During my latest travels, I spent May through November 2019 enjoying South Africa’s Western Cape. I became aware of two orcas – nicknamed Starboard and Port – who were earning a reputation as coastal predators. They’re named for their collapsed dorsal fins, to the left (Port) and right (Starboard).
Identifying Port and Starboard
Local scientists think the orca hunting partners are mature males about 30 years old – an average life expectancy for the species is 30 to 50. With age, orca dorsal fins “bend, weaken, collapse, or roll”. That’s the case with Port and Starboard’s distinct dorsals.
Cape Town to Gansbaai
I read accounts of them showing up indiscriminately between Cape Town and Gansbaai. They even cruised the marina at Cape Town’s Victoria and Alfred (V&A) Waterfront – eerily capturing the attention of diners at upscale restaurants.
After months in Cape Town, I moved to Hermanus, a seaside town along the “whale coast”. The area is famous for beautiful beaches and renown whale watching. Near Hermanus, Gansbaai is a resort and fishing town known as the world’s “Great White Shark Capital”.
Mutilated Shark Carcasses
Shark carcasses began appearing on False Bay beaches and seabeds inside Table Mountain National Park Marine Protected Area. Initially, “humans were blamed, but when more and more dead sharks surfaced, it became clear that killer whales were responsible for the shark carnage”.
For years, killer whale sightings were rare in the Western Cape. Normally, they remain further out to sea feeding on seals, dolphins, and whales. However, research shows that “killer whales can adapt when their food is scarce”. Local marine biologists speculate that the pair are part of a new “sub-group killer whale species specializing in shark hunting”.
According to False Bay Shark Spotters, “the 2017-18 summer season recorded an all-time low number of great white sharks across Cape Town beaches”. In 2019, another decline in sightings occurred in False Bay and at Seal Island. Some blamed the “shark-eating killer whales”.
How Orcas Hunt
Port and Starboard target the “nutrient-rich livers” of their prey. It’s easier for them to ambush slower moving sharks rather than chase fast-moving dolphin pods. Experts say focusing on livers is an “efficient” hunting method, because orcas can “use more energy eating an entire carcass than they gain in nutrition”.
Local marine biologists speculate that the pair are part of a new “sub-group of killer whale species specializing in shark hunting”.
The shark carcasses found had striking similarities. Their throats were ripped out with almost “surgical precision”. Scientists described a classic shark killing “modus operandi” – two orcas “grab a pectoral fin each, flip the shark over, tug to split open the throat and chest cavity, and suck out the liver”.
Killer whales locate sharks using echolocation (reflected sound). Applying “force to the shark’s pectoral fins ruptures the pectoral girdle and allows easy access to their liver”. Orcas love to feast on delicious high-fat livers that can “weigh up to 600 pounds and account for buoyancy and a third of a shark’s total body mass”.
Coastal Ecosystem Disruption
Historically, seals are the primary prey for great white sharks. Studies show the presence of orca scares them away from the seal colonies where they feed. Broadnose sevengills and great whites “play a key role as apex predators in the ecosystems they inhabit”. A “reduction in their numbers due to predation from killer whales, combined with prolonged absence from traditional gathering sites”, can affect an entire coastal ecosystem.
Scientists say “ongoing research is needed to better understand the drivers behind killer whale presence along South Africa’s coast”. The impact on “long‐term behavior and movement patterns of apex shark species” is unknown.
Although I enjoyed spending time along the coast whale watching, hiking, swimming, and kayaking, I never saw Port and Starboard. I didn’t have enough nerve to try shark cage diving. South Africa was the culmination of a fourteen-month solo trip beginning in Berlin Germany in October 2018 and then through Croatia, Montenegro, Bosnia-Herzegovina, Serbia, Sicily, and Malta, before ending in South Africa. I’ve been back in the US since December 2019 – still absorbing the memories of my extraordinary experiences!