Date of Award


Publication Type


Degree Name



Earth and Environmental Sciences


Catherine Febria



Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


There are over 300 species of freshwater mussels (Family: Unionidae) across North America with many populations at risk or in decline. Mussels provide essential ecosystem services, yet they remain largely underexplored in terms of distribution, population sizes, life history traits, and co-existence with hosts, making species conservation efforts a challenge. To advance the conservation of freshwater mussel species at risk of extinction (SAR), this thesis aims to extend understanding of freshwater mussel SAR distributions in a biodiverse but vulnerable watershed in the Laurentian Great Lakes basin. This thesis asks: How can freshwater mussel SAR distribution data be leveraged through existing collaborations and other available knowledge? Further, how can we address uncertainty in freshwater mussel distributions through a better understanding of their host fish requirements? My work was conducted in the Sydenham River watershed, which is the most biodiverse in Canada with 35 different mussel species, 14 of which are federally listed as at risk of extinction. I employed multiple research methods including: an empirical field survey of existing mussel assemblages and environmental conditions across the watershed, a literature synthesis to compile all available host fish data, and expert input to refine local host information for the watershed. In my empirical survey, I found two major patterns in assemblages across the watershed: habitats within the main stem East branch of the watershed were significantly richer and significantly different based on environmental characteristics than the North branch. Additionally, host fishes were not very good predictors for where SAR freshwater mussels reside. Further, habitat characteristics informed mussel assemblage composition. My results offered multiple lines of evidence to demonstrate that harmonizing available datasets can help better understand mussel communities and therefore be applied to watershed-scale restoration efforts in the Great Lakes and beyond.