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Five decades on: use of historical weaning size data reveals that a decrease in maternal foraging success underpins the long-term decline in population of southern elephant seals (Mirounga leonina)

Citation

Clausius, E and McMahon, CR and Hindell, MA, Five decades on: use of historical weaning size data reveals that a decrease in maternal foraging success underpins the long-term decline in population of southern elephant seals (Mirounga leonina), PLoS One, 12, (3) Article e0173427. ISSN 1932-6203 (2017) [Refereed Article]


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Copyright Statement

Copyright: 2017 Clausius et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1371/journal.pone.0173427

Abstract

The population of Southern elephant seals (Mirounga leonina) at Macquarie Island has declined since the 1960s, and is thought to be due to changing oceanic conditions leading to reductions in the foraging success of Macquarie Island breeding females. To test this hypothesis, we used a 55-year-old data set on weaning size of southern elephant seals to quantify a decrease in weaning size from a period of population stability in 1950s to its present state of on-going decline. Being capital breeders, the size of elephant seal pups at weaning is a direct consequence of maternal foraging success in the preceding year. During the 1940-1950s, the mean of female pups at weaning was similar between the Heard and Macquarie Island populations, while the snout-tail-length length of male weaners from Heard Island were longer than their conspecifics at Macquarie Island. Additionally, the snout-tail-length of pups at weaning decreased by 3cm between the 1950s and 1990s in the Macquarie Island population, concurrent with the observed population decline. Given the importance of weaning size in determining first-year survival and recruitment rates, the decline in the size at weaning suggests that the decline in the Macquarie Island population has, to some extent, been driven by reduced maternal foraging success, consequent declines in the size of pups at weaning, leading to reduced first-year survival rates and recruitment of breeding females into the population 3 to 4 years later.

Item Details

Item Type:Refereed Article
Keywords:elephant seals, climate change, weaning size
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and Estuarine Ecology (incl. Marine Ichthyology)
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Antarctic and Sub-Antarctic Environments
Author:Clausius, E (Miss Ella Clausius)
Author:Hindell, MA (Professor Mark Hindell)
ID Code:117139
Year Published:2017
Web of Science® Times Cited:3
Deposited By:Ecology and Biodiversity
Deposited On:2017-06-01
Last Modified:2018-05-28
Downloads:31 View Download Statistics

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