Least chub | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Cypriniformes |
Family: | Cyprinidae |
Subfamily: | Leuciscinae |
Genus: | Iotichthys D. S. Jordan & Evermann, 1896 |
Species: | I. phlegethontis |
Binomial name | |
Iotichthys phlegethontis (Cope, 1874) | |
Synonyms | |
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The least chub (Iotichthys phlegethontis) is a species of ray-finned fish in the family Cyprinidae, the only member of the genus Iotichthys. This species is found only in Utah [2] and more recently in Idaho [3] in the United States. Due to habitat degradation and introduction of non-native fishes, it is currently limited to a few spring complexes in Utah and the Snake River Valley in Idaho. [3]
The least chub is a small fish, with a maximum size of less than 2.5 inches (64 mm). They have an olive-green black with steel blue upper sides and a golden stripe running from the upper end of the gill opening to the base of the caudal fin. Its lower sides and belly are golden, and they have yellowish fins. While breeding, males develop a reddish hue on their belly and lower sides. The mouth is very oblique, extending to the front of the eye, which is large, and the species lack barbels. The dorsal fin contains 8-9 rays, with its origin just behind the pelvic fin insertion, and the caudal fin is slightly forked. There are 34-38 scales in the lateral series, and the lateral line is either absent or only features 1-3 pored scales. [4] It is the smallest of seven chubs native to Utah. Least chub eat primarily algae and small invertebrates, including mosquito larvae.
Least chub are small bodied fish that occupy still or slow-moving water bodies that have few predators. [5] They are endemic to the Bonneville Basin of Utah. [6] Historically, their range included Utah Lake, Provo River, Sevier River, streams, freshwater ponds, springs, and swamps near the Great Salt Lake. [7] Least chub populations have declined in the 20th century due to the impacts of introduced non-native fishes. These introduced fishes became established and competed better due to being better adapted to the environmental conditions. [8] One of the most significant impact that contributed to the decline of least chub was caused by the Western Mosquitofish (Gambusia affinis). These fish are commonly known to be aggressive and predate on eggs and young of other fish. [9] Consequently, they were found in 9 isolated spring pools in the desert regions of Utah. [10]
In 2021, new populations of least chub were documented in Idaho’s Snake River drainage, suggesting the species’ potential range could be larger than previously thought. [11]
Given that least chub typically inhabit slow-moving waters, their burst and sustained swimming speeds are relatively low. However, these speeds tend to improve as the fish grow larger. [5] These fish usually spawn in seasonally flooded areas or the shallow edges of springs and ponds, mainly during the spring season. These habitats serve as crucial nursery areas for their eggs and newly hatched larvae. For the rest of the year, adults tend to prefer the deeper pools of springs and ponds. Data from 2012-2014 showed that groundwater levels are essential for the habitat and breeding of the least chub in the Leland Harris Spring Complex. When groundwater levels drop, surface water decreases, resulting in less available habitat space, eventually breaking up populations. In 2013, a significant drop in groundwater caused most of the surface water to disappear, leaving fewer places for fish to live and breed. During wet periods, large ponds form where the least chub can spawn and grow, but during dry periods, the fish move to deeper springs to survive. [12]
Least chub spawn in the spring when the water temperatures reach 16°C. They are polyandrous broadcast spawners, releasing their eggs over vegetation, mainly algae. They do not construct nests or provide any parental care for their young. [13] The fertilized eggs hatch in about two days at a water temperature of 22°C. [14] Submerged vegetation provides essential oxygen and food for eggs and larvae. Least chub is an intermittent spawner, with females releasing a small number of eggs over extended periods, ranging from 300 to 2,700 eggs at a time. The breeding season typically lasts from April to August, with peak activity in May, though it can extend longer depending on environmental conditions. Rather than temperature increases, spawning is triggered by changes in light. Least chub reproduce in marshes when water temperature, alkalinity, pH, and conductivity are highest. After the breeding season, they return to the springs. These reproductive adaptations, including extended spawning periods and tolerance to fluctuating water conditions, allow the least chub to thrive in the variable environments of spring and marsh complexes. [15]
The least chub populations suffered a steep decline in the 1940s and 50s, though the decline wasn't noticed until the 70s. Reasons for the decline include habitat destruction from cattle grazing on and trampling streamside vegetation, water diversion, mineral and energy development, and non-native fishes. Studies indicate that where non-native fishes such as mosquitofish [16] are introduced, few if any least chub remain.
Though the distribution of the least chub is still limited, the Utah Division of Wildlife Resources and other conservation groups have reintroduced the fish into suitable habitats, often removing non-native fish prior to stocking. Other conservation efforts include working with ranchers to fence off critical spring complexes to prevent habitat destruction from cattle grazing.
Recently the Utah Division of Wildlife Resources teamed up with mosquito abatement districts in Davis and Salt Lake counties to distribute the fish to 240 backyard ponds to evaluate it as a potential mosquitofish replacement. Researchers will monitor how well the chub compete against the more aggressive mosquitofish in ponds where they are both stocked. Ponds with only the least chub will be monitored to determine whether they can control mosquito larvae as effectively as the mosquitofish or if more chubs will be required to do the same job. [17]
Conservation efforts for the least chub has also included the establishment of introduced populations as a key strategy to protect the species from habitat loss and other threats. Introduced populations have proven to be successful due to the species’ ability to adapt to various water quality conditions and rapid reproductive cycles. From 2014 onwards, ten stable populations were established in artificial ponds, providing a buffer against environmental threats such as drought and climate change. These introduced populations were crucial in the U.S. Fish and Wildlife Service’s 2014 decision not to list the least chub under the Endangered Species Act, citing that these populations offered sufficient habitat redundancy and genetic diversity to safeguard the species’ future. While non-native species like the western mosquitofish pose a continuous threat, habitat restoration efforts, such as removing invasive species and improving breeding grounds, have played a significant role in stabilizing key populations. Conservationists continue to monitor both natural and introduced populations to ensure long-term survival, particularly in the face of climate change and groundwater depletion. [8]
The Virgin River is a tributary of the Colorado River in the U.S. states of Utah, Nevada, and Arizona. The river is about 162 miles (261 km) long. It was designated Utah's first wild and scenic river in 2009, during the centennial celebration of Zion National Park.
