Induced nest failure as a mechanism for controlling invasive smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides) A Dissertation SUBMITTED TO THE FACULTY OF UNIVERSITY OF MINNESOTA BY Grace L. Loppnow IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Advised by Paul A. Venturelli February 2017 © Grace L. Loppnow 2017 Acknowledgements “Nobody achieves anything alone.” -Leslie Knope, Parks and Recreation That is certainly true of this dissertation, which would not have been possible without the collaboration and support of many. First, a huge thank you to my advisor, Paul Venturelli. From our first meeting onward, you have gone out of your way to make grad school an enjoyable experience. Thank you for building me into a scientist, and for always encouraging me to grow. Thanks especially for knowing when to push me and when to let me hole up in “the writing cave.” When I was choosing an advisor 6 years ago, someone warned me that joining a new lab might be difficult. I found it to be quite the opposite. I’ve enjoyed growing with you, and have benefitted from your mentorship right from the start. Most of all, thank you for always having a sense of humor. Google will never be the same… Special thanks to my advisory committee: Bruce Vondracek, Ray Newman, Don Pereira, Tom Hrabik, and a guest appearance by Przemek Bajer. Your insights and willingness to help have been of great assistance. Thanks also to the fellow students who accompanied me on this journey. I’d like to acknowledge the support and fellowship of my “academic brothers and sisters,” my labmates: Kyle Chezik, Jason Papenfuss, Fernanda Cabrini Araujo, Cha Thao, Andrew Honsey, Megan Tomamichel, Leslie Schroeder, Tim Martin, Nate Huempfner, Natnael i Hamda, and Manu Garcia. Special thanks to Jason for being a calm presence throughout the grad school storm. Thanks also to my Conservation Biology cohort. You have made this process much more enjoyable, and I count you all as good friends. Thanks especially to Justine Dauphinais, for friendship above and beyond the call of duty and for being a level-headed sounding board who I could always rely on. My deepest appreciation to the many collaborators who took part in this work. Thanks to Clifford Kraft and Mark Ridgway for their help in the pilot stage of this project. Special thanks to Brian Shuter for providing code and advice that helped steer me in the right direction while making the IBM. I am indebted to the Minnesota DNR, especially Mike McInerny and Jeff Reed, for all of their assistance finding study sites, coordinating with local landowners, obtaining permits, and collecting and aging scales. Thanks to the National Park Service, especially Ryan Maki and Claire Kissane, for sampling assistance and for their interest in this project. And thank you to the countless field assistants who volunteered their time to work with me in tough field conditions. Though there is no way to adequately express my appreciation here, I would like to thank my family. Thank you for the many forms of support that you have provided over 25 years of education. Thank you for always believing in me, so that I never had to question that I could do this. The biggest thank you goes to Maria Succio, who I love, and who has buoyed me up during the tough times and made the good times that much better. ii Table of Contents List of tables vii List of figures viii Chapter 1: Invasive smallmouth bass (Micropterus dolomieu): History, impacts, and control 1 Summary 1 Introduction 2 Smallmouth bass invasions: Past, present, and future 3 Impacts of invasive smallmouth bass 8 Controlling invasive smallmouth bass 13 Removal 13 Electrofishing 13 Netting 14 Explosives 15 Angling 16 Options for enhancing removal 16 Chemical 17 Biological control 18 Predation 18 Pathogens and parasites 19 Sterilization 20 Environmental manipulation 21 iii Water level manipulation 21 Dissolved oxygen concentration 22 Targeting specific life stages 23 Conclusion 24 Acknowledgements 26 Chapter 2: Stage-structured simulations suggest that removing young-of-the -year is an effective method for controlling invasive smallmouth bass 27 Summary 27 Introduction 28 Methods 31 Model structure 31 Young-of-the-year removal and overcompensation 32 Young-of-the-year removal as a control option 33 Young-of-the-year removal combined with supplemental removal 33 Results 35 Young-of-the-year removal and overcompensation 35 Young-of-the-year removal as a control option 35 Young-of-the-year removal combined with supplemental removal 36 Discussion 39 Acknowledgements 42 Chapter 3: Individual-based simulations to optimize the control of invasive smallmouth bass (Micropterus dolomieu) via induced nest failure 43 iv Summary 43 Introduction 43 Methods 45 Model description 45 Environmental variables 47 Development 50 Spawning 51 Foraging 54 Growth 55 Natural sources of mortality 57 Simulations 58 Results 60 Discussion 64 Acknowledgements 68 Chapter 4: Practical applications of induced nest failure for control of invasive smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides) 69 Summary 69 Introduction 70 Methods 73 Experimental nest-guarding male removal 73 Whole-lake control effort 76 v Results 78 Experimental nest-guarding male removal 78 Whole-lake control 80 Discussion 81 Acknowledgements 85 Chapter 5: General discussion and future directions 86 References 91 Appendix. Fortran 90 code for individual-based model from Chapter 3 123 vi List of Tables Table 1.1. Known smallmouth bass introductions by country. 