Cui-ui
Encyclopedia
The cui-ui, Chasmistes cujus, is a large sucker
fish
endemic
to Pyramid Lake and, prior to its desiccation
in the 20th century, Winnemucca Lake
in northwestern Nevada
. It feeds primarily on zooplankton
and possibly on nanoplankton (such as algae
and diatoms). The maximum size of male cui-ui is approximately 53 cm (21 in) and 1.6 kg (3.5 lb), while females reach approximately 64 cm (25 in) and 2.7 kg (6 lb). The life span of cui-ui is typically about forty years, but the fish do not reach sexual maturity until at least age eight. The cui-ui is not only a critically endangered species
, but is also one of the few surviving members of its genus
.
The cui-ui population is generally improving in numbers, having attained an estimated population exceeding one million in 1993, thanks to the efforts of the U.S. Environmental Protection Agency
in analysis of the Truckee River
spawning
grounds and of the Nevada Department of Environmental Protection and EPA in following up on protection measures. The reason the cui-ui remains critically endangered is the recent history of recruitment variation, illustrating that in many years of the 1970s and 1980s there was virtually no recruitment whatsoever due to unsuccessful spawning in an unfavorable water quality and water flow environment of the Truckee River. The species' outlook is somewhat sanguine, since there is a published recovery plan based on an enhanced understanding of Pyramid Lake and Truckee River water quality, and the adoption of a protection plan by the U.S. Congress.
Pyramid Lake, the second largest natural lake in the western U.S. prior to construction of the Derby Dam
, has been the focus of several water quality investigations, the most detailed starting in the mid-1980s. Under direction of the U.S. Environmental Protection Agency
, a comprehensive dynamic hydrology transport model was developed by Earth Metrics Inc.; the model's name was subsequently changed to DSSAM
, and it was applied to analyze impacts of a variety of land use and wastewater management decisions throughout the 3120 square miles (8,080.8 km²) Truckee River
Basin. Analytes addressed included nitrogen
, reactive phosphate
, dissolved oxygen and ten other parameters. Based upon use of the model, some decisions have been influenced to enhance Pyramid Lake water quality and aid the viability of Pyramid Lake biota
, including the cui-ui. The dynamic river model was particularly useful for analyzing Truckee River temperature variations, since the cui-ui often swim upstream to spawn, and their fry
are vulnerable to elevations in river temperature.
to spawn in mid-April. If inflow is insufficient to permit this, the cui-ui may attempt to spawn in Pyramid Lake, but generally with little success due to the salinity
of that lake. Water releases from the Boca
and Stampede reservoirs are currently (as of 2004) timed to assist the spawning run, although in drought
years this water is reserved for the Reno
metropolitan area. These releases are critical to successful spawning since low warm flows at the Truckee River delta are inhospitable to upstream migration of adults. Several hatcheries are maintained by the Paiute
nation to ensure that such a situation does not impact the long term viability of the cui-ui. These measures have greatly increased cui-ui populations, although it is still listed as an endangered species
.
The Pyramid Lake band of Northern Paiute called themselves the "Cuiyui Ticutta", which means cui-ui eaters. Together with the Lahontan cutthroat trout
the cui-ui was an important food supply for the Cuiyui Tikutta and neighboring Paiute bands who would travel to Pyramid Lake to share in the harvest during the spring spawning runs.
Subsequent to white settlement of western Nevada in the 1860s many Cuiyui Ticutta made a living by selling fish, although the whites generally preferred trout to cui-ui. Cui-ui were also still important for subsistence, despite Bureau of Indian Affairs
attempts to encourage farming and discourage fishing. Following the construction of Derby Dam
in 1905 and diversion of much of the Truckee River's flow, the Pyramid Lake fishery declined and by 1930 it was no longer capable of supplying even subsistence food. Although conditions have improved recently, the cui-ui are now managed for symbolic and ecological purposes, and are not a food source.
Catostomidae
Catostomidae is the sucker family of the order Cypriniformes. There are 80 species in this family of freshwater fishes. Catostomidae are found in North America, east central China, and eastern Siberia...
fish
Fish
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...
endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to Pyramid Lake and, prior to its desiccation
Desiccation
Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...
in the 20th century, Winnemucca Lake
Winnemucca Lake
Winnemucca Lake, just east of Pyramid Lake in the northwestern portion of the U.S. state of Nevada is on the dividing line between Washoe County and Pershing County counties.- Geography :...
in northwestern Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
. It feeds primarily on zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
and possibly on nanoplankton (such as algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and diatoms). The maximum size of male cui-ui is approximately 53 cm (21 in) and 1.6 kg (3.5 lb), while females reach approximately 64 cm (25 in) and 2.7 kg (6 lb). The life span of cui-ui is typically about forty years, but the fish do not reach sexual maturity until at least age eight. The cui-ui is not only a critically 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...
