Paiute cutthroat trout
Encyclopedia
Paiute cutthroat trout (Oncorhynchus clarki seleniris) is a subspecies of cutthroat trout
native only to Silver King Creek, a headwater tributary of the Carson River
in the Sierra Nevada Mountains of California
, U.S.A.
The Carson River lies within the Great Basin
interior drainage system, within the historic range of Lahontan cutthroat trout
(O. c. henshawi). The subspecies is named after the native Paiute
people.
Lake Lahontan
during the Pleistocene
. Although Lahontan cutthroats are heavily spotted, the isolated sub-population lost virtually all spotting, perhaps because spots made fish more visible and susceptible to predation in the ultra-clear and shallow mountain stream. Paiute cutthroats are also notable for a purple coloration, whereas Lahontan cutthroats have bronze coloration. The Paiute strain must have adapted to a diet mainly of insects and become less migratory since juvenile fish swimming downstream in search of larger waters would have passed below downstream barriers and left the isolated gene pool.
sheepherders began grazing sheep along upper Silver King Creek in the 1800s. They noticed the unusual trout and by 1912 had transplanted them above Llewellyn Falls which had originally been the upper limit. This is fortunate because by 1924 hybrids with ordinary Lahontan cutthroat and introduced
rainbow trout
(cutbow
s) were found below Llewellyn Falls, either due to ill-considered stocking or barriers in the gorge washing out.
Since the finite and localized population of Paiute cutthroats was vulnerable to forest fire and angling
as well as hybridization, relatively unhybridized Paiute cutthroats from upstream were transplanted into virtually all available tributaries of Silver King Creek above the gorge, into Stairway and Sharktooth Creeks to the south in the Sierra Nevada, and into Cottonwood Creek
and Cabin Creek in the White Mountains
.
The subspecies was listed as an endangered species
in 1967. In 1975 it was upgraded to threatened status.
Subsequent studies have found some degree of hybridization in virtually all populations of Paiute cutthroats. This was initially addressed by poisoning stream segments with higher levels of hybridization and transplanting fish from other stream segments thought to be less hybridized. In the 1980s the focus shifted somewhat to electrofishing, which temporarily stuns fish so they can be captured and examined. Fish showing more evidence of hybridization are removed to other drainages, while relatively pure Paiute cutthroats are returned to the water unharmed.
Angling is prohibited in most streams where Paiute cutthroats predominate, however future plans include downstream expansion of Paiute cutthroat range by removing other trout and installing barriers. When populations are sufficient, the subspecies may be de-listed and limited angling may be permitted.
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 Silver King Creek, a headwater tributary of the Carson River
Carson River
The Carson River is a northwestern Nevada river that empties into the Carson Sink, an endorheic basin. The main stem of the river is long....
in the Sierra Nevada Mountains of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, U.S.A.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
The Carson River lies within the Great Basin
Great Basin
The Great Basin is the largest area of contiguous endorheic watersheds in North America and is noted for its arid conditions and Basin and Range topography that varies from the North American low point at Badwater Basin to the highest point of the contiguous United States, less than away at the...
interior drainage system, within the historic range of Lahontan cutthroat trout
Lahontan cutthroat trout
Lahontan cutthroat trout is the largest subspecies of cutthroat trout, and the state fish of Nevada.-Natural history:...
(O. c. henshawi). The subspecies is named after the native Paiute
Paiute
Paiute refers to three closely related groups of Native Americans — the Northern Paiute of California, Idaho, Nevada and Oregon; the Owens Valley Paiute of California and Nevada; and the Southern Paiute of Arizona, southeastern California and Nevada, and Utah.-Origin of name:The origin of...
people.
Natural history
It is believed that a sub-population of Lahontan cutthroats became isolated in Silver King Creek above Silver King Canyon Gorge after erosion made the gorge impassible to trout swimming upstream, probably between 5,000 and 8,000 years ago. The upstream population then adapted to local conditions independent of the larger population below that had evolved in pluvialPluvial lake
A pluvial lake is a landlocked basin which fills with rainwater during times of glaciation, when precipitation is higher. Pluvial lakes that have since evaporated and dried out may also be referred to as paleolakes.-Geology:...
Lake Lahontan
Lake Lahontan
Lake Lahontan was a large endorheic Pleistocene lake of modern northwestern Nevada that extended into northeastern California and southern Oregon...
during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
. Although Lahontan cutthroats are heavily spotted, the isolated sub-population lost virtually all spotting, perhaps because spots made fish more visible and susceptible to predation in the ultra-clear and shallow mountain stream. Paiute cutthroats are also notable for a purple coloration, whereas Lahontan cutthroats have bronze coloration. The Paiute strain must have adapted to a diet mainly of insects and become less migratory since juvenile fish swimming downstream in search of larger waters would have passed below downstream barriers and left the isolated gene pool.
Conservation
BasqueBasque-American
Basque Americans are citizens of the United States who are of Basque ancestry. According to the 2000 US census, there are 57,793 Americans of full or partial Basque descent...
sheepherders began grazing sheep along upper Silver King Creek in the 1800s. They noticed the unusual trout and by 1912 had transplanted them above Llewellyn Falls which had originally been the upper limit. This is fortunate because by 1924 hybrids with ordinary Lahontan cutthroat and introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
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....
(cutbow
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) were found below Llewellyn Falls, either due to ill-considered stocking or barriers in the gorge washing out.
Since the finite and localized population of Paiute cutthroats was vulnerable to forest fire and angling
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...
as well as hybridization, relatively unhybridized Paiute cutthroats from upstream were transplanted into virtually all available tributaries of Silver King Creek above the gorge, into Stairway and Sharktooth Creeks to the south in the Sierra Nevada, and into Cottonwood Creek
Cottonwood Creek (Inyo County, California)
Cottonwood Creek originates in the Ancient Bristlecone Pine Forests of the White Mountains of California. The creek flows eastward from the 14,000-foot crest of the White Mountains and steeply descends through groves of aspen, eventually flowing into a sagebrush desert. Numerous springs feed the...
and Cabin Creek in the White Mountains
White Mountains (California)
The White Mountains of California are a triangular fault block mountain range facing the Sierra Nevada across the upper Owens Valley. They extend for approximately as a greatly elevated plateau about wide on the south, narrowing to a point at the north, with elevations generally increasing...
.
The subspecies was listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
in 1967. In 1975 it was upgraded to threatened status.
Subsequent studies have found some degree of hybridization in virtually all populations of Paiute cutthroats. This was initially addressed by poisoning stream segments with higher levels of hybridization and transplanting fish from other stream segments thought to be less hybridized. In the 1980s the focus shifted somewhat to electrofishing, which temporarily stuns fish so they can be captured and examined. Fish showing more evidence of hybridization are removed to other drainages, while relatively pure Paiute cutthroats are returned to the water unharmed.
Angling is prohibited in most streams where Paiute cutthroats predominate, however future plans include downstream expansion of Paiute cutthroat range by removing other trout and installing barriers. When populations are sufficient, the subspecies may be de-listed and limited angling may be permitted.