[MARMAM] New paper on the acoustic behaviour of Antarctic killer whales
elena_schall at web.de
Sun Mar 19 05:28:41 PDT 2017
Dear Marmam Community,
my co-author Ilse Van Opzeeland and I are very pleased to announce the
publication of our newest paper on the acoustic behaviour of Antarctic
Elena Schall & Ilse Van Opzeeland (2017). Calls Produced by Ecotype C
Killer Whales (Orcinus orca) Off the Eskström Iceshelf, Antarctica.
Aquatic Mammals, 43(2), 117-126.
Killer whales (/Orcinus orca/) are highly social top predators
distributed throughout the worldʼs oceans. They are divided into
different ecotypes according to foraging specializations, phenotype, and
social organization. For Northern Hemisphere killer whale ecotypes,
acoustic behaviour has been shown to relate to foraging strategies and
social organization. In contrast to the intensively studied Northern
Hemisphere ecotypes, distribution patterns, social structures, and
acoustic behaviour of the Southern Hemisphere killer whale ecotypes are
poorly known. One of the Southern Hemisphere ecotypes, the Antarctic
Ecotype C killer whale, is known to occur in regions with dense pack
ice. The limited accessibility of these areas make passive acoustic
monitoring (PAM) methods a very effective investigation tool to derive
information on ecotype-specific abundance and distribution. During 2 d
in February 2013, it was possible to collect concurrent visual and
acoustic information of Ecotype C killer whales off the Antarctic
continent. From these events, a call type catalogue was compiled. The
2,238 examined calls were subjectively classified into 26 discrete call
types. Ten percent of the examined calls were re-classified by two
additional independent observers to examine robustness of the
classification. Mean classification accordance among observers was 68%.
Most call types were composed of more than one call part. Sixty-five
percent of all call types were monophonic, and 35% were biphonic. Almost
two-third of all call types started with a short, broadband pulse. The
variability within call types was relatively high. The Ecotype C vocal
repertoire contained typical acoustic features such as biphonation, high
call complexity, and generally high variability in frequency modulation.
For future studies, the distinct characteristics of some of the call
types described herein could potentially serve as acoustic markers for
PAM-based differentiation of killer whale ecotypes in the Southern Ocean.
For a PDF version of the paper please contact me (elena_schall at web.de).
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