[MARMAM] Sound exposure and southern resident killer whales report
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
Marla M. Holt, Ph.D.
NRC Postdoctoral Associate
Marine Mammal Program
NOAA NMFS Northwest Fisheries Science Center
2725 Montlake Blvd East
Seattle, WA 98112
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