|Scientific Name:||Iotichthys phlegethontis|
|Species Authority:||(Cope, 1874)|
|Red List Category & Criteria:||Endangered B2ab(ii,iii,iv,v) ver 3.1|
|Reviewer/s:||Smith, K. & Darwall, W.R.T.|
|Facilitator/s:||Hammerson, G.A. & Ormes, M.|
This species is listed as Endangered because area of occupancy is probably less than 500 sq km, wild populations exist at no more than 5 locations, and (despite helpful conservation actions) habitat quality/quantity and the species' distribution and abundance are subject to ongoing declines from continuing threats. Long-term viability of populations introduced into refugia is uncertain, so these are not included in the number of locations.
|Range Description:||Historically, this species was widely distributed in the Bonneville Basin, including streams near Salt Lake City, ponds and swamps around the Great Salt Lake, Utah Lake, Beaver River, Parowan Creek, Clear Creek, Provo River, Snake Valley, and elsewhere (Sigler and Sigler 1996).
Currently, only five wild populations of Least Chub remain (USFWS 2010). Three populations are in Snake Valley in Utah's West Desert. They include the Leland Harris Spring Complex, Gandy Salt Marsh, and Bishop Spring Complex. The remaining two wild populations are located on the eastern border of the native range near the Wasatch Front. Those populations in the Mills Valley and Clear Lake are in the Sevier River drainage. A functionally extirpated site exists at Mona Springs in the Utah Lake drainage.
In an attempt to create refuge (an artificial place of protection for a species) populations and reestablish wild populations, 19 introductions of Least Chub to new locations rangewide were attempted between 1979 and 2008 (see USFWS 2010). Of these, two sites are currently stable and secure (one has persisted for 3 years and another for 1 year), seven introductions failed, and three are not secure. The long-term success of seven of the transplants is currently unknown.
|Range Map:||Click here to open the map viewer and explore range.|
Naturally occurring populations are currently restricted to 6 populations in 4 general areas (Mock and Miller 2005). USFWS (2010) recognized five existing wild populations.
Total adult population size is unknown. Individual populations are small.
Decline was first noted in the 1940s and 1950s, continued through at least the 1980s. Recent recovery efforts have resulted in an increasing trend in abundance and in the number of populations (Muck 1999). However, data from the 1990s suggested that Least Chub numbers may have been declining within the Gandy Salt Marsh (Perkins et al. 1998).
Trend over the past 10 years or three generations is uncertain.
|Habitat and Ecology:||Historically this species occurred in slow rivers, clear creeks, springs, ponds, and marshes (Sigler and Sigler 1996, Page and Burr 2011). Now it is basically an alkaline spring inhabitant. Typically it is found in moderate-dense submergent and emergent vegetation, at depths of 10-90 centimetres, over bottoms of clay, muck, mud, and peat (Sigler and Miller 1963, Lee et al. 1980).|
USFWS (2010) found that listing the Least Chub as threatened or endangered is warranted due to the effects of livestock grazing and water withdrawal and diversions on the species and its habitat. Although the agencies have worked to protect Least Chub habitat with grazing enclosures where possible and grazing management plans in some areas, livestock-grazing-related impacts are still observed at most Least Chub sites. There is substantial evidence showing the negative effect of historical groundwater withdrawal on Least Chub. While uncertainty exists on the magnitude of effects to the Least Chub from proposed large-scale groundwater pumping, concern regarding the remaining five extant, wild populations is sufficient to indicate that the species is at risk of extinction in the foreseeable future, especially when combined with the threat of drought.
USFWS (2010) found also that listing the Least Chub as threatened or endangered is warranted due to the continuing threat of nonnative species, particularly Mosquitofish, for which there is no known means of control. Several significant efforts have been made to remove Mosquitofish from Least Chub habitats, without success. The wild least chub population at Mona Springs is functionally extirpated due to Mosquitofish, and nonnative fish are present at two of the five remaining viable populations.
