The vertical distribution and developmental stage composition of Rhincalanus gigas, Calanoides acutus, Calanus propinquus and krill, Euphausia superba larvae, were a good index for a general assessment of the seasonal condition of the plankton communities. There were five zones differing in seasonal situation: (1) the Polar Front and the southern ACC, (2) the Weddell Front, (3) the Weddell Gyre interior, (4), the Maud Rise area, and (5) the Coastal Current zone. In the eastern part of the Weddell Front (compared to the western part) seasonal development of both phytoplankton and herbivorous zooplankton is delayed in spring but prolonged in late autumn.