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.
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
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.
- Federal Register Notice October 15, 2008 90-Day Finding on a Petition To List the Least Chub (Iotichthys phlegethontis) as Threatened or Endangered With Critical Habitat
- Press Release October 15, 2008 Least Chub May Warrant Protection Under the Endangered Species Act