[MARMAM] Two new papers on marine mammal behavioral responses

Brandon Southall brandon.southall at sea-inc.net
Sun Jul 7 00:10:36 PDT 2013


MARMAM subscribers,

On behalf of my colleagues in the Southern California Behavioral 
Response Study (SOCAL-BRS), I am pleased to let you know that we had two 
papers published recently on beaked and blue whale responses to 
simulated and actual mid-frequency sonar and other sounds. The 
references and abstracts are given below for each paper as well as the 
link to get the actual papers (available through Open Access).

Thank you,
Brandon Southall


DeRuiter SL, Southall BL, Calambokidis J, Zimmer WMX, Sadykova D, 
Falcone EA, Friedlaender AS, Joseph JE, Moretti D, Schorr GS, Thomas L, 
Tyack PL. 2013 First direct measurements of behavioural responses by 
Cuvier’s beaked whales to mid-frequency active sonar. Biol Lett 9: 
20130223. http://dx.doi.org/10.1098/rsbl.2013.0223

Available via Open Access at: 
http://rsbl.royalsocietypublishing.org/content/9/4/20130223.full

Abstract: Most marine mammal strandings coincident with naval sonar 
exercises have
involved Cuvier’s beaked whales (Ziphius cavirostris). We recorded animal
movement and acoustic data on two tagged Ziphius and obtained the first
direct measurements of behavioural responses of this species to 
mid-frequency
active (MFA) sonar signals. Each recording included a 30-min playback (one
1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also
incidentally exposed to MFA sonar from distant naval exercises. Whales
responded strongly to playbacks at low received levels (RLs; 89–127 dB
re 1 mPa): after ceasing normal fluking and echolocation, they swam rapidly,
silently away, extending both dive duration and subsequent non-foraging 
interval.
Distant sonar exercises (78–106 dB re 1 mPa) did not elicit such responses,
suggesting that context may moderate reactions. The observed responses to
playback occurred at RLs well below current regulatory thresholds; 
equivalent
responses to operational sonars could elevate stranding risk and reduce
foraging efficiency.

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Goldbogen JA, Southall BL, DeRuiter SL, Calambokidis J, Friedlaender AS, 
Hazen EL, Falcone EA, Schorr GS, Douglas A, Moretti DJ, Kyburg C, 
McKenna MF, Tyack PL. 2013 Blue whales respond to simulated 
mid-frequency military sonar. Proc R Soc B 280: 20130657. 
http://dx.doi.org/10.1098/rspb.2013.0657

Available via Open Access at: 
http://rspb.royalsocietypublishing.org/content/280/1765/20130657.full

Abstract: Mid-frequency military (1–10 kHz) sonars have been associated 
with lethal
mass strandings of deep-diving toothed whales, but the effects on endangered
baleen whale species are virtually unknown. Here, we used controlled
exposure experiments with simulated military sonar and other mid-frequency
sounds to measure behavioural responses of tagged blue whales (Balaenoptera
musculus) in feeding areas within the Southern California Bight. Despite 
using
source levels orders of magnitude below some operational military systems,
our results demonstrate that mid-frequency sound can significantly affect
blue whale behaviour, especially during deep feeding modes. When a
response occurred, behavioural changes varied widely from cessation of
deep feeding to increased swimming speed and directed travel away from
the sound source. The variability of these behavioural responses was largely
influenced by a complex interaction of behavioural state, the type of 
midfrequency
sound and received sound level. Sonar-induced disruption of
feeding and displacement from high-quality prey patches could have 
significant
and previously undocumented impacts on baleen whale foraging
ecology, individual fitness and population health.


-- 
Brandon L. Southall, Ph.D.
President, Senior Scientist, SEA, Inc.
Research Associate, University of California, Santa Cruz
9099 Soquel Drive, Suite 8, Aptos, CA 95003, USA
831.332.8744 (mobile); 831.661.5177 (office); 831.661.5178 (fax)
Brandon.Southall at sea-inc.net; www.sea-inc.net



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