Distribution and Abundance of Killer Whales in the Central North Atlantic, 1987-2015
Keywords:killer whale, abundance, distribution, north atlantic, cetacean survey, NASS, NAMMCO
The North Atlantic Sightings Surveys (NASS), covering a large but variable portion of the Central and Eastern North Atlantic, were conducted in 1987, 1989, 1995, 2001, 2007 and 2015. Sightings of killer whales (Orcinus orca), a non-target species, were relatively rare in the Central Atlantic (Icelandic and Faroese) portions of the survey area. In cases where sighting numbers were insufficient, we pooled sightings over several surveys to derive a distance detection function and used this to estimate abundance using standard Distance Sampling methodology. Uncorrected estimates were produced for all surveys, and estimates corrected for perception bias were produced for the 2001 and 2015 surveys. Killer whales were sighted in all areas but were most common in the eastern part of the survey area. Uncorrected abundance in the NASS core area ranged from a low of 4,736 (95% CI: 1,842–12,176) in 1995 to a maximum of 15,142 (95% CI: 6,003–38,190) in 2001. The low precision of the estimates makes the detection of temporal trends unlikely. In 2007 an extension survey revealed relatively high numbers of killer whales to the east of the survey area, in conformity with Norwegian survey estimates in this area. The NASS and other surveys conducted over the period indicate that killer whales number in the low tens of thousands in the Central and Eastern North Atlantic.
Baird, R. W., Hanson, M. B., & Dill, L. M. (2005). Factors influencing the diving behaviour of fish-eating killer whales: Sex differences and diel and interannual variation in diving rates. Canadian Journal of Zoology, 83(2), 257–267. https://doi.org/10.1139/z05-007
Buckland, S. T., Anderson, D., Burnham, K., Laake, J., Borchers, D., & Thomas, L. (2001). Introduction to distance sampling estimating abundance of biological populations. Oxford: Oxford University Press.
Buckland, S. T., & Turnock, B. J. (1992). A Robust Line Transect Method. Biometrics, 48(3), 901–909. https://doi.org/10.2307/2532356
Burt, M. L., Borchers, D. L., Jenkins, K. J., & Marques, T. A. (2014). Using mark–recapture distance sampling methods on line transect surveys. Methods in Ecology and Evolution, 5(11), 1180–1191. https://doi.org/10.1111/2041-210X.12294
Canadas, A., Desportes, G., & Borchers, D. L. (2004). The estimation of the detection function and g(0) for short-beaked common dolphins (Delphinis delphis), using double-platform data collected during the NASS-95 Faroese survey. Journal of Cetacean Research and Management, 6(2), 191–198.
Foote, A. D., Víkingsson, G., Øien, N., Bloch, D., Davis, C. G., Dunn, T. E., Harvey, P. V., Whooley, P., & Thompson, P. M. (2007). Distribution and abundance of killer whales in the North East Atlantic. SC/59/SM5 for the IWC Scientific Committee. 10.
Gunnlaugsson, Th., & Sigurjónsson, J. (1990). NASS-87: Estimation of whale abundance based on observations made onboard Icelandic and Faroese survey vessels. Report of the International Whaling Commission, 40, 571–580.
Hammond, P. S., Lacey, C., Gilles, A., Viquerat, S., Boerjesson, P., Herr, H., Macleod, K., Ridoux, V., Santos, M., & Scheidat, M. (2017). Estimates of cetacean abundance in European Atlantic waters in summer 2016 from the SCANS-III aerial and shipboard surveys. Wageningen Marine Research. https://synergy.st-andrews.ac.uk/scans3/files/2017/04/SCANS-III-design-based-estimates-2017-04-28-final.pdf
Hammond, P. S., Macleod, K., Berggren, P., Borchers, D. L., Burt, M. L., Cañadas, A., Desportes, G., Donovan, G. P., Gilles, A., Gillespie, D. M., Gordon, J. C. D., Hiby, L., Kuklik, I., Leaper, R., Lehnert, K., Leopold, M., Lovell, P., Øien, N., Paxton, C. G. M., … Vázquez, J. A. (2013). Cetacean abundance and distribution in European Atlantic shelf waters to inform conservation and management. Biological Conservation 164, 107–122. http://dx.doi.org/10.1016/j.biocon.2013.04.010
Hansen, R. G., Boye, T. K., Larsen, R. S., Nielsen, N. H., Tervo, O., Nielsen, R. D., Rasmussen, M. H., Sinding, M. H. S., & Heide-Jørgensen, M. P. (2019). Abundance of whales in West and East Greenland in summer 2015. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4689
Hedley, S. L., & Buckland, S. T. (2004). Spatial models for line transect sampling. Journal of Agricultural, Biological, and Environmental Statistics, 9(2), 181. https://doi.org/10.1198/1085711043578
Innes, S., Heide-Jørgensen, M. P., Laake, J. L., Laidre, K. L., Cleator, H. J., Richard, P., & Stewart, R. E. (2002). Surveys of belugas and narwhals in the Canadian High Arctic in 1996. NAMMCO Scientific Publications, 4, 169–190. https://doi.org/10.7557/3.2843
International Whaling Commission (IWC) (2020). Population Estimates. https://iwc.int/estimate
Jourdain, E., Ugarte, F., Víkingsson, G. A., Samarra, F. I. P., Ferguson, S. H., Lawson, J., Vongraven, D., & Desportes, G. (2019). North Atlantic killer whale Orcinus orca populations: A review of current knowledge and threats to conservation. Mammal Review, 49(4), 384–400. https://doi.org/10.1111/mam.12168
Laake, J. L., & Borchers, D. L. (2004). Methods for incomplete detection at distance zero. In ‘Advanced Distance Sampling’. (Eds S. T. Buckland, D. R. Anderson, K. P. Burnham, J. L. Laake, D. L. Borchers and L. Thomas.) pp. 108–189. Oxford: Oxford University Press.
