Copepoda (Crustacea) associated with commercial and non-commercial Bivalvia in the East Scheldt, The Netherlands

Six species of Copepoda Poecilostomatoida of the families Myicolidae, Sabelliphilidae, Lichomolgidae, and Mytilicolidae are recorded from six different species of intertidal bivalves in the East Scheldt (The Netherlands), a branch of the southern bight of the North Sea. One bivalve species may harbour more than one species of copepod, and one copepod species may use more than one species of bivalves as host. Mytilicola orientalis and Myicola ostreae are new to the North Sea, both being undoubtedly carried in accidentally with oriental oysters, successfully introduced for mariculture. In the light of the damage that was caused by Mytilicola intestinalis to Dutch mussel cultures in the past, the acclimatization of M. orientalis is a matter of concern, the more so since it infests not only its original oriental host, Crassostrea gigas, but also the native European species, Ostrea edulis and Mytilus edulis, both important fisheries resources in the East Scheldt region.