The animals responsible for the killings were recognized by their twisted dorsal fins. Local residents who have developed a liking for sharks have become familiar with Port and Starboard’s behavior.
The sharks that were killed were mainly broad-nosed seven-gills and one spotted gully shark. Towner said that Port and Starboard had caused white sharks to disappear from some of the waters near Cape Town.
In a scientific study released in October 2022, footage showed Starboard and another four orcas chasing and killing a great white shark.
Simon Elwen, who heads Sea Search, a scientific collective, said that the two killer whales were first spotted near Cape Town in 2015.
The whales like to hunt near the coast and have been spotted in southern Africa, from as far west as Namibia to as far east as Port Elizabeth.
The orcas’ killing technique is “surgical,” said marine biologist Ralph Watson, as they target the liver, which is “a very nutritious organ, full of oils.”
The concern is that the behavior of Port and Starboard could spread as studies have shown that killer whales have the ability to teach hunting techniques.
The attacks on great whites have confirmed that sharks have a flight response and could have broader implications. South African National Parks’ shark expert and marine biologist, Dr. Alison Kock, said that the sharks ultimately abandoned former key habitats, which had significant knock-on effects for both the ecosystem and shark-related tourism.
While the danger posed by Port and Starboard is limited, the discovery of the dead sharks is “fascinating and frustrating,” said Elwen.
However, hundreds of thousands of sharks are fished out of the sea every year, said Watson, and “two killer whales are not going to wipe out a species.”