Desert pupfish
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The desert pupfish (''Cyprinodon macularius'') is a rare species of bony fish in the family Cyprinodontidae. It is a small fish, typically less than 7.62 cm (3 in) in length. Males are generally larger than females, and have bright-blue coloration, while females and juveniles are silvery or tan. A notable attribute of the desert pupfish is their ability to survive in environments of extreme salinity, pH, and
temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer. Thermometers are calibrated in various Conversion of units of temperature, temp ...
, and low oxygen content. The desert pupfish mates in a characteristic fashion, wherein compatible males and females will come in contact and collectively jerk in an s-shape. Each jerk typically produces a single egg that is fertilized by the male and deposited in his territory. Breeding behavior includes aggressive arena-breeding and more docile consort-pair breeding. The desert pupfish is a federally listed endangered species in the
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 territori ...
. The desert pupfish was once a common fish, but it is now
extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...
from most of its historical natural range. The decrease in population has been a trend since the early 1900s due to
habitat destruction 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 ...
and fragmentation. It has been, and continues to be, preyed upon and displaced by non-native fishes, such as
tilapia Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most ...
. Currently, the desert pupfish occurs only in three
drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
s: the
Salton Sea The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf ...
,
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, the
Colorado River Delta The Colorado River Delta is the region where the Colorado River flows into the Gulf of California (also known as the Sea of Cortez) in eastern Mexicali Municipality in the north of the state of Baja California in northwesternmost Mexico. The ...
,
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
, and in
Sonora, Mexico Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...
. Historically, the desert pupfish occurred in the drainage basins of the Gila, Santa Cruz, San Pedro, and
Salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...
, and lower
Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. s ...
. The range stretched from Arizona to the
Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja C ...
and Sonora.


Taxonomy and phylogeny

''Cyprinodon macularius'' was first described by
Spencer Baird Spencer Fullerton Baird (; February 3, 1823 – August 19, 1887) was an American naturalist, ornithologist, ichthyologist, herpetologist, and museum curator. Baird was the first curator to be named at the Smithsonian Institution. He eventually ...
and Charles Girard in 1853. Originally, it was considered to be made up of three subspecies: the nominal desert pupfish (''Cyprinodon macularius macularius''), the Quitobaquito pupfish ('' Cyprinodon macularius eremus'') and the undescribed Monkey Spring pupfish (''
Cyprinodon ''Cyprinodon'' is a genus of pupfishes found in waters that range from fresh to hypersaline. The genus is primarily found in Mexico, the Caribbean Islands and southern United States (Arizona, California, Florida, Nevada, New Mexico, Oklahoma and ...
'' sp.). The study of mitochondrial DNA variation between different populations of pupfish traditionally considered as ''C. macularius'' provide the basis for the species distinction between ''C. macularius'' and ''C. eremus.'' The mtDNA
haplotypes A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA org ...
of the pupfish endemic to the Rio Sonoyta Basin/Quitobaquito Springs and the pupfish endemic to the Salton Sea/Lower Colorado River Basin suggest sustained, mutually exclusive evolutionary histories. Furthermore, the differences between the frequency of inherited
alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...
of each species are significant enough to suggest that these individuals became separate species about 100,000 years ago. As a result, the three subspecies have been reclassified as three distinct species: the desert pupfish (''C. macularius''), the Sonoyta (Quitobaquito) pupfish (''C. eremus''), and the Santa Cruz (Monkey Spring) pupfish ('' C. arcuatus''), with the Santa Cruz pupfish being described in 2002.


Description

The desert pupfish is a small fish that is typically less than 7.62 cm (3 in) long; males are larger than females and generally have more vivid markings, especially during breeding seasons. Females and juveniles typically have tan or olive backs and silvery sides with narrow, dark vertical bars situated laterally. These bars are often interrupted to give the impression of a disjunct, lateral band. During mating season, males become bright blue on the dorsal portion of the head and sides, and yellow or orange on the
caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
and posterior
caudal peduncle Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
.51 FR 10843 (1986-03-31). The dorsal profile of the desert pupfish is smoothly rounded, while its body is thickened and laterally compressed. The desert pupfish has a protruding mouth equipped with
tricuspid The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right ven ...
teeth.


