Oncorhynchus mykiss - (Walbaum, 1792)
Rainbow Trout or Steelhead
Synonym(s): Parasalmo mykiss ;Salmo gairdneri
Taxonomic Status: Accepted
Related ITIS Name(s): Oncorhynchus mykiss (Walbaum, 1792) (TSN 161989)
French Common Names: truite arc-en-ciel
Unique Identifier: ELEMENT_GLOBAL.2.105164
Element Code: AFCHA02090
Informal Taxonomy: Animals, Vertebrates - Fishes - Bony Fishes - Salmon and Trouts
Kingdom Phylum Class Order Family Genus
Animalia Craniata Actinopterygii Salmoniformes Salmonidae Oncorhynchus
Genus Size: C - Small genus (6-20 species)
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Concept Reference
Concept Reference: Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Concept Reference Code: B91ROB01NAUS
Name Used in Concept Reference: Oncorhynchus mykiss
Taxonomic Comments: This highly variable species formerly was known as Salmo gairdneri, but this taxon is closely related to Pacific salmon and is conspecific with Asiatic steelhead (Oncorhynchus mykiss). For a complete taxonomic history, see Smith and Stearley (1989), Robins et al. (1991), and Behnke (1992).

"Redband" trout has been used as the name for nonanadromous populations adapted to harsh arid environments (Wishard et al. 1984); however, the term "redband" should not be used to imply a taxonomic relationship among all groups of rainbow trout in interior basins of Oregon and adjacent areas of Idaho, Nevada, and California (Wishard et al. 1984, Currens et al. 1990). Currens et al. (1990) found no evidence that all isolated groups of rainbow trout with plesiomorphic characteristics in the White River, Oregon desert basins, and northern California represent a monophyletic group.

Behnke (1992) included in O. mykiss three major groups: (1) the redband trout of the Columbia River basin east of the Cascade Mountains, and in upper Fraser River basin and the Athabasca headwaters of the Mackenzie River basin (subspecies gairdneri); (2) the redband trout of the Sacramento River basin, which he regarded as comprising two Kern River drainage subspecies (aguabonita and gilberti), plus the McCloud River subspecies (provisionally denoted as subspecies stonei); and (3) the coastal rainbow trout (nominal subspecies irideus of North America and mykiss of eastern Asia, though no known taxonomic characters separate mykiss from irideus). Behnke concluded that other forms, such as the redband trout native to Oregon desert basins, Upper Klamath Lake, the Pit River drainage, and Eagle Lake, California, cannot be consistently distinguished from the three groups listed above. He noted that their classification is a matter of personal preference and professional judgment. However, in the same publication, he stated that "the trout specialized for lacustrine conditions in Klamath Lake...is well differentiated from other groups of both redband and coastal rainbow trout and could be recognized as a subspecies, O. m. newberrii."

Hatchery rainbow trout derived mainly from coastal steelhead are widely stocked throughout the ranges of western trout (Behnke 1992). These hatchery fishes have led to hybridization with most populations of resident redband trout in the upper Sacramento River basin, the Oregon desert basins, and much of the Columbia River basin (Behnke 1992).

Oncorhynchus mykiss freely interbreeds with cutthroat trout (O. clarki) and Gila trout (O. gilae), producing fertile offspring (Sublette et al. 1990).
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 10May2016
Global Status Last Changed: 12Sep1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: Very large range; abundant; secure on a range-wide scale. See also information for the many subspecies and stocks (e.g., steelhead, redband trout, etc.).
Nation: United States
National Status: N5 (05Dec1996)
Nation: Canada
National Status: N5B,N5N,N5M (27Dec2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (SNA), Alaska (S4), Arizona (SNA), Arkansas (SNA), California (SNR), Colorado (SNA), Connecticut (SNA), Delaware (SNA), Georgia (SNA), Hawaii (SNA), Idaho (SNA), Illinois (SNA), Indiana (SNA), Iowa (SNA), Kansas (SNA), Kentucky (SNA), Maine (SNA), Maryland (SNA), Massachusetts (SNA), Michigan (SNA), Minnesota (SNA), Mississippi (SNA), Missouri (SNA), Montana (S5), Navajo Nation (SNA), Nebraska (SNA), Nevada (S2), New Hampshire (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), North Carolina (SNA), North Dakota (SNA), Ohio (S5), Oklahoma (SNA), Oregon (S5), Pennsylvania (SNA), Rhode Island (SNA), South Dakota (SNA), Tennessee (SNA), Texas (SNA), Utah (SNA), Vermont (SNA), Virginia (SNA), Washington (S5), West Virginia (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada Alberta (S2), British Columbia (S5), Manitoba (SNA), New Brunswick (SNA), Newfoundland Island (SNA), Northwest Territories (SNA), Nova Scotia (SNA), Ontario (SNA), Prince Edward Island (SNA), Quebec (SNA), Saskatchewan (SNA), Yukon Territory (S3)

Other Statuses

Implied Status under the U.S. Endangered Species Act (USESA): PS
Comments on USESA: Subspecies whitei is listed by the USFWS as Threatened (as O. aguabonita whitei).

The following steelhead populations (ESUs) are listed under the U.S. Endangered Species Act: Endangered: Southern California, Upper Columbia River; Threatened: Central California Coast, South-Central California Coast, Snake River Basin, Lower Columbia River, California Central Valley, Upper Willamette River (winter run), Middle Columbia River, Puget Sound ESU, Northern California ESU. The Klamath Mountains Province ESU is under review in the candidate process for listing under the U.S. Endangered Species Act. The Oregon Coast ESU is a NMFS species of concern.

McCloud River redband trout and Middle Columbia River Steelhead are Candidates for listing under the U.S. Endangered Species Act.

NMFS (Federal Register, 14 May 1999) determined that listing of summer steelhead in the Middle Fork of the Eel River, California, is not warranted.

USFWS (1998) found that petitioned listing of redband trout as threatened or endangered in the Great Basin may be warranted; a status review was initiated. Part of the status review is the consideration of whether one or multiple ESUs would be recognized and listed. USFWS (Federal Register, 20 March 2000) determined that listing of Great Basin redband trout in southeastern Oregon, northeastern California, and northwestern Nevada is not warranted.

USFWS (2002) found that a petition to list O. mykiss aguabonita under the U.S. Endangered Species Act presented substantial information indicating that listing may be warranted; a status review was initiated.

NMFS (Federal Register, 39 March 2006) proposed Threatened status for the Puget Sound population.

Implied Status under the Committee on the Status of Endangered Wildlife in Canada (COSEWIC):PS:E
Comments on COSEWIC: The Athabasca River populations, Thompson River population, and Chilcotin River population are designated Endangered.

