Date of Award


Document Type


Degree Name

Master of Science in Coastal Marine and Wetland Studies


Coastal and Marine Systems Science


College of Science

First Advisor

Juliana M. Harding

Second Advisor

Eric N. Powell

Third Advisor

Erin J. Burge


The Eastern oyster (Crassostrea virginica) co-occurs with the protozoan parasite Perkinsus marinus (the causative agent for "Dermo") in US Atlantic and Gulf of Mexico estuaries. Oyster host functions as an ecological engineer and agent for benthic-pelagic coupling are compromised when P. marinus infections are common in populations (prevalence) and high in individuals (intensity). P. marinus infections in oysters from North Inlet estuary, South Carolina were quantified in relation to shell height (60-76 mm, ≥76 mm), sex (functional female, male, indeterminate), water temperature, and salinity. Three fringing reefs on a longitudinal transect from the inlet mouth into the watershed were sampled approximately monthly from March-October 2018. Oyster density varied by site and month with maximum densities of 116, 684, 305 (oysters m-2) observed moving from polyhaline (inlet mouth) to mesohaline environments (up estuary), respectively. Nearly all North Inlet oysters were infected with P. marinus regardless of reef, temperature, salinity, or density (prevalence >0.90). Oyster infection intensity was high (Mackin Score ≥3) at all date, shell height, sex, temperature, and salinity combinations. Infection intensity increased with increasing water temperature. The highest oyster infection intensities were observed at temperatures >18°C. Oysters from salinities <34 psu had higher infection intensities than oysters from higher salinities. Infection intensity was positively related to seasonal increases in chlorophyll a and changes in oyster biomass. The observed year-round P. marinus prevalence and high infection intensity indicate that related mortality and declines in oyster fecundity, biomass, reef surface area, and ecosystem services are likely ongoing in South Carolina salt marsh estuaries.

Available for download on Wednesday, May 06, 2026