Etudes sur la biologie des mollusques, sur leur reproduction et sur la fixation du naissain

The study of the reproduction of oysters was carried out in 1921 by the Marine Fisheries Scientific and Technical Office. In Brittany, in the ponds provided by M. d'Argy, M. Dollfuss conducted different spat fixation trials on sun dried and bleached oyster and cockle shells, studying the temperature and salinity conditions necessary for a successful fixation. At the same time, some monitoring points, equipped with thermometers and densimeters, were positioned at different spots on the Auray river: they enabled us to monitor the physical conditions of the water and to determine their relationship with the precise time when spat was released by the mother oysters: "This way, we will be able to put the collectors in place at the right time, and not at random or for empirical reasons," M. Joubin, head of the Fisheries Office, wrote in his annual report, "The observation chart displayed everyday on the door of the Locmariaquer town hall helped the oyster farmers not to put their tiles in place too early because of the low water temperature at night."