The Devils Hole pupfish (Cyprinodon diabolis) is a species of fish native to Devils Hole (Nevada, U.S.), a geothermal aquifer-fed pool within a limestone cavern, in the Ash Meadows National Wildlife Refuge east of Death Valley. It has been described as the world's rarest fish, with a population of fewer than 200 since 2005. Recent genetic analyses indicate that this species may have first colonized the hole within the past 1,000 years, or as long ago as 60,000 years.
The pupfish have been protected since being declared an endangered species in 1967. Conflicts over the ownership and use of the groundwater around Devils Hole caused litigation in the 1980s. The litigation triggered further protections of the pupfish. However, since the late 1990s, the pupfish population has substantially decreased. The reasons for the decrease are unknown. As of 2015, the U.S. Fish and Wildlife Service maintains two captive populations of pupfish at the Ash Meadows Fish Conservation Facility.
|Devils Hole pupfish|
Devils Hole pupfish are less than 25 mm (1 in) long and resemble other pupfish in shape. They are the smallest of the desert pupfish species, averaging 19 mm (0.75 in) in length. They lack pelvic fins and have large heads and long anal fins. Devils Hole pupfish have a low fecundity and are much less aggressive than other pupfish. Breeding males are solid deep blue and have a black band on the caudal fin.
There are a number of pupfish species scattered near Death Valley. Earlier pluvial (wet) periods allowed colonization of present sites; subsequent xeric (dry) conditions served to isolate the aquatic habitats, although genetic analyses suggest that gene flow still connects these habitats and may enable their continued persistence as such small population sizes.
The Devils Hole pupfish is considered an annual species, with the historic spring populations ranged between 150 and 250; while the autumn population grew to 400–500 individuals.
Devils Hole and the pupfish are located in the Amargosa Desert ecosystem, in the Amargosa Valley, of southwestern Nevada, USA, east of Death Valley and the Funeral Mountains and Amargosa Range. The Amargosa River is part of Devil Hole and the region's aquifer hydrology.
Although pupfish have been found as deep as 80 feet (24 m), they depend on a shallowly submerged limestone shelf of only 2 by 4 metres (6.6 by 13.1 ft) in area for spawning as well as for much of their diet (primarily diatoms). Natural threats from flash floods to earthquakes have been known to disrupt this fragile ecosystem, but in the 1960s and 1970s, the major threat was groundwater depletion due to agricultural irrigation.
Research indicates that the annual fluctuation of population is caused by the amount of algae present on the shelf. The algal growth depends, in turn, on the amount of solar radiation the shelf receives and the concentration of nutrients in the water. Finally, recent evidence suggests that nutrient availability is highest when the cave is used by barn owls (Tyto alba) as a roosting/nesting site. The owls increase the pool nutrient levels by casting nutrient-rich pellets into the water.
The water level in Devils Hole is monitored daily by the National Park Service and occasionally by the U.S. Geological Survey. During the late 1960s, the water level dropped dramatically in response to pumping in the Ash Meadows area, in the immediate vicinity of the cavern. After the cessation of pumping, the water levels recovered until about 1986, when the water level began to decline. Pronounced changes in the water level resulted in response to the 1992 Landers/Little Skull Mountain earthquakes and the 1999 Hector Mine earthquake. Since December 2005, the water level in Devils Hole has been rising, and by December 2008, the water level had risen to its highest level since 1993.
The age of the species is subject to considerable debate. Some scientists argue that vertebrate species with small populations cannot persist for long, and estimate the age of the species to be 360 years. Recent genetic analyses indicate that this species may have first colonized the hole within the past 1,000 years. Other phylogenetic studies suggest the species is as old as 60,000 years. These estimates depend heavily on knowledge of the mutation rate in this species, which is unknown, but is predicted to be one of the highest for any vertebrate due to its small population size.
