Oncorhynchus nerka
Oncorhynchus nerka
(Sockeye Salmon)
Native Transplant
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Oncorhynchus nerka (Walbaum in Artedi, 1792)

Common name: Sockeye Salmon

Taxonomy: available through www.itis.govITIS logo

Identification: Kokanee have a bluntly pointed, a conical head, "fang-like" teeth at the end of their jaws, and 30–40 fine rakers on their first gill arch. Males develop prominent snouts. Non-spawning kokanee are dark to greenish blue on the head and back, silver on the sides, silvery or white on the underbelly, and they exhibit no definite spotting on head, back, or tail. Spawning males develop a bright to olive green coloring on the heads with black on the snout and upper jaw, and a red coloring over their bodies and combinations of fins that vary between populations. Spawning females exhibit a less brilliant coloration than males. See also Moyle (1976a); Scott and Crossman (1973); Wydoski and Whitney (1979); Morrow (1980); Eschmeyer et al. (1983); Page and Burr (1991).

Size: 84 cm

Native Range: Arctic and Pacific drainages from Point Hope, Alaska, to Sacramento River drainage, California. Landlocked populations in Alaska, Yukon, British Columbia, Washington, and Oregon. Also in northeastern Asia (Page and Burr 1991).

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Alaska auto-generated map
Hawaii auto-generated map
Caribbean auto-generated map
Puerto Rico &
Virgin Islands
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Guam Saipan
Native range data for this species provided in part by NatureServe NS logo
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: This species was stocked in Ashurst, Luna, and Mojave lakes and the Lake Mead National Recreation Area, Arizona (Miller and lowe 1967; Minckley 1973; Rinne 1995; Tilmant 1999); many lakes in California in the Sacramento, Klamath, Lahontan, Mojave, and San Joaquin drainages (La Rivers 1962; Cordone et al. 1971; Moyle 1976a, 1976b); more than 24 coldwater lakes and reservoirs in Colorado, including Blue Mesa, Dillon, Shadow Mountain, Navajo, and Lake Granby (Everhart and Seaman 1971; Ellis 1974; Tyus et al. 1982; Wiltzius 1985; Walker 1993; Beckman 1952); East Twin Lakes in Litchfield, Housatonic drainage, Connecticut (Behnke and Wetzel 1960; Whitworth et al. 1968; Webster 1940; Schmidt 1986; CU 10587); Bear Lake, Redfish Lake, and Priest Lake, Idaho (Sigler and Sigler 1987; Idaho Fish and Game 1990, 1997; Beckman 1952); unspecified areas of Maine (Buss 1957 cited in Scott and Crossman 1973); the Connecticut, Housatonic, and Thames drainages, Massachusetts (Collins 1971; Schmidt 1986; Hartel 1992; Cardoza et al. 1993; Hartel et al. 1996; USFWS 2005); lakes Huron, Michigan, and Erie in Michigan (Buss 1957 cited in Scott and Crossman 1973; Parsons 1973; Emery 1985); several lakes in Cook County and Larson Lake in George Washington State Forest, Minnesota (Eddy and Underhill 1974); Lake Taneycomo in Missouri (Pflieger 1971); many areas of Montana, including the Pend Orielle, Kootenai, St. Mary, Yellowstone, and Missouri drainages and Glacier National Park (Brown 1971; Cross et al. 1986; Holton 1990; Tilmant 1999); Conestoga Lake, Lake Ogallala and Lake McConaughy, Nebraska (Jones 1963; Morris et al. 1974; Cross et al. 1986; Nebraska Game and Parks Commission); lakes Tahoe and Mohave, Walker, Pyramid, Topaz, and Virginia lakes, Wildhorse Reservoir, and Lahontan Reservoir, Nevada (Miller and Alcorn 1946; La Rivers 1962; Bradley and Deacon 1967; Cordone et al. 1971; Deacon and Williams 1984; Sigler and Sigler 1987; Insider Viewpoint 2001; Tilmant 1999; Vinyard 2001); Canadian, Rio Grande, and San Juan drainages, New Mexico (Tyus et al. 1982; Sublette et al. 1990); several areas of New York including Green Lake in Onondaga County, lakes and ponds in the Black and Richlieu drainages, the lower Hudson River, Susquehanna, Adirondack Mountains, Lake Champlain, and Lake Ontario (Parsons 1973; Werner 1980; Emery 1985; Smith 1985; Underhill 1986; museum specimens at Cornell University; Mills 1993); the Tennessee drainage, North Carolina (Menhinick 1991); unspecified areas of North Dakota (Buss 1957 cited in Scott and Crossman 1973; North Dakota Game and Fish Department 1994); nonindigenous areas of Oregon (Bond 1973, 1994; State of Oregon 2000; Behnke, personal communication); Upper Woods Pond and Lake Winola, both near Scranton, the Monongahela drainage, and in Harvey's Lake, Luzurne County, Pennsylvania (Denoncourt et al. 1975a; Cooper 1983; Hocutt et al. 1986; Stauffer et al. 1995); unspecified areas of South Dakota (Hanten, personal communication; North Dakota Game and Fish Department 1994); the Little Tennessee River and Watauga Reservoir, Tennessee (Etnier and Starnes 1993); Scofield, East Canyon, Deer Creek, Flaming Gorge, Porcupine, and Strawberry reservoirs; the Uinta Mountains; and Bear, Navajo and Panguitch lakes, Utah (Buss 1957 cited in Scott and Crossman 1973; Sigler and Miller 1963; Tyus et al. 1982; Sigler and Sigler 1987, 1996; Teuscher and Luecke 1996; Tilmant 1999); unspecified areas of Vermont (Buss 1957 cited in Scott and Crossman 1973; Cox and T. Hess, personal communication); found in the Potomac River drainage in Virginia (Hocutt et al. 1986); Banks Lake (Grant County) on the Columbia River, and in Loon Lake, Stevens County, Washington (Wydoski and Whitney 1979; Tilmant 1999); Upper Bass Lake in Menominee County, a lake in Langlade County, and probably other lakes in Wisconsin (Becker 1983; Fago 1992; Wisconsin Department of Natural Resources 1997); several high mountain impoundments in the Potomac drainage in West Virginia (Cincotta, personal communication); and Crystal Reservoir, Freemont Lake and Flaming Gorge Reservoir, Wyoming (Buss 1957 cited in Scott and Crossman 1973; Baxter and Simon 1970; Tyus et al. 1982; Hubert 1994; Teuscher and Luecke 1996).