7 Table 1.2. Invasive fish control methods, examples of their use for smallmouth bass control, the bass life stage they target, and their pros and cons. 12 Table 2.1. Population parameters used in the smallmouth bass matrix model (adapted from Zipkin et al. 2008). 35 Table 3.1. Prey parameters used in the SMB model (adapted from DeAngelis et al. 1991 and Shuter et al. 1980). 50 Table 4.1. Analysis of variance of the two binomial GLMs that best describe nest success. 80 vii List of Figures Figure 1.1. The invasion status of smallmouth bass worldwide. 7 Figure 1.2. Elasticities of the annual survival probability (si) and fertility (fi) at age i for four smallmouth bass matrix population models. 24 Figure 2.1. A schematic of the stage-structured population model from Zipkin et al. (2008) with underlined alterations. 34 Figure 2.2. Percentage of young-of-the-year removal required annually to reduce simulated smallmouth bass population abundance by at least 75% in 10 years. 37 Figure 2.3. Years of management required to decrease the abundance of simulated smallmouth bass populations by 75% under all possible combinations of young of the year removal and supplemental removal for three supplemental removal strategies and two parameter sets. 38 Figure 3.1. Schematic of individual-based smallmouth bass model. 47 Figure 3.2. Relationships that regulate the amount and timing of reproduction. 53 Figure 3.3. Years of management required to reduce simulated SMB abundance by 75% for different levels of both nest failure and supplemental removal (A, C, E), and box plots of the years to control when using only supplemental removal (B, D, F). 62 Figure 3.4. Box plots of the years of nest failure required to reduce total abundance of a simulated SMB population by 75% for every 10% interval of nest failure from 0 to 100%. 63 viii Figure 3.5. Mean nest failure required at each application to approach a target goal of 75% reduction in total abundance after 10 years of various types of management, and the actual reduction in abundance. 63 Figure 4.1. Locations of study sites. 74 Figure 4.2. The proportion of failed bass nests by treatment and stage of nest development. 79 Figure 4.3. DD-specific age-1 growth of LMB (mm/DD) in Union Lake from years for which data were available. 81 ix Chapter 1: Invasive smallmouth bass (Micropterus dolomieu): History, impacts, and control Grace L. Loppnow, Kris Vascotto and Paul A. Venturelli Published in 2013 in Management of Biological Invasions Vol. 4, Issue 3, pp. 191-206 Summary In this review, we (i) describe smallmouth bass (Micropterus dolomieu Lacepède, 1802) invasions past, present, and future; (ii) summarize the impact that this species can have on native communities; and (iii) describe and discuss various options for control. M. dolomieu are invasive throughout much of the United States, southern portions of Canada, and in countries in Europe, Asia, and Africa. Historically, this species spread via stocking programs intended to improve sport fisheries. Currently, their spread is facilitated by anglers and global climate change. Models predict that M. dolomieu will continue to spread with consequences for native prey fish, sport fish, and food webs through predation, competition, and hybridization. Effective control methods are necessary to mitigate these impacts. Options for M. dolomieu control include biological control, chemical control, environmental manipulation, and physical removal. However, our review of the literature suggests that only a handful of the possible control options have been explored (usually in isolation and with limited success), and that there is a clear need for focused research and informed management. For example, our elasticity analysis of published M. dolomieu matrix population models suggests that M. dolomieu control will be most effective when it targets eggs, larvae, and juveniles. We recommend targeting these life stages by using nest failure as part of an adaptive and integrated pest 1 management approaches that incorporate existing and emerging technologies. However, we also emphasize that M. dolomieu control, where necessary and possible, is more likely to take the form of suppression rather than permanent eradication. Therefore, we also recommend efforts to prevent M.