Habitat and distribution

The desert pupfish is found in shallow waters of desert springs, small streams, and marshes below 1,524 m (5,000 ft) in elevation. The species can tolerate high
salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
, water temperatures, and lower
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
content than most fish, and will occupy habitats inhospitable to invasive fish. Pupfish typically prefer clear waters with either rooted or unattached aquatic plants, restricted surface flow, or sand-silt substrates, and will do well if their habitats have little vegetation apart from mats of
benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
. The distribution of the desert pupfish historically ranged from the lower
Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. s ...
in
Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
and
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
to the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
and onto its delta in
Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...
and
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
. Specifically, the desert pupfish occurred the
Salton Sink The Salton Sink is the low point of an endorheic basin, a closed drainage system with no outflows to other bodies of water, in the Colorado Desert sub-region of the Sonoran Desert. The sink falls within the larger Salton Trough and separates the ...
basin in California; the
Gila River The Gila River (; O'odham ima Keli Akimel or simply Akimel, Quechan: Haa Siʼil, Maricopa language: Xiil) is a tributary of the Colorado River flowing through New Mexico and Arizona in the United States. The river drains an arid watershed of n ...
basin in Arizona and Sonora, including the Gila, Santa Cruz, San Pedro, and Salt Rivers; the Rio Sonoyta in Arizona and Sonora;
Puerto Peñasco Puerto Peñasco ( ood, Geʼe Ṣuidagĭ) is a small city located in Puerto Peñasco Municipality in the northwest of the Mexican state of Sonora, from the border with the U.S. state of Arizona. According to the 2020 census, it has a population ...
, Sonora; and the
Laguna Salada Laguna Salada (, ''Salt Lake'') is a municipality (''municipio'') of the Valverde province in the Dominican Republic. Within the municipality there are three municipal districts (''distritos municipal''): Cruce de Guayacanes, Jaibón and La ...
basin in
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
. A large population of desert pupfish is protected at the
Cibola National Wildlife Refuge Cibola National Wildlife Refuge is a U.S. National Wildlife Refuge in the floodplain of the lower Colorado River between Arizona and California and surrounded by a fringe of desert ridges and washes. The refuge encompasses both the historic Colorad ...
. Due to both
habitat destruction 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 ...
and species reclassification, however, the desert pupfish has a smaller territory distribution than previously thought. As of 2010, naturally occurring populations of the desert pupfish are restricted in the United States to two tributaries and various shoreline pools and irrigation drains of the Salton Sea in California. In Mexico, the desert pupfish is scattered along the
Colorado River Delta The Colorado River Delta is the region where the Colorado River flows into the Gulf of California (also known as the Sea of Cortez) in eastern Mexicali Municipality in the north of the state of Baja California in northwesternmost Mexico. The ...
and the Laguna Salada basin. Collectively, there are 11 known populations of
extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...
wild desert pupfish within the
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 territori ...
and
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
. Attempted reintroductions have yielded 16 transplanted populations in Arizona, as well as 46 captive or refuge populations in Arizona, California, and Mexico.


Diet

Pupfish are
omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
s that forage in shallow water during early morning and late evening; they will move out of the shallows during the day when water temperatures may rise to 36 °C or higher to avoid
heat death Heat death may refer to: *Heat death of the universe, a proposed cosmological event ** Heat death paradox, a philosophical examination of the cosmological event *Hyperthermia, injury up to and including death, from excessive heat *Thermal shock ...
. The rate of surface foraging drops when water temperatures fall below 21 °C. Pupfish show some dietary preference towards
nektonic Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms t ...
organisms, going so far as to suppress or even eliminate local populations of mosquitoes. In the absence of mosquito prey, pupfish will consume
benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
chironomid The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many specie ...
midges A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midg ...
(both from substrate and from midwater when midges attempt to come to the surface), algae, small
invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
, aquatic
crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
, aquatic insect
larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...
, snails,
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
, and occasionally the eggs and young of its own species. Exposed eggs are typically and readily eaten by other pupfish of the same species if not laid in an inconspicuous area, while mobile fry are ignored unless adults are very hungry. Furthermore, though pupfish may engage in
filial cannibalism Filial cannibalism occurs when an adult individual of a species consumes all or part of the young of its own species or immediate offspring. Filial cannibalism occurs in many animal species ranging from mammals to insects, and is especially prevalen ...
, males have been observed using
olfactory The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it ...
cues to distinguish between eggs fertilized by themselves and those
fertilized Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
by other males. This has been considered analogous to the defensive behavior of avian victims of
nest parasitism Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own ...
, wherein they will reject alien eggs. Similarly, pupfish eggs are typically only consumed by females that do not spawn them; these two factors, coupled with the fact that males show sexual preference towards larger (and therefore more
fecund Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to pr ...
) females, are consistent with parents maximizing the chances of offspring survival.


