Life history, growth, and genetic diversity of the spotted gar Lepisosteus oculatus from peripheral and core populations by Solomon R. David A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Natural Resources and Environment) in The University of Michigan 2012 Doctoral Committee: Professor Michael J. Wiley, Chair Professor James S. Diana Professor Barry M. OConnor Adjunct Associate Research Scientist Edward S. Rutherford Spotted Gar illustration by Solomon R. David, age 12 © Solomon R. David 2012 To my parents and sisters Ignatius and Esther, Rachel and Sarah Without their love and support I would not have made it this far To my grandparents Rangappa and Wazirbai Yesudas, Jambiah and Kanthamma David For inspiring me to learn more about the natural world around us ii Acknowledgements Funding and material support for this study were provided by the University of Michigan (School of Natural Resources and Environment, Rackham Graduate School, Museum of Zoology), the Michigan Department of Natural Resources Institute for Fisheries Research, NOAA Great Lakes Environmental Research Laboratory, USGS Great Lakes Science Center, Nicholls State University, University of Windsor, Fish Doctors, and the North American Native Fishes Association. This was truly a collaborative effort and I am grateful for all the support allowing me the opportunity to carry out my research. I would like to thank my dissertation committee, Drs. Michael Wiley, James Diana, Edward Rutherford, and Barry OConnor; I have known them all for many years and they have pushed, challenged, supported, and been patient with me exactly as I needed it (realized the most in retrospect) over the course of my doctoral research. I am grateful for their guidance and allowing me to pursue research topics I am most passionate about, and in doing so become a better scientist. Thanks to my dissertation chair Mike Wiley for showing me how to view and explain my research from the “bigger picture” perspective. Thanks to Ed Rutherford for supporting me in so many ways through both my masters and doctoral research, especially in the areas of experimental design and fisheries management. Thanks to my cognate Barry OConnor, for whom I also taught parasitology for a record number of years, it was a privilege to work with him and have his insight on my dissertation research. Special thanks to Jim Diana, who took a chance on bringing me in as one of his (masters) students so many years ago, and again (with Ed and Mike) taking me on as a PhD student. Jim never hesitated to challenge my methods, ideas, and writing, and I am a much better scientist because of it. It was truly a privilege to have all of these great ecologists as advisors, to also consider them friends, and now colleagues. iii I would also like to thank the many scientists, colleagues, and friends who provided support over the course of my doctoral studies; I could not have completed my research without them. Thanks to Kevin Wehrly, Jim Breck, Dave Allan, Lizhu Wang, Doran Mason, Chuck Madenjian, Jeff Schaeffer, Dave Jude, Steve Hensler, Bo Bunnell, Kurt Kowalski, Pete Esselman, Ron Oldfield, Catherine Riseng, Doug Nelson, Dave Brenner, and Gerald Smith for their support and willingness to discuss my research. Thanks to Joe Nohner, James Roberts, Greg Jacobs, Jesse Moore, and Bridget Hohner for their help with field sampling, also known as “garspotting”. Many thanks to Brad Utrup for all his assistance with maintaining gars and field sampling gear at Saline over the years. Special thanks to Madison Schaeffer who served as field and lab assistant and was integral to carrying out my experiments. Greg Hughes and Amy Poopat also provided assistance with experiments. Thanks to Tom Campbell and the staff of Fish Doctors for all their help with resources for my experiments. Jeremy Wright was instrumental in all the molecular analyses, and I am grateful for all his help and the opportunity to collaborate with him. Special thanks to Professor Terry Keiser of Ohio Northern University; also a gar- enthusiast, his ichthyology course was the catalyst for my pursuit of further studies in aquatic ecology. Also many thanks to Barb Diana for all her support and encouragement over the years; she and Jim truly created a sense of family among the aquatics students of SNRE. I thank my students from over the years, I learned a lot from them, and hope they learned (and retained at least a little) about fishes and parasites from me as well. Many thanks to Drs. Allyse Ferrara and Quenton Fontenot of Nicholls State University for their tremendous help and support; they (along with their graduate students Tim Clay, Mark Suchy, Olivia Smith, and Cynthia Fox) provided fish, aging structures, and took me field