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: Native to streams along the Pacific coast of North America from the Kuskokwim River, Alaska, south to northern Baja California; also the upper Mackenzie River drainage (Arctic basin), Alberta and British Columbia, and endorheic (i.e. having no outflow of water) basins of southern Oregon (Page and Burr 1991). The species has been widely introduced and established in suitable habitats all over the world (Lee et al. 1980). At sea, O. mykiss occurs throughout the North Pacific above 40° N from the North American coast to the Sea of Okhotsk (Burgner et al. 1992); it is most abundant in the Gulf of Alaska and eastern part of the North Pacific, conforming to the 5°C isotherm in the north and 15°C isotherm in the south. Seasonal shifts in distribution are correlated with changes in water temperature (Sutherland 1973).

Area of Occupancy: >12,500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: > 300
Number of Occurrences Comments: This species is represented by a very large number of occurrences (subpopulations).

In a survey of populations in the contiguous U.S., Huntington et al. (1996) identified 28 healthy native stocks of winter steelhead (20 in Washington, 7 in Oregon, 1 in California) and 6 healthy native stocks of summer steelhead, all in Oregon.

Population Size: >1,000,000 individuals
Population Size Comments: Total adult population size for all subspecies and stocks greatly exceeds 1 million.

Total annual abundance for all North American steelhead stocks was estimated at 1.6 million fish (Burgner et al. 1992).

Number of Occurrences with Good Viability/Integrity: Very many (>125)

Overall Threat Impact Comments: On a range-wide scale, this species is not significantly threatened. However, many subspecies and populations face serious threats (see separate accounts).

Declines in winter steelhead stocks from the Siuslaw River north to Tillamook Bay, Oregon, may have resulted from deterioration of ocean feeding conditions, widespread use of hatchery stock, predation by marine mammals, and ocean drift-net fishing (Nehlsen et al. 1991). Declining winter catches on the Illinois River (tributary to the Rogue River), Oregon, since the mid-1970s have been attributed to water withdrawal for irrigation (Nehlsen et al. 1991). In the Columbia River basin, winter stocks are threatened by habitat degradation, main stem passage problems, and interactions with hatchery fish (Nehlson et al. 1991). Declines in several winter populations in the Puget Sound area of Washington have resulted from habitat degradation (e.g., water quality problems, siltation, and sedimentation); predation by sea lions has been reported as a problem for the Lake Washington population (Nehlsen et al. 1991). Whirling disease has caused population declines in some areas. The disease is caused by a protozoan pathogen (inadvertently introduced from Europe) and involves tubifex worms as an alternate host. Brown trout (Salmo trutta) are unaffected by the protozoan and serve as a reservoir.

Short-term Trend Comments: Of 867 steelhead stocks in British Columbia and the Yukon, Slaney et al. (1996) categorized 9 as extirpated, 8 as high risk, 10 as moderate risk, 143 as special concern, 282 as unthreatened, and 415 as of unknown status. Many winter steelhead populations are at very low levels; populations have declined in nearly all streams in central and southern California (see Nehlsen et al. 1991 for further details). Winter steelhead stocks from Siuslaw River north to Tillamook Bay, Oregon, have been declining since 1990 (Nehlsen et al. 1991). In the Illinois River (tributary to the Rogue River), Oregon, winter steelhead catches have declined since the mid-1970s (Nehlsen et al. 1991). Several winter populations in the Puget Sound area of Washington have also experienced declines (Nehlsen et al. 1991).

Other NatureServe Conservation Status Information

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Native to streams along the Pacific coast of North America from the Kuskokwim River, Alaska, south to northern Baja California; also the upper Mackenzie River drainage (Arctic basin), Alberta and British Columbia, and endorheic (i.e. having no outflow of water) basins of southern Oregon (Page and Burr 1991). The species has been widely introduced and established in suitable habitats all over the world (Lee et al. 1980). At sea, O. mykiss occurs throughout the North Pacific above 40° N from the North American coast to the Sea of Okhotsk (Burgner et al. 1992); it is most abundant in the Gulf of Alaska and eastern part of the North Pacific, conforming to the 5°C isotherm in the north and 15°C isotherm in the south. Seasonal shifts in distribution are correlated with changes in water temperature (Sutherland 1973).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, ALexotic, ARexotic, AZexotic, CA, COexotic, CTexotic, DEexotic, GAexotic, HIexotic, IAexotic, IDexotic, ILexotic, INexotic, KSexotic, KYexotic, MAexotic, MDexotic, MEexotic, MIexotic, MNexotic, MOexotic, MSexotic, MT, NCexotic, NDexotic, NEexotic, NHexotic, NJexotic, NMexotic, NNexotic, NV, NYexotic, OH, OKexotic, OR, PAexotic, RIexotic, SDexotic, TNexotic, TXexotic, UTexotic, VAexotic, VTexotic, WA, WIexotic, WVexotic, WYexotic
Canada AB, BCnative and exotic, MBexotic, NBexotic, NFexotic, NSexotic, NTexotic, ONexotic, PEexotic, QCexotic, SKexotic, YTnative and exotic