Hocutt et al. (1986) listed this species as introduced into the Potomac drainage but did not give a state. Jenkins and Burkhead (1994) did not list it in Virginia; Stauffer et al. (1995) did not list it in West Virginia; and Rohde et al. (1993) did not list it in Maryland. On-line searches of the Philadelphia Academy of Sciences, the National Museum of Natural History, Cornell University, Museum of Comparative Zoology, and University of Michigan also returned no specimens for the Potomac drainage, nor for the three states included in that drainage. Presumably if it occurred there, it no longer does.

The first stocking in the Great Lakes occurred in 1950 in Lake Ontario tributaries by the New York Department of Environmental Conservation (Parsons 1973). Concern for the imbalance of the Great Lakes ecosystem and the abundance of nonindigenous alewife and smelt prompted the Province of Ontario to introduce kokanee salmon into Lake Huron as a fishery resource and forage fish beginning in November of 1964 (Collins 1971, 1978). Between 1950 and 1970, 19 million kokanee were planted in the Great Lakes, primarily in Lakes Ontario and Huron (Parsons 1973). Parsons (1973) gave a detailed account of the Great Lakes stockings.

Ecology: Sockeye is an anadromous fish, beginning life in freshwater streams, swimming out to sea to feed and mature for 2 years, and then returning to the stream of its birth to spawn and die. This fish primarily eats plankton but is also known to feed on insects and bottom dwelling organisms.

