Two orcas renowned for terrorizing great white sharks were again seen hunting off the coast of South Africa. The killer whales, which are dubbed Port and Starboard, are known to kill great whites and rip out their livers. Last month, marine scientists witnessed the deadly duo killing a record 17 sharks in one day at Pearly Beach, South Africa.
“We observed the two orcas repeatedly diving down in a small area for almost two hours before they departed offshore,” said Ralph Watson, a researcher with Marine Dynamics Academy, a Gansbaai, South Africa, organization that uses ecotourism to further marine research and conservation goals, in a Facebook post.
A few days later Watson and his team retrieved the carcasses of several broadnose sevengill sharks from a nearby beach. “Each sevengill shark was torn open and missing its liver,” said Alison Towner, a Ph.D. student who is leading a study on killer whale hunting behavior. She participated in performing necropsies on the sharks. “They were all females measuring between 1.6 to 2.3 meters and had similar injuries to those killed in False Bay by the same orca pair,” Towner said.
A July 2021 study led by Towner found that Port and Starboard were ripping sharks open by grasping them by their pectoral fins. The whales then removed the sharks’ livers, which are highly fatty and calorie-rich, before leaving the carcasses to wash up on shore. The pair hunt together and often prey on great whites and other sharks by forcing them to the surface and attacking from below. The study used telemetry tracking to show that the orcas’ behavior was causing great whites to abandon their territory near Gansbaai—once considered the shark-diving capital of the world—when the killer whales showed up, sometimes fleeing hundreds of miles and staying away from the area for up to half a year.
While earlier research documented on video the ruthless efficiency of the orca duo’s cooperative hunting tactics, this recent killing spree suggests just how dramatic an impact that killer whales could make on many shark species that are already threatened by factors like climate change and overfishing that have led to big declines in their numbers over the last half-century. “This is the largest amount of sharks these orcas have killed in this area in one sitting,” Towner observed. “There could well be more that didn’t wash out.”
Port and Starboard were first seen killing and eating sharks in 2015. They earned their names from their collapsed dorsal fins: Port’s bends to the left and Starboard’s bends to the right. Bent dorsals are fairly common in captive orcas but are rare in the wild.