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Least Chub


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  • Least chub. Credit: USFWS.

    Least chub. Credit: Esther J. Stokes.

  • Least chub. Credit: USFWS.

    Least chub. Credit: USFWS.

Least chub (Iotichthys phlegethontis)

Species Description: The least chub is a small minnow, with a maximum size of less than 2.5 inches.  It is a colorful species with a gold stripe along blue sides with white to yellow fins.  The chub eats primarily algae and small invertebrates and is considered a slow-growing species that rarely lives beyond 3 years of age.

Currently, only five wild populations of least chub remain.  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.

Recent actions & links »

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Recent Actions:The U.S. Fish and Wildlife Service has removed the least chub from the Candidate Species List through a not warranted 12-month finding published in the Federal Register on August 26, 2014.  The decision was reached after the Service worked with state, local, and federal partners to finalize an amendment to a previous conservation agreement, which will provide landscape-level protection to the species across its range.  The 2014 conservation agreement amendment, signed by the Service, Bureau of Land Management, Utah Division of Wildlife Resources, Utah Reclamation Mitigation and Conservation Commission, Central Utah Water Conservancy District, Southern Nevada Water Authority, and Bureau of Reclamation, in combination with substantial modifications to previously proposed large-scale groundwater development projects, comprehensively address all the threats to the species, to the point that it no longer meets the definition of a threatened or endangered species under the Endangered Species Act (Act).  The documents for public review can be downloaded by clicking on the following links:

Federal Register Notice

2014 Candidate Conservation Agreement Amendment

2014 Candidate Conservation Agreement with Assurances

PECE Analysis

Groundwater Analysis

Archived Actions: The U.S. Fish and Wildlife Service received an application from the Utah Division of Wildlife Resources for an enhancement of survival permit under the Endangered Species Act of 1973, as amended. The permit application includes a proposed programmatic Candidate Conservation Agreement with Assurances (CCAA) for the least chub, a fish endemic to the Bonneville Basin of Utah. The conservation goals of the Programmatic CCAA are to reduce the threats to least chub and its habitat, as outlined in the 12-month finding, and increase the number of viable, stable, and secure least chub populations within the species’ historic range. Under a CCAA, participating landowners voluntarily undertake management activities on their property to enhance, restore, or maintain habitat benefiting species that are proposed for listing or candidates for listing under the Endangered Species Act. CCAAs encourage private and other non‑Federal property owners to implement conservation efforts for species by assuring property owners that they will not be subjected to increased land use restrictions as a result of efforts to attract or increase the numbers or distribution of a listed species on their property, if that species becomes listed under the Act in the future. The CCAA project area includes all non-Federal lands in the Bonneville Basin of Utah encompassed by the current and historic distribution of least chub. We request public comment on the draft Programmatic CCAA.

The Fish and Wildlife Service has determined that listing the least chub as a threatened or endangered species under the Endangered Species Act is warranted, but that listing the fish at this time is precluded by the need to complete other listing actions of a higher priority.  The least chub will be classified as a candidate species until a listing proposal can be prepared.

Least chub populations are impacted by livestock grazing and groundwater withdrawals; predation and competition from nonnative fish, particularly mosquitofish; inadequate regulatory mechanisms controlling groundwater withdrawals; and the cumulative effects of drought, current and future groundwater withdrawals, and climate change.

News Release:  June 21, 2010: Listing of the Least chub Under the ESA Is Warranted
Federal Register Notice: June 21, 2010 12-Month Finding on a Petition to List the Least Chub as Threatened or Endangered

Archives »

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Archived Actions: After review of a petition seeking to protect the least chub under the Endangered Species Act (ESA), the U.S. Fish and Wildlife Service (Service) will undertake a more thorough review of the species to determine whether to propose adding the least chub to the list of threatened or endangered species.

This petition finding indicated that the Service finds it appropriate to conduct a complete status review of the least chub under the ESA.  The 90-day finding is only the first step in a process that triggers a review of all the biological information available.

The public is invited to provide comments and information about the species and its habitat.  Please see the Federal Register notice for more information.

The Endangered Species Listing Program 


The mission of the U.S. Fish and Wildlife Service is working with Others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American People.
Last modified: July 08, 2015
All Images Credit to and Courtesy of the U.S. Fish and Wildlife Service Unless Specified Otherwise.
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