Effects of Sea-Ice Persistence on the Diet of Adélie Penguin ( Pygoscelis adeliae ) Chicks and the Trophic Differences between Chicks and Adults in the Ross Sea, Antarctica

• Published in: Biology
• Main Authors: Deborah Maccapan, Giulio Careddu, Edoardo Calizza, Simona Sporta Caputi, Loreto Rossi, Maria Letizia Costantini
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: Pygoscelis adeliae; trophic ecology; isotopic niche; sea-ice break-up; feeding strategies; stable isotopes; Biology (General); QH301-705.5; Antarctic; Guano; Ross Sea; The Antarctic; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.3390/biology12050708; https://doaj.org/article/86e726d9a8fc4c6399dc5bb9ced2ddf9

In Antarctica, prey availability for the mesopredator Adélie penguin, Pygoscelis adeliae , depends on sea-ice dynamics. By affecting cycles of sea-ice formation and melt, climate change could thus affect penguin diet and recruitment. In the light of climate change, this raises concerns about the fate of this dominant endemic species, which plays a key role in the Antarctic food web. However, few quantitative studies measuring the effects of sea-ice persistence on the diet of penguin chicks have yet been conducted. The purpose of this study was to fill this gap by comparing penguin diets across four penguin colonies in the Ross Sea and evaluating latitudinal and interannual variation linked to different sea-ice persistence. Diet was evaluated by analysing the δ 13 C and δ 15 N values of penguin guano, and sea-ice persistence by means of satellite images. Isotopic values indicate that penguins consumed more krill in colonies with longer sea-ice persistence. In these colonies, the δ 13 C values of chicks were lower and closer to the pelagic chain than those of adults, suggesting that the latter apparently catch prey inshore for self-feeding and offshore for their chicks. The results indicate that sea-ice persistence is among the principal factors that influence the spatiotemporal variability of the penguins’ diet.