Shellfish Growing Areas (NSI)

Reducing the extent of permanently closed shellfish growing areas through regulatory modernization: enteric virus contamination and mitigation strategies

Stephen Jones, University of New Hampshire

In the Northeastern United States, many acres of productive shellfish growing waters are permanently closed to aquaculture and harvesting activities due to concerns associated with human fecal pollution from municipal wastewater treatment plant outfalls. Often, these potential aquaculture sites are highly productive, sheltered, near-shore locations with good commercial access. The main outcome for this project is to increase coastal areas that are permitted for shellfish growing and harvesting. The size of these areas is based in part on fecal coliform levels, yet scientific investigations have demonstrated that fecal coliform levels are often unrelated to enteric virus occurrence and are misleading with respect to virus contamination. Norovirus (NoV) is responsible for the majority of shellfish consumption related viral disease worldwide with significant health costs in the U.S. Male-specific coliphage (MSC), a bacteriophage of E. coli bacteria and a small, round, RNA virus like NoV, has been proposed as a specialty viral indicator organism that better reflects the persistence of viruses in molluscan shellfish meats impacted by wastewater. The proposed approach is a well-defined, comprehensive approach to determining the feasibility of expanding aquaculture and harvest of hard clams and oysters in the Northeast U.S. The approach involves determining seasonal environmental conditions for minimal enteric virus contamination, and the effectiveness of seasonal MSC relay and depuration for purging of low-level microbial contamination. Highly similar previous studies in Maine with soft-shelled clams led to successful re-opening of closed, highly productive areas with significant local economic benefits. This project has a high probability of success in leading to changes in the National Shellfish Sanitation Program and increasing available growing areas in New England and nationally. The project will also positively impact aquaculture development, quality assurance processes, and ultimately consumer confidence, thus successfully achieving our overall outcome.