A multi-year study of narwhal occurrence in the western Fram Strait—detected via passive acoustic monitoring

  • Heidi Ahonen Norwegian Polar Institute, Tromsø, Norway
  • Kathleen M. Stafford Applied Physics Laboratory, University of Washington, Seattle, WA, USA
  • Christian Lydersen Norwegian Polar Institute, Tromsø, Norway
  • Laura de Steur Norwegian Polar Institute, Tromsø, Norway
  • Kit M. Kovacs Norwegian Polar Institute, Tromsø, Norway
Keywords: Arctic, echolocation, Monodon monoceros, seasonal distribution, vocalization, whales


Passive acoustic monitoring (PAM) has proven to be an efficient method for studying vocally active marine mammals in areas that are difficult to access on a year-round basis. In this study, a PAM recorder was deployed on an oceanographic mooring in western Fram Strait (78°50'N, 5°W) to record the acoustic presence of narwhals (Monodon monoceros) over a 3-yr period. Acoustic data were recorded for 14–17 min at the start of each hour from 25 September 2010 to 26 August 2011, from 2 September 2012 to 11 April 2013 and from 8 September 2013 to 27 April 2014. Pulsed and tonal signals, as well as echolocation clicks, were detected throughout the recording periods, demonstrating that this species is present in this region throughout the year. Generalized linear mixed-effect models showed a negative correlation between the acoustic presence of narwhals and very dense sea-ice cover (≥90%). Surprisingly, a positive correlation was found between the acoustic presence of narwhals and the presence of warm Atlantic Water in the area. Available data suggest that there might be a unique stock of narwhals in the Eurasian sector of the Atlantic Arctic that do not exhibit the “traditional” narwhal pattern of seasonal migration between coastal summering areas and offshore wintering grounds, but rather remain resident year-round in deep, offshore waters.


Download data is not yet available.


Aagaard K. & Coachman L.K. 1968. The East Greenland current north of Denmark Strait: part I. Arctic 21, 181–200, http://dx.doi.org/10.14430/arctic3262.

Ahonen H., Stafford K.M., de Steur L., Lydersen C., Wiig Ø. & Kovacs K.M. 2017. The underwater soundscape in western Fram Strait: breeding ground of Spitsbergen’s endangered bowhead whales. Marine Pollution Bulletin 123, 97–112, http://dx.doi.org/10.1016/j.marpolbul.2017.09.019.

Beszczynska-Möller A., Fahrbach E., Schauer U. & Hansen E. 2012. Variability in Atlantic Water temperature and transport at the entrance to the Arctic Ocean, 1997–2010. ICES Journal of Marine Science 69, 852–863, http://dx.doi.org/10.1093/icesjms/fss056.

Blackwell S.B., Tervo O.M., Conrad A.S., Sinding M.H.S., Hansen R.G., Ditlevsen S. & Heide-Jørgensen M.P. 2018. Spatial and temporal patterns of sound production in East Greenland narwhals. PLoS One 13, e0198295, http://dx.doi.org/10.1371/journal.pone.0198295.

Boertmann D. & Mosbech A. 2012. The western Greenland Sea: a strategic environmental impact assessment of hydrocarbon activities. Scientific Report from Danish Centre for Environment and Energy 22. Aarhus: Danish Centre for Environment and Energy, Aarhus University.

Bourke R., Weigel A. & Paquette R. 1988. The westward turning branch of the West Spitsbergen current. Journal of Geophysical Research—Oceans 93, 14065–14077, http://dx.doi.org/10.1029/JC093iC11p14065.

Breed G.A., Matthews C.J., Marcoux M., Higdon J.W., LeBlanc B., Petersen S.D., Orr J., Reinhart N.R. & Ferguson S.H. 2017. Sustained disruption of narwhal habitat use and behavior in the presence of Arctic killer whales. Proceedings of the National Academy of Sciences of the United States of America 114, 2628–2633, http://dx.doi.org/10.1073/pnas.1611707114.

Cavalieri D.J., Markus T. & Comiso J.C. 2014. AMSR-E/Aqua daily L3 25 km brightness temperature & sea ice concentration polar grids, version 3. NASA National Snow and Ice Data Center Distributed Active Archive Center, Boulder, CO. http://dx.doi.org/10.5067/AMSR-E/AE_SI25.003. Accessed on the internet at https://nsidc.org/data/ae_si12 on 31 August 2016.

