Date of Award



© 2015 Elizabeth Prochaska

Document Type


Degree Name

Master of Science in Marine Sciences


Marine Science

First Advisor

Charles Tilburg

Second Advisor

Phil Yund

Third Advisor

Anna Bass


Using an interdisciplinary approach, this study examined the population connectivity of the blue mussel Mytilus trossulus within Machias Bay, Maine, near its inshore southern boundary range. The Eastern Maine Coast Current (EMCC) flows southwestward along the northern Gulf of Maine coastline, just outside of Machias Bay and is a potential pathway for M. trossulus larvae. This study compared results to two historical studies that assayed M. trossulus and M. edulis species distributions to evaluate any temporal changes. Both similarities and differences were found in species composition in Machias Bay. Historical data suggested that the lower Machias Bay was supplied by larvae via the EMCC, and that conclusion was consistent with this study due to similar species composition in the lower bay. However, in upper Machias Bay, this study found a complete shift in species composition. Since earlier sampling, a M. trossulus population has become established in the upper bay and appears to be maintained by self-seeding via locally produced larvae. Additionally, hybrids between M. trossulus and M. edulis are now abundant in upper Machias Bay, likely due to a breakdown in conspecific sperm precedence at low densities of M. trossulus. The persistence of hybrids will probably be dependent upon the size of future M. trossulus populations.


Master's thesis

This digital object has been funded in part with Federal funds from the National Science Foundation, Division of Graduate Education, under Award No. #0841361, "The Interactions of Biology, Chemistry and Physics at the Land-Ocean Interface: A Systemic PARTnership Aimed at Connecting University and School (SPARTACUS)", to the University of New England.