Comparison of Multi-Piscivore Foraging Success on Native and Invasive Prey Fish Under Variable Light Intensities

Comparison of multi-piscivore foraging success on native and invasive prey fish under variable light intensities A THESIS SUBMITTED TO THE FACULTY OF UNIVERSITY OF MINNESOTA BY Noland Otis Michels IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE Allen F. Mensinger, Advisor Thomas R. Hrabik, Advisor May 2020 © Noland Michels 2020 1 Acknowledgements Thank you to the many people who have helped make this project a success; it would have been impossible without your help. First and foremost, thank you to my advisors Dr. Allen Mensinger and Dr. Thomas Hrabik for always pushing me to go a little deeper into an idea and providing me the freedom to pursue what interested me most. I would also like to thank my committee member Dr. Donn Branstrator for his valuable input and broader questions that helped spark further interests. Without the many field assistants collecting fish, this project would have been impossible. A huge thank you goes out to Brian Borkholder and Nick Bogyo, along with the rest of the Fond-du-Lac Tribal Management and 1854 Authority agency employees, who were always willing to help collect more fish when necessary. Similarly, thank you to Quinnlan Smith, Bradley Dawson, Emily Fleissner, and Dr. Rosalyn Putland for their assistance in the field and in lab. I was always able to bounce ideas off of all of you to get new perspectives which has only improved this project as a whole. I would also like to thank the Integrated Biosciences program for supporting me financially the last three years, as well as challenging me to take more holistic approaches in my research. Finally, the IBS program has put in me in contact with many lifelong friends who have helped me work through anything; Riley Pizza, Emily Fleissner, Rosalyn Putland, and Quinn Smith, thank you for always being there and I could not have completed this without you. i Table of Contents ACKNOWLEDGEMENTS .................................................................................. I TABLE OF CONTENTS .................................................................................... II LIST OF TABLES ........................................................................................... III LIST OF FIGURES .......................................................................................... IV CHAPTER 1 A brief background on predator-prey interactions .......................................... 1 Works Cited .............................................................................................. 8 CHAPTER 2 Comparison of multi-piscivore foraging success on native and invasive prey fish under variable light intensities ................................................................16 ABSTRACT ...................................................................................................17 INTRODUCTION ............................................................................................18 METHODS ....................................................................................................22 RESULTS ......................................................................................................29 DISCUSSION .................................................................................................35 WORKS CITED .............................................................................................46 TABLES AND FIGURES .................................................................................58 BIBLIOGRAPHY ............................................................................................63 ii List of Tables TABLE 2.1: Probability of occurrence at each stage of a predator interaction. ............... 58 iii List of Figures FIGURE 2.1: Reaction distances for Smallmouth to Mottled Sculpin or Round Gobies ....................................................................................................................................................................... 59 FIGURE 2.2: Average peak reaction distance models for Smallmouth Bass…………..60 FIGURE 2.3: Reaction distances for Burbot to Mottled Sculpin or Round Gobies….....61 FIGURE 2.4: Parabolic function of the average peak reaction distance of Burbot……..62 iv Chapter 1 A brief background on predator-prey interactions 1 1 Ecological community structure is often heavily impacted by invasions from nonnative species (Ricciardi & MacIssac 2000) in various ways including altered energy pathways (Johnson et al. 2005), species compositions (Karatayev et al. 2002, Stiers et al. 2011), and habitat and landscape modifications (Crooks 2002). Changes in species diversity caused by invasive species are driven by competition with the nonnative species for food (Bergstrom & Mensinger 2009) and