Baltimore City

Shellfish harvesting temporarily closed in parts of Chesapeake Bay due to sewage overflow, MDE says

A broad swath of the Chesapeake Bay near Baltimore is temporarily closed to shellfish harvesting as a precaution due to a sewage overflow, the Maryland Department of the Environment announced.

The agency issued a temporary order Thursday that expands an area already closed to shellfish harvesting east and south of Hart-Miller Island, according to a MDE news release.


About 10,400 acres of the bay directly off of Baltimore City and Baltimore and Anne Arundel counties are temporarily being reclassified to restrict shellfish harvesting, MDE said.

Map showing the notice of changes to shellfish waters.

This is a precautionary measure “after an estimated volume” of sewage overflow in Baltimore County “showed a potential impact” to shellfish waters downstream in the bay, MDE said.


It was reported to MDE as a break in a Baltimore County sewage line, said department spokesperson Jay Apperson. This break was not related to the Back River Wastewater Treatment Plant, which is across the Back River and owned by Baltimore City, he said.

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The agency said it received the data Thursday. Baltimore County initially notified MDE on Dec. 12 of an overflow to Muddy Gut, which is a small Back River tributary in Essex and is not considered shellfish waters, the release says.

“Due to the location of the spill, it was difficult to assess and estimate the volume of the discharge,” MDE said. “As of yesterday, a conservative estimate was provided by the County showing potentially more than two million gallons were lost to surface waters in Muddy Gut.”

The overflow had been stopped as of Thursday, and the area will reopen to shellfish harvesting Jan. 11, according to the release. The order does not impact harvesting in other areas that are approved or conditionally approved for shellfish harvest.

The Department of Natural Resources reported to MDE that there is no shellfish harvesting activity currently in the affected area and there are no aquaculture leases, the release states.

Shellfish are filter feeders with the ability to filter water and get food from microscopic organisms in the water. If the waters are polluted, this filtering process can concentrate disease-causing organisms associated with raw sewage and other sources such as animal waste in the shellfish, according to the release.

Oysters and clams are often eaten raw or partially cooked and must come from waters that are not polluted, said MDE, which monitors bacteriological water quality and conducts pollution source surveys to determine which areas are safe for shellfish harvesting.

As a protection to consumers, all shellfish are required to be tagged by harvesters and dealers under the National Shellfish Sanitation Program. Tags include the date and location of harvest. In Maryland, shelffish can only come from approved or conditionally approved waters, MDE said in the release.