Date of Award
2026
Degree Type
Thesis
Degree Name
Master of Science in Oceanography
Department
Oceanography
First Advisor
Chris Kincaid
Abstract
Open net salmon aquaculture introduces substantial anthropogenic nutrient loads into coastal ecosystems, with potential consequences ranging from beneficial productivity enhancement in nutrient limited waters to excessive enrichment that drives hypoxic conditions. This study investigated the transport of nitrogen inputs from Cooke Aquaculture’s three salmon farms in Eastern Bay (EB), ME to the broader Chandler, Englishman, and Machias Bays area (CEM). These three farms collectively discharge hundreds to thousands of pounds of total nitrogen (TN) daily, primarily as NH4: with summer 2020 inputs being 1,500 lbs./day in July and 1,907 lbs./day in August, coinciding with seasonal stratification and regional hypoxia (dissolved oxygen < 2.86 mg/L; Diaz & Rosenberg, 2008).
Using the Regional Ocean Modeling System (ROMS), coastal circulation and nutrient dynamics across the CEM region were simulated during the high input period of July - October 2020. Dimensionless passive dye tracers and Lagrangian floats were used to characterize water parcel pathways, quantify water parcel retention, and evaluate whether subtidal flows efficiently flushed farm-derived TN to the open ocean. It was hypothesized that rather than being exported offshore, anthropogenic TN would be transported inland and recirculated around embayments and islands, increasing local TN concentrations. Results confirm this hypothesis: ~88% of floats were transported into sensitive areas, while only ~1.4% flushed directly offshore. Cooke inputs consumed 20-40% of available assimilative capacity within EB during peak summer months. These results indicate that Cooke-derived nitrogen reaches Class SA water and exceeds the eelgrass threshold under certain background TN values within EB.
Recommended Citation
Cunningham, Teagan Julia, "MODELING THE TRANSPORT OF NITROGEN INPUT FROM SALMON FARMS IN EASTERN BAY, ME, USA" (2026). Open Access Master's Theses. Paper 2757.
https://digitalcommons.uri.edu/theses/2757