Biology and ecology


Motor patterns

The desert pupfish exhibits characteristic
movements Movement may refer to: Common uses * Movement (clockwork), the internal mechanism of a timepiece * Motion, commonly referred to as movement Arts, entertainment, and media Literature * "Movement" (short story), a short story by Nancy Fu ...
that can be grouped into various units as follows: *''Meandering''—the female swims somewhat aimlessly in midwater or near the surface in slightly exaggerated movements. *''Nuzzling''—the male swims directly under the meandering female, tilting his body upwards while keeping his head against or near the abdominal region of the female. *''Contacting''—as the female moves slowly, the male stays beside and slightly behind her, typically maintaining contact either side-to-side or snout-to-side. *''Tilting and nipping''—while swimming slowly, the female tilts her body downwards towards the substrate; from the tilted position, the female takes up a mouthful of substrate and drops her body to the bottom of the habitat. The female then expels the substrate and may nip two or three more times from the horizontal position. This action has been interpreted as food-seeking, and has been observed in other species as a signal for the moment of spawning. *''Halting and sidling''—after nipping, the female will halt, whereupon the male will swim forward and laterally against the female, thrusting the area at the base of his anal fin against the posterior line of the female's abdomen. *''S-shaping''—seen from above, the pupfish forms an s-shape. Typically, both male and female will couple in parallel s-shapes on the bottom of their habitat during mating. *''Wrapping''—while both fish maintain an s-shape, the male will wrap his anal fin around the posterior area of the female's belly, forming a crude cup beneath her vent. *''Jerking''—while still in an s-shape, the pupfish will jerk its head in the opposite direction it is situated in, causing a contraction that reverses the direction of the s-shape. During jerking, the female will extrude an egg, while the male presumably releases his sperm. *''Patrolling''—the territorial male will swim forwards in small, fast spurts, then stop abruptly before swimming in another direction. The male will patrol his entire territory in this way. *''Facing and eyeing''—two territorial males will approach each other head-on and face each other eye-to-eye with one to one-half body length between them. *''Arching''—the pupfish will form a c-shape with the concave side facing the opponent fish. *''Tail beating''—a competing male will beat his caudal towards the opponent fish, causing the beating fish to swing away from its opponent. *''Circling''—two fish will circle each other at high speeds in a head-to-tail orientation; this is likely due to each fish simultaneously attempting to charge into the flank of its respective opponent, while dodging the charge of the other by turning. *''Fleeing''—a fleeing pupfish will swim rapidly towards cover, or, in its absence, towards the water's surface. *''Escaping''—a pupfish will dive into the substrate of its habitat and remain motionless.


Reproduction

The breeding season of the desert pupfish typically occurs during early spring and into winter when water temperatures exceed about 20 °C. Under conditions of abundant food and suitable temperature, the desert pupfish may become sexually mature as early as six weeks of age. Though they may start to breed during their first summer, most pupfish do not reproduce until their second. Breeding behavior includes both territorial arena-breeding (high aggression) and consort-pair breeding (low aggression). The former occurs in large habitats with high primary productivity, limited breeding substrates, and high population density, and it is the most common; the latter occurs in habitats with low primary productivity, abundant breeding substrates, and low population density. During the breeding season, male pupfish establish and actively patrol and defend individual territories that are typically less than 1 meter deep and 1–2 meters in area; these territories vary in size based on individual fish size, density of other male pupfish, and water temperature, and are associated with small structures or incongruities of substrate. Adult females will swim in loose schools and forage inconspicuously. When a female is ready to spawn, she will leave the school to enter the territory of an attractive male, and the mating process described above will commence.United States fish and Wildlife Service (1993). Desert Pupfish (Cyprinodon macularius) Recovery Plan. (Unpublished). Prepared for the USFWS, Region 2. Temperature plays a significant factor in egg production. The most optimal temperature for eggs to be produced typically occurred at a constant temperature of 24-32 °C and a fluctuating temperature of 32-28 and 36-28 °C. Additionally, the quality of eggs was affected by temperature, with temperature and yolk diameter having an inverse relationship. The salinity the egg is placed in also has an effect on reproductive performance. The most optimal reproductive performance occurred at 10% salinity and decreased when above or below 10%.


Breeding

The reproductive behavior of the desert pupfish occurs in a characteristic fashion. Typically, males remain in their territory, while females, either alone or in groups, visit them: this is characteristic of arena-breeding. If a single female enters his territory, spawning occurs immediately; however, if multiple females are present, the male will swim from one female to the next until the proper response is given, whereupon spawning will occur. Females out of
oestrus The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous ...
will continuously forage. Occasionally, a male from a neighboring territory will rush to the side of the female opposite the resident male and spawn with the pair. When a female is ready to spawn, she will typically nip and tilt every 3 to 5 seconds. At this point, the male will immediately contact and attempt to sidle the female. After the third to fifth nip, the female will halt, allowing the male to fully sidle. Sidling by the male causes the female to form an S-shape, which causes the male to also form an S-shape and concurrently wrap his anal fin around the female's vent. After the female is wrapped, both fish jerk; jerking typically causes the female to release one egg, while ostensibly causing the male to fertilize said egg. Though the pair usually separates to leave one fertilized egg in the substrate, the female will very occasionally immediately form an S-shape and both fish will again perform the jerking sequence. Spawning lasts from 30 minutes to 2 hours, with larger females spawning more than smaller females. Typically, the last coupling of the pupfish is the most prolonged, and several eggs are laid in succession. After
copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
, both fish lie in the substrate, and after about 2 seconds, the male will contact the female again. If the female is finished spawning, she will flee in a "panicky" style with the male in pursuit. This chase lasts for about 5 minutes before the male swims to the bottom and both fish begin foraging.


