Between February and June 2017, five white shark carcasses washed ashore near Gansbaai, a fishing town on South Africa’s Western Cape coast. Each of the four most recent bodies was missing its liver, and one was also missing its heart. Necropsies found tears across the pectoral girdle, the cartilage arch anchoring the front fins, and rake marks consistent with killer whale teeth. Tooth impressions on the pectoral fins were also matched to killer whales.
The deaths followed a period of unusually heavy white shark activity in the area. A 2022 paper led by Alison Towner of Rhodes University described the waters around nearby Dyer Island as the largest aggregation site for white sharks in the country, with a local population estimated at 800 to 1,000 sharks by The Guardian. In early February 2017, guides and tourists on a cage diving boat watched two killer whales with bent dorsal fins cruise past the diving area. The next day, a 2.6-meter female white shark washed up at Pearly Beach. Sightings of live sharks dropped for almost two weeks before returning to normal by May. Then the carcasses began appearing.
On May 3, 2017, a 4.9-meter female, estimated at 1,110 kilograms, was found at Franschhoek Kraal. Marine Dynamics reported that she was the largest white shark ever dissected in South Africa, and that her liver was gone entirely. The following day, a 3.5-meter male came ashore on the same beach, missing his liver and heart. Kelly Baker, a guiding biologist at Marine Dynamics, matched him to a shark she had photographed on April 29 on the Jouberts Dam reef, using marks on the lower lobe of his tail. On May 7, a 4.5-meter male reached the beach at Struisbaai. A six-hour necropsy found his liver removed and his heart still in place. Cape fur seal remains and shark vertebrae were found in his stomach. A fifth carcass washed up in June.
Towner described the removal of the liver as almost surgical, with the rest of the shark left intact. The researchers had a cause of death within a week of the May strandings. They also had suspects: two male killer whales with collapsed dorsal fins had been appearing along the coast since 2015.
The pair had been given names based on which way their fins folded. Dave Hurwitz, who runs licensed whale watching trips in False Bay near Cape Town, called them Port and Starboard, sailor terms for the left and right sides of a ship. The whales were first seen near Luderitz in Namibia in 2009, and their first sightings around the Cape came in 2015. Hurwitz kept a sighting log that eventually held 55 entries from Luderitz to Port Elizabeth.
Before the white shark deaths, the pair had been linked to a series of killings in False Bay. In November 2015, divers found a dense gathering of broadnose sevengill sharks at Miller’s Point had vanished, replaced by several carcasses with wounds near their pectoral fins. Researchers initially suspected human activity. In April 2016, divers brought up more dead sevengills from the seabed, each with the same wound across the pectoral girdle and a missing liver. Bite marks on the pectoral fins with bruising underneath pointed to the killer whales. Sighting records of Port and Starboard from local boat operators lined up with the locations where the carcasses were found. The findings were published in a 2019 paper in the journal Ecosphere titled Running Scared. About 20 sevengills were killed that year, counting only bodies that washed up or were found by divers.
Until May 2022, every case against the pair rested on carcasses found after the fact. Nobody had recorded a killer whale opening a white shark in South African water. On May 16, 2022, a hobbyist with a drone over Mossel Bay recorded it.
Christian Stopforth sent his drone up above Hartenbos Beach and picked out five killer whales heading toward the Hartenbos River Mouth. One of them had a fin folded hard to the right; that whale was Starboard. The footage showed a killer whale using its snout to push a white shark of about three meters to the surface, rolling it onto its right side before biting near the pectoral fins. A cloud of blood spread through the water. Overhead, Dudley Archer of Mossel Bay Helicopters was flying short tourist trips across the same stretch of water and saw two white sharks killed. He took phone clips of Starboard trailing a large shark and a sequence of images showing what appeared to be a whale eating a free-floating liver.
