Date of Award

Spring 2022

Thesis Type

Open Access

Degree Name

Honors Bachelor of Arts




Fiona M. Harper

Committee Member

Kathryn P. Sutherland

Committee Member

Jay N. Pieczynski


The Gulf of Maine (GOM) in the United States is the fastest warming body of water in the world. Due to a complex history of glaciation, the GOM has restricted circulation that causes it to function more akin to an enclosed sea. As climate change has disrupted the stable flow of the Gulf Stream, more warm-water currents are entering the GOM at higher frequency. This warming has had a profound impact on the distribution of the blue mussel, Mytilus spp., which inhabits the rocky intertidal habitat within the GOM as the main prey species to a keystone predator. Two sister species, M. edulis and M. trossulus, both inhabit the GOM and hybridize in areas of sympatry. However, in recent years, the population of both hybrids and M. trossulus have been retreating northward in the GOM towards the Canadian coast. This study builds upon previous assessments of Mytilus species distribution along the GOM using two genetic markers, SOD and TAUT, that differentiate between members of each species. Results indicate a dominance of M. edulis, with few remaining refuges for either M. trossulus or hybrid individuals. These refuges are mostly islands, suggesting a potential correlation between exposure and/or temperature caused by increased distance from the mainland. The trends in the GOM are troubling for the intertidal ecosystem, as decreased biodiversity in a key prey species could lead to increased vulnerability to disease and other population threats, which could lead to drastic negative effects on the rest of the local food web.

Rights Holder

Daniel J. Woods

Available for download on Thursday, May 04, 2023