Key foraging areas for Adélie Penguins at Esperanza/Hope Bay, Antarctic Peninsula

This study presents novel insights into the foraging behavior of Adélie penguins (Pygoscelis adeliae) breeding at Esperanza/Hope Bay, one of the largest colonies on the Antarctic Peninsula. Combining GPS, depth, and accelerometer data collected during the 2022/23 and 2023/24 breeding seasons, we identified foraging zones based on the occurrence of prey capture attempts. Results show substantial interannual variation in trip duration and distance, likely reflecting variability in krill availability. Only ~21% of recorded dives were classified as foraging dives, with mean depths exceeding 60 m. Most activity occurred within 30 km of the colony, across two different proposed krill management units. The integration of accelerometer-based behavioral data allows for finer-scale inference of krill availability, revealing that limited prey accessibility— but not necessarily overall biomass decline— might constitute a significant ecological stress. These findings highlight the importance of including predator behavior in ecosystem monitoring and spatial management under both the Krill Fishery Management Approach (KFMA) and the proposed Domain 1 Marine Protected Area (D1MPA). Expanding CEMP indicators to include (whenever possible) foraging depth, capture attempts, and colony-specific risk assessments is crucial to understanding the cumulative impacts of climate variability and fisheries on predator populations.