For oyster farmers, the year-end holiday period is a vital one as they make around a third to half of their annual sales during this time. But last year was catastrophic for some oyster producing regions in France after sales were banned following a spate of food poisonings in parts of the country. Along with a tarnished image, oyster farmers also have to deal with an uptick in poaching, and rising seawater temperatures which threaten production.

Thierry Lafon has farmed oysters in Arcachon Bay for nearly 40 years. Like many of the 300 oyster farms in the area, Lafon’s business took a major blow last winter when sales of Arcachon Bay oysters were banned on December 27, 2023 following a number of foodborne infections. Analysis revealed the presence of norovirus in the oysters, the pathogen that causes gastroenteritis. It was a disaster for the local oyster industry which relies on the Christmas season for up to half of its revenue. "But that’s just the tip of the iceberg", Lafon said, adding: "oyster prices have collapsed as a whole".

While sales of Arcachon Bay oysters have improved after a 50 percent drop at the beginning of 2024, many oyster farmers say the root of the problem has yet to be addressed, citing polluted waters in the bay.

Oysters contaminated by raw sewage

The pollution can be traced back to severe flooding, triggered by major storms that hit the region last autumn. While the Intercommunal Union of Arcachon Bay (SIBA) which handles local sanitation, blamed the pollution on heavy rainfalls, a video shot by a local resident showed raw sewage and effluent deliberately dumped into a stream that feeds Arcachon Bay. Lafon, who heads a local environmental defence group, was the first oyster farmer to file a complaint against SIBA.

SIBA did not respond to requests for an interview and continues to blame the weather. In October, the group announced an investment of 120 million euros over five years, which includes a new water treatment facility in the bay area.

Environmental groups however say it’s not enough to solve the problem, which, according to them, stems from urbanisation. When the rainwater can no longer infiltrate the soil, the runoff increases exponentially. A popular tourist destination, Arcachon Bay is undergoing further development with 30,000 new homes slated to be built by 2040.

Professional Poaching

On top of sewage dumping which lead to contamination risks, there’s another cause for concern. Oyster farmers have long had to cope with theft, particularly around the holiday season. "It’s always a sensitive time for oyster farmers as a big chunk of their annual revenue depends on this period. So, we boost patrols, almost daily." Commander Jérôme Goussard of the Arcachon Nautical Brigade said.

Oysters under threat from global warming

It's not just pollution and poaching that have proven to be major headaches for oyster farmers either. Climate change too has had a major effect on the industry, with some oyster species of unable to adapt to the warming waters.

In Carantec in Brittany, oyster farmer Gireg Berder has had to struggle with green algae which have multiplied around the region because of both the fertilisers used for intensive agriculture, and rising temperature of the local waters. “The algae overgrows, and everything underneath decomposes, and it kills off all the species living there,” Berder said.

Due to global warming, the water is also becoming more acidic, which poses a danger for oysters. According to scientist Frédéric Gazeau, who co-authored a study on the environmental impact on oysters, lower water pH weaken oysters’ calcium carbonate shell, forcing the molluscs to use more energy for protection.

This means that the oysters “won’t be able to use that energy for other vital processes like reproduction, tissue growth, feeding, and so on. Our study shows a 20 percent reduction in growth by 2050," Gazeau said.

In the face of all these difficulties, oyster farmers in France have no choice but to change their practices. In the Arcachon Basin, Lafon is criticised by some for his outspokenness, which some believe damages the industry’s image. Nonetheless, Lafon is no longer willing to remain silent, as he believe that polluters must shoulder responsibility in order to protect his line of work.