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AND BROOK TROUT (Salvelinus Fontinalis): IMPLICATIONS

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AND BROOK TROUT (Salvelinus Fontinalis): IMPLICATIONS EVIDENCE OF NICHE SIMILARITY BETWEEN CUTTHROAT TROUT (Oncorhynchus clarkii) AND BROOK TROUT (Salvelinus fontinalis): IMPLICATIONS FOR DISPLACEMENT OF NATIVE CUTTHROAT TROUT BY NONNATIVE BROOK TROUT by Bradley Bernard Shepard A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Fish and Wildlife Biology MONTANA STATE UNIVERSITY Bozeman, Montana May 2010 ©COPYRIGHT by Bradley Bernard Shepard 2010 All Rights Reserved ii APPROVAL of a dissertation submitted by Bradley Bernard Shepard This dissertation has been read by each member of the dissertation committee and has been found to be satisfactory regarding content, English usage, format, citation, bibliographic style, and consistency, and is ready for submission to the Division of Graduate Education. Dr. Alexander V. Zale Approved for the Ecology Department Dr. David W. Roberts Approved for the Division of Graduate Education Dr. Carl A. Fox iii STATEMENT OF PERMISSION TO USE In presenting this dissertation in partial fulfillment of the requirements for a doctoral degree at Montana State University, I agree that the Library shall make it available to borrowers under rules of the Library. I further agree that copying of this dissertation is allowable only for scholarly purposes, consistent with “fair use” as prescribed in the U.S. Copyright Law. Requests for extensive copying or reproduction of this dissertation should be referred to ProQuest Information and Learning, 300 North Zeeb Road, Ann Arbor, Michigan 48106, to whom I have granted “the exclusive right to reproduce and distribute my dissertation in and from microform along with the non- exclusive right to reproduce and distribute my abstract in any format in whole or in part.” Bradley Bernard Shepard May 2010 iv DEDICATION I dedicate this dissertation to my wife, Mary E. Lennon, and our two children, Ben and Madison, who supported me tirelessly through the pursuit of this degree. Words cannot adequately express my gratitude. I also thank God whom I believe led me to this degree so that I could more fully understand my need for both faith and science in the pursuit of truth. “Science without religion is lame. Religion without science is blind.” (Albert Einstein, "Science, Philosophy and Religion: a Symposium", 1941). v ACKNOWLEDGMENTS Funding for this research was provided by the Wild Fish Habitat Initiative through the Montana University System Water Center, administered by Gretchen Rupp, and by the Montana Department of Fish, Wildlife and Parks, including funding from the State Wildlife Grants program. I received direct assistance for my education through the Western Division of the American Fisheries Society’s Magnuson Scholarship and the National Science Foundation. My employer, Montana Department of Fish, Wildlife and Parks, allowed me to pursue this PhD while under their employ and Ken McDonald, Don Skaar, and Chris Hunter all provided supervision, encouragement, and support. I want to thank my two major advisors, Drs. Alexander V. Zale and Mark L. Taper, who provided both technical and moral support throughout my career at MSU, especially through this PhD experience. My committee members, Drs. Robert Gresswell, Dan Goodman, Steve Cherry, and Mr. Don Skaar, provided useful technical and editorial advice. I also feel obligated to other mentors who helped guide me during my career including Joe Huston, Bruce May, Pat Graham, Dr. Ted Bjornn, and Dick Vincent. I feel indebted to my colleagues who helped collect field data and by sharing their ideas. This research would not have been possible without the tireless work of numerous folks who worked with me in the field. You know who you are and I thank you for the great times. I would also like to thank my fellow graduate students at MSU who made life fun. Lastly, I would like to thank all my brothers and sisters in Christ who supported me and my family with deeds and prayer. vi TABLE OF CONTENTS 1. INTRODUCTION TO DISSERTATION ..................................................................... 1 Review of Literature ....................................................................................................... 4 Cutthroat Trout........................................................................................................... 4 Brook Trout ................................................................................................................ 7 Nonnative Species Invasion and Establishment ...................................................... 10 Niche, Competition, and Predation .......................................................................... 11 Literature Cited ............................................................................................................ 16 2. INVESTIGATION INTO BIAS AND VARIABILITY IN ESTIMATES OF POPULATION SIZE AND BIOMASS WHEN CATCHES OF INDIVIDUALS ARE LARGE RELATIVE TO THE TOTAL POPULATION .................................... 33 Abstract ........................................................................................................................ 33 Introduction .................................................................................................................. 35 Methods ........................................................................................................................ 37 Traditional (OLD) Method ...................................................................................... 38 Finite Population Correction (FPC) Methods .......................................................... 39 Estimates for Fish Captured but Not Weighed ........................................................ 42 Simulations .............................................................................................................. 43 Field Estimates ......................................................................................................... 44 Data Analyses .......................................................................................................... 47 Results .......................................................................................................................... 49 Simulations .............................................................................................................. 49 Field Estimates ......................................................................................................... 53 Discussion .................................................................................................................... 54 Acknowledgements ...................................................................................................... 59 Literature Cited ............................................................................................................ 60 3. REMOVAL OF BROOK TROUT BY ELECTROFISHING TO CONSERVE WESTSLOPE CUTTHROAT TROUT ....................................................................... 87 Abstract ........................................................................................................................ 87 Introduction .................................................................................................................. 88 Study Area .................................................................................................................... 91 Methods ........................................................................................................................ 91 Results .......................................................................................................................... 94 Successful Removals ............................................................................................... 95 Unsuccessful Removals ........................................................................................... 97 Costs of Removal Treatments .................................................................................. 97 vii TABLE OF CONTENTS - CONTINUED Discussion .................................................................................................................... 98 Brook Trout Removals ............................................................................................. 98 Cost of Removals ................................................................................................... 101 Need for Barriers .................................................................................................... 103 Recommendations ...................................................................................................... 104 Acknowledgments ...................................................................................................... 107 Literature Cited .......................................................................................................... 108 4. EVIDENCE FOR NICHE SIMILARITIES BETWEEN WESTSLOPE CUTTHROAT TROUT AND BROOK TROUT: RECOVERY OF WESTSLOPE CUTTHROAT TROUT POPULATIONS FOLLOWING REMOVAL OF BROOK TROUT ............................................................................. 125 Abstract ...................................................................................................................... 125 Introduction ................................................................................................................ 126 Study Area .................................................................................................................. 130 Methods .....................................................................................................................
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