Short Note

Polar Biology

, Volume 34, Issue 2, pp 303-306

First online:

Observations of a distinctive morphotype of killer whale (Orcinus orca), type D, from subantarctic waters

  • Robert L. PitmanAffiliated withProtected Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration Email author 
  • , John W. DurbanAffiliated withProtected Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration
  • , Michael GreenfelderAffiliated with
  • , Christophe GuinetAffiliated withCEBC-CNRS
  • , Morton JorgensenAffiliated with
  • , Paula A. OlsonAffiliated withProtected Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration
  • , Jordi PlanaAffiliated withQuaternary Research Center (CEQUA)
  • , Paul TixierAffiliated withCEBC-CNRS
  • , Jared R. TowersAffiliated withMarine Education and Research Society

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Abstract

Studies have shown that killer whale (Orcinus orca) communities in high latitudes regularly comprise assemblages of sympatric ‘ecotypes’—forms that differ in morphology, behavior, and prey preferences. Although they can appear superficially similar, recent genetic evidence suggests that breeding is assortative among ecotypes within individual communities, and species-level divergences are inferred in some cases. Here, we provide information on a recently recognized ‘type D’ killer whale based on photographs of a 1955 mass stranding in New Zealand and our own six at-sea sightings since 2004. It is the most distinctive-looking form of killer whale that we know of, immediately recognizable by its extremely small white eye patch. Its geographic range appears to be circumglobal in subantarctic waters between latitudes 40°S and 60°S. School sizes are relatively large (mean 17.6; range 9–35; n = 7), and although nothing is known about the type D diet, it is suspected to include fish because groups have been photographed around longline vessels where they reportedly depredate Patagonian toothfish (Dissostichus eleginoides).

Keywords

Killer whale Orcinus orca Subantarctic Type D