The Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus) is a subspecies of 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...

 native only to the Green

Green River (Utah)

The Green River, located in the western United States, is the chief tributary of the Colorado River. The watershed of the river, known as the Green River Basin, covers parts of Wyoming, Utah, and Colorado. The Green River is long, beginning in the Wind River Mountains of Wyoming and flowing...

 and Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 basins, which are west of 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...

. 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...

 found in other river basins belong to other subspecies.

Range

In the past, this subspecies was found throughout portions of the Colorado River drainage in Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, Utah

Utah

Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

, Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, and New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

. However, today scientists believe this fish occupies 13% of its historic range (Range-Wide Status of Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus):
2005).

Colorado River cutthroats are thought to have occupied the basin of upper Muddy Creek, a tributary of the Little Snake River

Little Snake River

The Little Snake River is a tributary of the Yampa River, approximately 150 mi long, in southwestern Wyoming and northwestern Colorado in the United States....

 (which ultimately flows into the Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

) in southern Carbon County

Carbon County, Wyoming

Carbon County is a county located in the U.S. state of Wyoming. As of 2010, the population was 15,885. Its county seat is Rawlins.- History :Carbon County was organized in 1868....

, Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

. Historical accounts in letters and diaries refer to them as "mountain trout" or "speckled trout." The fish may have begun to disappear from the upper Muddy Creek in the 1850s as a result of physical changes made to the environment by travelers, the introduction of the brook trout

Brook trout

The brook trout, Salvelinus fontinalis, is a species of fish in the salmon family of order Salmoniformes. In many parts of its range, it is known as the speckled trout or squaretail. A potamodromous population in Lake Superior are known as coaster trout or, simply, as coasters...

 and other non-native species, and possibly the over-trapping of beaver

American Beaver

The North American Beaver is the only species of beaver in the Americas, native to North America and introduced to South America. In the United States and Canada, where no other species of beaver occurs, it is usually simply referred to as "beaver"...

s, which affected dams and dependent habitats.

Conservation

Rangewide Conservation Agreements and Managment Stratagies are in place for this species (www.fws.gov/.../CRCT_Conservation_Agreement_Final_Dec06.pdf) .

The Wyoming Game and Fish Department in cooperation with the Bureau of Land Management, Little Snake Conservation District, and Trout Unlimited have successfully reintroduced Colorado River cutthroat into the Little Snake River basin. Efforts have included improving stream habitat and removing non-native species.