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Crabeater seal diving behaviour in eastern Antarctica

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Wall, SM and Bradshaw, CJA and Southwell, CJ and Gales, NJ and Hindell, MA (2007) Crabeater seal diving behaviour in eastern Antarctica. Marine Ecology - Progress Series, 337. pp. 265-277. ISSN 0171-8630

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Abstract

Southern Ocean waters are highly productive and contain important food resources for
many indigenous predators, including humans. Management of these resources has fallen under
the regulation of the Convention for the Conservation of Antarctic Marine Living Resources
(CCAMLR), which has identified a suite of predators as indicator species for monitoring ecosystem
fluctuations, including crabeater seals. For crabeater seals to fulfil this role, however, they must
respond predictably to fluctuations in krill distribution and abundance. Here, we investigated the
validity of using the diving behaviour of this species as an indicator of krill distribution and abundance.
We used behavioural data collected from 23 crabeater seals fitted with satellite-linked timedepth
recorders off eastern Antarctica to quantify habitat use as a function of the amount of time they
spent within geographic regions with varying environmental characteristics. This was then linked
with diving behaviour in those regions. By integrating geographic location and diving parameters,
we demonstrated that habitat use and foraging behaviour within eastern Antarctic waters fluctuated
in response to seasonal and spatial environmental variability. Our attempts to use oceanographic
variables to develop models of crabeater seal habitat use and behaviour demonstrated real limitations
in inferring behaviour from a simple set of environmental factors, but we identified ocean depth and
the proximity to the ice edge as factors influencing seasonal habitat use and diving behaviour. Whilst
our understanding of the influences driving crabeater seal distribution has improved as a result of
telemetry studies, it would appear premature to infer cross-species patterns in distribution and abundance
with krill given the low predictive power of models derived in the present study. Furthermore,
the dynamic and regionally variable use of pelagic habitat by this widely abundant Antarctic predator
has important implications for the estimation of crabeater seal biomass.

Item Type: Article
Keywords: Southern Ocean · Crabeater seal · Krill · Diving behaviour · Habitat use · Satellite telemetry · Generalised linear models
Journal or Publication Title: Marine Ecology - Progress Series
Publisher: Inter-Research
Page Range: pp. 265-277
ISSN: 0171-8630
Identification Number - DOI: 10.3354/meps337265
Additional Information:

Copyright © 2007 InterResearch

Date Deposited: 07 Apr 2008 14:19
Last Modified: 18 Nov 2014 03:34
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