Crawford R., Vagle S. & Carmack E. 2012. Water mass and bathymetric characteristics of polar cod habitat along the continental shelf and slope of the Beaufort and Chukchi seas. Polar Biology 35, 179–190, http://dx.doi.org/10.1007/s00300-011-1051-9.

Daase M. & Eiane K. 2007. Mesozooplankton distribution in northern Svalbard waters in relation to hydrography. Polar Biology 30, 969–981, http://dx.doi.org/10.1007/s00300-007-0255-5.

de Steur L., Hansen E., Gerdes R., Karcher M., Fahrbach E. & Holfort J. 2009. Freshwater fluxes in the East Greenland Current: a decade of observations. Geophysical Research Letters 36, L23611, http://dx.doi.org/10.1029/2009GL041278.

Dietz R., Heide-Jørgensen M.P., Born E.W. & Glahder C.M. 1994. Occurrence of narwhals (Monodon monoceros) and white whales (Delphinapterus leucas) in East Greenland. Meddelelser om Grønland Bioscience 39, 69–86.

Dietz R., Heide-Jørgensen M.P., Richard P.R. & Acquarone M. 2001. Summer and fall movements of narwhals (Monodon monoceros) from northeastern Baffin Island towards northern Davis Strait. Arctic 54, 244–261, http://dx.doi.org/10.14430/arctic785.

Fetterer F., Knowles K., Meier W., Savoie M. & Windnagel A.K. 2017. Sea ice index, version 3. National Snow and Ice Data Center, Boulder, CO. http://dx.doi.org/10.7265/N5K072F8. Accessed on the internet at https://nsidc.org/data/g02135 on 16 November 2017.

Ford J. & Fisher H.D. 1978. Underwater acoustic signals of narwhal (Monodon monoceros). Canadian Journal of Zoology 56, 552–560, http://dx.doi.org/10.1139/z78-079.

Frouin-Mouy H., Kowarski K., Martin B. & Bröker K. 2017. Seasonal trends in acoustic detection of marine mammals in Baffin Bay and Melville Bay, northwest Greenland. Arctic 70, 59–76, http://dx.doi.org/10.14430/arctic4632.

Gjøsæter H., Wiebe P.H., Knutsen T. & Ingvaldsen R.B. 2017. Evidence of diel vertical migration of mesopelagic sound-scattering organisms in the Arctic. Frontiers in Marine Science 4, article no. 1177, http://dx.doi.org/10.3389/fmars.2017.00332.

Heide-Jørgensen M.P. 2017. Narwhal Monodon monoceros. In B. Würsig et al. (eds.): Encyclopedia of marine mammals. Pp. 627–631. San Diego, CA: Academic Press.

Heide-Jørgensen M.P. & Dietz R. 1995. Some characteristics of narwhal, Monodon monoceros, diving behaviour, in Baffin Bay. Canadian Journal of Zoology 73, 2120–2132, http://dx.doi.org/10.1139/z95-249.

Heide-Jørgensen M.P., Dietz R., Laidre K. & Richard P. 2002. Autumn movements, home ranges, and winter density of narwhals (Monodon monoceros) tagged in Tremblay Sound, Baffin Island. Polar Biology 25, 331–341.

Heide-Jørgensen M.P., Dietz R., Laidre K.L., Richard P., Orr J. & Schmidt H.C. 2003. The migratory behaviour of narwhals (Monodon monoceros). Canadian Journal of Zoology 81, 1298–1305, http://dx.doi.org/10.1139/Z03-117.

Heide-Jørgensen M.P., Hansen R.G., Westdal K., Reeves R.R. & Mosbech A. 2013. Narwhals and seismic exploration: is seismic noise increasing the risk of ice entrapments? Biological Conservation 158, 50–54, http://dx.doi.org/10.1016/j.biocon.2012.08.005.

Heide-Jørgensen M.P., Nielsen N.H., Hansen R.G., Schmidt H.C., Blackwell S.B & Jørgensen O.A. 2015. The predictable narwhal: satellite tracking shows behavioural similarities between isolated subpopulations. Journal of Zoology 297, 54–65, http://dx.doi.org/10.1111/jzo.12257.

