RD409 - Shellfish Growing Area Assessment Activities Report – October 4, 2016
The 2015 General Assembly appropriated $225,000 in new funding for three positions in the Virginia Department of Health’s (VDH) Division of Shellfish Sanitation (DSS) intended to allow VDH to assess sources of bacterial contamination in shellfish waters and to develop data in support of conditional management plans to allow for the safe harvest of shellfish from Virginia’s shellfish growing areas. The 2016 Appropriations Act (Item 298) directs VDH to report on the agency’s activities pursuant to the 2015 appropriation.
Virginia’s coastal zone has approximately 84,000 acres of waters with bacteriological impairments to the extent they are closed to the direct harvest of shellfish. While some of these areas have persistently elevated bacteria levels, many are subject to episodic pollution events with periods of low bacteria levels. Shellfish closures (and the lifting of closures) are the result of assessments conducted by the Virginia Department of Health pursuant to criteria set by the National Shellfish Sanitation Program (NSSP). The Commonwealth is required to comply with NSSP criteria in order for its shellfish industry to sell products in interstate commerce.
The two primary shellfish growing area management approaches outlined in the NSSP are “Adverse Pollution Condition” based on the worst case conditions observed, and “Systematic Random” management which is based on randomly collected data over all environmental conditions. These two approaches are thoroughly documented by the NSSP, and state shellfish programs may utilize either method without additional studies to support its efficacy for providing public health protection. VDH utilizes the Systematic Random management method for all 105 VDH designated shellfish management areas.
The NSSP recognizes a third management option called “Conditional” management which is based on predictable pollution conditions. Water quality in a given area can be influenced by a number of factors including rainfall, tide stage, winds, seasons, etc. Since these effects are very site-specific, the use of conditional management strategies requires growing-area specific research to assess impacts associated with environmental or seasonal influences on water quality. The data generated then must show the level of predictability associated with the condition or conditions selected, and a management plan must be developed that implements controls to adequately address the identified risks and provide the necessary public health protection. Conditional management requires significantly more active oversight by state regulatory programs, but it provides opportunities for shellfish industry utilization of growing areas that are otherwise closed to harvest year-round.
To date 116 acres in Westmoreland County have been placed under conditional management allowing shellfish harvesting during seven months of the year; 782 acres in the Nansemond River have been placed under conditional management based on rainfall. This report details the activities of the Marine Science branch of DSS since its inception in 2015 through September 30, 2016.