From 22 May to 1 June 2015 a research cruise took place on board R/V Oceania. All the research was supervised by Mirosław Darecki and carried out by the staff and PhD students of the Institute of Oceanology, Polish Academy of Sciences. During the cruise a pre-planned series of measurements relating to marine bio-optics was carried out: temperature, salinity, concentrations of sea water constituents (e.g. chlorophyll, suspended particulate matter, CDOM), light fields, optical properties of sea water. The parameters measured will enrich the SatBałtyk project’s database.1