Herpes-Afflicted Oyster Industry in France Gets Glimmer of Hope
Denis Bellocq, an oyster farmer in Arcachon Bay, the cradle of France’s 158-year-old oyster industry, points with pleasure to stacked red brick tiles covered in dozens of black specks in the basin’s tidal waters.
It has been a while since his oyster crop looked this rich. This year’s catch of wild juvenile oysters, table-ready in three years, is the biggest since 2008, says researcher Institut Francais de Recherche pour l’Exploitation de la Mer. That’s giving farmers like Bellocq hope after a herpes virus slashed France’s oyster harvest by 40 percent in the past four years.
“We’re starting to be optimistic again,” Bellocq said. “In three years, we should have more oysters to put on the market. We have to survive until then.”
France’s 630-million euro ($817 million) oyster industry has been stumped by a variant of Ostreid herpesvirus 1, or OsHV- 1, that first appeared in 2008. The virus can kill most of a farm’s stock of young shellfish in a day, and has since spread to the U.K. and Ireland, as well as Australia and New Zealand.
The deadly disease mostly strikes oysters under a year old, according to marine research by Ifremer. The virus has pushed up oyster prices ahead of the year-end holiday season, which accounts for half of the delicacy’s annual sales in France.
“Little by little the growers have raised the price of oysters, that was necessary to keep our companies afloat,” said Olivier Laban, head of Arcachon Bay’s shellfish growers’ committee. “Oyster prices are about 30 percent higher compared to 2008; that’s entirely in line with the mortality rate.”
Wholesale prices for French oysters in October climbed 10 percent from a year earlier and are up 37 percent from the same period in 2008, data from the National Institute of Statistics and Economic Studies in Paris show.
Bellocq has seen as many as 80 percent of his baby oysters die before reaching maturity in the past four years. He’s hoping 2012 will mark a turnaround.
Growers in the bay capture floating wild oyster larvae by submerging tiles or plastic discs to which the juveniles attach themselves. The young ones are then left to grow in the bay for about eight months before they’re transferred to oyster parks, where they’re placed in rows of plastic mesh bags on metal racks that dry out at low tide. Over a three-year period, the farmers turn and clean the oysters and move them to bigger wire bags as the shellfish grow before they are ready to be shucked and served at restaurants and for year-end celebrations.
Bellocq said he’s collected 500 to 1,000 young oysters per tile this year, compared with 20 to 50 in past years.
“Let’s say we’re hopeful,” Bellocq said. “As long as we have 20 percent left in the end, we’d rather have 1,000 per tile than 50. We’ll probably have the same mortality next year, but we should have some oysters.”
Arcachon Bay matters particularly to French shellfish growers because the basin, which gave birth to France’s oyster- farming tradition in 1854, produces as much as 70 percent of the nation’s natural oyster spats, known as “naissains.”
The Pacific oysters grown in the bay, introduced from Japan in the 1970s after disease wiped out the local Portuguese oyster population, spawn billions of eggs twice a year.
Capture in the western bay was an average 247 oyster spat per plastic disc this year, up from 15 last year, while in the east the count jumped to 228 spat from 8, according to researcher Ifremer.
The oyster virus first made a noticeable dent in sales in 2010, as French oyster production plunged 38 percent to 80,000 metric tons from about 130,000 tons a year earlier, according to the country’s shellfish-growers committee.
With the virus still prevalent along France’s 5,500- kilometer (3,418-mile) coastline, between 40 percent and 90 percent of France’s young oysters died this year, depending on location, according to Ifremer.
The disease starts killing oysters when water temperatures reach about 16 degrees Celsius (61 degrees Fahrenheit), and Laban expects a fifth year of die-off starting next spring.
“I don’t see how we can slip through the net,” Laban said. “There’s a big chance the oysters will be hit at a level of 60 percent to 80 percent.”
An Ifremer study published last year found evidence of resistance to the herpes virus in some oysters. The study also showed the virulence of the disease, with all juvenile oysters becoming infected with OsHV-1 seven days after being placed in the waters of Marennes-Oleron Bay, north of Arcachon.
“We’re condemned to living with this virus,” Laban said. “The virus is in the water, in the products and in the animals. We don’t have a choice, we have to work, selectively finding oysters that are resistant.”
In Arcachon Bay, 71 percent of juveniles died this year, according to Ifremer. That’s similar to the 70 percent rate in 2011 and compares with 79 percent mortality two years ago.
French oyster production has bottomed, and 80,000 tons is the volume that can be produced even with only 30 percent of the juveniles surviving, according to Laban.
For Bellocq, one of the biggest producers in Arcachon Bay with 1.5 million euros in annual sales and six full-time employees, the drop in production has cut profitability.
“Even though you increase the price, you have to pay your fixed costs, the workers,” he said. “The margins are reduced, because we have much less product to sell.”
That’s prompted the oyster farmer to find a different way to resist the virus. He’s set up a shack on the edge of the sandy peninsula shielding Arcachon Bay from the Atlantic Ocean, serving oysters and white wine to holiday makers in Cap Ferret, an upscale summer destination.
“It’s a new way of working in the oyster industry,” Bellocq said. “The oysters are getting very scarce, so we need to get to markets with a bit of money. We’re showing people our job, our oysters. We’re selling dreams now.”
To contact the editor responsible for this story: Vidya Root at email@example.com