Date of Award


Publication Type

Master Thesis

Degree Name



Earth and Environmental Sciences

First Advisor

Hugh J MacIsaac

Second Advisor

Sarah A Bailey




Domestic ballast is considered a low risk vector of nonindigenous species introductions within the Great Lakes - St. Lawrence River, and is unregulated. I examined establishment risk posed by taxa contained in domestic ballast, biological and environmental similarities between St. Lawrence River and Great Lakes ports, and identified invertebrates through 454 pyrosequencing of 18S rDNA. Ballast samples contained 12 brackish potential nonindigenous species, while St. Lawrence River port samples contained two fresh and 27 brackish species. Québec City poses the greatest establishment risk due to high environmental matching with recipient ports, and because it is the only St. Lawrence River port with freshwater species (two oligochaetes: Aeolosoma viride and Rheomorpha neiswestonovae) not yet present in the Great Lakes. Pyrosequencing effectively identified invertebrates. Pyrosequencing, but not traditional taxonomy, identified the freshwater potential nonindigenous species in this study.