Abstract
The diets and trophic interactions among Weddell, crabeater, Ross, and leopard seals in the eastern Ross Sea, Antarctica, were investigated by the use of stable isotope techniques during the 1999–2000 summer seasons. The δ13C and δ15N values in seal serum clearly distinguished the three Antarctic pack-ice seal species at different trophic positions (Weddell>Ross>crabeater). These patterns appeared to reflect a close linkage to their known foraging ecology and diving behaviors, and agreed well with their presumed dietary diversity. The more enriched δ13C and δ15N values in male Weddell seals than those in females suggested differences in foraging preferences between them. Significant differences in δ15N were also found among different age groups of Weddell seals. A strong correlation between the C:N ratios and serum cholesterol was probably due to extremely high cholesterol levels in phocids. Comparisons of isotope data with harbor seals revealed distinct differences between Antarctic phocids and the northern seal species.
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Acknowledgements
This research was supported by grant OPP 9815176 from the National Science Foundation to M.A. Castellini. Blood samples from Antarctic seal species were collected under MMPA permit no. 495-1524 with University of Alaska Fairbanks Institutional Animal Care and Use Committee (IACUC) approval. Archived harbor-seal blood samples were collected under EVOS project no. 97001. Blood samples from Atlantic harbor seals were collected under permits issued to G.T. Waring (NMFS-NEFSC) and J. Gilbert (The University of Maine, Orono). Cholesterol analysis was conducted by Drs. P.K. Yochem and B.S. Stewart.
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Zhao, L., Castellini, M.A., Mau, T.L. et al. Trophic interactions of Antarctic seals as determined by stable isotope signatures. Polar Biol 27, 368–373 (2004). https://doi.org/10.1007/s00300-004-0598-0
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DOI: https://doi.org/10.1007/s00300-004-0598-0