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
CA Alameda (06001), Amador (06005), Butte (06007), Calaveras (06009), Colusa (06011), Contra Costa (06013), Del Norte (06015), El Dorado (06017), Fresno (06019), Glenn (06021), Humboldt (06023), Lassen (06035), Los Angeles (06037), Madera (06039), Marin (06041), Mendocino (06045), Merced (06047), Modoc (06049), Monterey (06053), Napa (06055), Nevada (06057), Placer (06061), Riverside (06065), Sacramento (06067), San Diego (06073), San Joaquin (06077), San Luis Obispo (06079), San Mateo (06081), Santa Barbara (06083), Santa Clara (06085), Santa Cruz (06087), Shasta (06089), Siskiyou (06093), Solano (06095), Sonoma (06097), Stanislaus (06099), Sutter (06101), Tehama (06103), Trinity (06105), Tulare (06107), Tuolumne (06109), Ventura (06111), Yolo (06113), Yuba (06115)
MT Flathead (30029), Lincoln (30053)
NV Elko (32007), Washoe (32031)
OR Baker (41001)*, Benton (41003), Clackamas (41005), Clatsop (41007), Columbia (41009), Coos (41011), Crook (41013), Curry (41015), Douglas (41019), Gilliam (41021), Grant (41023), Harney (41025), Hood River (41027), Jackson (41029), Jefferson (41031), Josephine (41033), Klamath (41035)*, Lake (41037), Lane (41039), Lincoln (41041), Linn (41043), Malheur (41045)*, Marion (41047), Morrow (41049), Multnomah (41051), Polk (41053), Sherman (41055), Tillamook (41057), Umatilla (41059), Union (41061), Wallowa (41063), Wasco (41065), Washington (41067), Wheeler (41069), Yamhill (41071)
WA Asotin (53003), Benton (53005), Chelan (53007), Clallam (53009), Clark (53011), Columbia (53013), Cowlitz (53015), Douglas (53017), Franklin (53021), Garfield (53023), Grays Harbor (53027), Jefferson (53031), King (53033), Kitsap (53035), Kittitas (53037), Klickitat (53039), Lewis (53041), Mason (53045), Okanogan (53047), Pacific (53049), Pierce (53053), Skagit (53057), Skamania (53059), Snohomish (53061), Thurston (53067), Wahkiakum (53069), Walla Walla (53071), Whatcom (53073), Whitman (53075), Yakima (53077)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Middle Savannah (03060106)
16 Upper Quinn (16040201)+*, Long-Ruby Valleys (16060007)+
17 Upper Kootenai (17010101)+, Fisher (17010102)+, Yaak (17010103)+, Lower Kootenai (17010104)+, Stillwater (17010210)+, Priest (17010215), Pend Oreille (17010216), Upper Spokane (17010305), Hangman (17010306), Lower Spokane (17010307), Little Spokane (17010308), Franklin D. Roosevelt Lake (17020001), Kettle (17020002), Colville (17020003), Sanpoil (17020004), Chief Joseph (17020005)+, Okanogan (17020006)+, Similkameen (17020007)+, Methow (17020008)+, Lake Chelan (17020009), Upper Columbia-Entiat (17020010)+, Wenatchee (17020011)+, Moses Coulee (17020012), Upper Crab (17020013), Banks Lake (17020014), Lower Crab (17020015), Upper Columbia-Priest Rapids (17020016)+, Upper Yakima (17030001)+, Naches (17030002)+, Lower Yakima, Washington (17030003)+, Upper Snake-Rock (17040212), Salmon Falls (17040213), C. J. Idaho (17050101), Bruneau (17050102), Middle Snake-Succor (17050103), Upper Owyhee (17050104), South Fork Owyhee (17050105)+, East Little Owyhee. Nevada, (17050106), Middle Owyhee (17050107), Jordan (17050108)+, Crooked-Rattlesnake (17050109), Lower Owyhee (17050110)+, North and Middle Forks Boise (17050111), Boise-Mores (17050112), South Fork Boise (17050113), Lower Boise (17050114), Middle Snake-Payette (17050115), Upper Malheur (17050116)+, Lower Malheur (17050117)+, Bully (17050118), Willow (17050119), South Fork Payette (17050120), Middle Fork Payette (17050121), Payette (17050122), North Fork Payette (17050123), Weiser (17050124), Brownlee Reservoir (17050201), Burnt (17050202), Powder (17050203)+, Hells Canyon (17060101)+, Imnaha (17060102)+, Lower Snake-Asotin (17060103)+, Upper Grande Ronde (17060104)+, Wallowa (17060105)+, Lower Grande Ronde (17060106)+, Lower Snake-Tucannon (17060107)+, Palouse (17060108), Rock (17060109), Lower Snake (17060110)+, Upper Salmon (17060201), Middle Salmon-Panther (17060203), Lemhi (17060204), Upper Middle Fork Salmon (17060205), Lower Middle Fork Salmon (17060206), Middle Salmon-Chamberlain (17060207), South Fork Salmon (17060208), Lower Salmon (17060209), Little Salmon (17060210), Upper Selway (17060301), Lower Selway (17060302), Lochsa (17060303), Middle Fork Clearwater (17060304), South Fork Clearwater (17060305), Clearwater (17060306), Upper North Fork Clearwater (17060307), Lower North Fork Clearwater (17060308), Middle Columbia-Lake Wallula (17070101)+, Walla Walla (17070102)+, Umatilla (17070103)+, Willow (17070104)+, Middle Columbia-Hood (17070105)+, Klickitat (17070106)+, Upper John Day (17070201)+, North Fork John Day (17070202)+, Middle Fork John Day (17070203)+, Lower John Day (17070204)+, Upper Deschutes (17070301), Little Deschutes (17070302), Beaver-South Fork (17070303)+, Upper Crooked (17070304)+, Lower Crooked (17070305)+, Lower Deschutes (17070306)+, Trout (17070307)+, Lower Columbia-Sandy (17080001)+, Lewis (17080002)+, Lower Columbia-Clatskanie (17080003)+, Upper Cowlitz (17080004)+, Lower Cowlitz (17080005)+, Lower Columbia (17080006)+, Middle Fork Willamette (17090001), Coast Fork Willamette (17090002), Upper Willamette (17090003)+, Mckenzie (17090004), North Santiam (17090005)+, South Santiam (17090006)+, Middle Willamette (17090007)+, Yamhill (17090008)+, Molalla-Pudding (17090009)+, Tualatin (17090010)+, Clackamas (17090011)+, Lower Willamette (17090012)+, Hoh-Quillayute (17100101)+, Queets-Quinault (17100102)+, Upper Chehalis (17100103)+, Lower Chehalis (17100104)+, Grays Harbor (17100105)+, Willapa Bay (17100106)+, Necanicum (17100201)+, Nehalem (17100202)+, Wilson-Trusk-Nestuccu (17100203)+, Siletz-Yaquina (17100204)+, Alsea (17100205)+, Siuslaw (17100206)+, Siltcoos (17100207)+, North Umpqua (17100301)+, South Umpqua (17100302)+, Umpqua (17100303)+, Coos (17100304)+, Coquille (17100305)+, Sixes (17100306)+, Upper Rogue (17100307)+, Middle Rogue (17100308)+, Applegate (17100309)+, Lower Rogue (17100310)+, Illinois (17100311)+, Chetco (17100312)+, Fraser (17110001), Strait of Georgia (17110002)+, San Juan Islands (17110003), Nooksack (17110004)+, Upper Skagit (17110005)+, Sauk (17110006)+, Lower Skagit (17110007)+, Stillaguamish (17110008)+, Skykomish (17110009)+, Snoqualmie (17110010)+, Snohomish (17110011)+, Lake Washington (17110012)+, Duwamish (17110013)+, Puyallup (17110014)+, Nisqually (17110015)+, Deschutes (17110016)+, Skokomish (17110017)+, Hood Canal (17110018)+, Puget Sound (17110019)+, Dungeness-Elwha (17110020)+, Crescent-Hoko (17110021)+, Harney-Malheur Lakes (17120001)+, Silvies (17120002)+, Donner Und Blitzen (17120003)+, Silver (17120004)+, Summer Lake (17120005)+, Lake Abert (17120006)+, Warner Lakes (17120007)+, Guano (17120008)+