The Sacramento Perch is from the family, Centrarchidae, characterized by dorsal fins with spiny elements and known for its nesting behavior. There are about 31 species in this family, which include sunfishes, crappies, and basses. The Sacramento Perch is considered in the sunfish group. It is the only species of Centrarchidae whose native habitat resides west of the Rocky Mountains, while all the other species are native to the east.
The Shoshone pupfish is a subspecies of Amargosa pupfish from California in the United States. They are spring-dwelling fish, endemic to Shoshone Springs on the outskirts of Shoshone, Inyo County, California. In 1969, the Shoshone pupfish was declared extinct until their eventual rediscovery by a team of biologists during a survey of Shoshone Springs in 1986. Currently, they are listed as endangered by the American Fisheries Society and are a species of special concern according to the California Department of Fish and Wildlife. Several stocks of the fish are being cultivated in captivity at the University of Nevada, Las Vegas and University of California, Davis for reintroduction into the Shoshone Spring. Today, people pass through the town of Shoshone to visit the spring site and view the rare pupfish, where some infographics and signs educate visitors about them.
The Mohave tui chub is a subspecies of the tui chub endemic to the Mojave River.
The Utah chub is a cyprinid fish native to western United States, where it is abundant in the upper Snake River basin and the Bonneville basin.
The mountain whitefish is one of the most widely distributed salmonid fish of western North America. It is found from the Mackenzie River drainage in Northwest Territories, Canada through western Canada and the northwestern USA in the Pacific, Hudson Bay and upper Missouri River basins to the Truckee River drainage in Nevada and Sevier River drainage in Utah.
The boreal toad is the nominate subspecies of the western toad. They are commonly found in the western U.S. and western Canada. Boreal toad populations have declined recently due to an emerging amphibian disease, chytrid fungus. The boreal toad is currently listed as an endangered species by Colorado and New Mexico. It is known in Colorado as the only alpine species of toad.
The eastern mosquitofish is a species of freshwater fish, closely related to the western mosquitofish, Gambusia affinis. It is a member of the family Poeciliidae of order Cyprinodontiformes. The eastern mosquitofish is native to the eastern and southern United States from Florida to Pennsylvania and inland to Alabama and Tennessee, while the western mosquitofish has a larger distribution throughout the United States.
The Spanish toothcarp, also known as the Spanish toothcarp or Iberian killifish, is a small, endemic species of fish in the family Aphaniidae. Its risk of extinction is one of the greatest of any Iberian vertebrate. Its limited range, coupled with the drastic population decline the species has suffered in the last two decades, has caused it to be placed on endangered species lists, both in Spain and internationally. In addition, habitat fragmentation, likely due to humans, has resulted in this species becoming increasingly stagnant and has led to increased genetic drift. Also found to be contributing to their endangerment was genetic diversity of mitochondrial DNA. The mitochondrial DNA coupled with A. iberus’s geographic distribution has been able to affect their population genetic structure gradually in different spaces. Its conservation status in the south of the Iberian Peninsula has notably worsened.
The northern hogsucker is a freshwater ray-finned fish belonging to the family Catostomidae, the suckers. It is native to the United States and Canada where it is found in streams and rivers. It prefers clear, fast-flowing water, where it can forage on the riverbed for crustaceans, mollusks, aquatic insects, algae and detritus. It turns over small pebbles and scrapes materials off rocks and sucks up the particles, and other species of fish sometimes station themselves downstream from its activities. In addition this species also is common in flowing water near dams and other streams of water. Breeding takes place on gravel bottoms in shallow riffles in late spring. This fish is susceptible to such man-made disturbances as channelization, sedimentation, pollution, and dam construction. However, it has a wide range and is a common species so the International Union for Conservation of Nature has rated its conservation status as being of "least concern". This species only gets around 8-12 inches in length but given the right conditions can exceed 16 inches in length and even exceed a pound in weight. The Northern Hogsucker is typically a bronze to gold coloration with patches of brown and black on its body. It has brownish grayish eyes. It’s dorsal and pectoral fins are a dark brown color with the dorsal fin having a small bit of red on it as well. The northern hogsucker and other sucker minnow species have been seen in memes due to the unusual appearance of their mouths.
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The bonytail chub or bonytail is a cyprinid freshwater fish native to the Colorado River basin of Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming in the southwestern United States; it has been extirpated from the part of the basin in Mexico. It was once abundant and widespread in the basin, its numbers and range have declined to the point where it has been listed as endangered since 1980 (ESA) and 1986 (IUCN), a fate shared by the other large Colorado basin endemic fish species like the Colorado pikeminnow, humpback chub, and razorback sucker. It is now the rarest of the endemic big-river fishes of the Colorado River. There are 20 species in the genus Gila, seven of which are found in Arizona.
The Yaqui chub is a species of freshwater fish in the family Cyprinidae. It is found in northern Mexico and the United States. The Yaqui chub is a medium-sized minnow fish that historically occurred in streams of Rios Matape, Sonora, and the Yaqui systems of Sonora, Mexico. It is one of the five species of the genus Gila in Arizona. The Yaqui chub is closely related to G. ditaenia, and G. orcutti ; and shares several physical characteristics with the G. orcutti, but proves different by having a black wedge near the base of the caudal fin.
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