Killer Whale Update

Killer whales (Orcinus orca) have group-specific call repertoires that can be used to track groups and populations using passive acoustic monitoring. To provide a detailed description of the Icelandic killer whale repertoire and its variation, acoustic data collected in five locations between 1985 and 2016 were analyzed. A total of 91 call categories (including call types and subtypes) were defined. Most call categories were recorded in more than one location, with the highest proportion shared between herring grounds in Vestmannaeyjar (South) and Breiðafjörður (West). However, both locations included call categories that were not recorded elsewhere in Iceland. Recordings from past herring wintering grounds in eastern Iceland included few call categories that matched other locations. The relative occurrence of call categories in Vestmannaeyjar changed little over a 14-year period (2002–2016), although shorter-term changes between years were observed that appeared to correlate to changes in individuals identified. This suggests long-term site fidelity, meaning that the same groups of whales are likely returning to this area over time. This information can be valuable for conservation efforts, as it indicates areas of importance to the species. This comparison of acoustic repertoires also provides valuable information on the social structure and movement patterns of herring-eating killer whales around Iceland.

The study provides a more comprehensive and updated analysis of the call type repertoire of killer whales in Iceland, expanding on the foundational work of HSWRI scientists in 1988. It also offers insights into the long-term stability and variation in the call repertoire over time and across different locations.

Selbmann, A., Deecke, V.B., Filatova, O.A., Fedutin, I.D., Miller, P.J.O., Simon, M., Bowles, A.E., Lyrholm, T., Sigurjónsson, J., Lacey, L., Magnúsdóttir, E.E., Maunder, W., Wensveen, P. J., Svavarsson, J., and Samarra, F.I.P.  2023.  Call type repertoire of killer whales (Orcinus orca) in Iceland and its variation across different regions.  Marine Mammal Science 2023: 1-25.  DOI: 10.1111/mms.13039