[imagesource: Carl De Souza/AFP/Getty Images]
The disappearance of Cape Town’s great white sharks has been well documented, as well as the impact that’s having on the various industries reliant on their presence.
Whilst it’s not quite panic stations on the whale front, a recent survey of the population of southern right whales off the coast of Cape Town has shown the second-lowest incidence of the aquatic mammals in 24 years.
The disappearance of the sharks has attracted plenty of international media attention, and now CNN is wading in.
Focusing largely on False Bay’s Seal Island, we hear from Chris Fallows, a well-known shark expert, photographer and tour boat operator whose photos of the predators flying through the air mid-hunt gained him worldwide attention.
Sadly, those photos are all but a thing of the past:
After countless documentaries and Shark Week appearances on the Discovery Channel, in 2019, Fallows is forcing himself to talk about these awesome sharks in the past tense.
“For me, losing the great white is like losing part of my soul,” he says. “It shaped my life and it has given me some of the greatest highs of my life.”
Back in 2012, Fallows and his team witnessed 47 shark predations in False Bay in a single day. But for more than a year now, nobody here has recorded a great white. Not one.
The great whites of False Bay have vanished.
A graph plotting the frequency of these attacks on Cape fur seals yields a predictable tailing off:
One person who hasn’t been surprised by the disappearance of the apex predators is Stellenbosch University marine biologist Sara Andreotti, who was part of the team that released a paper in 2016 predicting what would come next:
The DNA analysis of the shark population, combined with a visual count, revealed numbers that shocked the team. Earlier estimates had put the great white numbers in the low thousands. Andreotti and her colleagues believed that the number, back in 2012 when they collected they collected the data, was just a few hundred.
Their DNA analysis of the shark tissue uncovered two deeply alarming facts.
First, it turns out that the genetic diversity of the South Africa whites is exceptionally low, making them more susceptible to external shocks like disease or environmental change. And second, and a more immediate danger, based on the genetic testing the breeding population one generation above the sharks sampled was around just 300 individuals.
“To maintain a population, you need more than 500,” says Andreotti.
The report found that 89% of all sharks here had the exact same lineage. That inbreeding has resulted in a species less able to adapt to the changing conditions.
The presence of orcas, and the infamous Port and Starboard, in particular, has been put forward as another reason for the sharks disappearing from False Bay.
Both Andreotti and Fallows believe that the local commercial fishing sector plays a role, too:
There has been a steady increase in demersal fishing for sharks and rays for consumption as fish and chips in Australia.
Great whites, particularly the young ones, eat smaller sharks rather than seals as their main diet during large parts of the year, and Fallows says there has been a collapse in the populations of some of these shark species. And large sharks are regularly caught accidentally as by-catch by trawlers and line fishing boats off the coast.
Whatever the reason, it’s incredibly sad to see these animals, which have ruled the underwater ecosystem for so long, being wiped out.
The CNN article also features this video, covering much of what has been spoken about above:
Back in 2012, False Bay, Cape Town, recorded 47 shark predations in a single day. But for more than a year now, nobody there has recorded a great white. Not one. The great whites of False Bay have vanished. https://t.co/skg0wluagC pic.twitter.com/qy0Znnrr4e
— CNN (@CNN) October 29, 2019
[source:cnn]
