The results suggest that in the Archipelago Sea the interannual variability juring spring and summertime of small zooplankton species such as Acartia spp, and Eurytemora affinis is controlled by the climate variability during winter time. No correlations with large scale climate patterns have been detected for the abundance of larger zooplankton, which seems to be controlled by the grazing pressure of herring. A significantly high correlation between the anomalies of recruitment of spring herring and the copepodites of Pseudocalanus minutus elongatus indicates the top-down control for this zooplankton species. (C) 2001 International Council for the Exploration of the Sea.