Why are oysters green?
La Fine de Claire Verte is the favorite product of the French who like thin oysters.
The Fine de Claire Verte oyster has a green color obtained thanks to the presence in the Claires de Marennes of the blue navicula, this micro algae is filtered by the oyster which retains its color.
The Seudre marshes, in which oysters are stored after farming at sea, are home to a microscopic algae which colors the oyster with its pigment “marennine”.
The Marennes oyster was already the favorite dish of Louis XIV. Although its green color seemed suspicious to his minister (Jean Baptiste Colbert Marquis de Seignelay thought that the Protestants wanted to poison the king), the Marennes oyster had a place of honor on the royal table.
Navicles live in a planktonic state on the coast. They periodically enter the clearings depending on the tides.
These clay basins which were once salt marshes offer excellent conditions for the development of diatoms.
If the environmental conditions are favorable, the microalgae settle on the clay soil of the clear then multiply, turn blue, and release the marennine which will attach itself to the gills of the oyster.
It is therefore impossible to reproduce this greening phenomenon elsewhere, since it is primarily the clayey soil of the Claires which allows the development of this magical algae!