C. diabolis was first noticed in 1890 but only identified as a unique and highly divergent species by Joseph Wales in 1930. Formal protection of the species began when Devils Hole was made part of Death Valley National Monument by presidential proclamation in 1952. Ten years later the NPS installed a hydrograph in the Hole to monitor water levels. Subsequently, the Hole was fenced after two divers drowned in its water. In 1967, the Devils Hole pupfish was officially listed as an endangered species.
In 1967, a farming corporation amassed 12,000 acres (4,900 ha) in the Ash Meadows area; by 1968, the hydrograph had begun to register a decline as large capacity wells were drilled and pumped in Ash Meadows. The water drop threatened to expose the critical spawning/feeding shelf and precipitated the formation of two groups to work for protection of Devils Hole: the Desert Fishes Council in the West, and the Desert Pupfish Task Force in Washington, D.C.
In August 1971 a federal court issued an injunction to halt further pumping, that threatened to completely expose the natural shelf. Further litigation finally resulted in the landmark Supreme Court decision of 1976 (Cappaert vs. U.S.). It recognized the prior water right of Devils Hole vis-a-vis its designation as part of a national monument. The permanent injunction did not halt pumping, but limited it to a level which guaranteed sufficient water to inundate the natural rock shelf.
In 1980, the U.S. Fish and Wildlife Service designated as essential habitat about 21,000 acres (8,500 ha) acres where the groundwater most influenced the water level in the Hole. One of the identified goals of the recovery plan was to maintain the aquifer at such levels that the population fluctuates from 300 in winter to 700–900 in late summer. The water source for the Devils Hole pupfish was now adequately secured, but the remainder of Ash Meadows was as yet unprotected. A land development company bought the Ash Meadows land from the farm corporation in 1980, planning to subdivide the area into 34,000 residential lots. Furthermore, in 1982, the U.S. Fish and Wildlife Service emergency-listed as endangered two more of the fish species in Ash Meadows, thereby conferring protection to all the pools in the area. Finally, in 1984, Ash Meadows National Wildlife Refuge was established by Congress. The Nature Conservancy bought the bulk of the land from the development company and resold it to the USFWS. By 1986, the USFWS had drafted a recovery plan for the entire Ash Meadows area, including Devils Hole.
In April 2016 the National Park Service recorded three men firing a shotgun and leaving beer cans, vomit, and boxer shorts in the water of Devils Hole that may have caused at least one pupfish death. The men were charged with killing an endangered animal and other property crimes.
In 1970, a floating artificial shelf, artificially lighted, was suspended in Devils Hole to substitute for the partially exposed natural rock shelf. The fish never used the artificial shelf.
A number of artificial "refugia" (concrete tanks approximating conditions in Devils Hole) were attempted to ensure species' survival should the natural population at Devils Hole die out; one at Hoover Dam established in 1972, and two near Devils Hole itself within the Ash Meadows National Wildlife Refuge established in 1980 and 1991.
In May 2005, nine pupfish were moved from the hole and a federal hatchery to both a Las Vegas Strip casino aquarium, at Mandalay Bay, and another federal hatchery in hopes of augmenting the population.
As of 2013, none of the previous attempts to establish refugia were successful. Studies have been undertaken to better understand energy flow in the system, water chemistry, pupfish genetics, organisms living in the water, and other factors.
As of 2015, the Ash Meadows Fish Conservation Facility has successfully propagated Devils Hole population in a 100,000 gallon refuge population built within the refuge. This refuge mimics the natural Devil's Hole, including water chemistry, spawning shelf, and natural sunlight. At least 30 captive fish now populate the refuge, including 1st generation fish naturally breeding within the refuge.
From 1970 through 1996, the average population was 324. Since 2005, the population at Devils Hole has been below 200 individuals, although the population fluctuates depending on the season. Low algae growth and other winter conditions cause spring populations to be 35–65% of the autumn population. The reasons for the decline of the population are unclear.
