Inter-population differences in diving behaviour of adult male southern elephant seals (Mirounga leonina)

• Main Authors: James, B.S. (Bridget), McIntyre, Trevor, Tosh, Cheryl A., Bornemann, Horst, Plotz, Joachim, Bester, Marthan Nieuwoudt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2012
• Subjects: Mirounga leonina; Dive behaviour; Adult males; Inter-population variation; Mixed-effects modelling; King George Island; Southern elephant seals (SES); Animal locomotion; Marion Island; Antarctic; Argentino; 25 de Mayo; isla 25 de Mayo; Alfred Wegener Institute; Antarc*; antartic*; Elephant Seals; Isla 25 de Mayo; Polar Biology; South African National Antarctic Programme; Southern Elephant Seals
• Online Access: http://hdl.handle.net/2263/20612; https://doi.org/10.1007/s00300.012-1214-3

Access to different environments may lead to inter-population behavioural changes within a species that allow populations to exploit their immediate environments. Elephant seals from Marion Island (MI) and King George Island (KGI) (Isla 25 de Mayo) forage in different oceanic environments and evidently employ different foraging strategies. This study elucidates some of the factors influencing the diving behaviour of male southern elephant seals from these populations tracked between 1999 and 2002. Mixed-effects models were used to determine the influence of bathymetry, population of origin, body length (as a proxy for size) and individual variation on the diving behaviour of adult male elephant seals from the two populations. Males from KGI and MI showed differences in all dive parameters. MI males dived deeper and longer (median: 652.0 m and 34.00 min) than KGI males (median: 359.1 m and 25.50 min). KGI males appeared to forage both benthically and pelagically while MI males in this study rarely reached depths close to the seafloor and appeared to forage pelagically. Model outputs indicate that males from the two populations showed substantial differences in their dive depths, even when foraging in areas of similar water depth. Whereas dive depths were not significantly influenced by the size of the animals, size played a significant role in dive durations, though this was also influenced by the population that elephant seals originated from. This study provides some support for interpopulation differences in dive behaviour of male southern elephant seals. The Alfred Wegener Institute for Polar and Marine Research (Germany), the Instituto Antartico Argentino within the Direccion National del Antarticio, and the Department of Science and Technology through the National Research Foundation (South Africa) and the South African National Antarctic Programme. http://www.springer.com/life+sci/ecology/journal/300 ab2012