Projects per year
Abstract
Understanding how marine predators encounter prey across patchy landscapes remains challenging due to difficulties in measuring the three-dimensional structure of pelagic prey fields at scales relevant to animal movement. We measured at-sea behaviour of a central-place forager, the little penguin (Eudyptula minor), over 5 years (2015-2019) using GPS and dive loggers. We made contemporaneous measurements of the prey field within the penguins' foraging range via boat-based acoustic surveys. We developed a prey encounter index by comparing estimates of acoustic prey density encountered along actual penguin tracks to those encountered along simulated penguin tracks with the same characteristics as real tracks but that moved randomly through the prey field. In most years, penguin tracks encountered prey better than simulated random movements greater than 99% of the time, and penguin dive depths matched peaks in the vertical distribution of prey. However, when prey was unusually sparse and/or deep, penguins had worse than random prey encounter indices, exhibited dives that mismatched depth of maximum prey density, and females had abnormally low body mass (5.3% lower than average). Reductions in prey encounters owing to decreases in the density or accessibility of prey may ultimately lead to reduced fitness and population declines in central-place foraging marine predators.
Original language | English |
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Article number | 220028 |
Pages (from-to) | 1-13 |
Number of pages | 13 |
Journal | Royal Society Open Science |
Volume | 9 |
Issue number | 9 |
Early online date | 14 Sept 2022 |
DOIs | |
Publication status | Published - Sept 2022 |
Bibliographical note
Copyright the Author(s) 2022. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.Keywords
- prey field
- active acoustics
- predator-prey interactions
- marine predator
- foraging ecology
- Eudyptula minor
Fingerprint
Dive into the research topics of 'Variability in prey field structure drives inter-annual differences in prey encounter by a marine predator, the little penguin'. Together they form a unique fingerprint.Projects
- 2 Finished
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Resolving the warming East Australian Current's impact on a marine food web
Jonsen, I., Harcourt, R., Suthers, I., Roughan, M., Doblin, M., Slip, D. & Cox, M.
16/12/16 → 30/06/21
Project: Research
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Marine predators, marine parks and marine hotspots: is zoning an effective conservation tool in changing environment?
Harcourt, R., Field, I. & Slip, D.
1/05/12 → 31/12/16
Project: Research