View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Waterloo's Institutional Repository Life History of Dwarf Longnose Sucker (Catostomus catostomus) in the Elk River Watershed by Paul LePage A thesis presented to the University of Waterloo in fulfilment of the thesis requirement for the degree of Master of Science in Biology Waterloo, Ontario, Canada, 2014 © Paul LePage 2014 I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. Page ii ABSTRACT In 2004, a population of dwarf longnose sucker was discovered co-existing with the normal form within the Elk River Watershed of south-eastern British Columbia. This thesis evaluated morphological, genetic and life history characteristics of this dwarf longnose sucker form to determine whether the dwarf morphotype warranted designation as an evolutionary significant unit and to determine any special habitat requirements. In addition to size, distinct morphological differences were indicated between Elk River Watershed dwarf and normal adult longnose sucker, with dwarf adults appearing to retain morphological features of juveniles and sharing morphological features with Salish sucker, which is a separate dwarf longnose sucker form that is considered endangered. Slight, but significant, genetic differences were indicated between Elk River Watershed dwarf and normal longnose sucker forms, and compared to Salish sucker, suggesting some basis for separate designation of the dwarf form. Dwarf longnose sucker are widespread in the Elk River Watershed, and most abundant in small, cool lentic water bodies that contained dense vegetative cover, potential oxycline fluctuation and/or limited fish species diversity. Dwarf adult longnose sucker showed some habitat preference differences compared to normal longnose sucker, with the findings suggesting that dwarf longnose sucker have adopted a more opportunistic life-history strategy than normal longnose sucker. It is postulated that an ontogenetic niche shift has allowed dwarf longnose sucker to more successfully exploit habitats experiencing periodic disturbances (e.g., hypoxia) that, in turn, has led to the occurrence of two longnose sucker morphotypes in the Elk River Watershed. Page iii ACKNOWLEDGEMENTS I would like to express my special appreciation and thanks to my advisor, Dr. George Dixon, as well as to my sponsoring company colleagues Patti Orr and Cynthia Russel, for encouraging my research and having the patience and understanding to see me follow it through. Without the assistance of my sponsoring company, Minnow Environmental Inc., who accommodated me with the time, equipment, logistical support and resources required for conducting my field research and putting words to paper, this document would not have been possible. I would also like to thank Dr. Kelly Munkittrick and Dr. Jonathon Witt, for not just being members of my committee, but also providing me with additional perspective, support and advice for improving the quality of my thesis. Further thanks are offered to Teck Coal Ltd., who allowed site access to certain study areas that were important to my research, and to Ms. Jess Tester, who was instrumental in preparation of the electronic version of this document while maintaining a cheerful disposition over its various renditions. Especially deep thanks to my mother and father, who championed me throughout the preparation of my thesis. And I will truly miss the goading of my family and friends upon (finally) completing this thesis - I hope that this document will provide the inspiration for at least one of them to pursue higher academic goals in the future so that I, too, will have the opportunity to offer similar ‘encouragement’! Finally, a sincere note of appreciation to Shari, whose timely support, guidance and presence made my thesis and defense that much more meaningful and enjoyable. Page iv TABLE OF CONTENTS ABSTRACT ........................................................................................................................... III ACKNOWLEDGEMENTS ................................................................................................. IV LIST OF TABLES ................................................................................................................ VI LIST OF FIGURES ........................................................................................................... VIII CHAPTER 1: GENERAL INTRODUCTION .....................................................................1 CHAPTER 2: MORPHOLOGICAL AND GENETIC COMPARISONS BETWEEN DWARF AND NORMAL LONGNOSE SUCKERS ..........11 Introduction ..........................................................................................................................11 Materials and Methods .........................................................................................................19 Study Area ...................................................................................................................... 19 Field Sampling and Fish Processing ............................................................................... 19 Laboratory Analysis ........................................................................................................ 24 Data Analysis .................................................................................................................. 26 Results ..................................................................................................................................28 Morphological Variation ................................................................................................. 28 Genetics ........................................................................................................................... 33 Discussion ............................................................................................................................37 CHAPTER 3: LIFE HISTORY CHARACTERISTICS OF ELK RIVER WATERSHED DWARF LONGNOSE SUCKER ....................................50 Introduction ..........................................................................................................................50 Study Area ...........................................................................................................................57 Materials and Methods .........................................................................................................59 General Population Features ........................................................................................... 59 Growth Characteristics .................................................................................................... 62 Reproduction ................................................................................................................... 63 Results and Discussion ........................................................................................................66 Distribution, Habitat and Habitat Use ............................................................................. 66 Age and Growth .............................................................................................................. 80 Reproduction ................................................................................................................... 83 Dwarf Longnose Sucker Life History Strategy............................................................... 89 CHAPTER 4: CONCLUSIONS ..........................................................................................96 REFERENCES .....................................................................................................................100 APPENDIX A: FISH MEASUREMENT DATA APPENDIX B: GENETICS DATA Page v LIST OF TABLES ...................................................................................................................... Page Table 2.1: Collection locations and sample sizes of longnose sucker used for the morphological and genetics analyses ...............................................................21 Table 2.2: Habitat and fish community characteristics of study areas used for longnose sucker morphological and genetic sampling. Areas marked by an asterisk indicate intensively monitored areas ..............................................22 Table 2.3: Loading coefficients for a principal component analysis of twelve external characteristics for dwarf adult, normal adult and juvenile, and Flathead River adult longnose sucker morphology. Eigen values from each principal component are listed below the column of coefficents ....................30 Table 2.4: Haplotype identification and count from longnose sucker collected in the Elk River, Grave Lake, Koocanusa Lake, and the Flathead River system for cytochrome b and ND2 genes ....................................................................34 Table 2.5: Fixation indices (FST) statistical comparisons (p-values) between Elk River Watershed dwarf and normal longnose sucker populations based on cytochrome b haplotype sequences ..................................................................36 Table 2.6: Fixation indices (FST) statistical comparisons (p-values) between Elk River Watershed dwarf and normal longnose sucker populations based on ND2 haplotype sequences .........................................................................................38