Heide-Jørgensen M.P., Richard P.R., Dietz R. & Laidre K.L. 2013. A metapopulation model for Canadian and West Greenland narwhals. Animal Conservation 16, 331–343, http://dx.doi.org/10.1111/acv.12000.

Jensen F.H., Beedholm K., Wahlberg M., Bejder L. & Madsen P.T. 2012. Estimated communication range and energetic cost of bottlenose dolphin whistles in a tropical habitat. Journal of the Acoustical Society of America 131, 582–592, http://dx.doi.org/10.1121/1.3662067.

Kelly B., Bengtson J.L., Boveng P.L., Cameron M.F., Dahle S.P., Jansen J.K., Logerwell E.A., Overland J.E., Sabine C.L., Waring G.T. & Wilder J.M. 2010. Status report on ringed seals (Phoca hispida). NOAA Technical Memorandum NMFS-AFSC-212. Springfield, VA: US Dept of Commerce.

Koblitz J.C., Stilz P., Rasmussen M.H. & Laidre K.L. 2016. Highly directional sonar beam of narwhals (Monodon monoceros) measured with a vertical 16 hydrophone array. PLoS One 11, e0162069, http://dx.doi.org/10.1371/journal.pone.0162069.

Laidre K.L. & Heide-Jørgensen M. 2005a. Arctic sea ice trends and narwhal vulnerability. Biological Conservation 121, 509–517, http://dx.doi.org/10.1016/j.biocon.2004.06.003.

Laidre K.L. & Heide-Jørgensen M. 2005b. Winter feeding intensity of narwhals (Monodon monoceros). Marine Mammal Science 21, 45–57, http://dx.doi.org/10.1111/j.1748-7692.2005.tb01207.x.

Laidre K.L. & Heide-Jørgensen M.P. 2011. Life in the lead: extreme densities of narwhals Monodon monoceros in the offshore pack ice. Marine Ecology Progress Series 423, 269–278, http://dx.doi.org/10.3354/meps08941.

Laidre K.L., Heide-Jørgensen M.P., Dietz R., Hobbs R. & Jørgensen O.A. 2003. Deep-diving by narwhals Monodon monoceros: differences in foraging behavior between wintering areas? Marine Ecology Progress Series 261, 269–281, http://dx.doi.org/10.3354/meps261269.

Laidre K.L., Heide-Jørgensen M.P., Logdson M.L., Hobbs R.C., Heagerty P., Dietz R., Jørgensen O.A. & Treble M.A. 2004. Seasonal narwhal habitat associations in the High Arctic. Marine Biology 145, 821–831, http://dx.doi.org/10.1007/s00227-004-1371-1.

Laidre K.L., Heide-Jørgensen M.P., Stern H. & Richard P. 2012. Unusual narwhal sea ice entrapments and delayed autumn freeze-up trends. Polar Biology 35, 149–154, http://dx.doi.org/10.1007/s00300-011-1036-8.

Laidre K.L., Stern H., Kovacs K.M., Lowry L., Moore S.E., Regehr E.V., Ferguson S., Wiig Ø., Boveng P.L., Angliss R., Born E.W., Litovka D., Quakenbush L., Lydersen C., Vongraven D. & Ugarte F. 2015. Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century. Conservation Biology 29, 724–737, http://dx.doi.org/10.1111/cobi.12474.

Laidre K.L., Stirling I., Lowry L.F., Wiig Ø., Heide-Jørgensen M.P. & Ferguson S.H. 2008. Quantifying the sensitivity of Arctic marine mammals to climate‐induced habitat change. Ecological Applications 18, S97–S125, http://dx.doi.org/10.1890/06-0546.1.

Lydersen C., Martin A.R., Gjertz I. & Kovacs K.M. 2007. Satellite tracking and diving behaviour of sub-adult narwhals (Monodon monoceros) in Svalbard, Norway. Polar Biology 30, 437–442, http://dx.doi.org/10.1007/s00300-006-0200-z.