In November 2005, divers counted just 84 individuals in the Devils Hole population, the same as the spring population, despite observations of egg-laying and baby fish during the summer. As many as 80 fish – one-third of the population – was estimated to have been destroyed during the summer of 2004 when a flash flood pushed a quantity of scientific equipment (fish traps) which had been left sitting on the edge of the hole into the hole; later, about 60 cubic feet (1.7 m3) of debris, washed into the cave by floods, was removed.
In 2007, between 38 and 42 fish were left in Devils Hole.
In 2008, the National Park Service began to feed the pupfish a special food to attempt to restore the population. The Devils Hole pupfish count rose in the autumn of 2008 to 126, the first steady increase in more than 10 years.
As of April 2013 U.S. Fish and Wildlife reported only 35 fish remain in their natural habitat, but increased to 92 when measured again in 2014.
As of spring 2016, a periodic count found 115 of the fish living in the waters.
The Catarina pupfish (Megupsilon aporus) is a diminutive species of fish in the Cyprinodontidae family, first described in 1972. It was endemic to a spring in Nuevo León, Mexico. In an attempt of saving the rapidly declining species, some were brought into captivity in the late 1980s and early 1990s, but it proved very difficult to maintain. In 1994 it became extinct in the wild, as still reflected by its last IUCN rating from 1996. Gradually the captive populations also perished. The last had disappeared by 2015 and the species became entirely extinct.In addition to its small size, it was characterized by absence of pelvic girdle and pelvic fins, and by having different numbers of chromosomes in male and female fish. In 2013, its behavior was described based on very limited field observations of the previous wild population and more detailed observations in aquaria.Cavefish
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypogean fish.The more than 200 scientifically described species of obligate cavefish are found on all continents, except Antarctica. Although widespread as a group, many cavefish species have very small ranges and are seriously threatened. Cavefish are members of a wide range of families and do not form a monophyletic group. Typical adaptations found in cavefish are reduced eyes and pigmentation.Cyprinodon
Cyprinodon is a genus of small pupfishes found in fresh, brackish and salt water. The genus is primarily found in Mexico, the Caribbean Islands and southern United States (Arizona, California, Florida, Nevada, New Mexico, Oklahoma and Texas), but C. variegatus occurs as far north as Massachusetts and along the entire Gulf of Mexico coastline, and C. dearborni and C. variegatus are found in northern South America. Many species have tiny ranges and are highly threatened, in some cases already extinct. Cyprinodon are small; the largest reaches 10 cm (3.9 in) in length and most other species only reach about half that.Devils Hole
Devils Hole is a geologic formation located within the Ash Meadows National Wildlife Refuge, in Nye County, Nevada, in the Southwestern United States.
Devils Hole—a detached unit of Death Valley National Park—is habitat for the only naturally occurring population of the endangered Devils Hole pupfish (Cyprinodon diabolis). The 40 acres (16 ha) unit is part of the Ash Meadows complex, an area of desert uplands and spring-fed oases that was designated as a National Wildlife Refuge in 1984.Diplacus rupicola
Diplacus rupicola, the Death Valley monkeyflower, is a flowering plant in the family Phrymaceae.Fish
Fish are gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered paraphyletic by excluding the tetrapods (i.e., the amphibians, reptiles, birds and mammals which all descended from within the same ancestry). Because in this manner the term "fish" is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology, unless it is used in the cladistic sense, including tetrapods. The traditional term pisces (also ichthyes) is considered a typological, but not a phylogenetic classification.
The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods.
