Sea ice loss and planktivorous migratory Arctic seabirds: challenge or opportunity?

• Main Authors: 3rd World Seabird Conference 2021, Will, Alexis
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Ecology; FOS Biological sciences; Ecosystem; Ornithology; Arctic; Fairbanks; Pacific; National Institute of Polar Research; Pacific Arctic; Sea ice; Zooplankton; Alaska
• Online Access: https://dx.doi.org/10.48448/pvjn-2z36; https://underline.io/lecture/34863-sea-ice-loss-and-planktivorous-migratory-arctic-seabirds-challenge-or-opportunityquestion

Abstract: The shelf ecosystems of the Pacific Arctic support millions of migratory seabirds during the summer and fall. Sea ice loss may pose a nutritional challenge to planktivorous seabirds that rely on lipid-rich zooplankton during reproduction. Conversely, delayed sea ice formation in the fall may provide access to ice-free habitat and improve post-breeding foraging conditions. We investigated the response of planktivorous auklets (crested, Aethia cristatella and least, A. pusilla) to variable winter sea ice conditions in 2015-2019. First, we examined whether auklet's exposure to nutritional stress during the breeding season is associated with their diet composition and reproductive performance on St. Lawrence Is., Alaska. In the summers of 2018 and 2019, after historic low winter sea ice formation, both crested and least auklet adults experienced severe food shortages, indicated by high concentrations of corticosterone in blood and feather tissues. Ongoing analysis of diets and isotopic niches will elucidate whether these responses were widely spread and accompanied by drastic changes in prey. Second, we used geolocators to track individuals during the post-breeding period of 2016-2017 (relatively early sea ice formation) and 2017-2018 (late sea ice formation) and found that the timing of sea ice formation in the fall did not determine when auklets departed the Arctic; departure was consistent across years and likely linked to disappearance of prey. In all years, feather corticosterone levels were higher during late winter than during the summer, and molecular damage (as reflected in telomere loss) accrued by crested auklets was higher during winters with historic low sea ice formation. Higher levels of nutritional stress and accrued molecular damage on the breeding and wintering grounds suggest that sea ice loss is currently a threat rather than an opportunity to migratory planktivores in the Pacific Arctic. Authors: Alexis Will¹, Jean-Baptiste Thiebot², Akinori Takahashi², Elena Golubova³, Alexei Pinchuk¹, Alexander Kitaysky¹ ¹University of Alaska Fairbanks, ²National Institute of Polar Research, ³Russian Academy of Sciences