Variation in saddle patch pigmentation in populations of killer whales ( Orcinus orca) from British Columbia, Alaska, and Washington State

Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Of the five types of saddle patch analyzed, all were observed on residents, but on...

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Bibliographic Details
Published in:Canadian Journal of Zoology
Main Authors: Baird, Robin William, Stacey, Pam Joyce
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1988
Subjects:
Online Access:http://dx.doi.org/10.1139/z88-380
http://www.nrcresearchpress.com/doi/pdf/10.1139/z88-380
Description
Summary:Patterns of pigmentation of the post dorsal fin patch, or saddle patch, were analyzed from photographs of 372 resident and 99 transient killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Of the five types of saddle patch analyzed, all were observed on residents, but only two occurred on transients. Differences in saddle patch shapes were independent of age and sex. Saddle patch pigmentation patterns were similar among clans within a community. Pigmentation patterns differed significantly between the resident and transient forms, between northern and southern residents, between northern and Alaskan residents, and between southern and Alaskan residents. As the saddle patch shape may be heritable to a large degree, these differences suggest genetic isolation of the populations. If so, this technique may be used to delineate stocks of killer whales from other areas.