As the result of new scientific classification information, the U.S. Fish and Wildlife Service (Service) is withdrawing its proposal to list two minnows, the headwater chub and a distinct population segment (DPS) of the roundtail chub in the Lower Colorado River Basin (Arizona and New Mexico), as threatened species under the Endangered Species Act (ESA).
In proposing to list the two chubs in October 2015, the Service relied upon a comprehensive species status assessment. At that time, the American Fisheries Society and the American Society of Ichthyologists and Herpetologists Joint Committee on the Names of Fishes – the recognized authority on fish taxonomy – considered the headwater chub and roundtail chub (and the currently listed Gila chub) to be separate species. In September 2016, the Joint Committee found the three fishes are actually a single species – the roundtail chub (Gila robusta). Because the entities previously proposed for listing are no longer recognized as species, we have determined that they are not listable entities and are withdrawing our proposed rule.
“Endangered Species Act determinations are founded on the best available science. When new science becomes available, especially midstream in a listing process, we evaluate it and respond accordingly,” said Steve Spangle, the Service’s Arizona Field Supervisor. “Our withdrawal of the listing proposal for the former headwater chub and roundtail chub DPS reflects this new science indicating that these are no longer valid species.”
The Service, together with conservation partners, intends to conduct a species status assessment of the now-larger roundtail chub taxon. This includes the Gila chub, which has been protected under the ESA since 2005. The taxonomic revision of the chubs resulted in Gila chub being recognized as a part of the larger roundtail chub species, necessitating a reevaluation of its ESA status. Pending this evaluation, the Gila chub will remain protected under the ESA.
American Fisheries Society and the American Society of Ichthyologists and Herpetologists Joint Committee on the Names of Fishes’ determination resolved a long-running debate that vexed fishery biologists in the field for decades – not being able to discern the identity of these chubs without considering the watershed where they were collected.
The Southwest’s unique headwater streams and the native fish they support are a source of local identity and sustainable water in our desert communities and economies. The Service remains committed to working closely with partner agencies such as the Arizona Game and Fish Department and the New Mexico Department of Game and Fish and others to prevent declines of the newly recognized roundtail chub.
Additional information on the chubs, including today’s withdrawal and FAQs, is available at www.fws.gov/southwest/es/arizona.
The U.S. Fish and Wildlife Service works with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information, visit www.fws.gov, or connect with us through any of these social media channels.
U.S. Fish and Wildlife Service News Release Public Affairs Office PO Box 1306 Albuquerque, NM 87103 505/248-6911 505/248-6915 (Fax)
