in lake-shore gravels rather than travel into tributaries, however. Adult rainbow trout eat insects (both aquatic and terrestrial), crustaceans, molluscs, fish eggs, and small fish. Young trout feed predominantly on zooplankton (GISD, 2019).

Means of Introduction: Beginning in the late 1800s, there have been many stockings of this species for sportfishing purposes by state and federal agencies and by private individuals, mostly into streams and spring branches. Some states stock on an annual basis.

Status: Established in many states, including Hawaii. Also frequently stocked in most states to replenish populations harvested by fishing pressures or in other areas where populations are not self sustaining. One specimen collected from Mississippi (Ross and Brenneman 1991). Stocked once, in 1991, in Louisiana. The stocking failed. Previously established in Soda Butte Creek in Yellowstone National Park. Extirpated via rotenone treatments in 2015 and 2016; currently monitoring and eDNA testing (Ertel 2018).

Impact of Introduction: The rainbow trout hybridizes with other, more rare trout species, thereby affecting their genetic integrity (Lee et al. 1980 et seq.; Rinne and Minckley 1985; Page and Burr 1991). In California, rainbow trout have hybridized with Lahontan cutthroat trout O. clarki henshawi, golden trout O. aguabonita, and redband trout O. mykiss subsp. to the point that all three are included in the threatened trout management program of the California Department of Fish and Game (McAffee 1966b; Moyle 1976b; Behnke 1992). In the Lahontan drainage and various Rocky Mountain rivers, hybridization with rainbow trout has been a major factor in the decline of native cutthroat trouts (McAffee 1966a). Rainbow trout have been shown to hybridize with Westslope cutthroat trout throughout the Flathead River system in Montana (Muhlfeld et. al, 2009). In Nevada, this species is also held responsible for the virtual extinction of Alvord cutthroat O. mykiss subsp. (Behnke 1992). In Arizona, the species has hybridized with native gila trout O. gilae and Apache trout O. apache (Minckley 1973; U.S. Fish and Wildlife Service 1979). Rainbow trout have replaced Lahontan cutthroat trout in areas where the cutthroat is native and Rainbow Trout have been introduced (McAffee 1966b). Introduced rainbow trout, and other trout species, were likely responsible for the near-extinction of Lahontan cutthroat in Lake Tahoe in the 1940s (McAffee 1966b). Oncorhynchus clarkii lewisi hybridization with O. mykiss, and the resulting backcrossing to pure parent populations, has resulted in strong introgression toward both populations in the Upper Oldman River, Alberta, Canada (Rasmussen et al. 2010).

Rainbow trout have been found to negatively affect Little Colorado spinedace Lepidomeda vittata through predation and by affecting spinedace behavior. The trout occupied undercut banks that the spinedace normally used for refuge. As a result, spinedace were displaced from preferred microhabitats and pushed into open water, making them vulnerable to predation (Blinn et al. 1993). Thibault and Dodsen (2013) found significant habitat niche overlap between introduced Rainbow Trout and two native salmonids, Atlantic salmon Salmo salar and brook trout Salvelinus fontinatlis, within eastern Quebec rivers, and increased habitat overlap between native salmonids in rivers containing rainbow trout.

Stocking of hatchery rainbow trout in rivers has led to introduction of whirling disease into open waters in approximately 20 states including, most recently, the Madison River and its tributaries in Montana (B. Nehring and R. White, personal communication). In the Madison River, the disease has reduced the rainbow trout population by 90% (White, personal communication). Rainbow trout have the potential to consume native fishes and compete with native salmonids (Page and Laird 1993). Introduced rainbow trout eat endangered humpback chub Gila cypha in the Little Colorado River, and may exert a major negative effect on the population there (Marsh and Douglas 1997). Fausch (1988), Clark and Rose (1997), and numerous papers cited in both, discussed several factors affecting competitive interactions between rainbow and brook trout. Rainbow trout drive nongame fishes such as suckers and squawfish from feeding territories (Li, personal communication to P. Moyle in Moyle 1976a). Introduced predatory fishes, including the rainbow trout, are likely at least partially responsible for the decline of the Chiricahua leopard frog Rana chiricahuensis in southeastern Arizona (Rosen et al. 1995).

Remarks: Tyus et al. (1982) mapped the distribution of rainbow trout in the upper Colorado basin.

References: (click for full references)

Anonymous. 2000. Northwestern Pa. waters. James's Northeastern Fishing Guide.

Behnke, R.J. 1992. Native trout of western North America. American Fisheries Society Monograph 6. American Fisheries Society, Bethesda, MD, 275 pp.

