[MARMAM] Sound exposure and southern resident killer whales report

Marla Holt Marla.Holt at noaa.gov
Fri Mar 7 16:36:15 PST 2008

A new paper is available online:

Holt, M. M.  2008.  Sound exposure and Southern Resident killer whales 
(Orcinus orca): A review of current knowledge and data gaps.  U.S. Dept. 
Commer., NOAA Tech. Memo. NMFS-NWFSC-89. 

This document reviews what is currently known about potential acoustic 
impacts on endangered Southern Resident killer whales (SRKWs).  Killer 
whales (/Orcinus orca/) use sound for echolocation, social 
communication, and passive listening.  Ambient noise, including that 
from natural and anthropogenic sources, has the potential to interfere 
with the reception and use of these important biological sounds.  
Significant sources of anthropogenic sounds that contribute to ambient 
background noise in critical habitats of SRKWs include sonar, acoustic 
harassment devices, vessel traffic, and construction noise.

Most measurements of ambient sounds made in SRKW habitat are greatly 
influenced by vessel traffic that, at close ranges, raises noise levels 
significantly above ambient levels.  In order to address potential 
acoustic impacts, particularly from anthropogenic sources, this document 
reviews parameters of sound that are pertinent to the auditory 
capabilities of killer whales and various studies on noise effects in 
killer whales and other dolphins.  The latter includes auditory 
ramifications such as auditory masking or hearing loss and behavioral 
effects such as disruption of foraging events or avoidance of an area. 
 With this information, the document then incorporates information on 
the soundscape of SRKW habitat and defines zones of audibility, 
responsiveness, masking, and hearing loss and addresses the likelihood 
of acoustic impacts on the SRKW population.

Lastly, recommendations are made for future work in order to address 
gaps in information that, if available, would increase confidence in 
predicting the likelihood of acoustic impacts on SRKWs.

PDF online at 
Best Regards,
Marla Holt

Marla M. Holt, Ph.D.
NRC Postdoctoral Associate
Marine Mammal Program
NOAA NMFS Northwest Fisheries Science Center
2725 Montlake Blvd East
Seattle, WA 98112
Phone: 206.860.3261
Fax: 206.860.3400
Web: http://www.nwfsc.noaa.gov/

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