Poster

IACS

JPCM08 - Impacts of climate change on the ocean

Prey capture dynamics of Weddell seals in the Amundsen Sea, Antarctica: Insights from seal-borne CTD data

Assessing the foraging behavior of Weddell seals (Leptonychotes weddellii) is crucial for understanding their adaptations as a top predator in the changing Antarctic ecosystem under a warming world. In the Amundsen Sea, especially near Thwaites and Pine Island Glaciers, a large amount of glacier melting produces numerous icebergs, while ice shelf regions become increasingly exposed and develop extensive cracks as confirmed by satellite imagery. However, despite their ecological importance, research on Weddell seals in the Amundsen Sea remains scarce due to logistical challenges. In this study, we investigated the foraging behavior of 23 seals in 2022 and 2024 by equipping them with CTD instruments near Thwaites Glacier in the Amundsen Sea. These instruments recorded dive profiles, head acceleration (indicating prey capture attempts), temperature, and salinity, revealing substantial individual variability in maximum dive depth and displacement from deployment sites. We found that seals dived around and beneath ice shelves and icebergs, accounting for 5,316 (11.4 �� 6.4% of total dives) and 960 dives (14.2 �� 22.0% of the total dives), respectively. Contrary to previous studies, seals appeared to exploit regions near ice shelves and icebergs, possibly related to nutrient supply and enhanced primary production, which may lead to increased prey availability. Collectively, these findings provide valuable insights into seals�� foraging strategies in response to changes in the surrounding ocean environment. * This work was supported by Korea Institute of Marine Science & Technology Promotion(KIMST) grant funded by the Ministry of Oceans and Fisheries (KIMST RS-2023-00256677; PM25020)