1. Marine Research Centre, Finnish Environment Institute, Helsinki, Finland;
2. Latvian Institute of Aquatic Ecology, Agency of Daugavpils University, Riga, Latvia;
3. Department of Experimental Ecology of Marine Organisms, Faculty of Oceanography and Geography, Institute of Oceanography, University of Gdańsk, Gdynia, Poland;
4. Keep the Archipelago Tidy Association, Turku, Finland