Most fish are ectothermic ("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature.Fish can communicate in their underwater environments through the use of acoustic communication. Acoustic communication in fish involves the transmission of acoustic signals from one individual of a species to another. The production of sounds as a means of communication among fish is most often used in the context of feeding, aggression or courtship behaviour. The sounds emitted by fish can vary depending on the species and stimulus involved. They can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder.Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., gulpers and anglerfish), although no species has yet been documented in the deepest 25% of the ocean. With 33,600 described species, fish exhibit greater species diversity than any other group of vertebrates.Fish are an important resource for humans worldwide, especially as food. Commercial and subsistence fishers hunt fish in wild fisheries (see fishing) or farm them in ponds or in cages in the ocean (see aquaculture). They are also caught by recreational fishers, kept as pets, raised by fishkeepers, and exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies.Killifish
A killifish is any of various oviparous (egg-laying) cyprinodontiform fish (including families Aplocheilidae, Cyprinodontidae, Fundulidae, Profundulidae and Valenciidae). All together, there are some 1270 different species of killifish, the biggest family being Rivulidae, containing more than 320 species. Because of living in ephemeral waters, the eggs of most killifish can survive periods of partial dehydration. Many of the species rely on such a diapause, since the eggs would not survive more than a few weeks if entirely submerged in water. Like seeds, the eggs can be sent by mail without water. The adults of some species, such as Kryptolebias marmoratus, can additionally survive out of the water for several weeks. Most killies are small fish, from one to two inches (2.5 to 5 cm), with the largest species growing to just under six inches (15 cm).
The word killifish is of uncertain origin, but is likely to have come from the Dutch kil for a kill (small stream). Although killifish is sometimes used as an English equivalent to the taxonomical term Cyprinodontidae, some species belonging to that family have their own common names, such as the pupfish and the mummichog.List of critically endangered fishes
As of July 2017, the International Union for Conservation of Nature (IUCN) lists 455 critically endangered fish species, including 87 which are tagged as possibly extinct. 3.0% of all evaluated fish species are listed as critically endangered.
The IUCN also lists four fish subspecies as critically endangered.
Of the subpopulations of fishes evaluated by the IUCN, 20 species subpopulations and one subspecies subpopulation have been assessed as critically endangered.
Additionally 3191 fish species (21% of those evaluated) are listed as data deficient, meaning there is insufficient information for a full assessment of conservation status. As these species typically have small distributions and/or populations, they are intrinsically likely to be threatened, according to the IUCN. While the category of data deficient indicates that no assessment of extinction risk has been made for the taxa, the IUCN notes that it may be appropriate to give them "the same degree of attention as threatened taxa, at least until their status can be assessed."This is a complete list of critically endangered fish species and subspecies evaluated by the IUCN. Species considered possibly extinct by the IUCN are marked as such. Species and subspecies which have critically endangered subpopulations (or stocks) are indicated.Owens pupfish
The Owens pupfish (Cyprinodon radiosus) is a rare species of fish in the family Cyprinodontidae, the pupfish. It is endemic to California in the United States, where it is limited to the Owens Valley. It is a federally listed endangered species of the United States. This pupfish is up to 5 centimetres (2.0 inches) long, the largest males sometimes longer. The male is blue-gray, turning bright blue during spawning. The female is greenish brown with a silvery or whitish belly.The pupfish tolerates a wide range of water conditions. Its native habitat includes desert marshes with water temperatures up to 33 °C in the summer and layers of ice during the winter. The water in some areas has four times the salt content of the ocean, as well as low oxygen.This fish was once common in the Owens Valley of California, occurring in most water bodies between Fish Slough and Lone Pine, which are 70 miles apart. It occurred in the Owens River and associated sloughs and marshes. At that time the Paiute people scooped them out of the water and dried them for the winter.The diversion of water from the Owens River to the Los Angeles Metropolitan Area during the California Water Wars eliminated most of the water bodies that were the pupfish's habitat. Predation by introduced species of fish may have decimated remaining populations. By 1942 this pupfish was believed to be extinct. It was rediscovered in 1964, when one population of about 200 individuals was found. When they were transferred to a safer location, the entire global population of this pupfish was contained in two buckets. The California Department of Fish and Game established six populations in carefully managed refuge using these fish. Four of these populations remain today.Threats to the four populations include the encroachment of cattails into the waterways. The plant clogs the habitat and collects detritus, which eliminates the pupfish's breeding substrates. The CDFG tends the four populations, clearing out the cattails. Introduced species of aquatic organisms also pose a threat. They include predatory fish such as largemouth bass (Micropterus salmoides), smallmouth bass (Micropterus dolomieu), brown trout (Salmo trutta), and bluegill (Lepomis macrochirus), as well as crayfish (Pacifastacus leniusculus) and bullfrogs (Rana catesbeiana). The severe reduction of the species into a single small population may have created a genetic bottleneck; genetic analysis is underway.Other local Cyprinodon include Death Valley pupfish (Cyprinodon salinus salinus), Shoshone pupfish (Cyprinodon nevadensis shoshone), the extinct Tecopa pupfish (Cyprinodon nevadensis calidae), Devils Hole pupfish (Cyprinodon diabolis), and the desert pupfish (Cyprinodon macularius).Pupfish
Pupfish are a group of small killifish belonging to ten genera of the family Cyprinodontidae of ray-finned fish. Pupfish are especially noted for being found in extreme and isolated situations. They are primarily found in North America, South America, and the Caribbean region, but Aphanius species are from southwestern Asia, northern Africa, and southern Europe. As of August 2006, 120 nominal species and 9 subspecies were known.
