Revisiting the East Antarctic Marine Protected Area proposal: Insights from long-term wintering distribution of Adélie penguins

Understanding the spatial and temporal at-sea distribution of marine predators throughout their annual cycle is crucial for identifying priority areas for conservation in the Southern Ocean. The Commission for the Conservation of Antarctic Marine Living Resources has proposed a representative network of Marine Protected Areas (MPA), including the candidate East Antarctic MPA (EAMPA). However, the delimitation of boundaries of the proposed EAMPA is largely based on species’ breeding distributions, overlooking potential seasonal and annual shifts driven by sea ice variability. We studied the non-breeding distribution and space use of a key Antarctic eco-indicator species, the Adélie penguin, by tracking 61 individuals from Terre Adélie over five years using geolocators. Moulting occurred in areas of low sea ice concentration (SIC), whereas during winter, penguins migrated on average 1,550 km westward from the colony to areas along the sea ice edge with high SIC (75%). The inter-annual overlap of wintering grounds revealed high spatio-temporal consistency, indicating productive regions. Despite variability across years, tracked individuals moulted predominantly outside the proposed EAMPA, and only 16.3% of winter locations fell within its boundaries, mainly in the D'Urville Sea-Mertz and Drygalski zones. These findings provide new insights into the non-breeding ecology of Adélie penguins, and highlight a relevant gap in spatial coverage of critical moulting and wintering areas of this highly mobile species in the current EAMPA proposal.