The phytoplankton diversity was generally speaking low in the Skagerrak and Kattegat areas, although the number of species and the total cell numbers were higher in the Skagerrak in comparison. The coccolithophorid Emiliania huxleyi was abundant, especially at Släggö. The chlorophyll concentrations were low but within normal for this month. Also at the Baltic stations the diversity was low and small cyanobacteria colonies, flagellates, ciliates and Gymnodiniales were common. Among the filamentous cyanobacteria, Aphanizomenon flosaquae was present at all stations except BY20. A few filament of Nodularia spumigena* were present at many stations and Dolichospermum sp. were found at BY38 and RefM1V1. As in Skagerrak and Kattegat, the chlorophyll concentrations in the Baltic Sea were low but within normal for June.