18 Smith (18010101)+, Mad-Redwood (18010102)+, Upper Eel (18010103), Middle Fork Eel (18010104)+, Lower Eel (18010105)+, South Fork Eel (18010106), Mattole (18010107)+, Big-Navarro-Garcia (18010108)+, Gualala-Salmon (18010109)+, Russian (18010110)+, Bodega Bay (18010111), Williamson (18010201)+, Sprague (18010202)+, Upper Klamath Lake (18010203)+, Lost (18010204), Butte (18010205), Upper Klamath (18010206)+, Shasta (18010207), Scott (18010208), Lower Klamath (18010209)+, Salmon (18010210)+, Trinity (18010211)+, South Fork Trinity (18010212)+, Goose Lake (18020001)+, Upper Pit (18020002), Lower Pit (18020003)+, Mccloud (18020004)+, Sacramento headwaters (18020005), Sacramento-Lower Cow-Lower Clear (18020101), Lower Cottonwood (18020102), Sacramento-Lower Thomes (18020103), Sacramento-Stone Corral (18020104)+, Lower Butte (18020105), Lower Feather (18020106), Lower Yuba (18020107), Lower Bear (18020108), Lower Sacramento (18020109), Lower Cache (18020110), Lower American (18020111)+, Sacramento-Upper Clear (18020112), Cottonwood headwaters (18020113), Upper Elder-Upper Thomes (18020114), Upper Stony (18020115)+, Upper Cache (18020116), Upper Putah (18020117), Upper Cow-Battle (18020118), Mill-Big Chico (18020119), Upper Butte (18020120), North Fork Feather (18020121), East Branch North Fork Feather (18020122), Middle Fork Feather (18020123), Honcut headwaters (18020124), Upper Yuba (18020125)+, Upper Bear (18020126)+, Upper Coon-Upper Auburn (18020127), North Fork American (18020128), South Fork American (18020129), Cow Creek (18020151)+, Cottonwood Creek (18020152)+, Battle Creek (18020153)+, Clear Creek-Sacramento River (18020154)+, Paynes Creek-Sacramento River (18020155)+, Thomes Creek-Sacramento River (18020156)+, Big Chico Creek-Sacramento River (18020157)+, Butte Creek (18020158)+, Honcut Headwaters-Lower Feather (18020159)+, Upper Coon-Upper Auburn (18020161)+, Upper Putah (18020162)+, Lower Sacramento (18020163)+, Upper Kern (18030001)+, South Fork Kern (18030002)+, Middle Kern-Upper Tehachapi- (18030003), Upper Poso (18030004), Upper Deer-Upper White (18030005), Upper Tule (18030006), Upper Kaweah (18030007), Mill (18030008), Upper Dry (18030009), Upper King (18030010), Upper Los Gatos-Avenal (18030011), Tulare-Buena Vista Lakes (18030012)*, Middle San Joaquin-Lower (18040001)+, Middle San Joaquin-Lower (18040002)+, San Joaquin Delta (18040003)+, Lower Calaveras-Mormon Slough (18040004), Lower Cosumnes-Lower Mokelumne (18040005), Upper San Joaquin (18040006), Upper Chowchilla-Upper Fresno (18040007)+, Upper Merced (18040008)+, Upper Tuolumne (18040009)+, Upper Stanislaus (18040010)+, Upper Calaveras (18040011)+, Upper Mokelumne (18040012)+, Upper Cosumnes (18040013)+, Panoche-San Luis Reservoir (18040014), Rock Creek-French Camp Slough (18040051)+, Suisun Bay (18050001)+, San Pablo Bay (18050002)+, Coyote (18050003), San Francisco Bay (18050004)+, Tomales-Drake Bays (18050005)+, San Francisco Coastal South (18050006)+, San Lorenzo-Soquel (18060001)+, Pajaro (18060002)+, Carrizo Plain (18060003), Estrella (18060004), Salinas (18060005)+, Central Coastal (18060006)+, Cuyama (18060007), Santa Maria (18060008)+, San Antonio (18060009), Santa Ynez (18060010)+, Alisal-Elkhorn Sloughs (18060011), Carmel (18060012)+, Santa Barbara Coastal (18060013)+, Ventura (18070101)+, Santa Clara (18070102)+, Calleguas (18070103)+, Santa Monica Bay (18070104)+, Los Angeles (18070105), San Gabriel (18070106), Seal Beach (18070201), San Jacinto (18070202), Santa Ana (18070203), Newport Bay (18070204), Aliso-San Onofre (18070301)+, Santa Margarita (18070302), San Luis Rey-Escondido (18070303), San Diego (18070304), Cottonwood-Tijuana (18070305), Honey-Eagle Lakes (18080003)+, Antelope-Fremont Valleys (18090206), Mojave (18090208)
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
U.S. Distribution by Watershed (based on multiple information sources) Help
Ecology & Life History
Basic Description: A partially anadromous salmonid.
Diagnostic Characteristics: Montana: both pure and moderately hybridized populations of westslope cutthroat trout have a high incidence of basibranchial teeth, whereas pure rainbow trout lack these teeth; presence of basibranchial teeth in some individuals of a rainbow trout population indicates hybridization with westslope cutthroat trout (Leary et al. 1996).
Reproduction Comments: Spawns usually in spring (February-June), or later depending on water temperature and location. Lays 200-9000 eggs (Wydoski and Whitney 1979), which hatch in 3-4 weeks at 10-15 C. Fry emerge from gravel 2-3 weeks after hatching. Many are sexually mature in 2-3 years. See Stearley (1992) for a discussion of the historical ecology and life history evolution of Pacific salmons and trouts (Oncorhynchus).
Ecology Comments: Normal life span 5-6 years (Simpson and Wallace 1982). Predation by Caspian terns and double-crested cormorants causes significant mortality of juvenile steelhead in the Columbia River estuary (Ryan et al. 2003). Aggressively defends feeding territories in streams. Has caused contraction of range of native brook trout in southern Appalachian Mountains region (Larson and Moore 1985).
Habitat Type: Freshwater
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: Y
Mobility and Migration Comments: Anadromous forms migrate up to at least hundreds of miles between spawning streams and nonspawning marine waters. Stream-dwelling trout may spend an entire life in few hundred meters of stream (Moyle 1976). Lake-dwelling trout typically migrate to tributaries to spawn.
Marine Habitat(s): Near shore, Pelagic
Estuarine Habitat(s): Bay/sound, Lagoon, River mouth/tidal river
Riverine Habitat(s): BIG RIVER, CREEK, High gradient, Low gradient, MEDIUM RIVER, Moderate gradient, Pool, Riffle
Lacustrine Habitat(s): Deep water, Shallow water
Special Habitat Factors: Benthic
Habitat Comments: Capable of surviving in a wide range of temperature conditions. Does best where dissolved oxygen concentration is at least 7 ppm. Anadromous populations occur in coastal rivers. Resident populations now inhabit small headwater streams, large rivers, lakes, or reservoirs; often in cool clear lakes and cool swift streams with silt-free substrate. In streams, deep low velocity pools are important wintering habitats (Sublette et al. 1990).

