The reproductive biology of Euchaeta antarctica Giesbrecht (Copepoda: Calanoida) at South Georgia
The reproductive biology of the predatory calanoid copepod Euchaeta antarctica Giesbrecht was investigated in two interconnected fjord systems at South Georgia. Counts of the number of spermatophores attached to adult females and the number of egg sacs encountered, indicated probable peaks of reproduction in summer and winter. Patterns of spermatophore placement were examined and compared with data for E. norvegica (Boeck) from boreal waters. Elemental analysis indicated a high proportion of carbon and a low proportion of nitrogen in adult females and egg sacs from both sites. High winter carbon levels in adults seem related to their predatory feeding habits allowing high food intake throughout the year whereas in egg sacs it probably reflects extended development times and/or non-feeding naupliar stages. Mean adult female and egg clutch dry weights were higher in Cumberland East Bay during winter than in Moraine Fjord during summer. These differences are discussed in the context of relationships between fjord morphology and production levels.