Life cycle and growth of the Antarctic gammarid amphipodParamoera walkeri(Stebbing, 1906)

Abstract

Abstract The life cycle and growth of the Antarctic amphipod Paramoera walkeri are described. Four year-classes were found in the Cape Bird population. A period of rapid growth during the summer was followed by reproduction and little growth during the winter. Growth was relatively fast in the first and second summer, but by the third summer slower, and there was negligible growth during the fourth summer. Sexual dimorphism with respect to length developed soon after the young were released from the brood pouch of the female. Both sexes matured 14 or 1.5 months after release from the brood pouch. Usually reproduction occurred during the second winter, but some females did not reproduce until their third winter. Having bred once females die. The adaptations of this life cycle to the Antarctic marine environment are discussed.