Extreme conditions

''C. macularius'' are
euryhaline Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly (''Poecilia sphenops'') which can live in fresh water, brackish water, or salt water. The green crab (''Carcinus maenas'') is an e ...
and
eurytherm A eurytherm is an organism, often an endotherm, that can function at a wide range of ambient temperatures. To be considered a eurytherm, all stages of an organism's life cycle must be considered, including juvenile and larval stages. These wide ...
al, tolerating temperatures between approximately 4º and 45 °C and
salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
ranging from 0 to 70 parts per thousand, exceeding the tolerances of virtually all other
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
fish. The desert pupfish can also survive dissolved-oxygen concentrations as low as 0.13 ppm. The desert pupfish has been noted to be more abundant in environments with high vegetative cover, pH and salinity, and low dissolved oxygen and sediment factors, thus suggesting that living in extreme conditions allows them to survive in environments that are hostile to invasive or nonnative fish.


Management factors

While the desert pupfish contains a remarkable tolerance to extreme conditions, the species is listed as endangered as of 1986. The desert pupfish has been the focus of many conservation studies and attempts. Beginning in the late 1800s, the disappearance of the fish has been associated to the increase of human activities. Specifically, the threats to desert pupfish survival include the destruction of habitat, including loss and/or degradation of habitat through groundwater pumping and water diversion; contamination from agricultural return flows and other contaminants; physical changes in water quality; and pesticide run-off. In addition to these
anthropogenic effects Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the needs ...
, desert pupfish have also been threatened by disease and predation due to invasive and nonnative species. The most recent decline of desert pupfish have shown to be correlated with environmental competition, predation and behavioral activities that interfere with reproduction, though the direct effects of these factors are unknown. Various management factors have been suggested as beneficial towards saving the desert pupfish, including the control and management of exotic and invasive species in pupfish habitats; the maintenance of water levels, quality, and the proper functioning condition of ponds, springs, and drains; the restoration and enhancement of degraded habitat; and the establishment of large primary refuge populations for each group of wild ''C. macularius''.United States Fish and Wildlife Service (2010). Desert Pupfish (Cyprinodon macularius); 5-Year Review: Summary and Evaluation. Phoenix, Arizona: USFWS. The reintroduction of the desert pupfish to wild habitats has been moderately successful, with the establishment of captive or refuge desert pupfish populations has been more fruitful. Water management has been largely cited as having the greatest impact on the survival of ''C. macularius''.


See also

*
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 Am ...
*''
Cyprinodon ''Cyprinodon'' is a genus of pupfishes found in waters that range from fresh to hypersaline. The genus is primarily found in Mexico, the Caribbean Islands and southern United States (Arizona, California, Florida, Nevada, New Mexico, Oklahoma and ...
'' - Genus *
Death Valley pupfish The Death Valley pupfish (''Cyprinodon salinus''), also known as Salt Creek pupfish, is a small species of fish in the family Cyprinodontidae found only in Death Valley National Park, California, United States. There are two recognized subspec ...
, Salt Creek pupfish, ''Cyprinodon salinus'' *
Shoshone Pupfish The Shoshone pupfish (''Cyprinodon nevadensis shoshone'') is a subspecies of '' Cyprinodon nevadensis'' from California in the United States. It is characterized by large scales and a "slab-sided," narrow, slender body, with the arch of the ven ...
, ''Cyprinodon nevadensis shoshone'' * Tecopa Pupfish, '' Cyprinodon nevadensis calidae'' (extinct) * Owens pupfish, ''Cyprinodon radiosus'' *
Devil's Hole pupfish The Devils Hole pupfish (''Cyprinodon diabolis'') is a critically endangered species of the family Cyprinodontidae (pupfishes) found only in Devils Hole, a water-filled cavern in the US state of Nevada. It was first described as a species in ...
, ''Cyprinodon diabolis'' * Julimes pupfish, ''Cyprinodon julimes''


References


External links


Arizona Desert Museum: - Pupfish
* {{Taxonbar, from=Q3768281 Cyprinodon Freshwater fish of Mexico Freshwater fish of the United States Fish of the Western United States Fauna of the Colorado Desert Fauna of the Lower Colorado River Valley Fauna of the Sonoran Desert Colorado River Natural history of Baja California Natural history of Sonora Fish described in 1853 Endangered fish Endangered fauna of California Endangered biota of Mexico ESA endangered species Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard