Since 2017, even great white sharks off the South African coast are no longer safe from predators: .»Port»and»Starboard», as the marine mammals are called, are not limited to great white sharks, as an event from the beginning of March-_2023 shows: In the feeding frenzy, the two whales killed at least 17 and perhaps even 19 Broadnose sevengill sharks (Notorynchus cepedianus), about three meters long and over 100 Kilogram species, as well as a spotted shark (Triakis megalopterus). This is reported by the media, citing shark researcher Alison Towner of the Dyer Island Conservation Trust.
The dead sharks were washed up after a storm and showed typical bite marks, the imprints of which point to the killer whales.»Port»and»Starboard»have previously been spotted in the waters of the region; and observational data showed that they repeatedly dived into a small area for two hours to hunt. As in the other cases, the killer whales had targeted the fatty liver of the sharks: Their belly was torn open in the area and the organ was missing. In addition, the superpredators partly ate the stomachs of the sharks and their contents.
«That’s the largest amount of sharks that the orcas have killed in this area at once,» Towner is quoted as saying. It is also the first observation that the two killer whales hunt other large shark species; until now, only their stalking on great white sharks was known. Because of the attacks, this species now avoids parts of the South African coast: off Cape Town they are hardly observed; as soon as»Port»and»Starboard»appear, the predatory fish flee and often do not return for weeks.As shark diving is an important industry for South African tourism operators, the behaviour of marine mammals also has economic consequences.
Because of their crooked dorsal fins,»Port»and»Starboard»are easily recognizable and have already been discovered in various parts of the coast from Namibia to Port Elizabeth on the South African east coast. In May 2022 it even managed to . Since then, biologists have been puzzling over whether the two killer whales pass on their behavior to conspecifics who learn it from them. If confirmed, shark hunting could spread – with consequences for the ecosystem: sharks are top predators, their failure changes the food chains in the sea. Overall, however, killer whales played a subordinate role when it comes to declining stocks of sharks: We humans fish hundreds of thousands of fish from the nbsp every year; Sea.
Source — https://www.spektrum.de/news/schwertwale-17-haie-im-fressrausch-getoetet/2118210