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  • Investigating noise effects on the acoustic signals and behavior of Southern Resident killer whales (Orcinus orca)


Northwest Fisheries Science Center (NWFSC) Conservation Biology CB - Ecosystem Science


SRKW Acoustic Noise Response
Investigating noise effects on the acoustic signals and behavior of Southern Resident killer whales (Orcinus orca)
In this study, vocal compensation is being investigated in Southern Resident killer whale (SRKW) calls to determine the degree to which whales can adjust to increased background noise levels. In addition, whale and vessel behavior data are also collected to determine what contribution vessel traffic has on noise levels and how noise levels influence whale behavior. The work was part of an NRC-postdoctoral project led by Marla Holt, and includes Dawn Noren (Adams) and Candice Emmons as internal collaborators. The specific work includes experimental design, data collection, data analysis, and writing for submission to peer-reviewed journals. This is a one-time project, and addresses key risk factors (vessel and noise interactions) of SRKW.

Research Themes

Recovery and rebuilding of marine and coastal species
The Pacific Northwest is home to several iconic endangered species, including Pacific salmon and killer whales, and several rockfish species. Mandates such as the Endangered Species Act, MagnusonStevens Act, and the Marine Mammal Protection Act, grant NOAA Fisheries the authority to manage the recovery of depleted species and stocks. The NWFSC contributes to species recovery through research, monitoring and analysis, providing NOAA managers and regional stakeholders the tools and information they need to craft effective regulations and develop sustainable plans for recovery.

Research Foci

Describe the relationships between human activities and species recovery, rebuilding and sustainability
Human activities play a major role in determining the status of species and stocks. Rebuilding and recovery therefore need to address how these activities affect their status. At the NWFSC, biophysical modeling is used to link specific human activities such as land use and pollution to habitat conditions, and then to link these conditions and other activities to particular life stages. These models can be used to quantitatively assess how human activities influence species abundance, productivity, distribution and diversity. Not surprisingly, altering human activities in some way is often necessary for species or stock recovery and rebuilding. It is therefore important to understand the socio-economic effects of alternative management structures. Gathering data on their economic costs and social impacts helps identify actions that are cost-effective. These actions will need to be resilient to potential changes in climate throughout the region. Research on how humans react to management strategies helps policy makers avoid those that lead to unintended consequences that can hinder rather than help recovery.


anthropogenic noise
human effects
southern resident killer whale
DPS that this study is focused on
the source of the anthropogenic noise


Holt et al. (2012). An investigation into sound use and behavior in a killer whale populatoin to inform passive acoustic sonar studies. Marine Mammal Science.
Holt, M.M. 2008. Sound exposure and Southern Resident killer whales (Orcinus orca): A review of current knowledge and data gaps. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-NWFSC-89, 59 p.
Holt, M.M., Noren, D., & Emmons, C. 2012. Does Vessel Noise Limit Foraging in Killer Whales? Pages 327-330. In A.N. Popper and A. Hawkins (eds.), The Effects of Noise on Aquatic Life, Advances in Experimental Medicine and Biology 730. Springer, New York.
Holt, M.M., Noren, D., Veirs, V., Emmons, C., and Veirs, S. 2009. Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise. Journal of the Acoustical Society of America (JASA) Express Letters. 125: EL27-EL32.
Holt, M.M., Noren, D., and Emmons, C. 2011. The effects of noise levels and call types on the source levels of killer whale calls. Journal of the Acoustical Society of America 130: 3100-3106.


Species Orcinus orca
grampus, killer whale, killer-trasher, orca


Candice Emmons
Internal Collaborator
Dawn Noren Adams
Internal Collaborator
Marla Holt
Principal Investigator