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Re: Great white sharks vanish from Cape Town and no one knows why

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Mystery of vanishing great white sharks after predators found with livers ripped out

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© Getty Images/EyeEm Great white sharks are reportedly being targeted by killer whales

Killer whales are thought to be slaughtering great white sharks off the coast of South Africa by ripping out their livers.

Not a single great white has been seen off the beaches of False Bay in South Africa so far this year.

That's compared to 50 sharks were spotted at the hotspot last year, already down from a average of 205 sightings between 2010 and 2016.

Five great whites washed up along the coastline in 2017 with gaping wounds on their side with their livers having been bitten out by two killer whales in the area.

Experts claim the predator whales have acquired a taste for the sharks' livers, which are rich in oil and fats, providing a valuable source of energy for the huge marine mammals.

The killer whales bite a large slit in the side of the great whites after attacking as a pair and then suck out the fatty liver which is 600lb meat delicacy in a phenomenon that has only recently been discovered.

The two Orca’s responsible – known as Port and Starboard as their dorsal fins hang to the left on one and to the right on the other – spurned their natural prey like seals having developed a taste for shark.

Tourists flock to False Bay every year to watch the sharks launching themselves out of the water around the nearby Seal Island.

But it's been two years since the Shark Spotters Applied Research Programme has picked up a signal from any of the great white’s that had been tagged by scientists and were resident in False Bay.

Marian Nieuwoudt, a Cape Town environment official, said: "To our knowledge the absence of great white sharks from False Bay has not been recorded or reported before.

"Great white sharks are top apex predators and we do not know how their absence from False Bay would impact the ecosystem.

"Neither do we know the causes for their disappearance.

Dead sharks have washed up on South African beaches with their livers missing

"We remain hopeful that the great whites will return to False Bay and will announce our first sighting when this happens."

South Africa's Western Cape boasts some of the world's best Great White Shark cage diving and thousands of adrenalin-hungry tourists flock there each year paying up to £150 a time to go down with them.

False Bay is the biggest bay in South Africa and Seal Island just 3 miles off shore with its deep water and 60,000 seals was one of the the best places to the predators breaching with seals in their jaws.

Tourists hoping to see the Great White's from cages will now have to travel up the coast to Gansbaai until they return.

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an animal swimming in the water: Killer whales have reportedly acquired a taste for shark livers© PA Killer whales have reportedly acquired a taste for shark livers

Marine biologist Alison Towner of the Dyer Island Conservation Trust said: “A study in California showed that great white sharks were being attacked by pods of killer whales and driven away from feeding grounds.

"This is a complex issue which is something we are trying to better understand but we do know that killer whales have regional impact on great whites as seen in South Africa, California and Australia,

"Although the presence of killer whales will obviously have an effect on great whites, there are many other factors that come into play, and my research on them is ongoing in Gansbaai where they have just returned after a two year absence".


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Re: Great white sharks vanish from Cape Town and no one knows why

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Our Burning Planet

Where have all the Great White Sharks gone?

By Noah Tobias• 12 September 2019

Great White sharks are the stuff of legend and Cape Town’s False Bay gained a worldwide reputation for its very visible population of the magnificent creatures. But now they’ve gone missing.

For the past 18 months, the Cape Town municipality has been monitoring the gradual disappearance of Great White sharks from False Bay. Working in tandem with a conservation group called Shark Spotters, researchers recorded a massive drop-off in the number of Great White sightings between 2016 and 2018.

There has not been a single confirmed sighting this year at a beach where spotters used to see upwards of 200 sharks annually. Where did they all go?

In 2009, Dr Sara Andreotti of Stellenbosch University began counting Great White sharks around the South African coastline. Her findings came as a surprise: there were between 353 and 522 sharks cruising around the seaboard – less than half the figure she had expected.

Using a process called genetic analysis, Andreotti and her team refined that sum, discovering that 333 breeding sharks were all that remained of the once-numerous species. That was a bad sign – shark populations need at least 500 breeders or inbreeding will cause genetic deficiencies, perhaps even keeping the group from reproducing entirely.

Those findings crystallised in 2016. Since then, the population has probably shrunk further. This raises another question: why was the population dwindling in the first place?

Because animal behaviour is complex and dynamic, it is difficult to point to a single exclusive circumstance that explains everything. However, one thing is clear: humans are, at least partly, responsible.

Human-shark interactions have been complicated from the beginning. Prehistoric predators with up to 300 razor-sharp teeth, Great White sharks instill a deep, primitive fear.

