COPEPODA (CRUSTACEA) ASSOCIATED WITH COMMERCIAL AND NONCOMMERCIAL BIVALVIA IN THE EAST SCHELDT, THE NETHERLANDS

Six species of Copepoda Poecilostomatoida of the families Myicolidae, Sabelliphilidae, Lichomolgidae, and Mytilicolidae are recorded from si x different species of intertidal bivalves in the East Scheldt (The Ne therlands), a branch of the southern bight of the North Sea. One bival ve species may harbour more than one species of copepod, and one copep od species may use more than one species of bivalves as host. Mytilico la orientalis and Myicola ostreae are new to the North Sea, both being undoubtedly carried in accidentally with oriental oysters, successful ly introduced for mariculture. In the light of the damage that was cau sed by Mytilicola intestinalis to Dutch mussel cultures in the past, t he acclimatization of M. orientalis is a matter of concern, the more s o since it infests not only its original oriental host, Crassostrea gi gas, but also the native European species, Ostrea edulis and Mytilus e dulis, both important fisheries resources in the East Scheldt region.