Lawson, J. W., & Gosselin, J. F. (2018). Estimates of cetacean abundance from the 2016 NAISS aerial surveys of eastern Canadian waters, with a comparison to estimates from the 2007 TNASS. SC/25/AE/09 for the NAMMCO Scientific Committee.
Leonard, D., & Øien, N. (2020a). Estimated abundances of cetacean species in the Northeast Atlantic from Norwegian shipboard surveys conducted in 2014–2018. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4694
Leonard, D. M., & Oien, N. (2020b). Estimated abundances of cetacean species in the Northeast Atlantic from two multiyear surveys conducted by Norwegian vessels between 2002–2013. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4695
Miller, P. J. O., Shapiro, A. D., & Deecke, V. B. (2010). The diving behaviour of mammal-eating killer whales (Orcinus orca): Variations with ecological not physiological factors. Canadian Journal of Zoology, 88(11), 1103–1112. https://doi.org/10.1139/Z10-080
North Atlantic Marine Mammal Commission (NAMMCO). (2017). Report of the 24th meeting of the NAMMCO Scientific Committee. Retrieved from https://nammco.no/wp-content/uploads/2017/01/24th-scientific-committee-meeting-report.pdf
North Atlantic Marine Mammal Commission (NAMMCO). (2020). Overview of cetacean abundance estimates in the North Atlantic. NAMMCO Scientific Publications, 11.
Øien, N. (1988). The distribution of killer whales (Orcinus orca) in the North Atlantic based on Norwegian catches, 1938–1981, and incidental sightings, 1967–1987. Rit Fiskideildar, 11, 65–78.
Øien, N. (1990). Sightings surveys in the Northeast Atlantic in July 1988: Distribution and abundance of cetaceans. Report of the International Whaling Commission, 40, 499–511.
Øien, N. (2009). Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995–2001. NAMMCO Scientific Publications, 7, 31–47. https://doi.org/10.7557/3.2704
Palka, D. l., & Hammond, P. S. (2001). Accounting for responsive movement in the transect estimates of abundance. Canadian Journal of Fisheries and Aquatic Sciences, 58(4), 777–787. https://doi.org/10.1139/f01-024
Paxton, C. G. M., Burt, M. L., Hedley, S. L., Víkingsson, G. A., Gunnlaugsson, Th., & Desportes, G. (2009). Density surface fitting to estimate the abundance of humpback whales based on the NASS-95 and NASS-2001 aerial and shipboard surveys. NAMMCO Scientific Publications, 7, 143–159. https://doi.org/10.7557/3.2711
Pike, D. G. (2009). North Atlantic Sightings Surveys. Introduction. NAMMCO Scientific Publications, 7, 7–18. https://doi.org/10.7557/3.2702
Pike, D. G., Gunnlaugsson, T., Desportes, G., Mikkelsen, B., Víkingsson, G. A., & Bloch, D. (2019b). Estimates of the relative abundance of long-finned pilot whales (Globicephala melas) in the Northeast Atlantic from 1987 to 2015 indicate no long-term trends. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4643
Pike, D. G., Gunnlaugsson, T., Mikkelsen, B., Halldórsson, S. D., & Víkingsson, G. (2019a). Estimates of the abundance of cetaceans in the central North Atlantic based on the NASS Icelandic and Faroese shipboard surveys conducted in 2015. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4941
Pike, D. G., Gunnlaugsson, T., Mikkelsen, B., Halldórsson, S. D., Víkingsson, G. A., Acquarone, M., & Desportes, G. (2020a). Estimates of the abundance of cetaceans in the Central North Atlantic from the T-NASS Icelandic and Faroese ship surveys conducted in 2007. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.5269
