Westslope cutthroat trout
The westslope cutthroat trout (Oncorhynchus clarkii lewisi), also known as the blackspotted cutthroat, is a subspecies of the cutthroat trout
Cutthroat trout
The cutthroat trout is a species of freshwater fish in the salmon family of order Salmoniformes. It is one of the many fish species colloquially known as trout...

 (Oncorhynchus clarkii) and is a freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...

 in the salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (family Salmonidae
Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...

) of order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Salmoniformes. The cutthroat is the Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

 state fish. This subspecies is a species of concern.


Westslopes are native in northern Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

's and British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

's upper Columbia system
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

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

, but not the Snake River's main stem to the south. Across the Continental Divide
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...

 in Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

 and Montana, westslopes are native to the upper Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

, Milk River
Milk River
-Rivers:Canada and the United States*The Milk River , a tributary of the upper Fraser River in Canada*The Milk River , United States*The Milk River , a tributary of the Missouri RiverJamaica*The Milk River...

 and North Saskatchewan River
North Saskatchewan River
The North Saskatchewan River is a glacier-fed river that flows east from the Canadian Rockies to central Saskatchewan. It is one of two major rivers that join to make up the Saskatchewan River....

, but not the Yellowstone River
Yellowstone River
The Yellowstone River is a tributary of the Missouri River, approximately long, in the western United States. Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National...

 to the south. Instead, Yellowstone cutthroat trout
Yellowstone cutthroat trout
The Yellowstone cutthroat trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of the order Salmoniformes. Native only to a few U.S...

 are found south of westslopes on both sides of the Continental Divide. However there is a remnant population of westslopes in Oregon. Small populations persist in upper tributaries of the John Day River
John Day River
The John Day River is a tributary of the Columbia River, approximately long, in northeastern Oregon in the United States. Undammed along its entire length, the river is the third longest free-flowing river in the conterminous United States. There is extensive use of its waters for irrigation. Its...

 in the Strawberry Mountains
Blue Mountains (Oregon)
The Blue Mountains are a mountain range in the western United States, located largely in northeastern Oregon and stretching into southeastern Washington...



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 8-12 inches (30 cm) and rarely exceeds 18 inches (46 cm). 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 (whence the name "cutthroat").


The westslope cutthroat trout is an indicator species of the health of the entire ecosystem of its habitat. It requires pure, cold water for survival, secure connected habitat (tributaries and main stems), and protection from introduced nonnative fish. When these requirements are not met, the number of individuals plummets. The subspecies is also in danger of hybridization and may in fact disappear from the Northern Rockies without a region wide, long-term effective protection and recovery effort.

Pure westslope cutthroat are extirpated throughout most of their historic range, and existing populations are in imminent danger from land-use activities and hybridization with introduced rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

 (resulting in cutbow
A Cutbow is a fertile hybrid between a rainbow trout and a cutthroat trout . While cutbow hybrids may occur naturally, most native populations of rainbows and cutthroats were separated by geography or habitat...

s) and Yellowstone cutthroat trout
Yellowstone cutthroat trout
The Yellowstone cutthroat trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of the order Salmoniformes. Native only to a few U.S...

. Even the strongest populations in Glacier National Park and the Flathead Basin
Flathead Lake
Flathead Lake is the largest natural freshwater lake in the western part of the contiguous United States. With a surface area of between and , it is slightly larger than Lake Tahoe. The lake is a remnant of the ancient inland sea, Lake Missoula of the era of the last interglacial. Flathead Lake...

 of Montana are in serious decline. Reasons for the critical condition of the subspecies include habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...

 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.

The Northern Rockies conservation community’s campaign to protect and recover the westslope cutthroat trout involves a broad coalition of scientists, conservationists, American heritage historians, the sportfishing community, the arts and humanities community, representatives of Native American and ranching communities, and politicians.

Origin of scientific name

The westslope cutthroat trout has the trinomial name Oncorhynchus clarkii lewisi, in honor of Meriwether Lewis
Meriwether Lewis
Meriwether Lewis was an American explorer, soldier, 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 William Clark...

 and William Clark who led the Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 of 1804–1806. The expedition discovered the subspecies at Great Falls of the Missouri in what is now Montana. One of Lewis and Clark’s missions was to bring back word and samples of the flora and fauna encountered during the expedition.

External links

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