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Marine Ecology Progress Series

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MEPS 526:227-239 (2015)  -  DOI:

Influence of intrinsic variation on foraging behaviour of adult female Australian fur seals

A. J. Hoskins1,5,*, D. P. Costa2, K. E. Wheatley3, J. R. Gibbens4, J. P. Y. Arnould1

1School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia
2Center for Ocean Health, University of California, 100 Shaffer Road, Santa Cruz, California 95060, USA
3School of Zoology, University of Tasmania, Private Bag 5, Hobart, Tasmania 7001, Australia
4Department of Zoology, University of Melbourne, Parkville, Victoria 3010, Australia
5Present address: CSIRO Land and Water Flagship, Canberra, ACT 2601, Australia
*Corresponding author:

ABSTRACT: Phenotypic variation and individual experience can create behavioural and/or dietary variation within a population. This may reduce intra-specific competition, creating a buffer to environmental change. This study examined how intrinsic variation affects foraging behaviour of Australian fur seals. Foraging movements of 29 female Australian fur seals were recorded using FastLoc GPS and dive behaviour recorders. For each individual, body mass, flipper length and axis length were recorded, a tooth was sampled to determine age and milk was collected for diet analysis. Clustering of fatty acid dietary analysis revealed 5 distinct groups in the population. Behaviour was described using 19 indices, which were then reduced to 7 principal components (>80% of the behavioural variation). Bayesian mixed effect models were developed to describe the relationship between these components and intrinsic variation. No association was found between diet and age or body shape; however, age had a negative relationship with component 1 (27% of variation). Older females spent less time at-sea and foraged nearer to the colony. Age had an effect on component 5 (7% of variation), which represented haul-outs and dive depth; older females made fewer visits to haul-out sites and dived deeper to the benthos. This suggests that as animals age they are able to utilise prior knowledge to exploit nearby foraging sites that younger animals are either unaware of, or have yet to gain the experience required to efficiently utilise. Mass had a negative effect on components representing the directedness of a foraging trip, suggesting heavier individuals were more likely to travel directly to a foraging site. 

KEY WORDS: Intrinsic variation · Foraging behaviour · Age effects · Phenotypic variation

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Cite this article as: Hoskins AJ, Costa DP, Wheatley KE, Gibbens JR, Arnould JPY (2015) Influence of intrinsic variation on foraging behaviour of adult female Australian fur seals. Mar Ecol Prog Ser 526:227-239.

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