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Yahoo
18-06-2025
- Science
- Yahoo
Great White Sharks Were Scared From Their Habitat by Just 2 Predators
No sea creature inspires terror – rightly or wrongly – as much as the white shark does. With its sleek body optimized for hunting, razor sharp teeth, and its (somewhat undeserved) reputation for enjoying human flesh, the 'great' white (Carcharodon carcharias) is widely regarded as one of the ocean's top predators. And that's true, it is – but there's something even the great white fears. Watch the video below for a summary of the research that revealed a predator other predators fear: From 2017, scientists have documented that the sharks have made themselves extremely scarce off the coast of South Africa, where they usually congregate. Initially, the strange disappearance was blamed on human activity, such as overfishing. But, in 2022, research confirmed in detail the true culprit: a pair of orcas (Orcinus orca), nicknamed Port and Starboard for the distinctive kinks in their dorsal fins, hunting the sharks and slurping out their delicious, nutritious, vitamin-rich livers. Once upon a time, the fishing town of Gansbaai on the South African coast was something of a mecca for shark-spotters – so heavily populated with the predators that nearby Dyer Island is considered the great white shark capital of the world. Over the last few years, however, the sharks' presence has been diminishing. In addition, since 2017, at least nine great white sharks have washed ashore at Gansbaai, several of them missing livers (and some without their hearts) – the hallmark of an orca attack. And white sharks aren't the only prey. Port and Starboard have been implicated in a broadnose sevengill shark killing spree, wiping out at least 17 in a single day. The wounds on these sharks are distinctive, and have been traced to the same pair of orcas. It's likely, scientists believe, that the pair are responsible for many more great white deaths that haven't washed ashore. We know from other studies that the presence of orcas can drive great white sharks away pretty adroitly. One study in 2020 found that great whites will scarper away, without fail, from preferred hunting waters off the coast of San Francisco if an orca makes an appearance in the region. In a study from 2022, using long-term sighting and tracking data from tagged sharks, a team of scientists led by marine biologist Alison Towner of the Dyer Island Conservation Trust found that orcas are the reason sharks are starting to avoid what used to be some of their favorite spots. "Initially, following an orca attack in Gansbaai, individual great white sharks did not appear for weeks or months," Towner explained. "What we seem to be witnessing though is a large-scale avoidance (rather than a fine-scale) strategy, mirroring what we see used by wild dogs in the Serengeti in Tanzania, in response to increased lion presence. The more the orcas frequent these sites, the longer the great white sharks stay away." Over the course of five years, the team tracked 14 sharks that had been GPS tagged as they fled the area when orcas were present. Sightings of great white sharks are also down, quite significantly, in several bays. This is a huge deal. Only twice before had great white sharks been noted as absent for a week or more in Gansbaai since record-keeping began: a period of one week in 2007, and a period of three weeks in 2017. The new absences, the researchers said, are unprecedented. They're also ongoing. In a paper published earlier this year, Towner and her colleagues documented two sightings of Port and Starboard attacking sharks and eating their livers. Worryingly, these attacks are altering the ecosystem. In the absence of great white sharks, copper sharks (Carcharhinus brachyurus) are moving in to fill the vacant ecological niche. These sharks are preyed upon by great whites; with no great whites around, the orcas are hunting the coppers instead. And, notably, they're doing so with the skill of predators who have had experience in hunting large sharks, the researchers said. "However, balance is crucial in marine ecosystems, for example, with no great white sharks restricting Cape fur seal behavior, the seals can predate on critically endangered African penguins, or compete for the small pelagic fish they eat. That's a top-down impact, we also have 'bottom up' trophic pressures from extensive removal of abalone, which graze the kelp forests these species are all connected through," Towner said. "To put it simply, although this is a hypothesis for now, there is only so much pressure an ecosystem can take, and the impacts of orcas removing sharks, are likely far wider-reaching." It's also worth considering the reasons why orcas might be hunting sharks. Their livers are rich sources of nutrition, huge, plump, and full of fats and oil that the sharks use to fuel their epic migratory journeys across the ocean. But it's unclear how the orcas figured this out, or why they might seek the shark livers as a preferred source of