Deep divers in even deeper seas : habitat use of male southern elephant seals from Marion Island
We describe the habitat use of 22 male southern elephant seals (Mirounga leonina) satellite tagged at Marion Island between 2004 and 2008. While a few areas of increased utilization appeared to be associated with areas of shallower bathymetry (such as sea-floor ridges and fracture zones), seals in o...
| Published in: | Antarctic Science |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press
2012
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| Subjects: | |
| Online Access: | http://hdl.handle.net/2263/21913 https://doi.org/10.1017/S0954102012000570 |
| Summary: | We describe the habitat use of 22 male southern elephant seals (Mirounga leonina) satellite tagged at Marion Island between 2004 and 2008. While a few areas of increased utilization appeared to be associated with areas of shallower bathymetry (such as sea-floor ridges and fracture zones), seals in our study did not target other areas of shallow bathymetry within close proximity to Marion Island. Rather, most elephant seals foraged pelagically over very deep water where much variation was evident in diel vertical migration strategies. These strategies resulted in generally deeper and longer dives than what has been reported for male elephant seals from other colonies. No significant differences were recorded for dive durations or dive depths between adults and sub-adults. However, younger animals displayed a positive relationship between dive durations and age, as well as between dive depths and age, while these relationships became negative for older animals. Mixed model outputs suggested that seals increased their aerobic fitness as migrations progressed, enabling them to undertake longer dives. We conclude that Marion Island male elephant seals exhibit much variability in dive strategy and are seemingly capable of exploiting a range of different prey types occurring in various depth layers. Supplemental material detailing links to dive and track data will be found at http://dx.doi.org/doi:10.1017/ S0954102012000570. The Department of Science and Technology through the National Research Foundation (South Africa), the South African National Antarctic Programme and the Alfred Wegener Institute for Polar and Marine Research (Germany) . http://journals.cambridge.org/action/displayJournal?jid=ans am2013 ab2013 |
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