Access Type

Open Access Dissertation

Date of Award

January 2019

Degree Type


Degree Name



Biological Sciences

First Advisor

Donna R. Kashian


The abundance and persistence of the invasive round goby (Neogobius melanostomus) has often resulted in antagonistic interactions between the invasive and its native competitors. In this study, I sought to quantify the consequences and environmental context of these interactions in Great Lakes tributaries. Specifically, I aimed to identify changes in feeding and reproductive behavior in a native competitor in response to round goby invasion, identify potential solutions to increase regular stream monitoring by tapping into citizen science programs, and quantify the environmental context associated with successful goby invasion. Surveys of fish communities were conducted over three years in seven Michigan tributaries to the Great Lakes. Each site was evaluated for fish assemblage composition, round goby abundance, and habitat quality. Individual round goby and a native competitor, the Johnny darter (Etheostoma nigrum), were dissected for a diet comparison and to identify investment in reproduction to illustrate changes in feeding and reproductive behavior by the native species. To inform better practices for stream management and invasion detection, a quality assessment of two citizen science programs in the area was completed. Citizen data was directly compared to traditional research focused sampling methods to verify the validity of the data and its potential inclusion in ecological research. Finally, a model was developed to identify the environmental context common to sites invaded by round goby. Results suggest that Johnny darter diet diversity decreases, trophic position increases, and reproductive timing changes when goby are present. Citizen science may provide a way to monitor stream degradation which can facilitate these negative interactions. Despite differences in sampling methodology, qualitative citizen data reached similar conclusions about site quality as quantitative research methods. As identified by the environmental context model, altered riparian land use and decreased native species diversity are common characteristics of sites invaded by round goby. Regular monitoring for these characteristics may help identify locations vulnerable to round goby invasion so prevention and mitigation resources can be efficiently allocated. This research provides background on round goby invasion that can be utilized to better manage native species and ecosystems to increase resistance to and reduce the impacts of invasion.