Photographs of an oyster “disgorger”...


But what is it?

A "disgorger" is a basin which fills and empties with seawater according to the tides. The oysters are placed in lockers there before being marketed to finish their filtration work and get rid of all the small impurities such as mud or grains of sand.

Below a Toulvern basin photographed in slow exposure at the rising tide.

When the rising tide outcrop the basin, it fills in a few minutes... Less than five minutes in the sequence presented in the slideshow below.

Find out more about oyster breeding

The different oyster bredding techniques.

Depending on the region, different breeding techniques are used: :

  • On foreshore: flat on the sandy ground or on metal tables. The latter technique, known as "breeding in elevated", is the most widespread on the Atlantic coast, in Brittany and Normandy, thanks to the tidal system.
  • In deep water: oysters are sown at the bottom of the water or suspended from moored ropes. These techniques are used in the absence of tide, particularly in the Mediterranean.
  • In pipeline: the oysters are suspended under floats at greater depths off the coast.

The different stages of oyster breeding: collection, breeding, finishing…

3 to 4 years. This is the average farming time before an oyster arrives on our plate.

First stage: collection.

Spat collection involves collecting small oysters in the process of developing. It takes place in a natural environment at sea.

Oyster farmers install collectors at sea on which the oyster larvae will settle and begin to develop. These collectors remain in place for 4 to 8 months until the spat can be harvested. They are then brought back to the farm where the small oysters are unhooked before being sorted, placed in small mesh bags and laid out on tables at sea so that the oysters can continue to grow

Second stage: breeding for 18 to 36 months.

Once the bags are in the sea, they will remain there for 2 to 3 years. Each year, the oyster farmer will ensure that the oysters develop properly by :

  • "Turning" the bags: the bags are turned regularly to encourage oyster growth and limit the development of algae.
  • Changing the bags: the oysters are brought back to the farm, transferred at a lower density into larger bags with a wider mesh, which allows the water to circulate better. They are then returned to the tables at sea.

Oysters feed mainly on phytoplankton and mineral salts.

Third stage: refining.

Refining is optional, but it does improve the oyster's taste.

Once they have reached marketable size, the oysters are placed in "claires", seawater basins that are generally shallow and have a clay bottom.

Refining is a regulated operation that produces "fines de claires" or "spéciales de  claires" oysters depending on the length of immersion.

Fourth stage: finishing.

At this stage, the oysters are between 3 and 4 years old.

Once their growth process is complete, the oysters are placed in finishing basins filled with seawater called disgorgers. Here the oysters are placed in racks, before being marketed, to finish their filtration work and get rid of any small impurities such as mud or grains of sand.

The oysters are then washed, sorted, graded, laid flat in baskets and sold to consumers or retailers.