Published online by Cambridge University Press: 11 May 2009
In order to improve their quality before commercial distribution, oysters in the Marennes-Oleron region of France are placed temporarily in sea water in either natural basins or artificial canals known as 'claires' (Korringa, 1976). It has been known for some time that these marine enclosures provide an environment particularly rich in a variety of micro-organisms many of which are valuable sources of food thus contributing to the growth of the oysters; one species in particular, the diatom Navicula ostrearia (Gaillon) Bory, gives them a green hue and a special flavour much appreciated by French consumers (Neuville & Daste, 1972). For some years, two of us (D.N and Ph. D.) have been concerned with detailed investigations of the diatoms of the 'claires', especially N. ostrearia (Daste & Neuville, 1976).