Pike, D. G, Gunnlaugsson, T., Sigurjónsson, J., & Víkingsson, G. A. (2020b). Distribution and abundance of cetaceans in Icelandic waters over 30 years of aerial surveys. NAMMCO Scientific Publications, 11. https://doi.org/10.7557/3.4805
Pike, D. G, Víkingsson, G. A., Gunnlaugsson, T., & Øien, N. (2009). A note on the distribution and abundance of blue whales (Balaenoptera musculus) in the Central and Northeast North Atlantic. NAMMCO Scientific Publications, 7, 19–29. https://doi.org/10.7557/3.2703
Samarra, F., Tavares, S., Béesau, J., Deecke, V., Fennell, A., Miller, P., Pétursson, H., Sigurjónsson, J., & Víkingsson, G. (2017). Movements and site fidelity of killer whales (Orcinus orca) relative to seasonal and long-term shifts in herring (Clupea harengus) distribution. Marine Biology, 164(8), 1–15. https://doi.org/10.1007/s00227-017-3187-9
Sigurjónsson, J., Lyrholm, T., Leatherwood, E., Jonsson, E., Víkingsson, G. (1988). Photoidentification of killer whales, Orcinus orca, off Iceland, 1981 through 1986. Rit Fiskideilar, 11, 99–114.
Sigurjónsson, J. (1984). Killer whale census off Iceland during October 1982. Report of the International Whaling Commission, 34, 609–612.
Sigurjónsson, J., Gunnlaugsson, Th., Ensor, P., Newcomer, M., & Víkingsson, G. A. (1991). North Atlantic Sightings Survey 1989 (NASS-89): Shipboard surveys in Icelandic and adjacent waters July-August 1989. Report of the International Whaling Commission, 41, 559–572.
Sigurjónsson, J., Gunnlaugsson, Th., & Payne, M. (1989). NASS-87: Shipboard sightings surveys in Icelandic and adjacent waters June-July 1987. Report of the International Whaling Commission, 39, 395–409.
Sigurjónsson, J., Gunnlaugsson, Víkingsson, G., & Gudmundsson, H. (1996). North Atlantic sightings survey 1995 (NASS). Aerial survey in coastal Icelandic waters July 1995. SC/4/17 for the NAMMCO Scientific Committee.
Similä, T. (1997). Sonar observations of killer whales (Orcinus orca) feeding on herring schools. Aquatic Mammals, 23(3), 119–126.
Similä, T., Holst, J. C., & Christensen, I. (1996). Occurrence and diet of killer whales in northern Norway: Seasonal patterns relative to the distribution and abundance of Norwegian spring-spawning herring. Canadian Journal of Fisheries and Aquatic Sciences, 53, 169–779. https://doi.org/10.1139/f95-253
Thomas, L., Buckland, S. T., Rexstad, E. A., Laake, J. L., Strindberg, S., Hedley, S. L., Bishop, J. R. B., Marques, T. A., & Burnham, K. P. (2010). Distance software: Design and analysis of distance sampling surveys for estimating population size. Journal of Applied Ecology, 47(1), 5–14. https://doi.org/10.1111/j.1365-2664.2009.01737.x
Víkingsson, G. A., Pike, D. G., Desportes, G., Øien, N., Gunnlaugsson, T., & Bloch, D. (2009). Distribution and abundance of fin whales (Balaenoptera physalus) in the Northeast and Central Atlantic as inferred from the North Atlantic Sightings Surveys 1987-2001. NAMMCO Scientific Publications, 7, 49–72. https://doi.org/10.7557/3.2705
Vogel, E. F. (2020). The influence of herring (Clupea harengus) biomass and distribution on killer whale (Orcinus orca) movements on the Norwegian shelf (Master’s thesis). UiT The Arctic University of Norway, Tromsø. Retrieved from https://munin.uit.no/handle/10037/19221
Williams, R., Lusseau, D., & Hammond, P. S. (2006). Estimating relative energetic costs of human disturbance to killer whales (Orcinus orca). Biological Conservation, 133(3), 301–311. https://doi.org/10.1016/j.biocon.2006.06.010
How to Cite
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).