Total acreage in local waterways where shellfish harvesting is not allowed decreased slightly in the past 12 months, from 7,344.7 on July 1, 2020, to 7,219.2 today.

Looking back further, the totals were 6,819 in 2019, and 5,714 in 2018.

The totals are compiled from records in the state’s Division of Shellfish Safety and Waterborne Hazards, an agency of the Virginia Department of Health.

Large areas of the condemned acreage in some of the waterbodies are opened to shellfish harvesting in cooler months. These are marked with an asterisk on the table that accompanies this article. A map showing condemned areas depicts these portions in green.

In a few cases, no area of a waterway can be opened to shellfish harvesting; this is a preventive measure taken, usually due to a sewage treatment plant outfall into the water.

According to the DSS website, the state evaluates all waterways at least six times a year, under any weather conditions, sampling for concentrations of fecal coliform bacteria.

The division said, “Fecal coliform organisms are used as an indicator of fecal pollution from warm blooded animals and the national standard is a geometric mean of 30 samples not to exceed 14 fecal coliforms per 100 ml of seawater. Analysis is done in state labs.”

The division website also notes that the shellfish growing standard is much more restrictive than that for swimming, which is a geometric mean of 200.

Detailed information for each waterway, including surveys that show which areas are condemned for shellfish harvesting, can be found on the DSS website, www.vdh.virginia.gov/environmental-health.

Follow the links to learn more about shellfish safety.