Fast ice variability in East Antarctica: observed repercussions for emperor penguins

Abstract

As a species highly reliant on stable fast ice as a breeding platform, emperor penguins are increasingly challenged in their breeding attempts due to changes in fast ice conditions. We collated habitat information of 27 emperor penguin colonies in East Antarctica (43°-167°E) from 2018 to 2023 using European Space Agency Sentinel-2 satellite images. Our objective was to examine the variability in habitat and ice conditions and associated repercussions for colony location and breeding success. Variables, such as location, colony movement and inter-annual variability in these parameters, were used to assess the adaptability of emperor penguins when local conditions change markedly. The major challenge emperor penguins currently face throughout Antarctica is untimely loss of breeding habitat resulting in increased or complete breeding failure, as observed in 8 colonies at least once during the study. One small colony at the West Ice Shelf lost its breeding area and has not been seen since 2021. The inter-annual movement of some colonies demonstrates the species’ adaptability and the need for ongoing monitoring of the global emperor penguin population using satellite imagery. We highlight caveats, such as availability of suitable satellite images and movement of colonies, that need to be accounted for to ensure sound interpretation of the monitoring findings. Ongoing Antarctic-wide monitoring is essential to quantify the impact of changing fast ice conditions on emperor penguins and also the cumulative impacts of other threats such as disease. The information presented is to provide background and empirical data for researchers, policy makers and managers.