State orders shutdown of Katama Bay oyster beds

In this file photo, a fresh harvest of oysters from Katama Bay awaits delivery. The area has been closed to oyster harvesting after three people reported illness. — File photo by Michael Cummo

The Massachusetts Division of Marine Fisheries (DMF) and Department of Public Health (DPH) ordered that Katama Bay oyster beds in Edgartown be closed to commercial harvesting beginning Thursday, August 26, for at least seven days, as a precaution following a third confirmed case of illness caused by eating raw oysters.

“Should more cases be confirmed, an extended U.S. FDA-enforced closure could be issued,” the state agencies said in a joint press release. “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 the coming days, and identification of a third confirmed case of Vibrio tied to the Katama Bay harvest area.”

All three individuals have recovered.

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.

“It thrives in warmer temperatures, multiplying as water and ambient air temperatures increase. The more Vibrio present in oysters, the greater the risk of infection. Current water temperatures in Katama Bay are consistent with water temperatures and environmental conditions that were associated with an increased occurrence for Vibrio illnesses in 2013 and 2014,” according to a press release.

The Vibrio season in Massachusetts runs from May to October. Health officials are reminding all persons who are at high risk, especially those who are elderly or immune-compromised, to avoid eating any raw shellfish.

Due to the increase in Vibrio cases in 2012, and continued reports of Vibrio among people reporting consumption of raw oysters in waters beyond Eastern Cape Cod Bay, the FDA advised Massachusetts to expand Vibrio controls to all oyster harvest areas in 2013.