[MARMAM] New publication on the foraging ecology of the Blainville´s beaked whales

Patty Arranz patty.arranz at gmail.com
Tue Dec 27 05:32:30 PST 2011


Dear colleagues,


We are pleased to announce that a new publication on the foraging
ecology of the Blainville´s beaked whales  is now available with open
access in

PLOS ONE at http://dx.plos.org/10.1371/journal.pone.0028353.


Citation:

Arranz P, Aguilar de Soto N, Madsen PT, Brito A, Bordes F, Johnson M
(2011). Following a Foraging Fish-Finder: Diel Habitat Use of
Blainville's

Beaked Whales Revealed by Echolocation. PLoS ONE 6(12): e28353.
doi:10.1371/journal.pone.0028353


*Abstract*

Simultaneous high resolution sampling of predator behavior and habitat
characteristics is often difficult to achieve despite its importance
in

understanding the foraging decisions and habitat use of predators.
Here we tap into the biosonar system of Blainville's beaked whales,
Mesoplodon

densirostris, using sound and orientation recording tags to uncover
prey-finding cues available to echolocating predators in the deep-sea.

Echolocation sounds indicate where whales search and encounter prey,
as well as the altitude of whales above the sea-floor and the density
of

organisms around them, providing a link between foraging activity and
the bio-physical environment. Tagged whales (n = 9) hunted exclusively
at

depth, investing most of their search time either in the lower part of
the deep scattering layer (DSL) or near the sea-floor with little diel

change. At least 43% (420/974) of recorded prey-capture attempts were
performed within the benthic boundary layer despite a wide range of
dive

depths, and many dives included both meso- and bentho-pelagic
foraging. Blainville's beaked whales only initiate searching when
already deep in the

descent and encounter prey suitable for capture within 2 min of the
start of echolocation, suggesting that these whales are accessing prey
in

reliable vertical strata. Moreover, these prey resources are
sufficiently dense to feed the animals in what is effectively four
hours of hunting per

day enabling a strategy in which long dives to exploit numerous
deep-prey with low nutritional value require protracted recovery
periods (average

1.5 h) between dives. This apparent searching efficiency maybe aided
by inhabiting steep undersea slopes with access to both the DSL and
the

sea-floor over small spatial scales. Aggregations of prey in these
biotopes are located using biosonar-derived landmarks and represent
stable and

abundant resources for Blainville's beaked whales in the otherwise
food-limited deep-ocean.


Patricia Arranz, PhD Student, Department of Animal Biology, University
of La Laguna. 38206 La Laguna - Tenerife, Islas Canarias, Spain.
Email:arranz at ull.es Website: http://webpages.ull.es/users/cetaceos/




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