[MARMAM] Article on a new killer whale morphotype (Robert Pitman)

Robert.Pitman Robert.Pitman at noaa.gov
Fri Aug 20 11:00:11 PDT 2010

The following article was just published online in /Polar Biology/: DOI 

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

R. L. Pitman, J. W. Durban, M. Greenfelder, C. Guinet, M. Jorgensen, P. 
A. Olson, J. Plana, P. Tixier, J. R. Towers

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/).

PDF available from robert.pitman at noaa.gov <mailto:robert.pitman at noaa.gov>

Robert L. Pitman
Protected Resources Division
Southwest Fisheries Science Center
National Marine Fisheries Service
National Oceanic and Atmospheric Administration
8604 La Jolla Shores Drive
La Jolla, California  92037

858-546-7092 phone
858-546-7003 fax
robert.pitman at noaa.gov

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