The bottom line is 3,942 acres in Gloucester and Mathews, as of June 30, 2011, according to figures released by the Virginia Department of Health, Division of Shellfish Sanitation.
By comparison, the 2010 figure was 4,053 acres. In 2009, the total was 5,822 acres. In 2008, the total was 7,224 acres, according to the Gazette-Journal’s annual tally.
Based on water samples taken every four to six weeks, the state calculates for an unacceptable presence of fecal coliform. Closure of waters to shellfish harvest is based upon a level of fecal coliform in the water considered unsafe, the shellfish sanitation division said. The state notes that while crabs and fish caught in condemned bodies of water are safe to eat, the harvesting of mollusks such as oysters and clams is prohibited as these species "can concentrate bacteria and viruses" to a level that may prove hazardous to persons eating them. However, most of these waters are safe for swimming, the state said.
Rainy periods may cause increased levels of pollution due to runoff from land, the state said.