Fig. 1. A curious killer whale among the fast ice in McMurdo Sound, Antarctica, "spyhops" to take a look at the photographer. The narrow, slanted eyepatch identifies this as a Type C killer whale -- a fish eater. Photo: R. L. Pitman
Fig. 2. NOAA Fisheries researcher Lisa Ballance sits on the frozen ocean and points to an adult male killer whale with a match-boxed size satellite tag attached to its dorsal fin (not visible in this photo). Photo: R. L. Pitman
Fig. 3. Russ Andrews from the Alaska SeaLife Center, Seward, attaches a satellite tag to the dorsal fin of an adult female killer whale as it swims through an open lead in the frozen sea ice. The dart shaft is fired by an airgun and the tag is anchored in the dorsal fin by barbed prongs. After contact, the shaft bounces back and is retrieved by the monofilament tether; the antenna for the tag is in the shaft. Photo: R. L. Pitman
During January/February 2006, SWFSC researchers performed field work in Antarctica to study killer whale (Orcinus orca) movement patterns. The research team satellite-tracked two different ecotypes of killer whales in McMurdo Sound, Ross Sea, using surface-mounted tags attached with sub-dermal darts. A single Type B whale (pinniped prey specialist), tracked for 27 days, traveled an average net distance of 56.8 ± 32.8 km per day, a maximum of 114 km per day, and covered an estimated area of 49,351 km2. It spent several days near two large emperor penguin (Aptenodytes forsteri) colonies, a potential prey item for this form. By contrast, four Type C killer whales (fish prey specialists) tracked for 7–65 days, traveled an average net distance of 20 ± 8.3 km per day, a maximum of 56 net km per day, and covered an estimated area of only 5,223 km2. These movement patterns are consistent with those of killer whale ecotypes in the eastern North Pacific where mammal-eating ‘transients’ travel widely and are less predictable in their movements, and fish-eating ‘residents’ have a more localized distribution and more predictable occurrence, at least during the summer months.
Click on the image below to view an animation of the tracks of killer whales (WMV format / 4.46 MB / duration = 60 seconds). The track of the mammal-eating killer whale (Type B) is shown in black and the other colors represent different fish-eating killer whales (Type C).
This research supported by:
- NOAA Fisheries Service
- National Science Foundation
- National Geographic Society
For more information:
Andrews, R. D., R. L. Pitman, and L. T. Ballance. 2008. Satellite tracking reveals distinct movement patterns for Type B and Type C killer whales in the southern Ross Sea, Antarctica. Polar Biology. In Press.