In the Skagerrak the plankton flora was poor with few diatoms and dinoflagellates. Toxic species as Dinophysis acuminata, Dinophysis rotundata, cf. Alexandrium pseudogonyaulax and Chrysochromulina spp. were present in low concentrations. In the Kattegat a diatom bloom of Guinardia flaccida, Proboscia alata and Dactyliosolen fragilissimus decreased between the two samplings. Small amounts of Baltic cyanobacteria were found, as well cf. Alexandrium pseudogonyaulax. In the Baltic blue-green algae were common at most stations, with a dominance of Aphanizomenon sp. and less of Nodularia spumigena. Most of the Nodularia chains were senescent and a lot of Nitzschia paleacea were attached to the chains. In Arkona a large Prorocentrum minimum bloom was going on.