Usually requires a gravel stream riffle for successful spawning. Lake populations move to tributaries to spawn. Eggs are laid in gravel in a depression made by the female. Salinity of 8 ppt is the upper limit for normal development of eggs and alevins (Morgan et al. 1992).

Adult Food Habits: Invertivore, Piscivore
Immature Food Habits: Invertivore, Piscivore
Food Comments: In lakes, feeds mostly on bottom-dwelling invertebrates (e.g., aquatic insects, amphipods, worms, fish eggs, sometimes small fish) and plankton. In streams, feeds primarily on drift organisms. May ingest aquatic vegetation (probably for attached invertebrates). Diet changes seasonally. In the ocean, the diet consists of fishes and crustaceans.
Phenology Comments: May feed at any time throughout a 24-hour period, but usually feeds most actively around dusk.
Length: 100 centimeters
Economic Attributes
Economic Comments: Important game fish. Various populations have been cultured and introduced due to unique qualities (e.g., large lake form Kamloops; Eagle Lake rainbow, adapted to alkaline waters and usually piscivorous; Arlee strain, noted for fast growth, disease resistance, and high catchability (Sublette et al. 1990). Used in carcinogen testing (Metcalfe 1989).
Management Summary
Species Impacts: Smolt-to-adult survival of spring/summer run chinook salmon is negatively associated with releases of hatchery-reared steelhead in the Snake River (Levin and Williams 2002).
Management Requirements: A management concern in the West: keeping rainbow trout out of waters inhabited by native salmonids such as cutthroat trout and Gila trout so that the native species maintain their genetic integrity.

Allendorf et al. (1997) proposed criteria for prioritizing Pacific salmon stocks for conservation; data limitations introduce subjectivity into the process, so expert judgment and peer review should be incorporated into the process.

Population/Occurrence Delineation
Group Name: Fishes with Anadromous Populations

Use Class: Freshwater
Subtype(s): Rearing & Migration Area, Spawning & Rearing Area
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals (including eggs and larvae) in appropriate habitat. For anadromous populations, occurrences are based on collection or reliable observation and documentation of one or more spawning adults, redds, other evidence of spawning, or larvae or juveniles in appropriate spawning/rearing habitat.
Mapping Guidance: Conceptually, the occurrence includes the entire freshwater area used by the population, including spawning, rearing, and migration areas. For anadromous populations, an occurrence should extend from the most upstream spawning areas downstream to the ocean. However, it is desirable (and practical) to subdivide this sometimes very large occurrence, sometimes overlapping with many other spaghetti-like occurrences extending down from the upstream spawning areas to the ocean, into separate source features or sub-occurrences, labeled with a feature label that reflects the life history stage in that area. Moreover, it may make practical sense to treat the areas downstream of spawning and/or rearing areas as a mixed element animal assemblage: Freshwater Salmon Migration Corridor. This negates the need to separately map each occurrence down to the ocean from its upstream spawning location. Information about areas with different life-history uses can be generated by using best professional judgment by district or regional fish biologists and may or may not incorporate specific locational information from spawning surveys or other surveys.
Separation Barriers: Dam lacking a suitable fishway; high waterfall; upland habitat that is very unlikely to be submerged even during periods of exceptionally high water (e.g., 100-year flood or 1% flood).
Alternate Separation Procedure: For anadromous populations and migratory populations that have distinct and separate spawning and nonspawning areas, the area used by each population whose spawning area is separated by a gap of at least 10 stream-km from other spawning areas within a stream system is potentially mappable as a distinct occurrence that extends down to the ocean (but see mapping guidance), regardless of whether the spawning areas are in the same or different tributaries.

For other (e.g., nonanadromous) populations in streams, separation distance is 10 stream-km for both suitable and unsuitable habitat. However, if it is known that the same population occupies sites separated by more than 10 km (e.g., this may be common for migratory, nonanadromous populations), those sites should be included within the same occurrence. In lakes, occurrences include all suitable habitat that is presumed to be occupied (based on expert judgment), even if documented collection/observation points are more than 10 km apart. Separate sub-occurrences or source features may usefully document locations of critical spawning areas within a lake.

Separation Justification: The separation distance is arbitrary but was selected to ensure that occurrences are of manageable size but not too small. Because of the difficulty in defining suitable versus unsuitable habitat, especially with respect to dispersal, and to simplify the delineation of occurrences, a single separation distance is used regardless of habitat quality.

"Restricted movement is the norm in populations of stream salmonids during nonmigratory periods," but there is considerable variation in movements within and among species (Rodriguez 2002). Redband trout in Montana had October-December home ranges of 5-377 m, consistent with small movements observed for radio-tagged brook trout and cutthroat trout during fall and winter (Muhlfeld et al. 2001). For nonanadromous populations, little is known about juvenile dispersal (e.g., how far fishes may move between between their embryonic developmental habitat and eventual spawning site).

In summer and fall, radio-tagged cutthroat trout in Strawberry Reservoir in Utah had single-month home ranges that were usually about 3-4 km in maximum length (Baldwin et al. 2002). In the Blackfoot River drainage, Montana, radio-tagged westslope cutthroat trout moved 3-72 km (mean 31 km) to access spawning tributaries (Schmetterling 2001). This indicates that migratory but nonanadromous populations may use extensive areas and that one should not invoke the 10-km separation distance without considering the full extent of the population.

Date: 25Nov2009
Author: Hammerson, G., and L. Master
Notes: This Specs Group comprises fish species that include anadromous populations (may also include nonanadromous populations), such as lampreys, sturgeons, herrings, shads, salmonids, and smelts.

Criteria for marine occurrences (Location Use Class: Marine) have not yet been established. These may not be needed for marine occurrences of species that likely will be dealt with as mixed element assemblages (e.g., Salmonid Marine Concentration Area).

Feature Descriptor Definitions:

Spawning Area: area used for spawning but not for rearing or migration.

Rearing Area: area used for larval/juvenile development but not for spawning or migration.

Migration Corridor: area used for migration but not for rearing or spawning.

Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 15Jan2008
Management Information Edition Date: 12Dec2002
Element Ecology & Life History Edition Date: 05Jan2004
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

  • Allen, C. R., S. Demarais, and R. S. Lutz. 1994. Red imported fire ant impact on wildlife: an overview. The Texas Journal of Science 46(1):51-59.

  • Allendorf, F. W., D. Bayles, D. L. Bottom, K. P. Currens, C. A. Frissell, D. Hankin, J. A. Lichatowich, W. Nehlsen, P. C. Trotter, and T. H. Williams. 1997. Prioritizing Pacific salmon stocks for conservation. Conservation Biology 11:140-152.

  • Anderson, Allison A., C. Hubbs, K. O. Winemiller, and R. J. Edwards. 1995. Texas freshwater fish assemblages following three decades of environmental change. The Southwest Naturalist 40(3):314-321.

  • Aquin, P. 1999. Évaluation de la situation des groupes taxonomiques des poissons du Québec. Ministère de l'Environnement et de la Faune. 9 pages.

  • Atton, F.M. and J.J. Merkowsky. 1983. Atlas of Saskatchewan Fish. Saskatchewan Department of Parks and Renewable Resources, Fisheries Branch Technical Report 83-2. 281pp.

  • Bain, C., S.T. Elliott, R.E. Johnson and G. Woods. 2003. Situk River steelhead: a review of historical data through 1996. Fishery Manuscript No. 03-01. Anchorage, AK: Alaska Department of Fish and Game.

  • Barnhart, R. A. 1986. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)--steelhead. U.S. Fish and Wildlife Service Biological Report 82(11.60).

  • Becker, G. C. 1983. Fishes of Wisconsin. Univ. Wisconsin Press, Madison. 1052 pp.

  • Begich, R.N. 1997. Assessment of the 1995 return of steelhead to the Karluk River, Alaska. Fishery Data Series No. 97-6. Anchorage, AK: Alaska Department of Fish and Game.

  • Behnke, R. J. 1992. Native trout of western North America. American Fisheries Society Monograph 6. xx + 275 pp.

  • Berg, D. R. 1995. Riparian silvicultural system design and assessment in the Pacific Northwest Cascade Mountains, USA. Ecological Applications 5:87-96.

  • Burgner, R.L., J.T. Light, L.Margolis, T.Okazaki, A. Tautz and S. Ito. 1992. Distribution and orgins of steelhead trout in offshore waters of the North Pacific Ocean. International North Pacific Fisheries Commission Bulletin No. 51. Vancouver, Canada: International North Pacific Fisheries Commission.

  • Burgner, R.L., J.T. Light, L.Margolis, T.Okazaki, A. Tautz and S. Ito. 1992. Distribution and orgins of steelhead trout in offshore waters of the North Pacific Ocean. International North Pacific Fisheries Commission Bulletin No. 51. Vancouver, Canada: International North Pacific Fisheries Commission.

  • Busby, P. J., T. C. Wainwright, G. J. Bryant, L. J. Lierheimer, R. S. Waples, F. W. Waknitz, and I. V. Lagomarsino. 1996. Status review of west coast steelhead from Washington, Oregon, and California. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-NWFSC-27. 261 pp.

  • Canadian Endangered Species Conservation Council (CESCC). 2016. Wild Species 2015: The General Status of Species in Canada. National General Status Working Group.

  • Coad, Brian W. 1995. Encyclopedia of Canadian Fishes. Canadian Museum of Nature and Canadian Sportfishing Productions Inc. 928 pp.

  • Currens, K. P., C. B. Schreck, and H. W. Li. 1990. Allozyme and morphological divergence of rainbow trout (Oncorhynchus mykiss) above and below waterfalls in the Deschutes River, Oregon. Copeia 1990:730-746.

  • Duncan, J.R. 1997. Conservation Status Ranks of the Fishes of Manitoba. Manitoba Conservation Data Centre MS Report 97-02. Winnipeg, MB. 10 pp.

  • Eaton, D.M. and F.J. Adams. 1995. The effects of global warming on the distribution of steelhead trout populations on the Alaska Peninsula, AK. U.S. Fish and Wildlife Service, AK Fisheries Technical Report Number 33, King Salmon, Alaska.

  • Etnier, David A. and Wayne C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press, Knoxville. 681 pp.

  • Fleming, D.F. 2000. Stock assessment of rainbow trout in summit lake and surveys of rainbow and steelhead trout in the Gulkana River, 1999. Fishery Data Series No. 00-33. Anchorage, AK: Alaska Department of Fish and Game.

  • Fuller, P. L., L. G. Nico, and J. D. Williams. 1999. Nonindigenous fishes introduced into inland waters of the United States. American Fisheries Society, Special Publication 27. x + 613 pp.

  • General Status 2015, Environment Canada. 2015. Manitoba fish species and subnational ranks proposed by DFO.

  • George, C.J. 1980. The fishes of the Adirondack Park. New York State Department of Environmental Conservation Albany, NY 94 pp.


  • Harding, R. and T. Brookover. 2003. Southeast Alaska trout and steelhead management report to the Alaska board of fisheries. Douglas, AK: Alaska Department of Fish and Game.

  • Hendrickson, D.A. (ed.). 1992. Proceedings of the Desert Fishes Council, Volumes XXII and XXIII, 1990 and 1991 Annual Symposia and Index for Volumes XVI through XXIII. Desert Fishes Council, Bishop, CA.

  • Hoover, E.E. (ED.) 1938. Biological Survey of the Merrimack Watershed. Survey Report No.3. New Hampshire Fish and Game Department., Concord. 238 pp.

  • Huntington, C., W. Nehlsen, and J. Bowers. 1996. A survey of healthy native stocks of anadromous salmonids in the Pacific Northwest and California. Fisheries 21(3):6-14.

  • Johnson, J.H. and N.H. Ringler. 1981. Natural reproduction and juvenile ecology of Pacific salmon and rainbow trout in tributaries of the Salmon River, New York. New York Fish and Game J. 28(1):49-60.

  • Johnson, S.W, J. Heifetz and K.V. Koski. 1986. Effects of logging on the abundance and seasonal distribution of juvenile Steelhead in some southeastern Alaska Streams. North American Journal of Fisheries Management 6:532-537.

  • Kido, M. H., D. E. Heacock, and A. Asquith. 1999. Alien rainbow trout (Oncorhynchus mykiss) (Salmoniformes: Salmonidae) diet in Hawaiian streams. Pacific Science 53:242-251.

  • Larson, G. L., and S. E. Moore. 1985. Encroachment of exotic rainbow trout into stream populations of native brook trout in the southern Appalachian Mountains. Transactions of the American Fisheries Society 114:195-203.

