Herpes Virus Makes Oysters Rare Treat in French Holiday Season

Virus Makes French Oysters Rarer Treat for Holiday Season
Oysters are typically left to grow for three years before they’re shipped to markets, restaurants and fish stores across France, ready for the table. Photographer: Damien Meyer/AFP/Getty Images

Thomas Catonnet listens for the tell-tale death rattle at his oyster farm in France’s Arcachon Bay, as a falling tide exposes victims of a lethal virus ravaging the nation’s 157-year-old shellfish industry.

“You smell a particular odor and you hear the sound of shells,” said Catonnet, 33, sorting baby oysters in a wooden shack near the end of a 20-kilometer (12-mile) sandbar that shelters the bay from the Atlantic Ocean west of the city of Bordeaux. “A putrid smell. Nobody understands it.”

A herpes virus has decimated oysters along France’s 5,500-kilometer coast for a fourth season, making the shellfish an ever-more exclusive treat for year-end holiday meals that account for half of the country’s oyster sales.

Farm-gate prices for oysters have jumped 65 percent in three years because of the disease, said Goulven Brest, head of France’s shellfish-growers committee. He frets that high prices, which help keep growers like Catonnet afloat, and fewer oysters threaten an industry with 630 million euros ($823 million) in sales in 2009.

“The consumer is losing interest in the product because we have less to market,” Brest said. “We can’t charge more. We’ve reached a price beyond which demand will plummet.”

Retail prices for oysters in Paris have climbed to between 14 and 17 euros a dozen in some neighborhoods, from 12 to 14 euros a dozen in 2010, he said. Wholesale prices in October climbed 8.2 percent from a year earlier and 26 percent from two years ago, according to the National Institute of Statistics and Economic Studies in Paris.

‘La Mortalite’

The disease killing France’s Pacific oysters, dubbed “la mortalite” by growers, first emerged in 2008. It mostly strikes oysters under a year old, research by the Institut Francais de Recherche pour l’Exploitation de la Mer shows.

Between 70 and 80 percent of France’s young stock died this year, according to the institute. Identified as a variant of Ostreid herpesvirus 1, or OsHV-1, the disease starts killing oysters when water temperatures reach about 16 degrees Celsius (61 degrees Fahrenheit).

“In 2008, researchers were stunned by the scale and distribution of the phenomenon,” said Marion Le Foll, a spokeswoman for the institute. All oyster regions in France have been hit, she said.

“Ifremer studies show there’s a tremendous genetic diversity in Pacific oysters; we can’t explain the mortality through a lack of genetic diversity,” Le Foll said.

Tumbling Production

Oysters are typically left to grow for three years before they’re shipped to markets, restaurants and fish stores across France, ready for the table. Last year was the first in which the virus made a noticeable dent in sales.

France’s oyster harvest plunged 38 percent in 2010 to 80,000 metric tons from about 130,000 tons a year earlier, according to the shellfish-growers committee. Production is little changed this year, according to Brest.

The death of young oysters in Arcachon Bay, whose sandy beaches and sunny weather have attracted holidaymakers since the 19th century, is a particular concern. The basin, which gave birth to France’s oyster-farming industry in 1854, produces about 70 percent of the nation’s naturally grown oyster spat, known as “naissains.”

Catonnet said about 60 percent of his spat died this year, matching the proportion of losses in 2010. The deaths extended into November as a long summer kept the bay unseasonably warm.

“We still had mortality late in the season,” he said. “We lost a little every day.”

Billions of Eggs

Catherine Roux, an oyster farmer in Cap Ferret, buys spat from Catonnet and raises them to a marketable size. Higher selling prices aren’t making up for the lower stock, she said.

“It’s not enough to compensate,” she said. “Oysters are in short supply.”

The Pacific oysters in Arcachon Bay, introduced from Japan in the 1970s, spawn billions of eggs twice a year. In summer, they take about 18 days to develop into larvae, says Christian Lapegue, an oyster farmer on the bay.

Farmers place larvae collectors in the bay that are taken out of the water from November to February. The baby oysters’ death becomes apparent by February, said his son Yannick.

“You don’t see the same thing from oyster grower to the next,” the 37-year-old said. “It depends on the location.”

In the bay, farmers grow oysters in rows of meshed plastic bags on wire stands that dry out at low tide. They use flat-bottomed aluminum boats to reach their oyster parks.

The shellfish may be handled 25 times over a three or four-year period as they’re turned, cleaned or moved to bigger wire bags before reaching restaurant size, said Lapegue senior.

Trying to Adapt

Some of Arcachon Bay’s 300 oyster growers are trying to adapt to their virus-ravaged crop. Catonnet said he’s placing more larvae collectors, although he says the extra work means “economically speaking, it’s not really viable.”

Catonnet, who ships spat and oysters up to 18 months to farmers in Normandy and Brittany, has started selling table-ready oysters in the nearby city of Bordeaux for extra cash.

“I don’t like it, but with the mortality we have to try and earn the same money with fewer oysters,” said Catonnet, who produces about 30 tons of oysters a year with one employee.

The government provides assistance, although it’s laughably meager, said Catonnet, whose business is still profitable. If he had to do it all over again, he wouldn’t be an oyster farmer.

“I’ve been in the business for 10 years,” he said. “In the same situation today, I wouldn’t do it again.”

In Piraillan, Veronique Lenoir, 47, charges holidaymakers for a tour down the wheelbarrow-wide, crushed-shell paths of the oyster-farming village. That’s added to earnings after her oyster output fell to 5 tons from as much as 8 tons in 2008.

“Some businesses will go under,” she said. “We’ll end up with a dozen oyster farmers in a little corner of the bay.”

Oyster Quality

One positive outcome of the diminished stock is that the oysters are meatier and better looking as farmers take greater care of them.

“They’re beautiful,” Brest said. “They have a handsome shape and there’s more meat inside.”

That may not be enough to create loyal consumers. The shortage of the shellfish has shrunk the oyster-selling season outside big cities to December and January from between September and May previously, according to Brest. Oysters also don’t travel well, making imports not an option.

The industry is in a vicious spiral, Brest says: with smaller quantities available, the number of retail points will shrink after the festive season because the oysters are too expensive. That in turn means consumers will see less and less of the shellfish, which may bring down demand and prices.

“That could cost us very dearly,” Brest said. “If prices fall again, it will be the whole industry that dies.”

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