Prey-Predation Relationships between Bivalves and Predatory Gastropods: Experiments on English Channel Populations

Predatory gastropods represent a potential menace for intertidal shellfish aquaculture along the French coast of the English Channel. Experimental studies have been established to analyse the predation of two drilling gastropods Ocenebra erinaceus and Ocinebrellus inornatus on the Manila clam (Ruditapes philippinarum) and the Japanese oyster (Crassostrea gigas) and to test if the feeding behaviour of these two predatory gastropods is influenced by the burying of the Manila clam in sediment. Both gastropods show significant predation on both bivalves, with feeding preference changing according to prey species and their availability. Moreover, the burying of clams does not significantly influence the feeding behaviour of their predators. Monitoring of this danger for oyster and clam farming should be encouraged on some sites of the western coast of Cotentin.