The westslope cutthroat trout (''Oncorhynchus clarkii lewisi''), also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the

cutthroat trout The cutthroat trout is a fish species of the family Salmonidae native to cold-water tributaries of the Pacific Ocean, Rocky Mountains, and Great Basin in North America. As a member of the genus '' Oncorhynchus'', it is one of the Pacific tro ...

(''Oncorhynchus clarkii'') and is a

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

in the

salmon Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

(family

Salmonidae Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

) of order

Salmoniformes Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

. The cutthroat is the

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

state fish.1-1-507. State fish
Montana Code, accessed 23 April 2009. This subspecies is a ''species of concern'' in its Montana and British Columbia ranges and is considered ''threatened'' in its native range in

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

Taxonomy

The scientific name of the westslope cutthroat trout is ''Oncorhynchus clarkii lewisi''. The subspecies was first described in the journals of explorer William Clark from specimens obtained during the Lewis and Clark Expedition from the Missouri River near

Great Falls, Montana Great Falls is the third most populous city in the U.S. state of Montana and the county seat of Cascade County. The population was 60,442 according to the 2020 census. The city covers an area of and is the principal city of the Great Falls, M ...

. Cutthroat trout were given the name ''Salmo clarki'' in honor of William Clark, who co-led the expedition of 1804–1806. One of Lewis and Clark's missions was to describe the flora and fauna encountered during the expedition. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

of ''S. clarki'' was described by naturalist John Richardson in 1836 from a tributary of the lower

Columbia River The Columbia River (Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, C ...

, identified as the "Katpootl", which was perhaps the Lewis River as there was a Multnomah village of similar name at the

confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...

. This type specimen was most likely the coastal cutthroat subspecies. In 1853, naturalist

George Suckley George Suckley (1830–1869) was an American physician and naturalist notable as an explorer of the Washington and Oregon territories in the 1850s, and describer of several new fish species. Life He was born in New York City, studied at the Colle ...

while working for the

Pacific Railroad Survey The Pacific Railroad Surveys (1853–1855) were of a series of explorations of the American West designed to find and document possible routes for a transcontinental railroad across North America. The expeditions included surveyors, scientists, and ...

led by

Isaac Stevens Isaac Ingalls Stevens (March 25, 1818 – September 1, 1862) was an American military officer and politician who served as governor of the Territory of Washington from 1853 to 1857, and later as its delegate to the United States House of Represen ...

collected specimens of westslope cutthroat trout by

fly fishing Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...

below the

Great Falls Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People * List of people known as "the Great" *Artel Great (born ...

on the Missouri River. In 1856, he described the trout as ''Salar lewisi'' to honor explorer

Meriwether Lewis Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with ...

. In

David Starr Jordan David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford Univer ...

and

Barton Warren Evermann Barton Warren Evermann (October 24, 1853 – September 27, 1932) was an American ichthyologist. Early life and education Evermann was born in Monroe County, Iowa in 1853. His family moved to Indiana while he was still a child and it was ...

's ''A Check-list of the Fishes and Fishlike Vertebrates of North and Middle America'' (1896), the name ''Salmo mykiss lewisi'' was given to Yellowstone trout or cut-throat trout and included a reference to specimens collected from the Missouri River by George Suckley. In 1898, Jordan and Evermann changed the name of cutthroat trout to ''Salmo clarki''. ''Salmo clarki lewisi'' persisted as the subspecies name for both the Yellowstone cutthroat and westslope cutthroat trout until 1971 when fisheries biologist Robert J. Behnke gave the name ''Salmo clarki bouvieri'' to the Yellowstone cutthroat with ''Salmo clarki lewisi'' reserved for the westslope cutthroat trout. In 1989, morphological and genetic studies indicated trout of the

Pacific basin The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

were genetically closer to Pacific salmon (''Oncorhynchus'' species) than to the ''

Salmo ''Salmo'' is a genus of ray-finned fish from the family Salmonidae. The single ''Salmo'' species naturally found in the Atlantic North America is the Atlantic salmon, whereas the salmon and trout of the Pacific basin belong to another genus, '' ...

''s–

brown trout The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morph ...

(''S. trutta'') or

Atlantic salmon The Atlantic salmon (''Salmo salar'') is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlantic salmon are ...

(''S. salar'') of the

Atlantic basin The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

. Thus, in 1989, taxonomic authorities moved the rainbow, cutthroat and other Pacific basin trout into the genus ''Oncorhynchus''.

Description

The fish has teeth under its tongue, on the roof of the mouth, and in the front of the mouth. Westslope cutthroat are common in both headwaters lake and stream environments. They feed mainly on insects and zooplankton. The average length of the fish is about 8- and rarely exceeds . The skin has small dark freckle-like spots clustered towards the tail, and is mostly orange-hued. They can be distinguished from rainbow trout by the red, pink, or orange marking beneath the jaw (hence the name "cutthroat").

Range

Westslope cutthroat trout are native in northern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

's and

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

's upper

system and northern tributaries of the

Snake River The Snake River is a major river of the greater Pacific Northwest region in the United States. At long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake ...