nutrition. It's possible that some orcas are adapting to preferentially hunt sharks, perhaps in response to declining numbers of their preferred prey. An unrelated pod in the Gulf of California has developed its own techniques for hunting whale sharks, too. However, given that great white populations are declining worldwide, the added pressure of an efficient predator is a cause for concern. "The orcas are targeting subadult great white sharks, which can further impact an already vulnerable shark population owing to their slow growth and late-maturing life-history strategy," Towner said. "Increased vigilance using citizen science (e.g. fishers' reports, tourism vessels), as well as continued tracking studies, will aid in collecting more information on how these predations may impact the long-term ecological balance in these complex coastal seascapes." The team's research has been published in the African Journal of Marine Science, and African Journal of Marine Science. An earlier version of this story was published in July 2022. Solid Rock Caught Flowing 1,700 Miles Beneath Surface in Experimental First Hundreds of Mysterious Giant Viruses Discovered Lurking in The Ocean Scientists Just Solved a 100-Million-Year-Old Mystery About Platypus Sex
Yahoo
12-03-2025
- Business
- Yahoo
Fears new cashless trend may cause offence: 'Very divisive'
As cash has been on a slow decline in Australia, people are opting for a more new-age approach to wedding gifts. Some happy couples have started to put their bank details on their wedding invites to avoid handling cash on their big day. The Bridal Journey founder Andie Towner's study found that 17 per cent of couples would prefer to go down this cashless route. While she admitted it's a small number, she told Yahoo Finance it's a sad sign of the times. 'I think adding your bank details seems like a demand rather than a suggestion and I think a lot of people would be quite offended by that," she said. RELATED Wedding shock leads Aussie bride to jump on new trend $6,500 Centrelink payment opens today for those impacted by ex-Tropical Cyclone Alfred 'Red flag' NAB banker noticed before blocking $440,000 payment: 'Didn't add up' 'It takes out some of that personal sentiment and tradition, which we have so few left when it comes to weddings these days. 'But there's a broader shift happening in how wedding gifts are given.' Traditionally, the happy couple would be inundated with bulky presents on their big day that came from their gift registry. But registries have changed to include experiences on a honeymoon or helping with their home renovation rather than physical items for the couple's there isn't a gift registry, then money is likely the preferred option, but some even instruct their guests to not give anything. Hundreds of ATMs and bank branches have closed in Australia recently, particularly in regional parts of the country where destination weddings are held, and that's where a simple bank transfer could come in handy. In the 2023-24 year alone, 230 branches were shuttered, with 1,615 closed in the last five years. Towner said in addition to bank transfers, she's even seen some couples opt for QR codes at their wedding venue or guests told to PayID them. But she highlighted one major problem with that. 'Half the people that are attending the wedding are older, so, like, my mum wouldn't have any clue how to use PayID,' she said. 'It's just a very divisive topic and controversial.' The Bridal Journey founder said every couple will be different, but she urged them to think about how they approach gifts to ensure they don't leave a bad taste. 'I think it really probably just comes down to how it's communicated,' she said. 'I think adding your bank details kind of seems like a demand rather than a suggestion and I think a lot of people would be quite offended by that.' Aussies were divided on the idea. 'NO WAY. wishing wells are perfectly fine/so common and also it's barely an issue spending a few minutes getting cash out and buying a $2-5 card,' said one person. 'Omg that's so embarrassing,' added another. A third wrote: "Honestly would save me a lot of hassle remembering to get cash out to put in the card en-route to the ceremony." If you do decide to go down this new-age route, make sure you get it right. One couple in the US accidentally put the wrong bank details down on their wedding invites and the mistake was discovered on their big day. The bride's cousin and his brother realised the error while helping their parents transfer money to the couple. They compared the bank details on the wedding website with the same information on the invitations and found a tiny but monumental discrepancy. 'This revelation killed the mood pretty much instantly,' Claudia Postigo, the wedding planner, explained to People. 'The couple immediately began freaking out, worried that half the guests' gifts had gone astray." While they were able to sort it out and have everyone's money go to the right place, it shows how a tiny error could cause a costly issue on what's meant to be your happiest day.
