The spring bloom was generally over at the Swedish west coast and mostly smaller cells and a few species of dinoflagellates were left. At the southern stations some diatoms were present. The chlorophyll concentrations were low at the Skagerrak stations but below normal at Kattegat stations. In the south-western part of the Baltic a clear spring bloom was recorded with a dominance of Skeletonema marinoi. At the other stations the cell numbers were more moderate with no tendency of a spring bloom. The filamentous cyanobacteria Aphanizomenon flosaquae was found at most stations in lower numbers. The integrated chlorophyll concentrations were well above normal in the south-western part. At the other stations they were with few exceptions low but within normal for the month.