Means of Introduction: Authorized as stocking for sportfishing in most states. Stocked as forage in California (Moyle 1976b). Stocked in Arizona in 1967 (Rinne 1995). Cordone et al. (1971) gave the stocking history for Lake Tahoe.

Status: Established locally in some areas; failed in others. Failed in Tennessee. Rinne (1994) listed it as not established in Arizona. First found to be reproducing in the Great Lakes in Lake Huron in 1968 (Parsons 1973). Great Lakes introduction of kokanee in the 1960s and 70s resulted in naturally reproducing populations, but after stocking programs were discontinued, kokanee populations dwindled to the point where they currently persist only in northern Lake Huron, spawning in streams on Manitoulin island (Mills 1993). No longer present in Vermont (Hess, personal communication).

Impact of Introduction: Kokanee was introduced to compete with, and reduce native Utah chub Gila atraria populations in Flaming Gorge Reservoir. However, it was found that under food-limiting conditions, the Utah chub was the superior competitor and was not affected by the kokanee (Teuscher and Luecke 1996). Seeley and McCammon (1966) gave a detailed discussion of impacts of kokanee on other species. Some of the impacts listed included: large kokanee populations can inhibit trout production because of competition for zooplankton; introductions of kokanee into small lakes can adversely affect even strongly established populations of rainbow trout; and late-run kokanee and brown trout may compete for the same spawning areas, especially in lower stream reaches. Introduced kokanee were at least partially responsible for the disappearance of three cladoceran species in Lake Tahoe (Morgan et al. 1978).

Sometimes stocked kokanee do not have an apparent negative effect. Some of the determining factors which may influence whether this species has negative impacts on a receiving ecosystem or not are waterbody size and depth, the forage base, stocking densities, other species present, and if early or late-run strains are stocked. Seeley and McCammon (1966) cautioned that kokanee's value as a forage fish may be overrated-the species may depress rather than bolster trout populations. Its presence may not enhance a fishery, especially in waters without a deep, cool, well-aerated hypolimnion. The species is not long-lived (2 years) and in many areas the fish is only accessible for fishing for short periods in the spring and fall. Therefore, the entire population may die off after only being briefly available to anglers.

Additionally, Weeber et. al  (2010) found that in the Deschutes River Basin, Oregon, groups of spawning kokanee did not scour the stream bed deeply enough to reach bull trout (Salvelinus confluentus) eggs.  Consequently, the data on bull trout fry emergence showed that kokanee redd superimposition did not affect bull trout egg-to-fry survival rates.

Remarks: Tyus et al. (1982) mapped the distribution the kokanee in the upper Colorado basin. Oncorhynchus nerka exhibits the greatest diversity of life history traits among pacific salmon (Burgner 1991). Taylor et al. (1996) found that populations of kokanee salmon share a more recent common ancestor with sockeye that reside downstream than kokanee that reside in another drainage basin. Mass spawning events of sockeye were found to greatly increase primary production in forested stream ecosystems (Johnston et al. 2004), while smolts were found to remove up to half of the nitrogen and phosphorus their parents transported in during those spawning events (Moore et al. 2004). In the 1960s, Great Lakes exotics including sea lamprey, alewives, and smelt were abundant while lake trout, a top predator, and many planktivorous fish such as cisco and various species of chub had drastically declined.

The addition of sockeye into the Great Lakes ecosystem was intended primarily to occupy the gap left by failing planktivorous fish populations and secondarily to function as a forage fish (Collins 1978). The two common names of O. nerka, "sockeye" and "kokanee" refer to anadromous and non-anadromous forms, respectively. In many cases populations of kokanee are more closely related to populations of sockeye that spawn downstream than they are to populations of kokanee in other geographic locations (Taylor et al. 1996).

References: (click for full references)

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.

Brown, P.J., H. Johnson, and A.V. Zale. 2011. Effect of rainbow trout size on response to rotenone and antimycin. North American Journal of Fisheries Management 31(6):1146-1152.

Burgner, R.L. 1991. Life History of Sockeye Salmon. In: C. Groot and L. Margolis eds. Pacific Salmon Life Histories. University of British Columbia Press, Vancouver, BC. pp. 3-117.

