Award: OCE-1333797

The overall goal of this project was to understand the mechanisms of mussel population connectivity in the eastern Gulf of Maine, particularly the role that cross-shelf transport processes play in establishing connectivity patterns. We set up a high-resolution ocean circulation model (the Eastern Gulf of Maine coastal model-EGoM) coupled with an offline 3-D particle tracking module to simulate larval mussel dispersal along the Maine coast. We conducted model simulations for the spawning season of 2014 with realistic spawning output, larval durations, and vertical migration. We identified the physical and biological factors that affected population connectivity. Physical factors included the distance between beds and cross-shelf transports induced by tidal currents interacting with coastal geomorphology. Important biological factors included reproductive output, and to a lesser extent, the timing of spawning. Vertical migration had a smaller effect because the strong tidal currents produce intense vertical motions of water. These findings have important implications for the commercial mussel aquaculture industry in Maine, which relies on natural settlement, hence a better understanding of larval supply patterns is useful to site selection. Similarly, the culture of sea scallops starts with the capture of wild seeds, which represents a critical bottleneck in the culture cycle. The modeling approach developed from this project can be used to identify spawning stocks and understand larval supply patterns of sea scallops along the coast of Maine. Moreover, the EGoM and our findings on cross shelf exchange and population connectivity have been used as a leverage for the ongoing NSF project on Sustainable Ecological Aquaculture NETwork (SEANET). This project has trained one graduate student and laid the foundation for two other students. Dr. Conlon graduated with a Ph.D. in 2018 and is now a postdoc in Los Alamos National Laboratory working on ocean models. The project has fostered inter-institutional and interdisciplinary exchange among the three participating labs, which provided the PI and the student an opportunity to broaden the knowledge in larval biology. Because of this, the PI gets involved in the Research Collaborative Network – Evolution in Changing Seas and serves in the steering committee. We have actively disseminated up-to-date results to communities at national and international conferences including the Ocean Sciences Meetings, American Geophysical Union Fall meetings, International Workshop on Modeling the Ocean, the Fourth Xiamen Symposium on Marine Environmental Sciences, Symposium on Ocean Circulation, Ecosystem, Hypoxia and Consequences, and Benthic Ecology Meeting. To date, we have produced a Ph.D. dissertation, two journal papers, and two additional manuscripts that are currently under review and in revision, respectively. Last Modified: 05/29/2019 Submitted by: Huijie Xue