Marennes-Oléron oysters
Thanks to an ideal habitat, suitable meteorological conditions and know-how that’s been handed down the generations, Marennes-Oléron oysters are the leading light in our local food and drink scene. Celebrated for its taste, it can boast of being the only kind of oyster in France to have ‘Label Rouge’ (a food quality assurance label) certification. They’re simply waiting for you to taste them!
From flat to hollow oysters
Whenever the name of Marennes Oléron comes up, naturally people think of oysters, the famous Marennes Oléron oysters which are served in the finest dining establishments. A familiar product since Roman times, the farming of Marennes Oléron oysters began in the middle of the 19th century with the creation of the first oyster farms. At this time, the salt-makers of the Charente coast were struggling to cope with competitors in the south of France and decided to concentrate on oyster farming. With the salt-harvesting industry in decline, the salt pans were taken over by the oyster farmers to be put to use in this new activity, which was soon a runaway success. At this time, the European flat oyster was found in the bassin.
An unexpected event spurred on the development of oyster farming in the Marennes Oléron basin. In 1868, the Morlaisien, a ship loaded with Portuguese oysters, was forced to jettison its cargo overboard due to a navigational error. This seemingly minor occurrence had a significant impact upon the history of oyster farming in the Marennes-Oléron region. Some of the Portuguese oysters thrown overboard found the local ecosystem – unique in France – very much to their liking and they grew quickly. The mix of freshwater – mostly from the Seudre River - and seawater encouraged this mollusc’s rapid growth. For many years, the flat oysters and the so-called ‘hollow’ Portuguese oysters coexisted without too many problems, although the hollow oyster constantly extended its range through the Marennes-Oléron basin, despite locals’ preference for the flat oyster. However, from 1922 on, an epidemic struck the flat oysters, devastating their population and forcing oyster farmers to farm hollow oysters. Unfortunately, this oyster was in turn struck down by disease in 1970. The decision was then taken to bring in more resilient, disease-resistant Pacific oysters. As a result, the industry was able to get back on its feet.
A job that requires a lot of patience...
Oyster farming is a long-term project, the oyster having undergone a long, complex process before it arrives on your plate. The first step is collection. An oyster produces about a million eggs, which, once fertilized, become larvae. To collect these ‘spats’, oyster farmers set up collectors along the coast (tubes, iron bars, series of interconnected plastic ‘coupelles’ etc). The oysters will attach themselves to these objects. These young oysters will stay on these collectors for one to one and a half years in order to grow.
We can then move onto the second stage, spat detaching, which involves gently detaching the oysters from each other. They can then be put back into the sea in bags placed on tables sitting on the seafloor. For a period of almost two years, the oyster feeds on plankton and gradually grows, under the watchful eye of the oyster farmer. During this period, the bags have to be moved almost 40 times depending on tides and currents. The oyster farmer has to check on his oysters every day. It’s a job that simultaneously demands physical toughness and great precision
Did you know that with around 6,000 hectares of oyster farms and 3,000 hectares of ‘claires’, Marennes-Oléron is Europe’s biggest oyster-farming centre? Between 45 and 60,000 tonnes of Marennes-Oléron oysters are produced here and exported every year - 50% of total French oyster production.
The last stage is unique to the bassin de Marennes Oléron area – maturing in ‘claires’. These claires are clay ponds in what used to be saltmarsh, where freshwater mixes with seawater with every tide. The oysters mature in these ponds for one to six months. This is when something magical starts to happen. As well as living in this very special underwater habitat, the oyster is able to feed on a particular microscopic species of algae, the blue navicula. The oyster’s yellow flesh will turn green when it comes into contact with this alga. The colour and taste the oyster acquires from this particular environment are so distinctive that they are found nowhere else in the world except in the Marennes Oléron area!
Oysters for all tastes
Marennes Oléron oysters are oysters that are matured or raised in ‘claires’. However, it’s more complicated than that. These oysters are placed in different categories depending on their size or the length of time they have spent in the claires. As far as size is concerned, it’s very simple. Oysters are graded from 0 to 5. 5 are the smallest and 0 the largest. Grades 3 and 4 are the most common.
In addition to size, there is also the question of oyster quality:
Fine de claires: these must have spent 28 days in the claires, which gives them their pronounced, very distinctive taste. They are recommended for people who prefer leaner oysters.
Spéciale de claires: of more regular shape, these are a little larger. Their maturing in the claires gives them a plumper texture when compared to the fine de claires.
Fine de claires verte label rouge: this is a product of superior quality. There are several criteria which must be met for this quality assurance label to be awarded, including: having an attractive, round shell and a striking green colour, which shows they have spent time in the claire.
Pousse en claires label rouge: These are the best of the best of Marennes Oléron oysters. They will stay in claires for 4 to 8 months and are raised at very low densities, a maximum of 2 to 5 per square metre. This gives the pousse en claires plumper flesh and a very pronounced flavour heavily influenced by its habitat or ‘terroir’.