The common name is said to derive from the mating habits of the males, whose activities vaguely resemble puppies at play.Carl L. Hubbs, a prominent fish biologist and one of the first people to take an interest in them, coined the name after he observed their "playful" circling and tussling, which is actually the aggressive behavior of territorial males.In spite of their name, the cyprinodontids are not closely related to Cyprinidae, or carp family. They were formerly considered near allies of the pikes and their relatives, as they share some features: a flat head with protractile mouth beset with cardiform, villiform, or compressed, bi- or tricuspid teeth, generally large scales, and the absence of a well-developed lateral line. However, they are now generally assigned to the order Cyprinodontiformes. Several forms occur in the fossil records of the Oligocene and Miocene beds of Europe. Pupfish from San Salvador island were able to diversify into multiple species with different eating habits due to interbreeding with pupfish from other islands, mainly Caribbean.Most pupfish are inhabitants of fresh and brackish waters. Many species are ovoviviparous. Most pupfishes diet consists, mainly, of algae, decaying vegetation, and any insects they can get.Seiche
A seiche ( SAYSH) is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbours and seas. The key requirement for formation of a seiche is that the body of water be at least partially bounded, allowing the formation of the standing wave.
The term was promoted by the Swiss hydrologist François-Alphonse Forel in 1890, who was the first to make scientific observations of the effect in Lake Geneva, Switzerland. The word originates in a Swiss French dialect word that means "to sway back and forth", which had apparently long been used in the region to describe oscillations in alpine lakes.
Seiches in harbours can be caused by long period or infragravity waves, which are due to subharmonic nonlinear wave interaction with the wind waves, having periods longer than the accompanying wind-generated waves.Shark Reef at Mandalay Bay
The Shark Reef Aquarium at Mandalay Bay is a public aquarium located at and owned by the Mandalay Bay Resort and Casino in Las Vegas, Nevada. Its main tank is 1,300,000 US gallons (4,900,000 l), one of the largest in North America. The facility is 95,000 sq ft (8,800 m2), and displays numerous different species of sharks, rays, fish, reptiles, and marine invertebrates. It also features a shark tunnel. The reef was developed in consultation with the Vancouver Aquarium.Shoshone pupfish
The Shoshone pupfish, Cyprinodon nevadensis shoshone, is characterized by large scales and a "slab-sided," narrow, slender body, with the arch of the ventral contour much less pronounced than the dorsal. It also has fewer pelvic fin rays and scales than the other pupfish subspecies.Winters v. United States
Winters v. United States, 207 U.S. 564 (1908), was a United States Supreme Court case clarifying water rights of American Indian reservations. This doctrine was meant to clearly define the water rights of American Indians in cases where the rights were not clear. The case was first argued on October 24, 1907 and a decision was reached January 6, 1908. This case set the standards for the United States government to acknowledge the vitality of American Indian water rights, and how rights to the water relate to the continuing survival and self-sufficiency of American Indian people.