Writing up both sets of footage for the January 2023 issue of Ecology, Towner, Stopforth, Hurwitz, and Elwen counted at least two white sharks dead and possibly a third over roughly 71 minutes. It was the first direct observation of killer whales killing white sharks in South Africa. The floating liver confirmed that the organ is buoyant enough to slip out of a torn body and rise to the surface.
A year later, Starboard hunted without help. On June 18, 2023, Esther Jacobs, founder of Keep Fin Alive, a marine conservation nonprofit, was off Mossel Bay’s Seal Island when she smelled shark liver oil and saw a slick spreading on the water. A white shark of about 2.5 meters broke the surface with Starboard behind it. Starboard seized the left pectoral fin, tore the shark open, and carried a piece of liver past a nearby boat in under two minutes. Port stayed about 100 meters off. The next day, a second white shark, 3.55 meters long, washed up on Hartenbos Beach. An examination found rake marks across the body, a long tear along the pectoral girdle and belly, and the liver and reproductive organs missing. The solo kill appeared in the March 2024 issue of the African Journal of Marine Science.
Both papers also recorded what the surviving sharks did next. In Mossel Bay, they left within minutes. At Gansbaai, Towner had already measured how long that kind of absence could last.
A displacement study, Fear at the Top, went online in June 2022 with 14 authors. It rested on two kinds of evidence: sightings per day logged by boat crews, and acoustic telemetry from small transmitters fitted to sharks that send coded pings to underwater receivers. Tagged sharks left Gansbaai right after the 2017 kills. Three were later detected as far east as Plettenberg and Algoa Bays, over 500 kilometers away. After the three carcasses in May and the fifth in June, crews went eight weeks without seeing a single white shark. Sightings stayed low for two and a half years. Bronze whalers, smaller coastal sharks also called copper sharks, moved into the gap.
A sixth dead white shark reached the Gansbaai shore in June 2021, and the survivors kept clear for roughly 12 more months. False Bay showed a similar break with a longer baseline. A study comparing standardized shark counts at Seal Island reported that sightings fell from 1.64 per hour between 2000 and 2015 to 0.30 per hour across 2016 through 2020, a drop of 82%. After August 2018, the surveys logged no white sharks at all. Mossel Bay followed. Speaking to The Guardian in January 2025, Jacobs said the sharks there had stayed scarce since the June 2023 kill, with fewer than 10 confirmed sightings she knew of across all of 2024.
A young white shark was filmed just north of Seal Island in False Bay on September 23, 2026. Rob Lawrence, who runs African Shark Eco Charters, told the Daily Maverick it was the first white shark his crews had seen there in eight years, and warned against reading it as a recovery. Hurwitz told the paper that the reasons for the long absence were still unclear and likely combined the killer whales, local fishing, and the shark nets off KwaZulu-Natal.
Three explanations for the sharks’ long absence have published evidence behind them. The first starts inside the shark. A shark carries no blubber, so its spare energy goes into its liver. In 2014, Heidi Pethybridge and colleagues at Australia’s national science agency, CSIRO, published lab tests on 21 dead white sharks from 1.5 to 3.9 meters long, most caught as bycatch or in shark control nets off South Australia and New South Wales between 2001 and 2012. The liver made up 8.2 to 16.2% of body weight, and between 51.6 and 70.4% of the wet liver was fat. White shark muscle held less than 0.9% fat. The team calculated that for a 428-kilogram shark, the liver held about 1,425 megajoules of energy against 867 in all the muscle together, even though the muscle weighed several times more. Pethybridge’s group wrote that white shark liver is richer in energy than whale blubber. The Mossel Bay paper in Ecology noted that an adult male killer whale needs about 1,394 megajoules a day, roughly the energy in the liver of that same 428-kilogram shark. Elwen put it plainly to the Daily Maverick in 2023, saying one adult killer whale needs the equivalent of one white shark liver a day.
One correction is needed here. Towner’s 2017 update called the Gansbaai livers squalene-rich. The Australian tests found white shark liver fat was 96.3% triacylglycerols, the same basic type of fat found in cooking oils. Squalene dominates the livers of sharks living deeper than 200 meters, a category that does not include white sharks.