sampling with them in Louisiana. Thanks also to Bill Glass and Lynda Corkum of University of Windsor, and David Buckmeier of the Texas Parks and Wildlife Department for providing me with additional data and research materials. It was a privilege to meet and work with people who were so enthusiastic about gar research and conservation. I relied on many fellow graduate students and friends for support over the years, and I am grateful for all of them. Fellow SNRE Aquatics students Shaw Lacy, Kyung- iv Seo Park, Yu-Chun Kao, Beth Sparks-Jackson, Ethan Bright, Thomas Neeson, Paul Steen, Lori Ivan, John Molenhouse, Mike Eggleston, Justin Londer, Andy Layman, Emily Chi, Shelly Sawyers, and Miling Li all helped me out over the years. Damon Duquaine, Andrea Walther, and Rakhi Kasat also provided support. Thanks to Emily Nicklett for her support and advice over the years, particularly with grant writing and statistical analyses, but more importantly in surviving the PhD process in general. Thanks to the roommates of “The Tank”, especially fellow founding members James Roberts and Damon Krueger, for all their support over the years and putting up with everything gar-related. Special thanks to Emily Taylor for all her help and support, keeping me sane as I headed down the very challenging home stretch of my dissertation. None of this research would have gotten into the water without the tremendous help and dedication of fellow gar-enthusiast Richard Kik IV. Richard joined me on his days off from work and we trekked throughout the state (and sometimes country) to sample for gars over the years of my dissertation research. I am forever grateful to him for all his help, and am lucky to have met someone as passionate about conservation of these much-maligned fish as I am. I was also privileged to have my best friend, Jeremy Roos, help me with field sampling and rigorous aging structure analyses. I could not have completed my life history analyses without him. Special thanks also to Beau and Eva Harvey for their integral support as I pursued my graduate studies. “Life happens” over the course of one’s graduate career, and I experienced much happiness and faced many challenges during my years in graduate school. Regardless of what came my way, my family was always there to support me, and I am truly blessed because of that. I cannot express it enough, how grateful I am for the love, support, and understanding of my parents, Ignatius and Esther, and my sisters, Rachel and Sarah, over all this time, but hope that I can make them proud. v Table of Contents Dedication………………………………………………………………………………...ii Acknowledgements……………………………………………………………………....iii List of Tables………………………………………………………………………….....vii List of Figures………………………………………………………………………….....ix Abstract…………………………………………………………………………………...xi Chapter 1. Introduction…………………………………………………………………....1 2. Countergradient variation in growth of the spotted gar Lepisosteus oculatus from core and peripheral populations…………………………………………....12 3. Variation in life history patterns of the spotted gar Lepisosteus oculatus from core and peripheral populations………………………………………………….45 4. Genetic variation and biogeography of the spotted gar Lepisosteus oculatus from core and peripheral populations………………………………………......106 5. Conclusion………………………………………………………………......148 vi List of Tables Table 2.1 Mean length (cm) and weight (g) at initiation and completion of experiment 1, along with total growth (Final-Initial), growth rate (cm·day-1, g·day-1), and descriptive statistics for LA and MI populations of spotted gars (N=30 fish per population)…………………35 2.2 Mean length (cm) and weight (g) at initiation and completion of experiment 2, along with total growth (Final-Initial), growth rate (cm·day-1, g·day-1), and descriptive statistics for LA and MI populations of spotted gars at 3 different temperature treatments (N = 6 fish per population in each treatment)…………………………………………………...36 3.1 Comparison of estimated age for 10 MI-p spotted gars collected fall 2008 using 3 aging structures (pectoral rays, branchiostegal rays, otoliths)…………………………...80 3.2 List of spotted gar population data used in life history analyses……………………81 3.3 Descriptive statistics for length (mm) and age (years) entire (overall) sample distributions of spotted gar populations used in life history analyses…………………...83 3.4 Descriptive statistics for length (mm) and age (years) for entire (overall) sample distributions of spotted gar populations used in life history analyses…………………...84 3.5 Matrix of pair-wise ANOVA comparisons for overall mean age and length of peripheral and core populations of spotted gars by sex………………………………….85 3.6 Matrix of pair-wise ANOVA comparisons for overall mean age and length of peripheral and