  • Leary, R. F., W. R. Gould, and G. K. Sage. 1996. Success of basibranchial teeth in indicating pure populations of rainbow trout and failure to indicate pure populations of westslope cutthroat trout. North American Journal of Fisheries Management 16:210-213.

  • Lee, D. C., and J. Hyman. 1992. The stochastic life-cycle model (SLCM): simulating the population dynamics of anadromous salmonids. United States Department of Agriculture, Forest Service, Intermountain Research Paper INT-459, Ogden, Utah. 30 pp.

  • 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. North Carolina State Museum of Natural History, Raleigh, North Carolina. i-x + 854 pp.

  • Legendre, V. et J.F. Bergeron. 1977. Liste des poissons d' eau douce du Québec. MLCP, Service Aménage. Expl. Faune. Rap. dact. 6

  • Levin, P. S., and J. G. Williams. 2002. Interspecific effects of artificially propagated fish: an additional conservation risk for salmon. Conservation Biology 16:1581-1587.

  • Lohr, S.C. and M.D. Bryant. 1999. Biological characteristics and population status of steelhead in Southeast Alaska. USDA, Forest Service, General technical report PNW-GTR-407, Juneau, AK.

  • MacCrimmon, H.R. 1971. World distribution of rainbow trout, Salmo gairdneri. Journal of the Fisheries Research Board of Canada 28(5):663-704.

  • MacCrimmon, H.R. 1972. World distribution of rainbow trout, Salmo gairdneri: Further observations. Journal of the Fisheries Research Board of Canada 29(12): 1788-1791.

  • Marshall, T.L. and R.P. Johnson. 1971. History and results of fish introductions in Saskatchewan: 1900 - 1969. Fisheries Report No 8. Fisheries and Wildlife Branch, Department of Natural Resources, Province of Saskatchewan.

  • McAfee, W. R. 1966. Rainbow trout. pp. 192-215 in A. Calhoun (editor), Inland fisheries management, California Department of Fish and Game, Sacramento, California. 546 pp.

  • Meffe, G.K. and C.R. Carroll. 1997. Principles of conservation biology. Pp. 217-219. Sinauar Associates Inc. Publishers, Sunderland, MA.

  • Metcalfe, C. D. 1989. Tests for predicting carcinogenicity in fish. Reviews in Aquatic Sciences 1(1):111-129.

  • Mooney, P. 2001. Yakutat forelands fish habitat and ATV assessment. Douglas, AK: Alaska Department of Fish and Game.

  • Morgan, J. D., J. O. T. Jensen, and G. K. Iwama. 1992. Effects of salinity on aerobic metabolism and development of eggs and alevins of steelhead trout (Oncorhynchus mykiss) and fall chinook salmon (Oncorhynchus tshawytscha). Canadian Journal of Zoology 70(7):1341-1346.

  • Morrow, J.E. 1980. The freshwater fishes of Alaska. Alaska Northwest Publishing Company, Anchorage, AK. 248 pp.

  • Moyle, P. B. 1976a. Inland fishes of California. University of California Press, Berkeley, California. 405 pp.

  • Moyle, P. B. 2002. Inland fishes of California. Revised and expanded. University of California Press, Berkeley. xv + 502 pp.

  • National Marine Fisheries Service (NMFS). 11 February 2000c. Threatened status for one evolutionarily significant unit of steelhead in California. Federal Register 65(29):6960-6975..

  • National Marine Fisheries Service (NMFS). 18 August 1997. Listing of several Evolutionary [sic] Significant Units (ESUs) of west coast steelhead. Federal Register 62(159):43937-43954.

  • Nehlsen, W., J. E. Williams, and J. A. Lichatowich. 1991. Pacific salmon at the crossroads: stocks at risk from California, Oregon, Idaho, and Washington. Fisheries 16(2):4-21.

  • Nelson, J. S., E. J. Crossman, H. Espinosa-Perez, L. T. Findley, C. R. Gilbert, R. N. Lea, and J. D. Williams. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American Fisheries Society, Special Publication 29, Bethesda, Maryland. 386 pp.

  • Page, L. M., H. Espinosa-Pérez, L. T. Findley, C. R. Gilbert, R. N. Lea, N. E. Mandrak, R. L. Mayden, and J. S. Nelson. 2013. Common and scientific names of fishes from the United States, Canada, and Mexico. Seventh edition. American Fisheries Society, Special Publication 34, Bethesda, Maryland.

  • Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.

  • Page, L. M., and B. M. Burr. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. Second edition. Houghton Mifflin Harcourt, Boston. xix + 663 pp.

  • Page, LM, H.Espinoza-Perez, L.Findley, C.Gilbert, R. Lea, N. Mandrak, R.Mayden and J.Nelson. 2013. Common and scientific names of fishes from the United States, Canada, and Mexico, 7th edition. American Fisheries Society, Special Publication 34, Bethesda, Maryland.

  • Pister, E.P. (ed.). 1991. Proceedings of the Desert Fishes Council, Volumes XX and XXI, the Twentieth & Twenty-first Annual Symposia. Desert Fishes Council, Bishop, CA.

  • Platania, S.P. 1990. Biological summary of the 1987 to 1989 New Mexico-Utah ichthyofaunal study of the San Juan River. Prepared by Department of Biology, University of New Mexico, Albuquerque, for New Mexico Department of Game and Fish, Santa Fe, under contract 78-516.6-01, and U.S. Bureau of Reclamation, Salt Lake City, UT, under cooperative agreement 7-FC-40-05060.


  • Rainbow Trout. 1999. B.C. Fish Facts. Conserv. Sect., Fish. Manage. Branch, B.C. Minist. Fish. 2pp.

  • Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.

  • Rodriguez, M. A. 2002. Restricted movement in stream fish: the paradigm is complete, not lost. Ecology 83(1):1-13.

  • Ryan, B. A., S. G. Smith, J. M. Butzerin, and J. W. Ferguson. 2003. Relative vulnerability to avian predation of juvenile salmonids tagged with passive integrated transponders in the Columbia River estuary, 1998-200. Transactions of the American Fisheries Society 132:275-288.

  • Ryden, D.W. and F.K. Pfeifer. 1993. Adult fish collections on the San Juan River (1991-1992): draft annual progress report, March 15, 1993. Submitted to U.S. Fish & Wildlife Service, Grand Junction, CO.

  • Ryden, D.W. and F.K. Pfeifer. 1994. Adult fish community monitoring on the San Juan River: 1993 annual progress report. Draft. Colorado River Fishery Project, U.S. Fish and Wildlife Service, Grand Junction, CO.

