PETITION TO LIST THE ROUNDTAIL AND HEADWATER CHUBS (Gila robusta and nigra) AS ENDANGERED SPECIES IN THE LOWER COLORADO RIVER BASIN CENTER FOR BIOLOGICAL DIVERSITY April 2, 2003 Ms. Gayle Norton Secretary of the Interior Office of the Secretary Department of the Interior 18th and "C" Street, N.W. Washington, D.C. 20240 The Center for Biological Diversity and Noah Greenwald hereby formally petition to list a distinct population segment of the roundtail chub (Gila robusta) in the Colorado River basin below Glen Canyon Dam, and the headwater chub (Gila nigra) throughout its range as endangered (or threatened) pursuant to the Endangered Species Act, 16 U.S.C. 1531 et seq. (hereafter referred to as "ESA"). This petition is filed under 5 U.S.C. 553(e) and 50 CFR 424.14 (1990), which grants interested parties the right to petition for issue of a rule from the Assistant Secretary of the Interior. Petitioners also request that Critical Habitat be designated concurrent with the listing, as required by 16 U.S.C. § 1533(b)(6)(C) and 50 CFR 424.12, and pursuant to the Administrative Procedures Act (5 U.S.C. 553). Petitioners understand that this petition action sets in motion a specific process placing definite response requirements on the U.S. Fish and Wildlife Service and very specific time constraints upon those responses. See 16 U.S.C. § 1533(b). Petitioners: Center for Biological Diversity is a non-profit public interest organization dedicated to protecting the diverse life forms of western North America. It has offices in New Mexico, Arizona, and California. 2 EXECUTIVE SUMMARY Like many southwestern native fish, roundtail and headwater chub have declined precipitously due to a combination of habitat loss and degradation related to livestock grazing, dams, diversions, groundwater pumping, mining, recreation, and human population growth, competition and predation from non-native fish, and inadequate existing laws and regulations. In the lower Colorado River basin, roundtail and headwater chub occupy only 18% and 40% of their historic ranges respectively, and their status is poor and declining. The small and isolated nature of remaining populations puts both species at a high risk of extinction. Many of the factors that lead to this significant diminution of range continue to threaten remaining populations. As a result, both the roundtail and headwater chub meet four of five factors for determination as threatened or endangered species: Present or threatened destruction, modification, or curtailment of habitat or range: Ø Livestock grazing is occurring in the watersheds of 29 of 30 remnant populations of roundtail or headwater chub. Forest Service documents determined that grazing is impacting chub populations on at least 17 allotments spread across five national forests and that livestock grazing on two allotments would eventually lead to a trend towards federal listing. The Forest Service failed to analyze impacts on 15-23 allotments, where the species is known to occur and there is active livestock grazing. Adverse effects from grazing also occur on other Federal, State, and private lands where the two chub persist. Ø A growing human population threatens to dewater substantial portions of the upper Verde River and its tributaries, where there are a number of remnant populations of roundtail and headwater chub, and one of the most intact native fish communities remaining in the Southwest. Dewatering also threatens at least 11 other chub populations and precludes recovery in large portions of their historic range. Ø At least 18 major dams have been constructed throughout the ranges of the roundtail and headwater chub in the lower Colorado River basin. They have destroyed substantial areas of historic range. Operations of these dams prevents or inhibits recovery in major areas and adversely affects chub populations in others. The reservoirs are stocked and managed for nonnative sport fishes, which are highly detrimental to roundtail and headwater chub. Ø Ongoing urban and suburban development threatens existing chub populations and limits recovery on the Verde, East Verde, Salt, San Pedro, and Gila Rivers and Oak, West Clear, Wet Beaver, Aravaipa, and Tonto Creeks. Ø Roads, mining, recreation and other factors continue to impact many roundtail and headwater chub populations. 