USFWS (2010) found also that the Least Chub is at risk of extinction in the foreseeable future due to inadequacy of existing regulations to regulate groundwater withdrawals and ameliorate their effects on Least Chub habitat.
Further, USFWS (2010) found that the Least Chub is at risk of extinction in the foreseeable future because of the cumulative effects of drought, current and future groundwater withdrawal, and climate change on the remaining naturally occurring populations in Snake Valley.
See also Miller and Behnke (1985), Sigler and Sigler (1996), Perkins et al. (1998), Muck (1999).
|Conservation Actions:||Threats from habitat degradation and introduced species have been alleviated by a recent conservation agreement.|
Crist, L. 1990. A study/monitoring plan for least chub (Iotichthys phlegethontis) in Snake Valley, Utah. Bio/West, Inc., Logan, Utah.
Hickman, T.J. 1989. Status report of the least chub, Iotichthys phlegethontis. Report to the U.S. Fish and Wildlife Service. Western Ecosystems, St. George, Utah.
IUCN. 2013. IUCN Red List of Threatened Species (ver. 2013.1). Available at: http://www.iucnredlist.org. (Accessed: 12 June 2013).
Lee, D.S., Gilbert, C.R., Hocutt, C.H., Jenkins, R.E., McAllister, D.E. and Stauffer, J.R., Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina.
Miller, D.L. and Behnke, R.J. 1985. Two new intergeneric cyprinid hybrids from the Bonneville Basin, Utah. Copeia 1985: 509-515.
Mock, K.E. and Miller, M.P. 2005. Patterns of molecular diversity in naturally occurring and refugial populations of the least chub. Transactions of the American Fisheries Society 134: 267-278.
Muck, J. 1999. Least chub candidate conservation. Endangered Species Bulletin 24: 16-17.
Nelson, J.S., Crossman, E.J., Espinosa-Perez, H., Findley, L.T., Gilbert, C.R., Lea, R.N. and Williams, J.D. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American Fisheries Society, Bethesda, Maryland.
Osmundson, D.B. 1985. 1985 status survey of least chub (Iotichthys phlegethontis) in desert springs of western Utah. Utah Division of Wildlife Resources, Salt Lake City, Utah.
Page, L.M. and Burr, B.M. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts.
Page, L.M. and Burr, B.M. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Harcourt, Boston, Massachusetts.
Perkins, M.J., Lentsch, L.D. and Mizzi, J. 1998. Conservation agreement and strategy for least chub (Iotichthys phlegethontis) in the state of Utah. Utah Division of Wildlife Resources Publication Number 98-25.
Robins, C.R., Bailey, R.M., Bond, C.E., Brooker, J.R., Lachner, E.A., Lea, R.N. and Scott, W.B. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society.
Sigler, W.F. and Miller, R.R. 1963. Fishes of Utah. Utah State Department of Fish and Game, Salt Lake City, Utah.
Sigler, W.F. and Sigler, J.W. 1987. Fishes of the Great Basin: a natural history. University of Nevada Press, Reno, Nevada.
Sigler, W.F. and Sigler, J.W. 1996. Fishes of Utah: a natural history. University of Utah Press, Salt Lake City, Utah.
U.S. Fish and Wildlife Service (USFWS). 1999. Withdrawal of the proposed rule to list the least chub as endangered with critical habitat. Federal Register 64(145): 41061-41068.
U.S. Fish and Wildlife Service (USFWS). 2010. 12-month finding on a petition to list the least chub as threatened or endangered. Federal Register 75(119): 35398-35424.
Workman, G.W., Valdez, R.A., Sigler, W.F. and Henderson, J.M. 1979. Studies on the least chub in geothermal active areas of western Utah. BLM, Utah State Office, Salt Lake City, Utah.
|Citation:||NatureServe 2013. Iotichthys phlegethontis. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 March 2014.|
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