, but is also one of the few surviving members of its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
The cui-ui population is generally improving in numbers, having attained an estimated population exceeding one million in 1993, thanks to the efforts of the U.S. Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
in analysis of the Truckee River
Truckee River
The Truckee River is a stream in the U.S. states of California and Nevada. The river is about long. Its endorheic drainage basin is about , of which about are in Nevada. The Truckee is the sole outlet of Lake Tahoe and drains part of the high Sierra Nevada, emptying into Pyramid Lake in the Great...
spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
grounds and of the Nevada Department of Environmental Protection and EPA in following up on protection measures. The reason the cui-ui remains critically endangered is the recent history of recruitment variation, illustrating that in many years of the 1970s and 1980s there was virtually no recruitment whatsoever due to unsuccessful spawning in an unfavorable water quality and water flow environment of the Truckee River. The species' outlook is somewhat sanguine, since there is a published recovery plan based on an enhanced understanding of Pyramid Lake and Truckee River water quality, and the adoption of a protection plan by the U.S. Congress.
Pyramid Lake water quality
Derby Dam
Derby Dam is a diversion dam on the Truckee River, located between Reno and Fernley in Storey and Washoe counties in the U.S. state of Nevada. It diverts water that would otherwise feed Pyramid Lake into the Carson River watershed for irrigation use. It is operated by the Truckee-Carson...
, has been the focus of several water quality investigations, the most detailed starting in the mid-1980s. Under direction of the U.S. Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
, a comprehensive dynamic hydrology transport model was developed by Earth Metrics Inc.; the model's name was subsequently changed to DSSAM
DSSAM Model
The DSSAM Model is a computer simulation developed for the Truckee River to analyze water quality impacts from land use and wastewater management decisions in the Truckee River Basin. This area includes the cities of Reno and Sparks, Nevada as well as the Lake Tahoe Basin...
, and it was applied to analyze impacts of a variety of land use and wastewater management decisions throughout the 3120 square miles (8,080.8 km²) Truckee River
Truckee River
The Truckee River is a stream in the U.S. states of California and Nevada. The river is about long. Its endorheic drainage basin is about , of which about are in Nevada. The Truckee is the sole outlet of Lake Tahoe and drains part of the high Sierra Nevada, emptying into Pyramid Lake in the Great...
Basin. Analytes addressed included nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, reactive phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
, dissolved oxygen and ten other parameters. Based upon use of the model, some decisions have been influenced to enhance Pyramid Lake water quality and aid the viability of Pyramid Lake biota
Biota (ecology)
Biota are the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biota of the Earth lives in the biosphere.-See...
, including the cui-ui. The dynamic river model was particularly useful for analyzing Truckee River temperature variations, since the cui-ui often swim upstream to spawn, and their fry
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
are vulnerable to elevations in river temperature.
Spawning behavior
The cui-ui is potamodromous, and will attempt to ascend the Truckee RiverTruckee River
The Truckee River is a stream in the U.S. states of California and Nevada. The river is about long. Its endorheic drainage basin is about , of which about are in Nevada. The Truckee is the sole outlet of Lake Tahoe and drains part of the high Sierra Nevada, emptying into Pyramid Lake in the Great...
to spawn in mid-April. If inflow is insufficient to permit this, the cui-ui may attempt to spawn in Pyramid Lake, but generally with little success due to the salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
of that lake. Water releases from the Boca
Boca Reservoir
Boca Reservoir is an artificial lake in the Tahoe National Forest of Nevada County, California, created by the construction of Boca Dam across Little Truckee River, approximately 10 km northeast of Truckee.-External links:...
and Stampede reservoirs are currently (as of 2004) timed to assist the spawning run, although in drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
years this water is reserved for the Reno
Reno, Nevada
Reno is the county seat of Washoe County, Nevada, United States. The city has a population of about 220,500 and is the most populous Nevada city outside of the Las Vegas metropolitan area...
metropolitan area. These releases are critical to successful spawning since low warm flows at the Truckee River delta are inhospitable to upstream migration of adults. Several hatcheries are maintained by the 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...
nation to ensure that such a situation does not impact the long term viability of the cui-ui. These measures have greatly increased cui-ui populations, although it is still 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...
.
Paiute tribe
Lahontan cutthroat trout
Lahontan cutthroat trout is the largest subspecies of cutthroat trout, and the state fish of Nevada.-Natural history:...
the cui-ui was an important food supply for the Cuiyui Tikutta and neighboring Paiute bands who would travel to Pyramid Lake to share in the harvest during the spring spawning runs.
Subsequent to white settlement of western Nevada in the 1860s many Cuiyui Ticutta made a living by selling fish, although the whites generally preferred trout to cui-ui. Cui-ui were also still important for subsistence, despite Bureau of Indian Affairs
Bureau of Indian Affairs
The Bureau of Indian Affairs is an agency of the federal government of the United States within the US Department of the Interior. It is responsible for the administration and management of of land held in trust by the United States for Native Americans in the United States, Native American...
attempts to encourage farming and discourage fishing. Following the construction of Derby Dam
Derby Dam
Derby Dam is a diversion dam on the Truckee River, located between Reno and Fernley in Storey and Washoe counties in the U.S. state of Nevada. It diverts water that would otherwise feed Pyramid Lake into the Carson River watershed for irrigation use. It is operated by the Truckee-Carson...
in 1905 and diversion of much of the Truckee River's flow, the Pyramid Lake fishery declined and by 1930 it was no longer capable of supplying even subsistence food. Although conditions have improved recently, the cui-ui are now managed for symbolic and ecological purposes, and are not a food source.