Blinn, D.W., C. Runck, D.A. Clark, and J.N. Rinne. 1993. Effects of rainbow trout predation on Little Colorado spinedace. Transactions of the American Fisheries Society 122:139-143.

Boogaard, M.A., T.D. Bills, and D.A. Johnson. 2003. Acute toxicity of TFM and a TFM/niclosamide mixture to selected species of fish, including lake sturgeon (Acipenser fulvescens) and Mudpuppies (Necturus maculosus), in Laboratory and Field Exposures. Journal of Great Lakes Research 29(Supplement 1):529-541.

Bradley, W.G., and J.E. Deacon. 1967. The biotic communities of southern Nevada. Nevada State Museum Anthropological Papers No. 13, Part 4. 201-273.

Burkhead, N.M., S.J. Walsh, B.J. Freeman, and J.D. Williams. 1997. Status and restoration of the Etowah River, an imperiled southern Appalachian ecosystem, p 375-444, In: G.W. Benz and D.E. Collins (eds). Aquatic Fauna in Perile: The Southeastern Perspective. Special Publication 1, Southeast Aquatic Research Institute, Lenz Design & Communications, Decatur, GA.

Champion, P., J. Clayton, and D. Rowe. 2002. Lake Manager's Handbook: Alien Invaders. New Zealand Ministry for the Environment, Wellington, New Zealand.

Clark, M.E., and K.A. Rose. 1997. Factors affecting competitive dominance of rainbow trout over brook trout in southern Appalachian streams: implications of an individual-based model. Transactions of the American Fisheries Society 126(2):1-20.

Clearwater, S.J., C.W. Hickey, and M.L. Martin. 2008. Overview of potential piscicides and molluscicides for controlling aquatic pest species in New Zealand. Science & Technical Publishing, New Zealand Department of Conservation, Wellington, New Zealand.

Courtenay, W.R., Jr., and J.R. Stauffer, Jr., eds. Distribution, Biology, and Management of Exotic Fishes. John Hopkins. Baltimore and London.

Crawford, S.S. 2001. Salmonine introductions to the Laurentian Great Lakes: an historical review and evaluation of ecological effects. Canadian Special Publication of Fisheries and Aquatic Sciences No. 132. 205 pp.

Cudmore-Vokey, B., and E.J. Crossman. 2000. Checklists of the fish fauna of the Laurentian Great Lakes and their connecting channels. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2500: v + 39 pp.

Ertel, B. 2018. Preservation of Native Cutthroat Trout in Northern Yellowstone. https://www.nps.gov/articles/preservation-of-native-cutthroat-trout-in-northern-yellowstone.htm. Accessed on 04/23/2018.

Fausch, K.D. 1988. Tests of competition between native and introduced salmonids in streams: what have we learned? Canadian Journal of Fisheries and Aquatic Sciences 45(12):2238-2246.

Feltmate, B.W., and D.D. Williams. 1989. Influence of rainbow trout (Oncorhynchus mykiss) on density and feeding behavior of a perlid stonefly. Canadian Journal of Fisheries and Aquatic Sciences 46(9):1575-1580.

Finlayson, B.J., R.A. Schnick, R.L. Cailteux, L. Demong, W.D. Horton, W. McClay, and C.W. Thompson. 2002. Assessment of antimycin A use in fisheries and its potential for reregistration. Fisheries 27(6):10-18.

Food and Agriculture Organization (FAO). 2011. Cultured Aquatic Species Information Programme: Oncorhynchus mykiss. Text by Cowx, I.G. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 15 June 2005. Available: http://www.fao.org/fishery/culturedspecies/Oncorhynchus_mykiss/en. Accessed 19 December 2011.

Gilderhus, P.A. 1972. Exposure times necessary for antimycin and rotenone to eliminate certain freshwater fish. Journal of the Fisheries Research Board of Canada 25(2):199-202.

Global Invasive Species Database. 2019. Species profile: Oncorhynchus mykiss. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=103 on 03-05-2019.

Graham, K. 2003. Diamond Lake sick with algae. OregonLive.com. July 21, 2003.

Hamblin, P.F., and P. Gale. 2002. Water quality modeling of caged aquaculture impacts in Lake Wolsey, North Channel of Lake Huron. Journal of Great Lakes Research 28(1):32-43.

Ivan, L.N., E.S. Rutherford, and T.H. Johengen. 2011. Impacts of adfluvial fish on the ecology of two Great Lakes tributaries. Transactions of the American Fisheries Society 140:1670-1682.

Kelch, D., F. Lichtkoppler, B. Sohngen, and A. Daigneault. 2006. The value of steelhead (Oncorhynchus mykiss) angling in Lake Erie tributaries. Journal of Great Lakes Research 32(3):424-433.

