INFORMATION TO USERS This manuscript ,has been reproduced from the microfilm master. lJ.M! films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The ,!uality of this reprodDcti('~ i~ d~P'J!!d~!!t !!PQ!! t!!e qn-2!!!:y ef the copy submitted. Broken or indistinct print, colored or poor quality illustrcUioll5 and photo~-csphs, print bleedmrough, substandard margins. and improper alignment can adversely affect reproduction. In the unlikely. event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, chans) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerograpbically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or i11ul\tranonl\ appearing in this copy for an additional charge. Contact UMI directly to order. UMl A Bel! & Howell Information Company 300 North Zeeb Road. Ann A~bor. MI48106-1346 USA 313!761-47oo 800:521-0600 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. OBSERVATIONS ON THE BIOLOGY OF THE HUMPBACK CHUB IN THE COLORADO RIVER BASIN 1980-1990 by Charles o. Minckley A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Biology Northern Arizona University May 1996 Approved: Ga~ C. B ternan, Ph.D. /.. U~t uJ. ~ Dean W. Blinn, Ph.D. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 9625766 UMI Microform 9625766 Copyright 1996, by Lll\1I Company . .L4..!! rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. lJlVfl 300 North Zeeb Road Ann Arbor, MI 48103 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT OBSERVATIONS ON THE HUMPBACK CHUB IN THE COLORADO RIVER BASIN, 1908-1990. Charles o. Minckley The humpback chub is listed as a federally endangered species primarily as the result of the impacts of hydroelectric dam operations and the introduction of nonnative fishes. Geographic distribution of the humpback chub in the Colorado River basin is well documented, occurring in the major tributaries of the upper basin including the Green, White, Yampa and Little Snake Rivers. Currently there are five upper basin popUlations to include: the Green, Yampa, and Colorado river (at Black Rocks, Westwater Canyon and Cataract Canyon). In the lower basin distribution is from Glen Canyon Dam into Lake Mead. In Grand Canyon, the largest population occurs in the Little Colorado River although fish occur consistently at five other areas along the river corridor. ii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The habitats used by humpback chubs are similar throughout the basin, varying with the life stage. Generally, larvae and fry occupy shoreline backwater habitats in slowly moving water. Young-of-the-year chub occur in slow to moderately moving eddies and adjacent backwaters. Juveniles live in deeper water such as low-velocity eddies and backwaters <10 m deep. Adults are in deep eddies and backwaters, presumably including depths >10 m. Adult humpback chubs are considered sedentary, occurring in canyon-bound reaches of the Colorado River Basin. However, there are exceptions when some individuals move further. The diet of this species consists of a variety of aquatic and terrestrial invertebrates, and occasionally fish. Reproduction has been confirmed throughout the basin but spawning has not been observed. Humpback chub host several parasites but only two present potential threats, the anchorworm and Asian tapeworm. These parasites have been found in the lower basin and may have negative impacts in the future. A recovery plan is in place for this species addressing the upper basin popUlation. No specific plan is extant for the lower basin. iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Chapter One - Introduction .....••••........•...... 1 Materials and Methods .....•••................ 6 Chapter Two: Fishes of the Colorado River ........ l7 History of Colorado River Basin .. o •••••• o ••• 1S Discovery and Description of Gila cypha ..... 20 General Distribution and status ............. 22 Description of Habitat •••...•.•...••........ 24 Geologic History .•...••.•..•...........•.... 24 Evolution of the Colorado River .......•..... 26 Colorado River Basin of Today ......•........ 28 Chapter Three: The Upper Colorado River Basin .... 32 Geographic Distribution •••.•..••..••.•...... 37 Distribution in Upper Basin Rivers ....•..... 40 Green River ......•..••••..••...•.••...• 40 Yampa River ....•....................... 44 Colorado River ...•••...•.•............. 45 Other Upper Basin Rivers .........•..... 45 Upper Basin Habitat Use ..................... 45 Life History Information, Upper Basin ....... 49 Upper Basin Recovery Actions ................ 59 Chapter Four: The Lower Colorado River Basin ..... 62 iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Summarv of Icthvoloqical Research in the Grand Canyon Region: •••••••••.•••••.••.••.••• 64 Geographic Distribution ••••••••••••.......... 67 Lower Basin Habitat Use ••••.•••••••.••....•.. 70 Colorado River .•••••••.•••.•••..•.•....• 76 Grand Canyon Tributaries ••.•.•..•.••.••• 79 Little Colorado River ••.•..•.•••••• 84 Factors Influencing Distribution and Abundance in Grand Canyon •••..••••••••••.•.•..••••.•••. 88 Effects of Introduced Fishes ..•.•••....••.••• 88 Impacts of Glen Canyon Dam ••..••..•....•.•••• 96 Life History Observations, Lower Basin .•...• lOa Lower Basin Recovery Efforts •••••••••••••••• 140 Chapter Five: Summary and Recommendations ... 142 Recommendations ••••••••••••.••••••••.....••• 143 Summary. • • • • • • • • • • • • . • • • • • • • • • • • • . • . • • • . • . 14 5 Literature cited ••••..•••••••••..•..•....••. 149 v Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Acknowledgments Dr. Stanley Wilkes is thanked for accepting me into the graduate program. Drs w. Linn Montgomery~ Charles C. Avery, Gary Bateman, and Dean Blinn, my committee are to be commended for persevering and assisting me in completing this program. Arizona Game and Fish Department is gratefully acknowledged for making data available for this project. Mr. Dave Wegner, provided funding through the Glen Canyon Environmental Studies Program Phase I, for this project (U.S. Bureau of Reclamation Contract No. IFC-40-10500 to Department of Biology, Northern Arizona University) and is thanked for his assistance. All of the other agencies/individuals which were contacted for information are also acknowledged. Individuals which are particularly thanked include Saundra King Minckley for helping me get started; L.T. Green for assisting me on the river and making some of the early shuttles to the head of the Salt Trail Canyon, and more importantly, the pick ups; Brian Bagley, Nancy Brian, John Cook, Adele Fegley, and Randy VanHaverbeke for the most recent help working on this fish; Drs Mike vi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Douglas: Paul Marsh and Wendell Minckley: Arizona state university for editorial assistance; Shane Murphy, Canyoneers and Bill Elwanger, Hatch Inc. for assistance in the canyon. To the many other people who assisted me I offer my thanks and gratitude. Finally, Nancy Gilbertson is particularly thanked for helping me through the completion of this task. vii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. List of Tables 1. List of organizations/individuals contacted for references on the humpback chub in the Colorado River Basin ..••................•..••.............. 7 2. List of fishes occurring in the Grand Canyon and Lake Mead (Species list developed from Jonez et al., 1951; Jonez and Sumner 1954, Carothers and Minckley 1981, and W.L. Minckley, 1973) ••••••••.. 77 3. Computed hatching dates for humpback chub in the Little Colorado. Data corresponds to Figure 10 ••••••••.••••••.••••••••••..•..•••••••••••..•. 115 viii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. II I I I List of Figures 1. Illustration of the humpback chub Gila cypha. Figure adapted from Miller (1946) .•••••.••.••..•. 2 2. Map of the Colorado River Basin illustrating the boundary between the Upper and Lower Colorado River Basins •••...•••••..•.•••••..••.•. 30 3. Distribution of the humpback chub in the Green, Yampa, Waite, Little Snake and Colorado rivers through 1990 ••.••...••••••.••••.....••.•. 38 4. Diagram illustrating distribution and collecting localities