Loyola University Chicago

Department of Biology

Margaret Ann Malone Thesis Defense: Project Description

Title: Early round goby (Neogobius melanostomus) invasion into Lake Michigan tributaries and competitive interactions with two native benthic fishes


The round goby is a prolific invasive species and is currently spreading into Great Lake tributary streams. There is a high potential for negative impacts on native benthic fishes in these stream habitats and the aim of this study is to assess the impacts of the round goby on two native darter species in particular (johnny darter and blackside darter). I review the history of round goby invasion in the Great Lakes and summarize hypotheses of the invasive characters of the round goby. Using game theory, I provide a G-function approach to understanding the outcomes of the round goby invasion in tributary streams. I conducted a field based laboratory study compare the fish communities in invaded and non-invaded reaches of two streams and found differences attributed to the CPUE of round gobies. CPUE of the johnny darter was different in invaded and non-invaded reaches, while it was not different for blackside darter. Stomach contents of the round goby and darters were analyzed and overlap was found between the invasive and native species. Finally, a laboratory experiment assessed the competitive behaviors of the round goby and the johnny darter and found that there were behavioral differences. The results for this study provide a baseline during the early invasion of two Lake Michigan tributaries and provide evidence of both exploitative and inference competition between the round goby and johnny darter. It is likely that these competitive interactions resulted in a realized niche shift of the johnny darter and there is a high likelihood that continued competition between the johnny darter and round goby will possibly result in a population decline of the johnny darter or even local extirpation.



I would like to thank many people who have helped me in the preparation of this degree.  I especially would like to thank Dr. Terry Grande for taking me into her lab and helping me structure a research project around my interests of fish ecology and evolution.  She provided me with invaluable knowledge in the subjects of ichthyology, evolution, comparative anatomy, and game theory.  Dr. Grande supported me to participate in a summer course, The Early Life History of Marine Fishes at the Virginia Institute of Marine Science, and has always been open to me exploring my interests in fishes!  Thank you for laying the foundations of my career in ichthyology.

I am also grateful to the members of the Grande Lab for their support of this project.  Undergraduates David Jurak, John Dompelinger, and Michael Hanson, as well as former lab mate Jeremy Harris volunteered their time for field collections in Wisconsin.  Undergraduates Anastasia Peters and Olivia Chan assisted in laboratory work including experimental set up, dissections, and video analysis.  I would also like to thank former Grande Lab members, Sarah Zack and Amanda Burdi, for welcoming me into the lab and for their friendship throughout.  Finally, I would like to thank Grande Lab post-doc, Dr. Cal Borden, for his help throughout this project.

Thanks to my co advisor, Dr. Marty Berg and members of my committee Dr. Timothy Hoellien and Dr. Joel Brown for their valuable conversations and contributions to this project.  Outside assistance in starting this project was graciously provided by John Janssen and Matt Kornis.

Finally, this degree would not be possible without my family.  My dog Petey was a great study partner and companion as I wrote this thesis. I am very lucky to have Colin Devitt’s assistance and support throughout this process; I am so thankful that he is always up for an adventure.


Margaret Ann (Meg) Malone graduated from the College of Charleston, South Carolina in May 2007 with a B.S. in Marine Biology.  As an undergraduate she studied pelagic fish feeding and aggregating behavior in the Fish Behavioral Ecology lab of Dr. Gorka Sancho.  Meg also obtained a National Science Foundation (NSF) Research Experience for Undergraduate (REU) at Rutgers University Marine Field Station, where she studied estuarine fish distributions through acoustic telemetry.  Meg’s undergraduate research resulted in two peer-reviewed articles, an oral presentation at American Fisheries Society Student Colloquium, and multiple poster presentations. 

Upon graduating from the College of Charleston, Meg moved back to the Midwest.  She worked as a laboratory manager at on optometry office, and as a research assistant at the Great Lakes WATER Institute in the Aguilar-Cuhel biogeochemistry Lab.  At the WATER Institute she participated in off-shore research cruises, collecting benthos and zooplankton samples.  She also worked on digitizing historical zooplankton records from Lake Michigan prior to the dreissenid and round goby invasion.

Meg began her master of science in Biology at Loyola University Chicago in 2010, focusing on aquatic ecology and invasive fish species. This thesis was presented in part at two Joint Meetings of Ichthyologists and Herpetologists (JMIH 2011 and 2013). During her time at Loyola, Meg enjoyed teaching Ecology Laboratory (BIO 266) at Lake Shore campus and LUREC. She also oversaw the independent research of Loyola Undergraduates in local Chicago streams, and at the John G. Shedd Aquarium. Meg is currently enrolled at University of Illinois at Chicago’s doctoral program in Ecology and Evolution, where she continues to study fishes.  


Committee Members:

Dr. Terry Grande

Dr. Martin Berg

Dr. Timothy Hoellein

Dr. Joel Brown