A new oyster predator, Ocinebrellus inornatus (Recluz, 1851), in the shellfish-culture bay of Marennes-Oleron.

The muricid gastropod, Ocinebrellus inornatus, originates from the coasts o f the Korean Sea and southern Japan. This species has been regularly sample d in the bay of Marennes-Oleron (France) since spring 1997, and allowed us to validate the taxonomic status of a previous report of the species in the bay in April 1995. O. inornatus was sampled only in the bay of Marennes-Ol eron and has not been observed in the other areas along the Charente-Mariti me coast. O. inornatus lives mainly in the same biotope as the local murici d Ocenebra erinacea (i.e. the level of Fucus serratus between MLWN and ELWS ) Now, this alien species seems to be very well settled in the bay of Maren nes-Oleron, where it causes damage to the farming oyster beds. In the areas of highest densities of Ocinebrellus inornatus, the local species Ocenebra erinacea is observed in comparatively reduced numbers. The probable causes of introduction of O. inornatus in the bay are discussed. (C) 2000 Academi e des sciences/Editions scientifiques et medicales Elsevier SAS.