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

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.

Collins, J.J. 1971. Introduction of kokanee salmon (Oncorhynchus nerka) into Lake Huron. Journal Fisheries Research Board of Canada 28(12):1857-1871.

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.

Dawson, V.K., L.L. Marking, and T.D. Bills. 1976. Removal of toxic chemicals from water with activated carbon. Transactions of the American Fisheries Society 105(1):119-123.

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.

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.

GLMRIS. 2012. Appendix C: Inventory of Available Controls for Aquatic Nuisance Species of Concern, Chicago Area Waterway System. U.S. Army Corps of Engineers.

Hocutt, C.H., R.E. Jenkins, and J.R. Stauffer, Jr. 1986. Zoogeography of the Fishes of the Central Appalachians and Central Atlantic Coastal Plain. In C.H. Hocutt and E.O. Wiley, eds. The Zoogeography of North American Freshwater Fishes. pp. 161-212.

Holton, G.D. 1990. A Field Guide to Montana Fishes. Montana Department of Fish, Wildlife and Parks. Helena, MT. 104 pp.

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

Johnston, N.T., E.A. MacIsaac, P.J. Tschaplinski, and K.J. Hall. 2004. Effects of the abundance of spawning sockeye salmon (Oncorhynchus nerka) on nutrients and algal biomass in forested  streams. Canadian Journal of Fisheries and Aquatic Sciences 61:384-403.

Kocik, J.F., and M.L. Jones. 1999. Pacific salmonines in the Great Lakes basin. In Taylor, W.W. and C.P. Ferreri, (Eds.). Great Lakes Fisheries Policy and Management: A Binational Perspective. Michigan State University Press, East Lansing, MI, pp. 455-488.

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.

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.

Mills, E.L., J.H. Leach, J.T. Carlton, and C.L. Secor. 1993. Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions. Journal of Great Lakes Research 19:1-54.

Moore, J.W., and D.E. Schindler. 2004. Nutrient export from freshwater ecosystems by anadromous sockeye salmon (Oncorhynchus nerka). Canadian Journal of Fisheries and Aquatic Sciences 61:1582-1589.

Morgan, M.D., S.T. Threlkeld, and C.R.Goldman. 1978. Impact of the introduction of kokanee (Oncorhynchus nerka) and opossum shrimp (Mysis relicta) on a subalpine lake. Journal Fisheries Research Board of Canada 35:1572-1579.

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

Seeley, C.M. and G.W. McCammon. 1966. Kokanee. In: A. Calhoun, ed., Inland Fisheries Management. California Department of Fish and Game. pp. 274-294.

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

Taylor, E.B., C.J. Foote, and C.C. Wood. 1996. Molecular evidence for parallel life-history evolution within a Pacific salmon (sockeye salmon and kokanee, Oncorhynchus nerka). Evolution 50:401-416.

Teuscher, D., and C. Luecke. 1996. Competition between kokanees and Utah chub in Flaming Gorge Reservoir, Utah-Wyoming. Transactions American Fisheries Society 125(4):505-511.

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

Weeber, M.A., G.R. Giannico, and S.E. Jacobs. 2010. Effects of redd superimposition by introduced kokanee on the spawning success of native bull trout. North American Journal of Fisheries Management 30:47-54.

Other Resources:
Tongass National Forest Salmon Identification Guide - U.S. Forest Service

Great Lakes Water Life - Great Lakes Sea Grant

FishBase Summary

Author: Fuller, P., G. Jacobs, J. Larson, T.H. Makled, and A. Fusaro

Revision Date: 7/8/2014

Peer Review Date: 4/1/2016

Citation Information:
Fuller, P., G. Jacobs, J. Larson, T.H. Makled, and A. Fusaro, 2018, Oncorhynchus nerka (Walbaum in Artedi, 1792): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=915, Revision Date: 7/8/2014, Peer Review Date: 4/1/2016, Access Date: 1/19/2018

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.

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Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [1/19/2018].

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