Katama Bay oyster farms resume harvest

Oyster farmers in Katama Bay have permission to begin harvesting once again. — Photo by Michael Cummo

On Wednesday, Sept. 10, the Massachusetts Division of Marine Fisheries and Department of Public Health lifted a ban on oyster harvesting in Katama Bay following a one-week closure.

The oyster farms were ordered shut down on Sept. 3, after state regulators confirmed four cases of illness in 35 days, and determined that environmental conditions in Katama Bay were conducive to further growth of Vibrio parahaemolyticus, the bacteria which caused the illnesses. Vibrio reproduces far more rapidly when water is warmer.

Edgartown shellfish warden Paul Bagnall said water temperature was one of the factors state regulators used to make their decision.

“No new illnesses, and they wanted at least to see steady, if not declining water temperature,” Mr. Bagnall said.  Mr. Bagnall said on Sept. 9 the water temperature in Katama Bay was 71 degrees, and is now about 68 degrees.

An interruption in the harvest comes with a cost to oyster producers.

“I think it has affected their market somewhat,” he said. “You shut down for a week and they [retailers] may buy from somebody else, and then it’s hard to get them back.”

Mr. Bagnall said he has sent samples to state labs for further testing, and to the University of New Hampshire, where scientists are studying the Vibrio bacteria to find ways to further safeguard oyster harvests.