3 Ø Stream channel alteration and channelization has destroyed extensive areas of roundtail and headwater chub habitat. Ongoing channelization and incremental channel alteration continue to alter chub habitat making it unsuitable for the two species and resulting in population losses. Other natural or manmade factors affecting the continued existence of the roundtail and headwater chubs: Ø Non-natives have been documented in 28 of the 30 streams with known populations of roundtail or headwater chub. Competition and habitat alteration by these non-natives has been highly detrimental to the two chub. New detrimental nonnative species continue to invade. Ø Stochastic disturbances, such as fire and drought, threaten remaining populations of roundtail and headwater chub. Serious ongoing drought may lead to losses of already highly stressed populations of both species. Disease or predation: Ø Largemouth bass, smallmouth bass, green sunfish, flathead catfish, channel catfish, black bullhead, yellow bullhead, and crayfish are all known or suspected to prey on native fish and have been introduced into the ranges of roundtail and headwater chub. Some stocking of these species is still ongoing within, or adjacent to, populations of roundtail and headwater chub. Ø Increased rates of parasitic infection, particularly anchor worm, have been observed in roundtail chub in recent decades. These observations in combination with observations of infestation occurring in habitat stressed fish suggest that declining habitat quality may be increasing disease rates for roundtail chub. Inadequacy of existing regulations: Ø No existing Federal laws, regulations, or policies provide sufficient protection to stem the ongoing decline of roundtail and headwater chub. Protections for federally listed species or habitat have not prevented the decline of these species or other native fish in the southwest and are insufficient to protect roundtail or headwater chub. Ø Existing State laws, regulations, and policies are inadequate to protect roundtail and headwater chub. In addition, substantial adverse activity is ongoing under existing State provisions. Conflict of interest between income from, and mandates for, sport fish stocking and conservation of native fish result in contradictory actions by State wildlife agencies that often harm native fish. Ø On private lands, little protection is available for roundtail and headwater chub. 4 TABLE OF CONTENTS: Introduction 1 I. Natural History 2 A. Description 2 B. Taxonomy 2 C. Reproduction/ontogeny/growth 4 D. Diet 6 E. Associated fish species 10 F. Habitat requirements 12 G. Historic and current distribution 19 II. The roundtail chub in the lower Colorado River basin constitutes a distinct population segment 25 III. Population status 37 IV. Present or threatened destruction, modification, or curtailment of habitat or range 40 A. Livestock grazing 41 B. Water withdrawal 52 C. Dams 54 D. Roads and Logging 55 E. Recreation 56 F. Mining 56 G. Urban development 56 H. Channelization 57 I. Cumulative effects 58 V. Other natural or manmade factors affecting the continued existence of roundtail and headwater chub 59 A. Nonnative species 59 B. Stochastic disturbance and population isolation 61 VI. Disease or predation 63 VII. Inadequacy of existing regulations 65 A. U.S. Fish and Wildlife Service 68 B. U.S. Forest Service 72 C. Bureau of Land Management 76 D. Bureau of Reclamation 77 E. U.S. Army Corps of Engineers 78 F. Other Federal Agencies 78 G. States 79 H. Private lands 94 I. Tribal lands 94 VIII. Request for Critical habitat designation 94 Literature cited 95 5 INTRODUCTION The unique and highly endemic fish fauna of the Colorado River basin has been decimated by a century of habitat degradation and non-native fish introductions (Miller 1961). Carlson and Muth (1989) report that of 54 species or subspecies in the Colorado River basin, “17 are either endangered, threatened or extinct, and most have experienced drastic abundance and range reductions.” Presently, 21 Colorado River basin fish species or subspecies are Federally listed as endangered or threatened or proposed for listing, one species is extinct, and one is being managed under a conservation agreement in-lieu of listing (50 CFR §17.11). In the genus Gila alone, of the six species endemic to the Colorado River basin, four are listed or proposed for listing and the other two are the subject of this petition. Non-native fish species dominate most fish communities in the Colorado River basin, and include at least 67 introduced species (Minckley 1973, Carlson and Muth 1989, USFWS 2001a). These introductions have been facilitated by drastic habitat modification, which favors non-natives over natives (Rinne et al. 1998, Minckley 1999). A majority of waters in the Colorado River basin are now regulated with associated changes in the hydrograph, channel geomorphology, water temperatures and mineral and sediment concentrations (Carlson and Muth 1989). Less than 1% of the river’s historic flow reaches the Colorado River delta. These changes have been compounded by groundwater pumping and diversion that reduce flows, and habitat altering activities, such as livestock grazing, construction of roads,