To further our understanding of Antarctic predator growth and seasonal physiology, field growth rates were measured for two soft-bodied Antarctic anemone benthic predators, Isotealia antarctica and Urticinopsis antarctica, using in situ sampling of anemones on uniquely marked tiles from Rothera Research Station from 2020-2023. Ex situ measurements of oxygen consumption and seven-day faecal output were obtained from recently collected specimens in aquaria and compared between summer and winter. Winter physiological data for Antarctic species are rare, and we tested the hypothesis that generalist feeders or predators continue to feed during the winter. There is a dearth of basic life history and physiological data from Southern Ocean species, particularly from benthic sessile predators. This is an important data gap because species inhabiting the Southern Ocean live in a more temperature stable but seasonally varying environment than temperate and tropical counterparts.

This work was supported by core funding from the NERC, UKRI, UK to the British Antarctic Survey.