Dear colleagues,
my co-authors and I are pleased to announce the publication of our work
on the directionality and scanning of narwhals in PLoS ONE:
Koblitz JC, Stilz P, Rasmussen MH, Laidre KL (2016)
Highly Directional Sonar Beam of Narwhals (/Monodon monoceros/) Measured
with a Vertical 16 Hydrophone Array
PLoS ONE 11(11): e0162069. doi:10.1371/journal.pone.0162069
The paper is available as OPEN ACCESS here:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162069
Abstract:
Recordings of narwhal (/Monodon monoceros/) echolocation signals were
made using a linear 16 hydrophone array in the pack ice of Baffin Bay,
West Greenland in 2013 at eleven sites. An average -3 dB beam width of
5.0° makes the narwhal click the most directional biosonar signal
reported for any species to date. The beam shows a dorsal-ventral
asymmetry with a narrower beam above the beam axis. This may be an
evolutionary advantage for toothed whales to reduce echoes from the
water surface or sea ice surface. Source level measurements show narwhal
click intensities of up to 222 dB pp re 1 μPa, with a mean apparent
source level of 215 dB pp re 1 μPa. During ascents and descents the
narwhals perform scanning in the vertical plane with their sonar beam.
This study provides valuable information for reference sonar parameters
of narwhals and for the use of acoustic monitoring in the Arctic.
Cheers,
Jens
--
Dr. Jens C. Koblitz
BioAcousticsNetwork
Eichenallee 32 a
41469 Neuss
Germany
Office: +41 (0) 56 55 876 20
Cell: +49 (0) 1512-2236452
