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Three Killer Whale EcotypesPhotographs below illustrate how the three recognized Northeast Pacific killer whale ecotypes can be distinguished based on examination of morphological differences in the dorsal fin and adjacent saddle patch region.
Three forms of killer whales, termed “resident,” “transient,” and “offshore” have been described in the coastal waters of the Northeast Pacific Ocean. These terms were originally designated by killer whale researchers to describe the whales’ patterns of occurrence, particularly in British Columbia and Washington. “Residents” were generally in inland waters all summer, whereas “transients” only appeared occasionally, and “offshore” whales were seen only in outer coast waters. As studies have increased over larger geographical and temporal scales, it has become apparent that these terms do not fully depict the ranging patterns of these three ecotypes. However, recent research continues to confirm that the three terms do refer to very distinct types of killer whales that can be distinguished based on genetics, acoustics, and morphology. Research also shows the terms apply to distinct types of feeding ecology. Resident killer whales are known to be primarily fish-eaters, in contrast to transients that feed primarily on marine mammals. Relatively few feeding observations have been made for the offshore type, but initial data suggest they also eat fish.
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