Perhaps that is why, in the 1930s, Australian fishermen began setting up gill nets, enormous fishing nets that float vertically in the water. A demonstrably ineffective way of protecting beachgoers, gill nets also have significant detrimental effects on marine animals, catching and killing everything from turtles and whales to Great White sharks. Although much of the world has banned their use, one can still see them along the KwaZulu-Natal coastline.

Because of the indiscriminate nature of shark nets, institutions like the KwaZulu-Natal Sharks Board now prefer drumlines, a more targeted method of reducing the shark population. Drumlines are large hooks attached to bait, which catch and kill curious sharks. There have been zero shark attack fatalities in KwaZulu-Natal since the introduction of drumlines, but that comes at a massive expense. According to statistics released by the Sharks Board, only a quarter of Great Whites caught between 2013 and 2017 were released alive.

The most egregious human attack on sharks, however, comes not from protection agencies but from fishers.

One study showed that fisheries tend to collide with Great Whites in certain hotspots, where both ships and sharks head to look for fish. In the ensuing interaction, sharks often get caught on baited hooks and suffer devastating internal injuries.

Researchers concluded that “sharks have limited spatial refuge from current levels of fishing effort in marine areas”. In other words, when the fishing boats come, sharks have nowhere to swim (run).

Years of conditioning by films like Jaws and Sharknado might make Great Whites difficult to empathise with. However, the loss of these creatures could massively imbalance the marine ecosystem.

According to Andreotti, “we cannot even grasp the negative ecological effects” of the changes. Without Great White sharks, seals and other predators will grow in numbers, eating enormous quantities of fish and crustaceans and significantly harming local fisheries.

Their disappearance might also damage the increasingly popular shark ecotourism business.

Stephen Frank, the owner of a tour agency that specialises in shark cage diving, called the impact on his business “absolutely tremendous”. “Tourists are obviously aware of it,” he said, noting, “It’s the first time in 17 years that sharks aren’t breaching in False Bay.”

Where did the Great Whites go? That is a difficult question, and it will take years to fully answer. We don’t know enough about shark behaviour and movement patterns, which can be erratic and difficult to explain.

According to a statement released by Dr Allison Kock, a marine biologist at SANParks, sharks “are capable of large migrations and, when conditions are not good in one place, they can move to a better one”.

Another theory holds that Great Whites might be fleeing larger predators. Two killer whales spotted in False Bay – true to their name – might be targeting sharks for their livers, which make high-fat, scrumptious meals for a hungry orca.

The research indicates that the population is in serious trouble. There are a lot of things we could have done – and could still do.

Scientists are hard at work creating non-lethal shark control methods, including an eco-friendly barrier that mimics kelp forests and doesn’t harm marine life. Fishers have a wide array of options, such as real-time satellite surveillance that explains where sharks are and how to avoid them. Other options include technology that sends irritating electronic or magnetic signals, deterring sharks by making use of their incredible sensory biology instead of killing them.

Here’s hoping these initiatives work and the charismatic predators return to False Bay one day.


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Re: Great white sharks vanish from Cape Town and no one knows why

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Scientists are hard at work creating non-lethal shark control methods, including an eco-friendly barrier that mimics kelp forests and doesn’t harm marine life. Fishers have a wide array of options, such as real-time satellite surveillance that explains where sharks are and how to avoid them. Other options include technology that sends irritating electronic or magnetic signals, deterring sharks by making use of their incredible sensory biology instead of killing them.
Too late once again O/


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Re: Great white sharks vanish from Cape Town and no one knows why

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Re: Great white sharks vanish from Cape Town and no one knows why

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One or two sharks have been spotted, which is good news, but it does not mean that the sharkS are back.


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Re: Great white sharks vanish from Cape Town and no one knows why

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Headless sharks, scarce great whites and the danger of fish and chips Down Under

BY DON PINNOCK - 21ST JANUARY 2020 - DAILY MAVERICK -

It was a bizarre and disturbing sight. About 100 sharks – beheaded, finned and gutted – dumped on Strandfontein beach along the False Bay coast. Why were they there? What was their intended destination before being illegally abandoned? Who was responsible?

The pile of dismembered bodies were mostly soupfin sharks. Word has it they were from either Gansbaai or Struisbaai, destined for a fish processing plant in Cape Town but had gone off and dumped. A problem of stage six loadshedding, perhaps. But was there a bigger backstory?

