DMF orders shutdown of oyster beds in Katama Bay

A fresh harvest of oysters from Katama Bay. — Photo by Michael Cummo

The Massachusetts Division of Marine Fisheries (DMF) and Department of Public Health (DPH) ordered Katama Bay oyster beds closed to commercial harvesting as of September 3, and for at least seven days, as a precaution following a fourth reported case of illness caused by eating raw oysters.

“This precautionary closure is due to the presence of environmental conditions conducive to the growth of Vibrio parahaemolyticus (Vibrio) in oysters harvested from the area based on information relative to closures in 2013,” DPH said in a press release Wednesday.

“We recognize the impact these actions have on many of our local businesses, and we do not take them lightly,” said Cheryl Bartlett, RN, Massachusetts Commissioner of Public Health.

DPH said this is the first time a specific harvest area in Massachusetts has been closed due to Vibrio this year. “The decision to issue a precautionary closure was made jointly between DPH and DMF officials in response to warming waters in Katama Bay, anticipated high air temperatures forecast for this week, and identification of a fourth confirmed case of Vibrio tied to the area. Current water temperatures in Katama Bay are consistent with water temperatures and environmental conditions that were associated with Vibrio illnesses in 2013.”

The most recent report of illness was associated with oysters harvested from Katama Bay on August 7, and consumed raw on August 8, according to DMF. State audits have shown no mishandling of the shellfish.

Edgartown shellfish warden Paul Bagnall said he has been closely monitoring compliance with the new regulations, which require the oysters to be kept out of the sun, and iced within two hours of harvest. “Compliance has been excellent,” Mr. Bagnall said. “The guys in Katama are willing to go over and above what the state requires. But we’re doing something we didn’t do 20 years ago, and that’s eating raw oysters in the summer months.”

Vibrio is a bacteria that occurs naturally in coastal waters in the United States and Canada. It has caused illnesses in the Gulf Coast and West Coast of the United States for a number of years. It is not related to pollution of Massachusetts shellfish.

Last September, an outbreak of Vibrio illness led to a month-long closure of oyster operations in Katama Bay and across the state, which has seen a steady rise in Vibrio cases since 2011. The sharp increase in illnesses caused federal authorities to mandate stricter regulation of the handling of raw oysters. Regulation is enforced locally by the DMF and DPH.