Adélie Penguins Revealed to Feast on Shelled Pteropods in East Antarctica
Researchers have documented a previously unconfirmed trophic link in East Antarctica, providing the first video evidence of Adélie penguins consuming shelled pteropods (Thecosomata). This groundbreaking study aimed to deepen understanding of Adélie penguin foraging behavior. The results of this significant research were published in Marine Biology on March 16, 2026.
Unveiling a New Diet
The study involved equipping eight chick-rearing Adélie penguins with cameras and GPS sensors. Over 86 hours of video footage were meticulously analyzed, revealing surprising dietary habits.
Seven of the eight penguins were observed consuming shelled pteropods, primarily species such as Clio pyramidata and Limacina rangii. For two individuals, these shelled pteropods constituted over 60% of their observed prey, indicating a substantial role in their diet.
Consumption rates appear to be influenced by a combination of factors, including preference, the individual energetic state of the penguin, and critically, prey availability. Penguins demonstrated opportunistic feeding behavior, consuming more pteropods when dense concentrations were encountered.
Despite this newfound evidence, the data indicates that krill remains the dominant food type for Adélie penguins, followed by pteropods.
Hina T. Watanabe, a corresponding author, stated that pteropods serve as an opportunistic yet substantial prey, indicating a potentially significant trophic pathway.
Broader Implications for the Southern Ocean
This discovery holds wider implications for the Southern Ocean food web. Thecosomata, commonly known as sea butterflies, are key components of this intricate ecosystem and are notably vulnerable to ocean acidification, a growing concern under climate change.
Researchers are particularly interested in understanding the potential cascading effects on the broader Southern Ocean food web and how these dynamics might shift under increasing climate-driven pressures.
Limitations and Future Research
The study acknowledges certain limitations, including observations derived from a single colony during one season. Additionally, the analysis was restricted to video evidence collected during the first half of foraging trips.
Future research endeavors will aim to determine if this newly identified trophic link is consistent across different years and colonies, or if it is a condition-specific foraging strategy adopted under particular environmental circumstances.
Research Team and Support
The research saw contributions from an international team including Hina T. Watanabe, Akinori Takahashi, Akiko Kato, Léo Marcouillier, Frédéric Angelier, Yan Ropert-Coudert, and Thierry Raclot. These contributors represent various institutions, including the National Institute of Polar Research, La Rochelle Université, Université de Strasbourg, and the Graduate Institute for Advanced Studies.
Funding for this important work was provided by WWF-UK, the National Institute of Polar Research, JSPS KAKENHI, and the Institut Polaire Francaise Paul-Emile-Victor.