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Soupfin sharks dumped on False Bay’s Strandfontein Beach. (Photo: Chris Fallows)

The search for answers would lead from demersal shark longliners, line fishermen and trawlers, by way of the Department of Environment, Fisheries and Forestry (DEFF), to the danger of eating fish and chips in Australia. It would also suggest, in part, reasons for the recent decline in the number of great white sharks and the current crisis in the lucrative shark-cage diving industry.

The source of the dumped sharks was probably line fishing boats, but the main shark fishing boats are the demersal shark longliners Mary Anne, White Rose and Suriam, which fish close to shore, are based in Port Elizabeth and which supply companies like Fisherman’s Fresh in their home port and probably Viking in Mossel Bay. They’re licensed by DEFF to catch sharks and there’s no upper catch limit, nor any body size limit.

These three boats zone in on smooth-hound and soupfin populations and focus their activities around marine protected areas (and occasionally in them) and pull out upwards of 30 000 of these sharks a year. DEFF has recommended slot limits (no catching younger or more mature animals) since at least 2007, and again in 2011, 2015 and 2017, but DEFF is ‘waiting for approval’ for this to be implemented.

DEFF scientific research, which is world class, has shown that the maximum sustainable upper limit should be set at 75 tonnes annually. However, this would make the industry less profitable so it hasn’t been implemented. The Department estimates that over the past 10 years annual catches of suoupfin alone has fluctuated between 146 and 472 tonnes. The result is that populations have crashed.

There are no fisheries observers on the boats and catches are only occasionally checked and mostly rely on commercial logbook data to track catches. Sharks are also caught as bycatch in other fisheries, so the final catch weight or composition is anybody’s guess.

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Caption: A great white shark illegally caught on a longline fishing boat and secretly photographed.

The Department managers knew these sharks were racing towards major problems. They also openly acknowledged that even if all fishing for these species stopped, the soupfin stocks would only bounce back by 2070. Yet they allowed the fishery to keep plundering at up to four times the level necessary to avert local species collapse. According to DEFF scientists, this is presently totally unsustainable.

But let’s start at the other end. Until recently, the fish you ate with your chips in Australia was predominantly snapper, the country’s favourite recreational and commercial fish. This was massively over-fished and last year the government banned catches in a number of key waters until 2023 (angering many fishermen) and imposed stiff fines for transgressions.

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Maybe sharks could fill the gap? However, in 1991 the Australian smooth hound shark industry had collapsed and they were being imported from New Zealand. Then that fishery became oversubscribed and the demand shifted to South Africa, an area which they must have known had poor shark management or legal compliance. They’d found the perfect suplier.

That was good news for local shark fishers. According to Dr Enrico Gennari of the Oceans Research Institute, the smooth hound catch numbers were 17 558 sharks in 2016, 18 298 in 2017 and 30 112 in 2018 (the 2018 numbers convert to around 210 tonnes). ‘Fishing at current mortality rates, a decline in harvestable stock is certain,’ he said. ‘I’m quite sure right now this species would be in the endangered category.’

But there’s a further problem the Australians may not know about and will be unhappy to discover. South African waters are far from pristine, with toxic runoff from factories and farms entering coastal waters. Local sharks are apex predators and, as bioaccumulators, they retain heavy metals like mercury and arsenic (eat a mako stark steak at your peril).

They take in high levels of these human-produced chemicals and heavy metals from both skin absorption and from consuming their prey. These dangerous chemicals and metals add up over time and quickly reach levels dangerous to humans. They can cause various neurological dieseases such as dementia.

According to a South African research report on shark meat, mercury readily vaporizes and may stay in the atmosphere for up to a year. It ultimately accumulates in lake and sea sediments where it’s transformed into toxic methyl mercury, accumulating in fish tissue, especially those at the top of the aquatic food-chain. By this means, it enters the human diet.

Arsenic is used in the production of pesticides, treated wood products, herbicides and insecticides and generally enters coastal waters through river runoff.

Research by Adina Bosch and others in Langebaan Lagoon found that one in three smooth hound sharks analysed in 2015 had methylmercury and arsenic levels WAY above allowable limits and contained 14 other heavy metals.

DEFF scientists have no idea whether sharks exported to Australia are tested for heavy metals and are not sure who should be doing this or at what stage in the commercial process. It’s certainly not being done by DEFF. When I asked Fisherman’s Fresh, which exports sharks to Australia, what checks they do for heavy metals in their exports, director Marius van Heerden refused to talk to me. The National Regulator for Compulsory Specifications says it tests sharks for mercury but refused to provide any proof or statistics?

Taken together, this means there’s a strong possibility that South Africa is exporting potentially hazardous shark meat that ends up in Australian fish and chips.