  • Saskatchewan Environment and Resource Management. 1996. The Fisheries Regulations being Chapter F-16.1 Reg 1 (effective 9 May 1995) as ammended by Saskatchewan Regulations 13/96.

  • Scarola, J.F. 1973. Freshwater Fishes of New Hampshire. New Hampshire Fish and Game Department. 131 pp.

  • Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. 966 pp.

  • Scott, W.B. and E.J. Crossman. 1979. Freshwater Fishes of Canada. Fisheries Research Board of Canada, Ottawa. 966 pp.

  • Shapovalov, L. and A.C. Taft. 1954. The life history of the steelhead rainbow trout and silver salmon with special reference to Waddell Creek, California, and recommendations for their management. California Department of Fish and Game, Fish Bulletin 98:1-375.

  • Simon, Thomas P. 2011. Fishes of Indiana. Indiana University Press. Bloomington, 345 pp.

  • Slaney, T. L., K. D. Hyatt, T. G. Northcote, and R. J. Fielden. 1996. Status of anadromous salmon and trout in British Columbia and Yukon. Fisheries 21(10):20-35.

  • Smith, C.L. 1985. The Inland Fishes of New York State. New York State Department of Environmental Conservation. Albany, NY. 522pp.

  • Smith, G. R., and R. F. Stearley. 1989. The classification and scientific names of rainbow and cutthroat trouts. Fisheries (Bethesda) 14(1):4-10.

  • Stark, T.C. 1999. Spawning stocks and juvenile summer habitat of rainbow trout and steelhead, Gulkana River, AK. M.S. thesis. University of Alaska, Fairbanks.

  • Stearley, R. F. 1992. Historical ecology of Salmoninae, with special reference to Oncorhynchus. Pages 622-658 in R.L. Mayden, editor. Systematics, historical ecology, and North American freshwater fishes. Stanford University Press, Stanford, California. xxvi + 969 pp.

  • Steelhead Trout. 1999. B.C. Fish Facts. Conserv. Sect., Fish. Manage. Branch, B.C. Minist. Fish. 2pp.

  • Stewart, K.W., McCulloch, B. Hanke, G. and J.R. Duncan. 1995. Preliminary ranking of Manitoba fish. Unpublished notes from an informal ranking workshop held at the University of Manitoba Fish Laboratory. 7 February 1995.

  • Stewart, K.W., and D. A. Watkinson. 2004. The freshwater fishes of Manitoba. University of Manitoba Press. Winnipeg. 276 p.

  • Stoltz, J., and J. Schnell (eds.). 1991. Trout: The Wildlife Series. Stackpole Books, Harrisburg, Pennsylvania. 384 pp.

  • Stow, C. A., S. R. Carpenter, L. A. Eby, J. F. Amrhein, and R. J. Hesselberg. 1995. Evidence that PCBc are approaching stable concentrations in Lake Michigan fishes. Ecological Applications 5:248-260.

  • Sublette, J. E., M. D Hatch, and M. Sublette. 1990. The fishes of New Mexico. University New Mexico Press, Albuquerque, New Mexico. 393 pp.

  • Sutherland, D.F. 1973. Distribution, seasonal abundance and some biological features of Steelhead Trout in the North Pacific Ocean. Northwest Fisheries Center, National Marine Fisheries Service, NOAA, Seattle WA.

  • Thedinga, T.F., S.W. Johnson, K.V. Koski, J.M. Lorenz and M.L. Murphy. 1993. Potential effects of flooding from Russel Fiord on salmonids and habitat in the Situk River, Alaska. Alaska Fisheries Science Center. Juneau, AK.

  • U.S. Fish and Wildlife Service (USFWS). 16 November 1998. 90-day finding on a petition to list the redband trout in the Great Basin as threatened or endangered. Federal Register 63(220):63657-63659.

  • VanHulle, F.D. 1985. Alaska steelhead workshop. Juneau, AK: Alaska Department of Fish and Game.

  • Walis, J. and D.T. Balland. 1983. Anchor River Steelhead Investigations. AFS-48. Juneau, AK: Alaska Department of Fish and Game.

  • Warfel, H.E. 1939. Biological Survey of the Connecticut Wa tershed. New Hampshire Fish and Game Dept. Concord, NH. 2 56pp.

  • Werner, R.G. 1980. Freshwater fishes of New York State. N.Y.: Syracuse University Press. 186 pp.

  • Wildlife Management Information System (WMIS). 2006+. Geo-referenced wildlife datasets (1900 to present) from all projects conducted by Environment and Natural Resources, Government of the Northwest Territories, Canada.  Available at http://www.enr.gov.nt.ca/programs/wildlife-research/wildlife-management-information-services

  • Williams, J. E., J. A. Lichatowich, and W. Nehlsen. 1992b. Declining salmon and steelhead populations: new endangered species concerns for the West. Endangered Species Update 9(4):1-8.

  • Wishard, L.N., J.E. Seeb, F.M. Utter and D. Stefan 1984. A genetic investigation of suspected redband trout populations. Copeia 1984(1):120-132.

  • Wydoski, R. S., and R. R. Whitney. 1979. Inland fishes of Washington. The University of Washington Press, Seattle. 220 pp.

References for Watershed Distribution Map
  • Behnke, R. J. 2002. Trout and salmon of North America. The Free Press, New York, New York. 359 pp.

  • Holton, G. D., and H. E. Johnson. 1996. A field guide to Montana fishes. 2nd edition. Montana Fish, Wildlife and Parks, Montana State Parks and wildlife Interpretive Association, Helena, Montana. 104 pp.

  • Marcy, B. C., Jr., D. E. Fletcher, F. D. Martin, M. H. Paller, and M.J.M. Reichert. 2005. Fishes of the middle Savannah River basin. University of Georgia Press, Athens. xiv + 460 pp.

  • Master, L. L. 1996. Synoptic national assessment of comparative risks to biological diversity and landscape types: species distributions. Summary Progress Report submitted to Environmental Protection Agency. The Nature Conservancy, Arlington, Virginia. 60 pp.

  • Master, L. L. and A. L. Stock. 1998. Synoptic national assessment of comparative risks to biological diversity and landscape types: species distributions. Summary Report submitted to Environmental Protection Agency. The Nature Conservancy, Arlington, VA. 36 pp.

  • Simpson, J. and R. Wallace. 1982. Fishes of Idaho. The University Press of Idaho, Moscow, Idaho. 238 pp.

  • State Natural Heritage Data Centers. 1996a. Aggregated element occurrence data from all U.S. state natural heritage programs, including the Tennessee Valley Authority, Navajo Nation and the District of Columbia. Science Division, The Nature Conservancy.

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