Depending on seasons, 73% to 99% of the copepod number in the subantarctic ecosystem of the Kerguelen Archipelago consists of Drepanopus peainatus. All developmental stages from copepodid 1 to 5 and adults are found all year through. The annual population cycle fluctuates between a maximum abundance during the summer (150 x 103 individuals per m 2) and a minimum during the winter (80 individuals per m2). A succession of 4 generations a year is discussed, based on the percentages of the various developmental stages in the population and changes in size of specimens in the various stages.