1. a Tvärminne Zoological Station , University of Helsinki , J.A. Palménin tie 260, FI 10900 Hanko , Finland
2. b Finnish Environment Institute, Marine Centre , P.O. Box 140, FI-00251 Helsinki , Finland
3. c Department of Biological and Environmental Sciences , University of Helsinki , P.O. Box 65, University of Helsinki, Finland
4. d Department of Systems Ecology , Stockholm University , SE-106 91 Stockholm , Sweden
5. e Haltiantie 8C 20, FI-01600 Vantaa , Finland
6. f Swedish Meteorological and Hydrological Institute , SE 42671 Nya Varvet , Västra Frölunda , Sweden
7. g Sea Fisheries Institute , ul.Kollataja 1 , 81-332 Gdynia , Poland
8. h Leibniz Institute for Baltic Sea Research , D-18119 Seestr. 15 , Warnemünde , Germany