Bacteria closes 12 Katama Bay oyster farms

Friday Afternoon oysters and wings special at Offshore Ale. — Photo by Ralph Stewart

All oyster farms in Katama Bay were ordered shut Monday by the Massachusetts Department of Public Health (DPH), because of bacterial contamination that has caused at least three confirmed cases of illness on Martha’s Vineyard, according to Edgartown shellfish constable Paul Bagnall.

DPH ordered a recall for all oysters shipped from Katama Bay after August 1.

“We recognize the impact these actions have on many of our local businesses, and we do not take them lightly,” said Cheryl Bartlett, Massachusetts Commissioner of Public Health in a news release. “We will continue to partner with federal and local health officials and industry to ensure the public’s health and safety.”

Mr. Bagnall said he expects oyster production from 12 active farms in the bay to be curtailed for at least four weeks. The July through December period is the most productive and lucrative harvest time for Katama Bay oyster farmers, Mr. Bagnall said. Production approaches five million commercially harvested oysters annually.

Mr. Bagnall said the bacteria could threaten the entire industry. “If I owned a farm, I would be really worried about next year,” he said.

Similar outbreaks have forced closure of aquaculture operations on Cape Cod, Plymouth Bay, and in Connecticut this summer.

Oyster bug

The bacteria that prompted the shutdown of Katama Bay farms is Vibrio parahaemolyticus, known by scientists by its initials Vp. A naturally occurring bacteria that thrives when water temperatures get warmer than 81 degrees, it can live and reproduce in temperatures as low as 60 degrees, either in the ocean or in the shells of harvested oysters. The bacteria causes severe stomach distress.

“When ingested, Vibrio parahaemolyticus causes watery diarrhea often with abdominal cramping, nausea, vomiting, fever, and chills,” according to the Centers for Disease Control. “Usually these symptoms occur within 24 hours of ingestion. Illness is usually self-limited and lasts three days. Severe disease is rare and occurs more commonly in persons with weakened immune systems. Vibrio parahaemolyticus can also cause an infection of the skin when an open wound is exposed to warm seawater.”

Last year, there were nine confirmed cases of illness from Vp statewide, according to DPH. The illnesses prompted regulators to order a control plan for the 2013 season. The plan included earlier icing of the shellfish after harvest, among other precautions. But with three cases confirmed at the Martha’s Vineyard Hospital in recent weeks, DPH ordered production shut down.

“If you get a confirmed case, there are probably some cases out there, either people didn’t present, or didn’t feel it was necessary to go to the hospital, or doctors missed it,” Mr. Bagnall said.

Tough day on the farms

Jack and Sue Blake operate Sweet Neck Farm, an oyster aquaculture operation in Katama Bay. Ms. Blake referred questions about the shutdown to Bob Rheault, executive director of the East Coast Shellfish Growers Association, a lobbying group based in New Jersey that represents 1,000 shellfish growers, according to its web site.

In a phone interview with The Times, Mr. Rheault cautioned that eating raw shellfish always carries some risk.

“I don’t want to make light of it, any illness is bad, but it’s quite rare,” Mr. Rheault said. “If it was a real problem, there would be thousands of illnesses, not just a few. They’ve sold thousands and thousands of oysters that have been consumed quite safely.”

Mr. Rheault said growers have taken aggressive steps to ensure their product is safe, but the organization faces a challenge in educating wholesalers, retailers, and food establishments.

“Most of the problem is mishandling,” Mr. Rheault said. “I refuse to believe that the product coming out of the water is unsafe.”

Retail recall

At the Net Result seafood market in Vineyard Haven, owner Louis Larsen sells raw Katama Bay oysters to retail customers and restaurants. The recall triggered a well-established protocol that required him to notify customers, pick up recalled oysters and store them, so that regulators can examine them, if needed. State regulations require careful tracking of raw shellfish. The product is tagged and recorded at every step of the process.

“Our recall was strictly on-Island, so it was pretty simple,” Mr. Larsen said. “We have a ledger, so it really wasn’t a problem.”

Mr. Larsen is puzzled by the bacterial contamination, which hasn’t been much of an issue in New England waters, until now.

“Why all of a sudden this year?” Mr. Larsen asked. “This year, the guys have done better at handling. The fishermen have to begin cooling as soon as they harvest.”

He said he thinks the contamination will affect oyster sales, even after the shutdown ends. “I think so, very much,” he said. “I’ve already had people say ‘I don’t know if I’ll eat oysters again.'”

Mr. Larsen has made calls to wholesalers in Canada to restock his cases with raw oysters.