The dominant Antarctic copepod species Calanoides acutus, Calanus propinquus, Rhincalanus gigas and Metridia gerlachei were investigated with respect to their abundance, vertical distribution, developmental stage composition, dry weight and lipid content. The specimens were sampled during three expeditions to the eastern Weddell Sea in summer (January/February 1985), late winter/early spring (October/November 1986) and autumn (April/May 1992) between 0 and 1000 m depth to follow the seasonal development of the populations. Three species were most abundant in April, only C.propinquus reached highest concentrations in February. A seasonal migration pattern was evident in all four species, but was most pronounced in C.acutus. In October/November, they inhabited deeper water layers, their ascent started by mid-November and in mid-February the species concentrated in the upper 50 m, except for M.gerlachei (50-100 m). Their descent was observed in April/May. The stage composition changed dramatically with season, the older developmental stages (CIII-CVI) dominated the populations in late winter/early spring, whereas younger stages (CI and CII) prevailed during summer (C.acutus, C.propinquus) or autumn (R.gigas, M.gerlachei). Only C.acutus ceased feeding in autumn and diapaused at depth. Strong differences between seasons were also detected in dry weight and lipid levels, with minima in late winter/early spring and maxima in summer (C.acutus, R.gigas) or autumn (C.propinquus, M.gerlachei). Lipid reserves seem to be most important for the older stages of C.acutus and C.propinquus. Based on these seasonal data, different life cycle strategies are suggested for the four species.
