The moapa dace (''Moapa coriacea'') is a rare

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...

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 ...

of southern

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, found only in the upper parts of the Muddy (formerly Moapa) River, and in the warm springs that give rise to the river. It is the only species of the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Moapa''. A small fish, with a maximum recorded length of 9 cm, its scales are small and embedded in the skin, resulting in a noticeably leathery texture (thus the species epithet, derived from Latin ''coriaceus'' "leathery"). General body shape is standard for cyprinids, with a vaguely conical head. Moapa dace require warm water, and can survive in a temperature range of 67 to 93 °F. They inhabit waters with abundant algae and shade over gravel, sand and mud, and have an omnivorous diet. Their reproduction cycle peaks in spring and is the lowest in fall, occurring in headwater tributaries. Spawning occurs within 150 m of headwaters springs, in water temperatures of 30-32° C. The Moapa Dace usually reproduce in areas where there are overhead instream cover and the water velocity is around 0.11 to 0.17 meters per second. The entire habitat of this species consists of less than 10 square kilometers within

Clark County, Nevada Clark County is located in the U.S. state of Nevada. As of the 2020 census, the population was 2,265,461. Most of the county population resides in the Las Vegas Census County Divisions, which hold 1,771,945 people as of the 2010 Census, across ...

. Moapa dace were first federally listed as endangered in 1967, then reclassified as vulnerable in 1986 and 1988. In 1994, a fire at the

Moapa National Wildlife Refuge The Moapa Valley National Wildlife Refuge (MVNWR) is a protected wildlife refuge administered by the U.S. Fish and Wildlife Service, located in the Warm Springs Natural Area in the Moapa Valley of Clark County, Nevada. The refuge is east of Death V ...

triggered a population decline, and by 1996 the species had been classified as critically endangered. Additional threats to this species include

loss of habitat 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 ...

due to resort development, the introduction of non-native fish species, and capping or depletion of spring-fed

headwaters The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

. The Moapa National Wildlife Refuge was established solely to protect this species, and was the first

National Wildlife Refuge National Wildlife Refuge System is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the system of public lands and waters set aside to c ...

created for the purpose of protecting an endangered fish species. Since then, researchers have created artificial streams mimicking the optimal conditions described above in hopes of spurring an increase in population. When analyzing the effects of stress on the fish, stressed fish experienced a high mortality rate of around 70% overall while the unstressed group of fish experienced around a 1.15% mortality rate per month. Ruggirello, J. E., Bonar, S. A., Feuerbacher, O. G., Simons, L. H., & Powers, C. (2018). Propagation of Endangered Moapa Dace. Copeia, 106(4), 652–662. https://doi.org/10.1643/ot-18-036

Notes

References

Ira La Rivers Ira or IRA may refer to: *Ira (name), a Hebrew, Sanskrit, Russian or Finnish language personal name * Ira (surname), a rare Estonian and some other language family name *Iran, UNDP code IRA Law * Indian Reorganization Act of 1934, US, on status o ...

, ''Fishes and Fisheries of Nevada'' (University of Nevada Press, 1994) Leuciscinae Cyprinid fish of North America Endemic fauna of Nevada Fauna of the Mojave Desert Fish of the Western United States Freshwater fish of the United States Clark County, Nevada Desert National Wildlife Refuge Complex Natural history of Nevada Fish described in 1948 Critically endangered fauna of the United States ESA endangered species {{Leuciscinae-stub