Passive Acoustic Monitoring Study

Principal Investigator: J. Craig George, Ph.D.
Collaborators: Kate Stafford, Ph.D. (University of Washington)
Funding: NSB, Univ. of Washington (in-kind)
Project Summary: We are trying to determine if counting bowhead calls during the bowhead migration near Barrow can be used as a population index. 


The NSB DWM has conducted acoustic surveys in most years since 1984 (more on this acoustics data here).  The acoustic data have been used to locate whales and make call counts through the spring migration and was used for abundance estimation. Acoustic information can also be used to examine changes in the spring migration including:  a) documenting the beginning and end of the migration based on first and last dates of calls recorded, b) estimating the number of “singers” and distinct songs by year, c) measuring the total “acoustic energy” as an index of the numbers of whales, and d) determining if other whales are present in the lead (for example, gray and killer whales).  

We are now trying to determine if counting bowhead calls might provide a useful “population index” of migrating bowhead whales at Barrow. Starting in 2015, we have been putting out a single hydrophone-recorder off the shorefast ice west of NARL. We are still analyzing acoustic data from 1984 to present to determine if it is correlated with population abundance. During the spring 2017 bowhead whale migration near Barrow, we are proposing to put a hydrophone off the lead edge in late March or early April, depending on ice conditions. 

Mooring Deployment:

The instrument will record continuously underwater for 2.5 months. The instrument package consists of ~100 lbs. of chain shackled together for an anchor, a recovery mechanism, a hydrophone, and one or two 14” subsurface floats. The instrument itself makes no noise. Both the hydrophone package and the floats are white per request in 2015 from the Barrow Whaling Captains Association. To deploy the mooring, we usually chop holes through thin ice near the lead edge. The mooring is deployed by lowering the anchor through the hole using a rope.Upon recovery of the acoustic recorder, the data will be downloaded. From these data, hourly occurrences of bowhead whales, bearded seals and beluga whales will be determined. Hours with bowhead whale signals will be examined in detail to determine sound counts. The number of sounds per hour will be used to compare with past sound counts based on a review of past reports.


Sounds of marine mammals near Barrow, Alaska, recorded by Kate Stafford. Kate Stafford has spent the last few springs in Barrow during the bowhead migration. Here are some sounds that she collected in the leads just outside of town.

Sounds recorded May 8, 2009: Singing bowheads, walrus and beluga sounds

Sounds recorded in April of 2012: These recordings were taken at the ice edge near a whaling camp. The sea ice coverage of the lead was about 90-95% leaving a few open water areas. While Kate was recording, three bowhead whales surfaced very closely together about 1/4 mile away from the hydrophone. These may have been the whales that are heard on the recording. (Photos by Kate Stafford)

Billy Adams, Subsistence Research Coordinator and whaler, accompanied Kate on the ice and spent some time listening to the whales.
Billy Adams, NSB-DWM Subsistence Research Coordinator and whaler, accompanied Kate on the ice and spent some time listening to the whales.

bowhead in lead
Click here to listen to the song Billy was listening to; Bowhead song

two bowheads in lead
Bowhead whales in lead near Barrow.

These sounds were recorded from a ringed seal hole found in a refrozen lead about 7 miles offshore from Barrow:

Two bowheads were heard singing on April 26, 2012: Two bowheads singing

Sounds recorded in April of 2015:

Sounds recorded in April of 2016:

Journal articles:

Moore, S.E., et al. 2006. Listening for large whales in offshore waters of Alaska. BioScience 56(1):49-55. 

Moore, S.E., et al. 2009. Acoustic and visual surveys for bowhead whales in the western Beaufort and far northeastern Chukchi seas. Deep-Sea Resarch II, doi:10.1016/j.dsr2.2009.08.013.

Stafford, K.M., et. al. 2012. Spitsbergen's endangered bowhead whales sing through the polar night. Endangered Species Research 18:95-103.

Stafford, K. 2013. Anthropogenic Sound and Marine Mammals in the Arctic: Increases in Man-Made Noises Pose New Challenges. Prepared for The Pew Charitable Trusts' US Arctic Program.

Johnson, H.D., et al. 2014. Song sharing and diversity in the Bering-Chukchi-Beaufort population of bowhead whales (Balaena mysticetus), spring 2011. Marine Mammal Science DOI: 10.1111/mms.12196

Popular articles:

Critically endangered whales sing like birds: new recordings hint at reboudn - with audio. UW Today, July 31, 2012. Read this article and listen to sounds recorded by Kate Stafford of the Spitsbergen stock of bowhead whales off of the eastern coast of Greenland. Read more about this work in this journal article.

Arctic Ballad: A Seattle scientist listens to whale songs to measure how melting ice affects mammals in the Arctic. Planet Magazine, March 16, 2017.

Sounds of the Arctic Poster This poster, with sound files, was put together by Catherine Berchok (National Marine Fisheries Service, NOAA) and Kate Stafford (University of Washington, Applied Physics Lab) with support from BOEM (Bureau of Ocean Energy Management) and the NSB. You can listen to the sounds of marine mammals and sea ice, sounds that were collected using hydrophones placed underwater in the Arctic Ocean.