Alien species

The origins of the diatom Thalassiosira punctigera are not really known. It is presumed that the species reached Europe through transportation with cultured oysters around 1978. By drifting with the prevailing currents, the diatom could spread further along the European coasts. This unicellular algae was first recorded in the Scheldt estuary in 1993. Although this is yet to be confirmed, it's more than likely that the species also occurs along the Belgian coast.