The expedition was performed within SMHIs regular marine monitoring programme and covered the Skagerrak, the Kattegat, the Sound and the Baltic Proper. Because of the flooding of the rivers Wisla and Oder a part of the expedition was destinated to study the effect of the overflow in the areas of the Pomeranian Bay and the Bay of Gdansk. Temperature, salinity and fluorescence (biological activity) at 4m depth were registered continuously throughout the expedition. The surface water temperatures were unusually high in the whole investigated area. No visible algae blooms were present. The bottom water oxygen situation in the Kattegat was satisfying. In the pomerian Bay a 2.5-5 m thick surface layer with elevated phosphate and silicate concentrations was discovered. The secchi depth was 1.5-3.5 m. In the Bay of Gdansk the traces of contaminated water were less evident. The central parts of the Bay contained, however, elevated silicate levels in the surface. The phosphate concentrations were just slightly elevated. The secchi depth was 2-3 m.