The U.S. Fish and Wildlife Service has found that a petition to protect the headwater chub and the Lower Colorado River basin population of the roundtail chub under the Endangered Species Act provides sufficient information to warrant further consideration. The Service is now seeking scientific and commercial information to determine whether to propose adding them to the list of threatened or endangered species. The chubs currently occur throughout much of Arizona and in New Mexicos Gila River headwaters.
"Our current finding does not express our final decision of whether the species should be listed," said H. Dale Hall, the Services Southwest Regional Director. "We will base our decision on that issue only after a thorough review of the species status. We will perform a rigorous, critical analysis of the best available scientific and commercial information, not just the information in the petition. Thats why were calling for information at this time."
The 9- to 14-inch roundtail chub (Gila robusta) is an olive-gray to silver minnow with a lighter belly. The species was historically considered common in deep pools and eddies of large streams throughout its range in the upper and lower Colorado River basins in Wyoming, Utah, Colorado, New Mexico and Arizona. The petition specifically targets the lower basin population in Arizona and New Mexico for protection. This population today occupies about 18 percent of its historical range and is limited to Arizonas Little Colorado, Bill Williams, Salt and Verde river drainages and Aravaipa Creek, and New Mexicos upper Gila River.
The smaller headwater chub (Gila nigra) is dark gray to brown with silvery sides and lives in the upper and middle reaches of moderately sized streams. Headwater chub occur in a number of tributaries of the Verde River, most of the Tonto Creek drainage, much of the San Carlos River drainage, and parts of the upper Gila River in New Mexico. They occur in these same areas today, but their numbers are much smaller.
Both chub species are threatened by predation and competition with nonnative fishes, and habitat destruction due to dewatering, impoundment and channelization. Mining, livestock overgrazing, road construction, water pollution, riparian riparian
Definition of riparian habitat or riparian areas.
Learn more about riparian habitat destruction, urban and suburban development, and groundwater pumping have also degraded water quality.
We will initiate a review of the species status to determine whether listing is warranted, not warranted, or warranted but precluded, and make our decision by April 6, 2006, We request additional information and suggestions from the public, other concerned governmental agencies, Native American Tribes, the scientific community, industry, or any other interested parties concerning the status of the roundtail and headwater chubs. We are seeking information regarding the chubs historical and current status and distribution, their biology and ecology, ongoing conservation measures for the species and their habitat, and threats to the chubs and their habitat.
Roundtail and headwater chub status and threat information, comments or questions concerning this petition and finding should be submitted to the Field Supervisor, Arizona Ecological Services Office, 2321 West Royal Palm Road, Suite 103, Phoenix, Arizona 85021-4951 prior to September 15, 2005.
Visit the Services website at http://www.fws.gov.
NOTE TO EDITORS: Photographs of chubs are available by contacting Jeff Humphrey (602-242-0210 or jeff_humphrey@fws.gov">) or at http://arizonaes.fws.gov .
