Great White Carcass Indicates Continued Predation by Orcas
A fourth great white shark carcass has been found washed up near Gansbaai, South Africa, with similar injuries as three previous carcasses found in May that were confirmed as having been killed by orcas.
Dyer Island Conservation Trust marine biologist Alison Towner, confirmed on Marine Dynamic's facebook page that a 4.1m male great white was found washed up with its liver, testes and stomach missing. The Facebook post states that the shark was found 'with the exact same injuries' as the three sharks washed ashore earlier in May.
Marine Dynamics, a great white conservation group and cage-diving tour operator, wrote in a blog post that they had been tracking two male orcas that had been sighted in the area since April, which are thought to be responsible for the attacks on the sharks.
Nicknamed 'Port' and 'Starboard' due to the respective directions in which their dorsal fins droop, the presence of the two orcas has also led to a decrease in shark sightings during the cave diving trips, indicating that the great whites have fled the area as a result.
'This is the fourth documented deceased white shark since May that we can connect to crca predation,' said Towner. Necropsies on the carcasses of the great whites washed ashore in early May confirmed that the great whites had been attacked by orcas, with bite barks on their pectoral fins confirmed to be those of orcas, and in all four cases now, the nutrient rich livers have been removed 'with surgical precision', but with the rest of the carcass mostly intact.
Orcas (also known as killer whales) are the only known predator of great white sharks, but the recent spate of attacks are the first time that the great white's carcasses have been washed ashore and therefore been available for more detailed study.