On the sidelines of Operation Icefish, the Sea Shepherd group saw one of the most spectacular sea creatures in the South Indian Ocean while chasing a Nigerian-poaching vessel from the Antarctic. The crew spotted of a rare type of killer whale which was not been seen for decades.
The crew of the MY Bob Barker ship encountered “Ecotype D Orcas” while passing between the Crozet and Kerguelen archipelagos in pursuit of the toothfish poaching vessel, Thunder, in late December.
Robert Pitman, Marine Ecologist and Antarctic Orca expert from the Southwest Fisheries Science Center of the National Oceanic and Atmospheric Administration in the US, confirmed the whales are type D orcas based on the photographs sent by the crew. While examining the photographs, Pitman also said he believed they have never before been filmed alive.
Scientists admitted that little is known about this type of Orca, which is infrequently seen in inaccessible subantarctic waters. The last sighting of the rare whales was in 1955 on Paraparaumu Beach, New Zealand.
The Type D orca is characterised by its large bulbous forehead, similar to that of the Pilot whale, and tiny post-ocular eye markings. From National Geographic:
While typical killer whales—types A, B, and C—have streamlined bodies and large, white eye-patches, type D whales have tiny eye markings and large, bulbous heads.
Researchers are said to have sequenced type D’s genome using material collected from a museum skeleton from 1955.
Bob Barker chief engineer Erwin Vermeulen recounts, ”The crew watched in awe as the 13 killer whales, including a small juvenile and a large male, used the six-metre swell to surf across the bow. For almost an hour the surf-show continued and was accompanied by bow riding, tail-slaps and breaches.”
Sea Shepherd said DNA retrieved from the 1955 stranding revealed that Ecotype D’s genetic differences point at a divergence from other Orcas about 390,000 years ago. This makes Ecotype D the second oldest Orca type, and second most genetically divergent.
Determining how many species of Orcas there are is critically important to establishing conservation measures and to better understand the ecological role of this apex predator in the world’s oceans, it concluded.