[MARMAM] New publication on high frequency ship noise and potential effects on small toothed whales

Line Hermannsen line.hermannsen at gmail.com
Fri Oct 10 01:27:58 PDT 2014

Dear MARMAMers,

For those interested, we wish to draw attention to a recent paper in the
Journal of the Acoustical Society of America on high frequency ship noise
and the potential effects on small toothed whales.
We show that a broad range of vessel types produce substantial levels of
noise at high frequencies, and that smaller toothed whales therefore must
be considered in impact assessments of ship noise. We also show that low
frequency noise bands are poor proxies for noise loads at higher
frequencies, and that current low frequency indicators, such as those in
the European Marine Strategy Framework Directive (MSFD), are insufficient
when it comes to assessing noise effects on small toothed whales.

*"High frequency components of ship noise in shallow water with a
discussion of implications for harbor porpoises (Phocoena phocoena)"*
Line Hermannsen, Kristian Beedholm, Jakob Tougaard and Peter T. Madsen

J. Acoust. Soc. Am. 136, 1640 (2014)
URL: *http://scitation.aip.org/content/asa/journal/jasa/136/4/10.1121/1.4893908
DOI: http://dx.doi.org/10.1121/1.4893908

*Full abstract*
Growing ship traffic worldwide has led to increased vessel noise with
possible negative impacts on marine life. Most research has focused on low
frequency components of ship noise, but for high-frequency specialists,
such as the harbor porpoise (Phocoena phocoena), medium-to-high frequency
noise components are likely more of a concern. To test for biologically
relevant levels of medium-to-high frequency vessel noise, different types
of Automatic Identification System located vessels were recorded using a
broadband recording system in four heavily ship-trafficked marine habitats
in Denmark. Vessel noise from a range of different ship types substantially
elevated ambient noise levels across the entire recording band from 0.025
to 160 kHz at ranges between 60 and 1000 m. These ship noise levels are
estimated to cause hearing range reduction of >20 dB (at 1 and 10 kHz) from
ships passing at distances of 1190 m and >30 dB reduction (at 125 kHz) from
ships at distances of 490 m or less. It is concluded that a diverse range
of vessels produce substantial noise at high frequencies, where toothed
whale hearing is most sensitive, and that vessel noise should be considered
over a broad frequency range, when assessing noise effects on porpoises and
other small toothed whales.

A pdf version of the paper can be requested from line.hermannsen at gmail.com

Best regards,

Line Hermannsen
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