Lee, D.S., C.R. Gilbert, C.H. Hocutt, R.E. Jenkins, D.E. McAllister, and J.R. Stauffer, Jr. 1980. Atlas of North American Freshwater Fishes. Volume 1980. North Carolina State Museum of Natural History, Raleigh.

Li, H.W. – Oregon State University, Corvallis, OR.

Lintermans, M. and T. Raadik. 2003. Local eradication of trout from streams using rotenone: the Australian experience. Pages 95-111 in Managing invasive freshwater fish in New Zealand: Proceedings of a workshop hosted by the Department of Conservation, Hamilton, New Zealand.

Loyacano, H.A. 1975. A List of Freshwater Fishes of South Carolina. Bulletin of the South Carolina Experimental Station. Bulletin 580, 9 pp.

Madison, D. 2003. Outlaw Introductions. Montana Outdoors. July/August 2003: 26-35.

Marking, L.L. and T.D. Bills. 1985. Effects of contaminants on toxicity of the lampricides TFM and Bayer 73 to three species of fish. Journal of Great Lakes Research 11(2):171-178.

Marotz, B. 2004. Tough Love, why it makes sense to kill some fish in order to save others. Montana Outdoors. March/April 2004.

Marsh, P.C., and M.E. Douglas. 1997. Predation by introduced fishes on endangered humpback chub and other native species in the Little Colorado River, Arizona. Transactions American Fisheries Society 126:343-346.

McAffee, W.R. 1966a. Rainbow trout. In A. Calhoun, ed. Inland Fisheries Management. California Department of Fish and Game. pp. 192-215.

McAffee, W.R. 1966b. Lahontan cutthroat trout. In A. Calhoun, ed. Inland Fisheries Management. California Department of Fish and Game. pp. 225-231.

McDowall, R.M. 1990: New Zealand freshwater fishes, a natural history and guide. Auckland, New Zealand, Heinemann Reed. 553 p.

Miller, R.R., and C.H. Lowe. 1967. Part 2. Fishes of Arizona, p 133-151, In: C.H. Lowe, ed. The Vertebrates of Arizona. University of Arizona Press, Tucson, AZ.

Minckley, W.L. 1973. Fishes of Arizona. Arizona Fish and Game Department. Sims Printing Company, Inc., Phoenix, AZ.

Morrow, J.E. 1980. The freshwater fishes of Alaska. Alaska Northwest Publishing Company, Anchorage, AK.

Moyle, P.B. 1976a. Inland Fishes of California. University of California Press, Berkeley, CA.

Moyle, P.B. 1976b. Fish introduction in California: history and impact on native fishes. Biological Conservation 9:101-118.

Muhlfeld, C.C., T.E. McMahon, M.C. Boyer, and R.E. Gresswell. 2009. Local habitat, watershed, and biotic factors influencing the spread of hybridization between native westslope cutthroat trout and introduced rainbow trout. Transactions of the American Fisheries Society 138:1036-1051.

National Park Service. 2011. Natural Resource Fact Sheet--Exotic Fish Management. National Park Service.

Nehring, R.B. – Colorado Division of Wildlife, Fort Collins, CO.

New York Department of Environmental Conservation (NYDEC). 2011. Fish stocking lists: 2010 lists by county. Bureau of Fisheries, Albany, NY. Available:http://www.dec.ny.gov/outdoor/7739.html

Page, L.M., and B.M. Burr. 1991. A Field Guide to Freshwater Fishes of North America North of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.

Page, L.M., and C.A. Laird. 1993. The identification of the nonnative fishes inhabiting Illinois waters. Report prepared by Center for Biodiversity, Illinois Natural History Survey, Champaign, for Illinois Department of Conservation, Springfield. Center for Biodiversity Technical Report 1993(4). 39 pp.

Parmenter, R.R., and Lamarra, V.A. 1991. Nutrient cycling in a freshwater marsh: The decomposition of fish and waterfowl carrion. Limnology and Oceanography 36(5):976-987.

Phillips, E.C., M.E. Washek, A.W. Hertel, and B.M. Niebel. 2003. The round goby (Neogobius melanostomus) in Pennsylvania tributary streams of Lake Erie. Journal of Great Lakes Research 29(1):34-40.

Powers, S.L., and P.A. Ceas. 2000. Ichthyofauna and biogeography of Russell Fork (Big Sandy River - Ohio River). Southeastern Fishes Council Proceedings 41:1-12.

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.

Rand, P.S., C.A.S. Hall, W.H. McDowell, N.H. Ringler, and J.G. Kennen. 1992. Factors limiting primary productivity in Lake Ontario tributaries receiving salmon migrations. Canadian Journal of Fisheries and Aquatic Sciences 49(11):2377-2385.

