DV-18-13 Determining causes of replicate variability in levels of Vibrio parahaemolyticus in Eastern oysters in order to improve the efficacy of a cold water pathogen reduction process

Meredith White

Mook Sea Farm


Some of the greatest risks facing oyster growers in Maine stem from ecosystem changes including increased temperature and changes to seawater chemistry that affect abundance of Vibrio species, an illness-causing bacteria. Illnesses linked to consumption of shellfish from cooler northeast waters had historically been rare but has increased in the Northeast. A closure of oyster growing areas could result in an enormous economic loss to Maine oyster growers because the growing area would remain closed until the ambient water temperature cools.


Oyster growers in the Damariscotta and New Meadows areas have already taken a proactive approach to reduce the risk of a Vibrio closure, developing a plan to ensure that raw product is subject to additional measures beyond the general National Shellfish Sanitation Program (NSSP) Model Ordinance.


Mook Sea Farm is researching ways to optimize conditions for post-harvest processing of market oysters to reduce Vibrio concentrations in oysters after harvest, prior to consumption. The densities of V. parahaemolyticus naturally present in individual oysters are highly variable oyster-to-oyster. Sea Grant funds for experimentation and analysis will help Mook further develop pathogen reduction methods by addressing this variability.


Sea Grant funds: $5,000

Additional support from University of Hampshire (S. Jones), SEANET, and the Alliance for Maine’s Marine Economy