Type D orcas

Type D orcas appear alongside Sea Shepherd vessel; images are via Sea Shepherd

Mysterious and rarely observed killer whales described simply as "Type D" were documented recently in the southern Indian Ocean by a Sea Shepherd Conservation Society crew that had been pursuing what it claimed to be poachers.

The orca encounter--which lasted about an hour and included wake surfing, bow riding, and tail slapping--occurred on December 26 in rough seas in the harsh and remote region between the Crozet and Kerguelen archipelagos (see video).

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In this area the mammals, which are characterized by their large bulbous foreheads, are known to eat toothfish--a popular type of cod marketed as Chilean seabass--after they've become hooked on longline gear.

The Sea Shepherd crew, aboard the Bob Barker, claimed to have been pursuing a vessel fishing illegally for toothfish when 13 Type D orcas appeared alongside the boat and were videotaped.

Robert L. Pitman, of NOAA's Southwest Fisheries Science Center in the United States, confirmed the sighting and is quoted in a Sea Shepherd press release as saying that before this encounter, "I don't think they have ever been filmed alive."

Type D orcas

A scientific paper on Type D orcas, produced by CNRS, states that they're one of three distinct "morphotypes" of killer whales that have been documented off the Crozet and Kerguelen islands, which are French territories.

The Type D group, first documented in Crozet waters in 2003, is the rarest and most mysterious. Little is known about these mammals' feeding habits, beyond depredation on hooked toothfish.

However, their appearance is distinct. Besides their bulbous foreheads they boast tiny eye patches compared to those of most killer whale types; also, their dorsal fins are shorter and narrower, and their teeth are smaller.

Most sightings, understandably, have been logged by longline fishermen.

Erwin Vermeulen, chief engineer aboard the Bob Barker, said of the December 26 encounter: "The crew watched in awe as the 13 killer whales, including a small juvenile and a large male, used a 6-meter 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 is a controversial group most famous for its annual harassment of Japanese whalers in the Antarctic. Sea Shepherd's campaign against illegal fishing for toothfish is called Operation Icefish.

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