Energy explains why the whales open the sharks at the pectoral girdle and take one organ. It says nothing about why sharks that were never touched also left for months. For that, the evidence comes from tags. The second explanation is what ecologists call a risk effect, meaning that animals shift their hunting grounds when a predator turns up, even if most of them are never attacked.
The first documented case came from California. On October 4, 1997, near Southeast Farallon Island off San Francisco, two killer whales killed a white shark while biologist Peter Pyle filmed from a small boat. The whales were seen feeding on its liver. Shark attacks on seals at the island almost stopped for the rest of that season. In 2019, Salvador Jorgensen of the Monterey Bay Aquarium put numbers on it. His team fitted acoustic tags to 165 white sharks at Central California seal colonies between 2006 and 2013. Their April 2019 paper in Scientific Reports described November 2, 2009, when killer whales spent a few hours at Southeast Farallon Island and all 17 tagged sharks in the area left within about eight hours, most not returning until the next season. In years with killer whale visits, shark kills of seals at the island fell by 3.5 to seven times.
South Africa produced exactly the kind of record Jorgensen had shown in California. At Gansbaai, tagged sharks left right after the 2017 kills, and three reached bays more than 500 kilometers east. At Mossel Bay, beach observers saw white sharks fleeing in several directions four minutes before the May 16, 2022 kill, some into water less than two meters deep. A 3.8-meter female carrying a satellite tag sent her last Hartenbos position on May 14, two days before the hunt, and her next one on May 25 came from Algoa Bay, 400 kilometers east. Crews from the cage diving company White Shark Africa had been logging 3.3 sharks on an average trip before the Mossel Bay kills, then went 45 days without one until a shark showed up on July 1, 2022.
Fear explains the leaving and the weeks of empty water. It explains less well why some sites stayed nearly empty for years when the whales were gone for months at a time. The third explanation looks at the people fishing along the same coast.
In September 2023, Heather Bowlby, Matt Dicken, Towner, Sarah Waries, Toby Rogers, and Geremy Cliff published a trend study in Ecological Indicators. Using data through 2020, they concluded that South Africa’s white sharks had stayed stable since the species was protected in 1991 and had shifted east, a shift they linked in part to the killer whales. Gennari of the Oceans Research Institute in Mossel Bay led a rebuttal in the same journal in early 2024. He told the Daily Maverick that the drop at the Western Cape sites began around 2011 and 2012, years before the pair appeared there in 2015. Sara Andreotti of Stellenbosch University, a co-author, said the comparison mixed very different data, with sightings in the west and angler reports and shark net catches in the east. The rebuttal argued that if the sharks had simply moved, Algoa Bay should hold about 10 times more of them.
A paper co-authored by Dicken, who heads the KwaZulu-Natal Sharks Board, recorded 1,317 white sharks caught in the province’s beach nets and drum lines between 1978 and 2018, with only 16% released alive, an average of about 28 killed each year. Gennari estimated that longline boats have killed at least 40 white sharks a year since 2005, with a peak around 2010 to 2012. Put together, those two sources kill considerably more white sharks than the killer whales are known to have taken, almost 10 times more over seven years by Gennari’s estimate. Wilfred Chivell, who founded the Dyer Island Conservation Trust, said the whales do set off a flight response, but that blaming them alone for every shark moving east was wrong. The environment department spokesperson, Peter Mbalengwa, answered that the rebuttal had offered no alternative analysis. How much of the decline belongs to whales and how much to nets is a split researchers still describe carefully.
Port and Starboard were back in Kalk Bay in 2025 and seen apart in 2026. The disagreement over why the sharks stayed gone continues. But the core facts are now on record: two male killer whales with folded fins have killed white sharks off South Africa, they take the liver and leave most of the body, and white sharks left several of their best known gathering sites afterward.