MacIntyre K.Q., Stafford K.M., Conn P.B., Laidre K.L. & Boveng P.L. 2015. The relationship between sea ice concentration and the spatio-temporal distribution of vocalizing bearded seals (Erignathus barbatus) in the Bering, Chukchi, and Beaufort seas from 2008 to 2011. Progress in Oceanography 136, 241–249, http://dx.doi.org/10.1016/j.pocean.2015.05.008.

Marcoux M., Auger-Methe M., Chmelnitsky E.G., Ferguson S.H. & Humphries M.M. 2011. Local passive acoustic monitoring of narwhal presence in the Canadian Arctic: a pilot project. Arctic 64, 307–316, http://dx.doi.org/10.14430/arctic4121.

Marcoux M., Auger-Méthé M. & Humphries M.M. 2011. Variability and context specificity of narwhal (Monodon monoceros) whistles, and pulsed calls. Marine Mammal Science 28, 649–665, http://dx.doi.org/10.1111/j.1748-7692.2011.00514.x.

Marcoux M., Ferguson S.H., Roy N., Bedard J.M. & Simard Y. 2017. Seasonal marine mammal occurrence detected from passive acoustic monitoring in Scott Inlet, Nunavut, Canada. Polar Biology 40, 1127–1138, http://dx.doi.org/10.1007/s00300-016-2040-9.

Miller L.A., Pristed J., Møshl B. & Surlykke A. 1995. The click-sounds of narwhals (Monodon monoceros) in Inglefield Bay, northwest Greenland. Marine Mammal Science 11, 491–502, http://dx.doi.org/10.1111/j.1748-7692.1995.tb00672.x.

Møhl B., Surlykke A. & Miller L.A. 1990. High intensity narwhal clicks. In J.A. Thomas & R.A. Kastelein (eds.): Sensory abilities of cetaceans. Pp. 295–303. New York: Plenum Press.

Moore S.E., Stafford K.M., Melling H., Berchok C., Wiig Ø., Kovacs K.M., Lydersen C. & Richter-Menge J. 2012. Comparing marine mammal acoustic habitats in Atlantic and Pacific sectors of the High Arctic: year-long records from Fram Strait and the Chukchi Plateau. Polar Biology 35, 475–480, http://dx.doi.org/10.1007/s00300-016-2040-9.

Mosby H. 1962. Water, salt, and heat balance of the North Polar Sea and of the Norwegian Sea. Geofysiske Publikasjoner, Geophysica Norvegica 24, 289–313.

Nordli Ø., Przybylak R., Ogilvie A.E.J. & Isaksen K. 2014. Long-term temperature trends and variability on Spitsbergen: the extended Svalbard Airport temperature series, 1898–2012. Polar Research 33, article no. 21349, http://dx.doi.org/10.3402/polar.v33.21349.

Onarheim I.H., Smedsrud L.H., Invaldsen R. & Nilsen F. 2014. Loss of sea ice during winter north of Svalbard. Tellus A 66, article no. 23933, http://dx.doi.org/10.3402/tellusa.v66.23933.

Palsbøll P.J., Heide-Jørgensen M.P. & Dietz R. 1997. Population structure and seasonal movements of narwhals, Monodon monoceros, determined from mtDNA analysis. Heredity 78, 284–292, http://dx.doi.org/10.1038/hdy.1997.43.

Pavlov A.K., Tverberg V., Ivanov B.V., Nilsen F., Falk-Petersen S. & Granskog M.A. 2013. Warming of Atlantic Water in two west Spitsbergen fjords over the last century (1912–2009). Polar Research 32, article no. 11206, http://dx.doi.org/10.3402/polar.v32i0.11206.

Rasmussen M.H., Koblitz J.C. & Laidre K.L. 2015. Buzzes and high-frequency clicks recorded from narwhals (Monodon monoceros) at their wintering ground. Aquatic Mammals 41, 256–264, http://dx.doi.org/10.1578/AM.41.3.2015.256.

Reeves R.R., Ewins P.J., Agbayani S., Heide-Jørgensen M.P., Kovacs K.M., Lydersen C., Suydam R., Elliott W., Polet G., van Dijk Y. & Blijleven R. 2014. Distribution of endemic cetaceans in relation to hydrocarbon development and commercial shipping in a warming Arctic. Marine Policy 44, 375–389, http://dx.doi.org/10.1016/j.marpol.2013.10.005.

