The phytoplankton diversity was high whilst the total cell counts were low in the Kattegat and Skagerrak areas, except at Å17 where the diversity was low as well as the cell numbers. The coccolithophorid Emiliania huxleyi was numerous and Dactyliosolen fragilissimus was the most abundant diatom present. The integrated chlorophyll concentration (0-20 m) was somewhat high at W Landskrona because of a maximum just below 20 m caused by Octactis speculum and small unidentified cells. The amounts of filamentous cyanobacteria in the Baltic was higher compared to May and was the highest at BY38 west of Gotland and at the most northern station BY29. Chlorophyll fluorescence peaks at BY5, BY20 and Hanö Bay were mainly caused by the potentially harmful group Prymnesiales*. The integrated chlorophyll concentrations (0-20 m) were above normal at BY32 and BCSIII-10, and within normal for the month at all other stations.