La maladie des branchies des huitres portugaises des cotes françaises de l'atlantique : données générales sur la maladie des branchies

In the summer of 1967, an abnormally high mortality rate struck the Portuguese oysters, Crassostrea angulata, of the Marennes and Arcachon sites and, less severely, those of the other farming sectors of the French Atlantic coast. Yet the examinations performed in the preceding months had brought to light the existence of rather deep lesions on the gills and sometimes on the labial palpi of a large number of the species' oysters that were not harbouring any pinnotheres. The successive appearance of the two phenomena led us to attribute the observed mortalities to what we have called, for convenience, "gill disease". The various specialised laboratories of the Institute of Fishing strove to determine the nature of the infection, its distribution in France and abroad where oyster farmers lay in supplies, its frequency and its development. They have attempted, moreover, just as others have done here and there, to identify the responsible organism or organisms. It seemed appropriate to introduce the current state of our observations and to publish the preliminary results of the research undertaken in the laboratories of the Institute of Fishing.