Rasmussen, J.B., M.D. Robinson, and D.D. Heath. 2010. Ecological consequences of hybridization between native westslope cutthroat (Oncorhynchus clarkii lewisi) and introduced rainbow (Oncorhynchus mykiss) trout: effects on life history and habitat use. Canadian Journal of Fisheries and Aquatic Sciences 67(2):357-370.

Rinne, J.N. and W.L. Minckley. 1985. Patterns of variation and distribution in Apache trout (Salmo apache) relative to co-occurrence with introduced salmonids. Copeia 1985(2):285-292.

Rohde, F.C., R.G. Arndt, J.W. Foltz, and J.M. Quattro. 2009. Freshwater Fishes of South Carolina. University of South Carolina Press, Columbia, SC. 430 pp.

Rosen, P.C., C.R. Schwalbe, D.A. Parizek, Jr., P.A. Holm, and C.H. Lowe. 1995. Introduced aquatic vertebrates in the Chiricahua region: effects on declining native ranid frogs. In: Biodiversity and Management of the Madrean Archipelago: The Sky Islands of Southwestern United States and Northwestern Mexico. pp. 251-261.

Rooney, R.C., and C.L. Podemski. 2010. Freshwater trout (Oncorhynchus mykiss) farming affects sediment and pore-water chemistry. Marine and Freshwater Research 61:513-526.

Sajna, M. 1998. Outdoors: El Nino spurs early arrival of peregrines. Pitsburgh Post-Gazette.

Starnes, W.C., J. Odenkirk, and M.J. Ashton. 2011. Update and analysis of fish occurrences in the lower Potomac River drainage in the vicinity of Plummers Island, Maryland—Contribution XXXI to the natural history of Plummers Island, Maryland. Proceedings of the Biological Society of Washington 124(4):280-309.

State of Oregon. 2000. Warm Water Game Fish Records. 7 pp.

Stripling, M. 2001. Trout: The jewels of the Chattahoochee. The Natural Georgia Series: The Chattahoochee River. Sherpa Guides. 9 pp. http://www.sherpaguides.com/georgia/chattahoochee/trout/

Texas Parks and Wildlife Department. 2001. Fish Records: Water Body - All Tackle. Texas Parks and Wildlife Department. April 24, 2001.

Thibault, I. and J. Dodson. 2013. Impacts of exotic Rainbow Trout on habitat use by native juvenile salmonid species at an early invasive stage. Transactions of the American Fisheries Society 142(4):1141-1150. http://dx.doi.org/10.1080/00028487.2013.799516

Tiegs, S.D., E.Y. Campbell, P.S. Levi, J. Rüegg, M.E. Benbow, D.T. Chaloner, R.W. Merritt, J.L. Tank, and G.A. Lamberti. 2009. Separating physical disturbance and nutrient enrichment caused by Pacific salmon in stream ecosystems. Freshwater Biology 54(9): 1864-1857.

Tilmant, J.T. 1999. Management of nonindigenous aquatic fish in the U.S. National Park System. National Park Service. 50 pp.

U.S. Fish and Wildlife Service. 1979. Arizona trout recovery plan. Arizona Trout Recovery Team, U.S. Fish and Wildlife Service, Albuquerque, NM. 37 pp.

U.S. Fish and Wildlife Service (USFWS). 2006. Economic effects of rainbow trout production by the national fish hatchery system. U.S. Fish and Wildlife Service, Atlanta, GA, 33 pp. Available: http://www.fws.gov/southeast/fisheries/pdf/RainbowTrout-05.pdf

U.S. Fish and Wildlife Service, Region 3 Fisheries Program, and Great Lakes Fishery Commission (FWS/GLFC). 2010. Great Lakes Fish Stocking database. Available: http://www.glfc.org/fishstocking/index.htm

Waldrip, L. 1993. Fish Stocking Report. Texas Parks and Wildlife News. March 5, 1993. 1993: 7-8.

Whittier, T.R., D.B. Halliwell, and R.A. Daniels. 2000. Distributions of lake fishes in the Northeast - II. The Minnows (Cyprinidae). Northeastern Naturalist 7(2):131-156.

Yoder, W.G. 1972. The spread of Myxosoma cerebralis into native trout populations in Michigan. The Progressive Fish-Culturist 34(2):103-106.

Other Resources:
Distribution in Illinois - Illinois Natural History Survey

Oncorhyncus mykiss - Global Invasive Species Database

Great Lakes Waterlife

Author: Fuller, P., J. Larson, A. Fusaro, T.H. Makled, and M. Neilson

Peer Review Date: 11/4/2013

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.