Title A lifetime at depth; vertical distribution of southern elephant seals in the water column
Author McIntyre, T.; de Bruyn, P.J.N.; Ansorge, I.J.; Bester, M.N.; Bornemann, H.; Plötz, J.; Tosh, C.A.
Author Affil McIntyre, T., University of Pretoria, Department of Zoology and Entomology, Pretoria, South Africa. Other: University of Cape Town, South Africa; Alfred Wegener Institute for Polar and Marine Research, Germany
Source Polar Biology, 33(8), p.1037-1048. Publisher: Springer-Verlag, Berlin, Germany. ISSN: 0722-4060
Publication Date Aug. 2010
Notes In English. 48 refs. GeoRef Acc. No: 309118
Index Terms Indian Ocean Islands--Marion Island; Southern Ocean; biogeography; Carnivora; Chordata; ecology; Eutheria; habitat; Indian Ocean Islands; Mammalia; Marion Island; migration; Pinnipedia; Prince Edward Island Group; subantarctic regions; Tetrapoda; Theria; Vertebrata
Abstract Although numerous studies have addressed the migration and dive behaviour of southern elephant seals (Mirounga leonina), questions remain about their habitat use in the marine environment. We report on the vertical use of the water column in the species and the potential lifetime implications for southern elephant seals from Marion Island. Long-term mark-resight data were used to complement vertical habitat use for 35 known individuals tagged with satellite-relay data loggers, resulting in cumulative depth use extrapolated for each individual over its estimated lifespan. Seals spent on average 77.59% of their lives diving at sea, 7.06% at the sea surface, and 15.35% hauled out on land. Some segregation was observed in maximum dive depths and depth use between male and female animals--males evidently being physiologically more capable of exploiting increased depths. Females and males spent 86.98 and 80.89% of their lives at sea, respectively. While at sea, all animals spent more time between 300 and 400 m depth, than any other depth category. Males and females spent comparable percentages of their lifetimes below 100 m depth (males: 65.54%; females: 68.92%), though males spent 8.98% of their lives at depths in excess of 700 m, compared to females' 1.84% at such depths. Adult males often performed benthic dives in excess of 2,000 m, including the deepest known recorded dive of any air- breathing vertebrate (›2,133 m). Our results provide a close approximation of vertical habitat use by southern elephant seals, extrapolated over their lifespans, and we discuss some physiological and developmental implications of their variable depth use.
URL http://hdl.handle.net/10.1007/s00300-010-0782-3
Publication Type journal article
Record ID 91195