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Spatially explicit estimates of prey consumption reveal a new krill predator in the Southern Ocean
Citation
Walters, A and Lea, M-A and van den Hoff, J and Field, IC and Virtue, P and Sokolov, S and Pinkerton, MH and Hindell, MA, Spatially explicit estimates of prey consumption reveal a new krill predator in the Southern Ocean, Plos One, 9, (1) Article e86452. ISSN 1932-6203 (2014) [Refereed Article]
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Copyright Statement
Copyright 2014 Walters et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
DOI: doi:10.1371/journal.pone.0086452
Abstract
Development in foraging behaviour and dietary intake of many vertebrates are age-structured. Differences in feeding
ecology may correlate with ontogenetic shifts in dispersal patterns, and therefore affect foraging habitat and resource
utilization. Such life-history traits have important implications in interpreting tropho-dynamic linkages. Stable isotope ratios
in the whiskers of sub-yearling southern elephant seals (Mirounga leonina; n = 12) were used, in conjunction with satellite
telemetry and environmental data, to examine their foraging habitat and diet during their first foraging migration. The
trophic position of seals from Macquarie Island (54°30'S, 158°57'E) was estimated using stable carbon (δ13C) and nitrogen
(δ15N) ratios along the length of the whisker, which provided a temporal record of prey intake. Satellite-relayed data loggers
provided details on seal movement patterns, which were related to isotopic concentrations along the whisker. Animals fed
in waters south of the Polar Front (>60°S) or within Commission for the Conservation of Antarctic Marine Living Resources
(CCAMLR) Statistical Subareas 88.1 and 88.2, as indicated by both their depleted δ13C (< -220%) values, and tracking data.
They predominantly exploited varying proportions of mesopelagic fish and squid, and crustaceans, such as euphausiids,
which have not been reported as a prey item for this species. Comparison of isotopic data between sub-yearlings, and 1, 2
and 3 yr olds indicated that sub-yearlings, limited by their size, dive capabilities and prey capture skills to feeding higher in
the water column, fed at a lower trophic level than older seals. This is consistent with the consumption of euphausiids and
most probably, Antarctic krill (Euphausia superba), which constitute an abundant, easily accessible source of prey in water
masses used by this age class of seals. Isotopic assessment and concurrent tracking of seals are successfully used here to
identify ontogenetic shifts in broad-scale foraging habitat use and diet preferences in a highly migratory predator.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | krill, predator, Southern Ocean, isotope, ecosystem |
| Research Division: | Biological Sciences |
| Research Group: | Ecology |
| Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
| Objective Division: | Environmental Management |
| Objective Group: | Coastal and estuarine systems and management |
| Objective Field: | Assessment and management of coastal and estuarine ecosystems |
| UTAS Author: | Walters, A (Dr Andrea Walters) |
| UTAS Author: | Lea, M-A (Professor Mary-Anne Lea) |
| UTAS Author: | Virtue, P (Associate Professor Patti Virtue) |
| UTAS Author: | Hindell, MA (Professor Mark Hindell) |
| ID Code: | 89062 |
| Year Published: | 2014 |
| Web of Science® Times Cited: | 23 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2014-02-24 |
| Last Modified: | 2017-11-01 |
| Downloads: | 518 View Download Statistics |
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