The moapa dace (''Gila coriacea'') is a species of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Leuciscidae Leuciscidae is a family of freshwater ray-finned fishes, formerly classified as a subfamily of the Cyprinidae, which contains the true minnows. Members of the Old World (OW) clade of minnows within this subfamily are known as European minnow ...

, which includes the

dace A dace is a small fish that can be one of many different species. The unmodified name is usually a reference to the common dace (''Leuciscus leuciscus''). This, like most fish called "daces", belongs to the family Leuciscidae, mostly in subfami ...

chub Chub is a common fish name. It pertains to any one of a number of ray-finned fish in several families and general. In the UK, the term ''chub'' usually refers to the species '' Squalius cephalus''. In addition, see sea chub. In family Cyprinid ...

s, Eurasian minnows and related species. This is a rare fish found in southern

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United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, found only in the upper parts of the Muddy (formerly Moapa) River, and in the warm springs that give rise to the river. A small fish, with a maximum recorded length of , 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 daces, with a vaguely conical head. Moapa dace require warm water, and can survive in a temperature range of . 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 of headwaters springs, in water temperatures of . The Moapa Dace usually reproduce in areas where there are overhead instream cover and the water velocity is around . The entire habitat of this species consists of less than within

Clark County, Nevada Clark County is the most populous County (United States), county in the U.S. state of Nevada with 2,265,461 residents as of the 2020 United States census, 2020 census. The county is the location of the state's three largest cities, Las Vegas (t ...

. Moapa dace were federally listed as endangered in 1967. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

assessed them as vulnerable in 1986 and 1988 on its Red List. In 1994, a fire at the Moapa National Wildlife Refuge 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 or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

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

headwater The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

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

National Wildlife Refuge The National Wildlife Refuge System (NWRS) is a system of protected areas of the United States managed by the United States Fish and Wildlife Service (FWS), an agency within the United States Department of the Interior, Department of the Interi ...

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

References

{{Authority control Gila (fish) 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 Taxa named by Carl Leavitt Hubbs Taxa named by Robert Rush Miller Critically endangered fauna of the United States ESA endangered species