, but not the Snake River's main stem to the south. East of the

Continental Divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...

and Montana, westslope cutthroat trout are native to the upper

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

Milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...

and

North Saskatchewan river The North Saskatchewan River is a glacier-fed river that flows from the Canadian Rockies continental divide east to central Saskatchewan, where it joins with the South Saskatchewan River to make up the Saskatchewan River. Its water flows eventual ...

s, but not the

Yellowstone River The Yellowstone River is a tributary of the Missouri River, approximately long, in the Western United States. Considered the principal tributary of upper Missouri, via its own tributaries it drains an area with headwaters across the mountains an ...

to the south. In Montana, the historic range extended east to the mouth of the

Judith River The Judith River is a tributary of the Missouri River, approximately 124 mi (200 km) long, running through central Montana in the United States. It rises in the Little Belt Mountains and flows northeast past Utica and Hobson. It is ...

and south into the

Madison Madison may refer to: People * Madison (name), a given name and a surname * James Madison (1751–1836), fourth president of the United States Place names * Madison, Wisconsin, the state capital of Wisconsin and the largest city known by this ...

, Gallatin and

Jefferson river The Jefferson River is a tributary of the Missouri River, approximately long, in the U.S. state of Montana. The Jefferson River and the Madison River form the official beginning of the Missouri at Missouri Headwaters State Park near Three For ...

systems. Isolated populations of westslope cutthroat trout exist in upper tributaries of the

John Day River The John Day River is a tributary of the Columbia River, approximately long, in northeastern Oregon in the United States. It is known as the Mah-Hah River by the Cayuse people, the original inhabitants of the region. Undammed along its entire ...

in the

Strawberry Mountains The Strawberry Range, also known as the Strawberry Mountains, is a mountain range in the U.S. state of Oregon. It is east of John Day, within Malheur National Forest. The highest peak is Strawberry Mountain. The Strawberry Range is part of the ...

of Oregon and Columbia River tributaries along the eastern side of the

Cascade range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. Isolated populations exist in the

Fraser River The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of Vancouver. The river's annual d ...

basin in British Columbia. Existing populations of genetically pure westslope cutthroat trout exist in less than three percent of its historic range.

Life cycle

Westslope cutthroat trout reflect three life strategies—adfluvial, fluvial, or stream resident. Adfluvial fish live in the large lakes in the upper Columbia River drainage and spawn in lake tributaries. Fluvial fish live in medium to large rivers but migrate to tributaries for spawning. Most adults return to the river or lake after spawning. Stream resident fish complete their entire life in tributaries. All three forms occur in most basins.

Conservation

Genetically pure westslope cutthroat trout have been

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

throughout most of their historic range due to habitat loss and introduction of non-native species. Remaining populations survive in isolated populations, mostly in headwater streams above natural downstream barriers. The introduction of

rainbow A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows c ...

and

into Missouri River tributaries eliminated the westslope cutthroat trout from most of its eastern range in Montana. Introductions of non-native

kokanee salmon The kokanee salmon (''Oncorhynchus nerka''), also known as the kokanee trout, little redfish, silver trout, kikanning, Kennerly's salmon, Kennerly's trout, or Walla, is the non-anadromous form of the sockeye salmon (meaning that they do not migrat ...

(''Oncorhynchus nerka''),

lake trout The lake trout (''Salvelinus namaycush'') is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, and grey trout. In Lake Superior, it can also ...

(''Salvelinus namaycush'') and

lake whitefish The lake whitefish (''Coregonus clupeaformis'') is a species of freshwater whitefish from North America. Lake whitefish are found throughout much of Canada and parts of the northern United States, including all of the Great Lakes. The lake white ...

(''Coregonus clupeaformis'') into

Flathead Lake Flathead Lake ( fla, člq̓etkʷ, label=Salish, kut, yawuʔnik̓ ʔa·kuq̓nuk) is a large natural lake in northwest Montana. The lake is a remnant of the ancient, massive glacial dammed lake, Lake Missoula of the era of the last interglacial. ...

and the

Flathead River The Flathead River ( fla, label= Salish, člq̓etkʷ ntx̣ʷetkʷ, , kut, kananmituk), in the northwestern part of the U.S. state of Montana, originates in the Canadian Rockies to the north of Glacier National Park and flows southwest into Fla ...

system caused drastic declines in westslope cutthroat trout populations. Existing populations are in imminent danger from land-use activities and hybridization with introduced

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

(resulting in

cutbow A cutbow ('' Oncorhynchus clarkii'' × ''mykiss'') is an interspecific fertile hybrid between a rainbow trout (''Oncorhynchus mykiss'') and a cutthroat trout (''O. clarkii''). Cutbow hybrids may occur naturally where the native ranges of both ...

s) and

Yellowstone cutthroat trout The Yellowstone cutthroat trout (''Oncorhynchus clarkii bouvieri'') is a subspecies of the cutthroat trout (''Oncorhynchus clarkii''). It is a freshwater fish in the salmon family (family Salmonidae). Native only to a few U.S. states, their ...

. Even the strongest populations in Glacier National Park and the Flathead Basin of Montana are in serious decline. Reasons for the critical condition of the subspecies include

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

from logging, road building, grazing, mining, urban development, agriculture and dams, introduction of non-native hatchery strains, competition and hybridization from introduced non-native fish species.

Notes

External links

*
Montana Fish, Wildlife & Parks :: Westslope Cutthroat Trout
{{Taxonbar, from=Q7989725 Oncorhynchus Cold water fish Freshwater fish of North America Fish of Canada Fish of the Western United States Freshwater fish of the United States Fauna of the Northwestern United States Fauna of the Rocky Mountains Natural history of Montana Symbols of Montana Taxa named by George Suckley Fish described in 1856