Richardson W.J., Greene C.R., Malme C.I. & Thomson D.H. 1995. Marine mammals and noise. San Diego, CA: Academic Press.

Roy N., Simard Y. & Gervaise C. 2010. 3D tracking of foraging belugas from their clicks: experiment from a coastal hydrophone array. Applied Acoustics 71, 1050–1056, https://doi.org/10.1016/j.apacoust.2010.05.008.

Shapiro A.D. 2006. Preliminary evidence for signature vocalizations among free-ranging narwhals (Monodon monoceros). Journal of the Acoustical Society of America 120, 1695–1705, http://dx.doi.org/10.1121/1.2226586.

Sjare B.L. & Smith T.G. 1986. The vocal repertoire of white whales, Delphinapterus leucas, summering in Cunningham Inlet, Northwest Territories. Canadian Journal of Zoology 64, 407–415, https://doi.org/10.1139/z86-063.

Stafford K.M., Citta J.J., Okkonen S.R. & Suydam R.S. 2016. Wind-dependent beluga whale dive behavior in Barrow Canyon, Alaska. Deep-Sea Research Part II 118, 57–65, http://dx.doi.org/10.1016/j.dsr.2016.10.006.

Stafford K.M., Laidre K.L. & Heide‐Jørgensen M.P. 2012. First acoustic recordings of narwhals (Monodon monoceros) in winter. Marine Mammal Science 28, E197–E207, http://dx.doi.org/10.1111/j.1748-7692.2011.00500.x.

Stafford K.M., Lydersen C., Wiig Ø. & Kovacs K.M. 2018. Extreme diversity in the songs of Spitsbergen’s bowhead whales. Biology Letters 14, article no. 20180056, http://dx.doi.org/10.1098/rsbl.2018.0056.

Stafford K.M., Moore S.E., Berchok C.L., Wiig Ø., Lydersen C., Hansen E., Kalmbach D. & Kovacs K.M. 2012. Spitsbergen’s endangered bowhead whales sing through the polar night. Endangered Species Research 18, 95–103, http://dx.doi.org/10.3354/esr00444.

Stafford K.M., Okkonen S.R. & Clarke J.T. 2013. Correlation of a strong Alaska Coastal Current with the presence of beluga whales Delphinapterus leucas near Barrow, Alaska. Marine Ecology Progress Series 474, 287–297, http://dx.doi.org/10.3354/meps10076.

Storrie L., Lydersen C., Andersen M., Wynn R.B. & Kovacs K.M. 2018. Determining the species assemblage and habitat use of cetaceans in the Svalbard Archipelago, based on recorded observations from 2002–2014. Polar Research 37, article no. 1463065, http://dx.doi.org/10.1080/17518369.2018.1463065.

Thomsen F., Franck D. & Ford J.K.B. 2001. Characteristics of whistles from the acoustic repertoire of resident killer whales (Orcinus orca) off Vancouver Island, British Columbia. Journal of the Acoustical Society of America 109, 1240–1246, http://dx.doi.org/10.1121/1.1349537.

Vacquié-Garcia J., Lydersen C., Marques T.A., Aars J., Ahonen H., Skern-Mauritzen M., Oien N. & Kovacs K.M. 2017. Late summer distribution and abundance of ice-associated whales in the Norwegian High Arctic. Endangered Species Research 32, 59–70, http://dx.doi.org/10.3354/esr00791.

Watt C.A., Heide-Jørgensen M.P. & Ferguson S.H. 2017. Spatial distribution of narwhal (Monodon monoceros) diving for Canadian populations helps identify important seasonal foraging areas. Canadian Journal of Zoology 95, 41–50, http://dx.doi.org/10.1139/cjz-2016-0178.

Williams T.M., Blackwell S.B., Richter B., Sinding M.-H.S. & Heide-Jørgensen M.P. 2017. Paradoxical escape responses by narwhals (Monodon monoceros). Science 358, 1328–1331, http://dx.doi.org/10.1126/science.aao2740.

How to Cite
Ahonen, H., Stafford, K., Lydersen, C., de Steur, L., & Kovacs, K. (2019). A multi-year study of narwhal occurrence in the western Fram Strait—detected via passive acoustic monitoring. Polar Research, 38. https://doi.org/10.33265/polar.v38.3468
Research Articles