Life-cycle strategies of Calanoides acutus, Calanus propinquus, and Metridia gerlachei (Copepoda: Calanoida) in the eastern Weddell Sea, Antarctica

Abstract

The dominant Antarctic copepods Colanoides acutus, Calanus propinquus, and Metridia gerlachei were studied in the eastern Weddell Sea during mid-winter (July/August 1986), late winter/early spring (October/November 1986), summer (January/February 1985), and autumn (April/May 1992). The investigations focused on abundance, distribution, population dynamics, reproductive activity, and lipid contents. All three species had highest abundances in autumn. C. acutus exhibited the most pronounced seasonal vertical migrations, whereas M. gerlachei was more dispersed throughout the water column. In contrast, the majority of C. propinquus remained in the upper 200 m for most of the year; only in late winter/spring was it located mainly between 200 and 500 m. For a better understanding of the life history of these species their stage compositions, gonad maturities, and lipid contents were determined. These data revealed remarkable interspecific variations and suggest different life-cycle strategies for the three species.