shelter (Dubs & Corkum 1996), while native species also face similar or greater amounts of predation pressure once displaced to a less preferred habitat since predators are naïve to the new prey (Sih et al. 2010). This imbalance continues until the predators recognize the new prey resource, which can take years (Lockwood et al. 2013). However, it’s unclear if this is purely based on predator behavior or if prey avoidance abilities differ between invasive and native prey. Predator- prey interactions are a vital piece of information that help predict and understand changes observed in community structure (Carpenter et al. 1985) and through observing specific interactions between species, we can better understand food web dynamics and invasion biology. Round Goby Invasion The Laurentian Great Lakes watershed has experienced more than 182 aquatic nonnative introductions (Ricciardi 2006) which includes invasive species (causing ecological, economical, or human health harm) and introduced species (nonnatives that were introduced for ecological or economical value; Lockwood et al. 2013). The Round Goby Neogobius melanostomus invaded the Laurentian Great Lakes in 1990 (Jude et al. 2 1992) and first appeared in the Duluth-Superior Harbor in 1998 (Leino & Mensinger 2016). Round gobies have been known to compete with many native benthic fishes including Mottled and Slimy Sculpins ( Cottus bairdii and C. cognatus , respectively; Janssen & Jude 2001, Bergstrom et al. 2009), and Common Logperch Percina caprodes (Bergstrom et al. 2009, Balshine et al. 2005) which includes competition for habitat, shelter, and food (Janssen & Jude 2001, Balshine et al. 2005, Bergstrom et al. 2009). Along with competing native fish for common prey such as macroinvertebrates, Round Gobies also utilize Dreissenid mussels which provides a source of energy native prey cannot access (Ghedotti et al. 1995) although Dreissenid mussels are not a preferred prey item (Coulter et al. 2011). When competing for shelter, Round Gobies are more aggressive and successful when compared to Mottled Sculpin (Dubs & Corkum 1996). This displacement from shelters, along with general displacement from preferred rocky habitats in situ should increase consumption of native prey due to less cover to hide in. After the lag phase where predation does not occur or occurs in very reduced amounts, the Round Goby has been integrated into predator diets (Johnson et al. 2005, Crane & Einhouse 2016) and have become the dominant prey item for Smallmouth Bass (Johnson et al. 2005, Crane & Einhouse 2016), Burbot (Johnson et al. 2005, Jacobs et al. 2010), and Lake Trout (Dietrich et al. 2006, Rush et al. 2012). High predation on Round Goby is likely driven by high densities in the great lakes with densities greater than 100 individuals m -2 (Chotkowski & Marsden 1999), but the efficiency of native predators to capture invasive compared to native prey has not been observed. 3 Background on predator-prey interactions Sequential binary decisions that occur during a predator-prey interaction may include location, pursuit, attack and capture (O’Brien 1979). Location is defined as predator orientation towards the prey (O’Brien 1979) and following successful location outside of the predator’s attack range, will pursue prey or immediately attack. Attack probabilities are correlated with distance, prey size and density, relative speeds of the predator and prey, predator satiation level, and habitat (Gill & Hart 1998, Gill 2003, Turesson et al. 2006, Curio 2012) while capture and retention success are often influenced by prey avoidance behaviors (Godin 1997, Lundvall et al. 1999) and habitat complexity (Scharf et al. 2006, DeBoom & Wahl 2013). Predators have two main strategies when hunting prey: pursuing or ambushing prey. However, the two strategies are not mutually exclusive because Largemouth Bass Micropterus salmoides utilize both strategies depending on plant density (Savino & Stein 1982). In open water and less densely vegetated areas, Largemouth Bass are characterized as pursuit predators but switch to ambush predators when in dense vegetation (Savino & Stein 1982). Pursuit predators search for food and actively chase and attack the prey (O’Brien 1979). If the first attack is unsuccessful or the prey fled prior to attack, pursuit predators will continue to pursue until the prey is either captured or lost. Conversely, ambush predators remain still, hiding in structure (weed beds, rocky outcrops, woody debris, etc.) until prey are located and wait until the opportune moment to attack prey (Savino & Stein 1989), although if the prey flees before a predator strike is initiated predator pursuit will not occur. 4 During each stage of an interaction, a variety of sensory systems are used including the visual,

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