Arcachon Oyster Problems in France
Disease and Pollution Damage Oyster Production in France
Jan 24, 2009
The huge lagoon at Arcachon produces all the young oysters for culturing in France, and there have been a number of setbacks and causes for concern.
Arcachon Bay
This large (15,000 hectares) lagoon in South West France has some of the finest oysters in the world, as well as more than its fair share of rich tourists. The bay opens through a very narrow and dangerous passage into the Atlantic Ocean at Cap Feret. It is where all the oysters reared in France come from, and although not that many adult oysters are reared there, it is where all the oyster fry that are grown on in Brittany, Normandy, and Charente-Maritime begin their lives.
Oysters in Arcachon Bay
Arcachon originally grew only the famous European Oyster (Ostrea edulis), and it still manages to produce a few each year, but this production was augmented when the Portuguese oyster (Crassosstrea angulata) was introduced. Unfortunately disease wiped these out in the 1970s and they were replaced with the Pacific Oyster (Crassostrea gigas).
Oyster Diseases in Arcachon Bay
- An unspecified oyster gill disease killed off most of the Portuguese Oysters in the early 1970s, and those that survived this began to show strange shell abnormalities in 1974.
- In the late 1970s the newly introduced Pacific Oysters also began to have problems – they were not reproducing. Initially the cause was a mystery, but it was later realised that a particular form of pollution was to blame.
- The people who work and live around the bay are unusually careful about pollution in the area (they know how important it is to keep the lagoon clean for the oysters), but it turned out that the problems with the oysters in the late 1970s and early ‘80s was due to an anti-fouling product used on the boats.
- Tributiltin (TBT) compounds were causing both the shell deformities in the early ‘70s and the infertilities in the ‘80s. (Read an article about TBT).
- In 1982 France outlawed the use of marine paint containing TBT on vessels up to 25 meters (about 80 ft), and soon after this the situation began to improve.
Oil Spills Affecting Arcachon Bay
- In 1978 a tanker (the "Amoco Cadiz") spilled 230,000 tons of crude oil, and a significant amount entered Arcachon Bay.
- Another tanker spilled oil in 2003 (the “Prestige”), but luckily the effects this time were minimal.
- In August 2008 the oysters were again causing concern and a temporary ban on their sale was imposed by the French government. Two people who had eaten local oysters had died, but whether or not the oysters were actually to blame remains uncertain.
- This action by the French government is an excellent example of the ‘Precautionary Principle’ in action.
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