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Diet of juvenile southern elephant seals reappraised by stable isotopes in whiskers

Citation

Newland, CB and Field, IC and Cherel, Y and Guinet, C and Bradshaw, CJA and McMahon, CR and Hindell, MA, Diet of juvenile southern elephant seals reappraised by stable isotopes in whiskers, Marine Ecology - Progress Series, 424, (March) pp. 247-258. ISSN 0171-8630 (2011) [Refereed Article]


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Copyright Statement

Copyright 2011 Inter-Research

DOI: doi:10.3354/meps08769

Abstract

Declines in marine predator populations have been attributed to anthropogenic activity and environmental change. Southern elephant seals Mirounga leonina are major consumers of biomass in the eastern region of the Southern Ocean and have been declining in numbers since the 1960s. Previous studies have identified evidence for habitat and diet partitioning over a range of spatial and temporal scales between juveniles and adults in the Macquarie Island population. We first analysed the stable isotopes (SI) of 6 entire vibrissae from a dead adult female southern elephant seal from Kerguelen Islands to determine moult and growth patterns. Secondly we analysed the SI from the vibrissae of 102 juvenile southern elephant seals to investigate diet. The results from the growth pattern analysis indicated that vibrissae do not grow or moult simultaneously. However, it is likely that at least part of the vibrissae will have been produced sometime during the most recent trip to sea and will give a broad indication of diet. The subsequent SI analysis confirmed that juveniles are consuming greater proportions of fish species, and identified myctophids as the primary component of juvenile diet. Myctophids are also consumed by king penguins Aptenodytes patagonicus which have greatly increased in numbers recently in the Macquarie Island area. This may have presented the juvenile southern elephant seals with increased competition and may influence survival.

Item Details

Item Type:Refereed Article
Keywords:resource partitioning, diet, vibrissae growth patterns
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:Newland, CB (Miss China Newland)
Author:Field, IC (Dr Iain Field)
Author:McMahon, CR (Dr Clive McMahon)
Author:Hindell, MA (Professor Mark Hindell)
ID Code:76855
Year Published:2011
Funding Support:Australian Research Council (DP0770910)
Web of Science® Times Cited:16
Deposited By:IMAS Research and Education Centre
Deposited On:2012-03-14
Last Modified:2017-11-01
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