But there’s also another problem. Great white sharks are disappearing from local waters. According to naturalist Chris Fallows of Apex Shark Expeditions who has worked with great whites in South Africa for over 30 years, ‘in the past few years there has been a calamitous crash of our great white populations along the Cape south and southwest coastline.’ In the past three years the False Bay Sharkspotter programme has seen counts go down to almost zero.

This was initially attributed to the presence of two orcas, Port and Starboard, which have been seen in False Bay at least a dozen times. According to Fallows, however, ‘our data shows them to have been present on many occasions since at least 2015 – at least five other pods have been in the bay since 2009.

‘At no time did we ever notice a decrease in white shark numbers when they were in the bay. I’m not saying they don’t have an effect, but the orca effect lasts maybe 4–8 weeks, not years.’ Are they migrating eastwards because of climate change is relocating food supply, are more orcas migrating north from the Southern Atlantic and scaring whites or is is something else?

According to Fallows the main cause is over-fishing. He says small sharks and not seals are the primary food source of great whites. DEFF says there’s no solid science to back this claim. But Fallows and Enrico Gennari say it’s based on many decades of local knowledge from cage dive operators and fishers as well as research done on great white stomach contents done by the Natal Sharks Board.

In the world’s largest study on great white diet, it was found that smaller shark species formed the most important food component in over 590 dead great whites analyzed.

‘Seals represent a seasonal component in the great whites diet,’ says Fallows, ‘but for more than half the year their food is mainly smooth hound and soupfin sharks, which used to appear in False Bay in great numbers. When the great whites were not at seal island we looked for them where the smooth hound sharks were known to aggregate.’

‘Then, in the late 1990’s DEFF gave out demersal shark longline permits and line fishing for sharks in the bay was suddenly on the increase. By the mid to late 2000’s we noticed a slow decline of white shark sightings at Seal Island, nothing drastic but an overall down trend.

‘Suddenly around 2015 three boats started fishing the resource hard. They learnt how, where and when to target the smooth hound and soupfin sharks. Their technique was highly focused and localised to sites where these species gather.

‘Their catches soared and our sightings of white shark in False Bay went through the floor. In a nutshell there are no longer enough smooth hounds and soupfins left in False Bay to sustain the white sharks for the eight months of the year they’re not at Seal Island.

‘Add to this the octopus fishery which started in earnest around the same time targeting the key food source of smaller sharks and you have a double whammy.’

According to Fallows, DEFF did not do an impact study (EIA) to determine what the effects of the removal of these smaller sharks would have on the greater ecosystem. Why not – that’s their job? Here’s a possible reason.

In the past 10 years, DEFF has lost around 80% of its fish scientists who were, and still are, among the best in the world. They now simply don’t have the human resources to cope with a complex and rapidly evolving climate and other enironmental issues and, furthermore, DEFF management often simply ignores their advice.

Policies are often just cut-and-paste from elsewhere and not based on targeted local science on specific species. It’s all bad news for fish, fishers – and tourism.

‘In order to sustain a fishery that’s causing ecological collapses, wiping out apex predators and contributing a miniscule amount to GDP, food security and job creation,’ says Fallows, we’re killing one of the Western Cape’s prime tourist attractions and the source of thousands of jobs.

‘What’s is also tragic is that coastal fishing communities that have relied for many decades on species now being caught as target species or bycatch by the demersal shark longline industry no longer have a viable income in the areas where these boats ply their trade.

‘All this to supply Australians with fish and chips, while they cleverly manage and conserve their own resources.’

The local solution to the fish and chips problem Down Under could turn out to be a Faustian bargain. Given the heavy metals in these sharks, we could be slow-poisoning many Australians.

The flavor of the day seems to be short term gain that makes no sense in terms of the environment, human health or sustainable income.

Original Article: https://www.dailymaverick.co.za/article ... stralians/


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Re: Great white sharks vanish from Cape Town and no one knows why

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Don Pinnock can do serious articles, too \O

Make entire False Bay a MPA, immediately!
Part of the False Bay is reserved as a marine protected area and no take zone, creating a sanctuary for large reef fish, abalone and small sharks. Fishing pressure in unprotected parts of False Bay is significant and pollution is also an issue in the area.

Meanwhile everybody stop eating fish and seafood and campaign for vegan diet around the world X#X (definetely better for the planet)


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Re: Great white sharks vanish from Cape Town and no one knows why

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\O


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Re: Great white sharks vanish from Cape Town and no one knows why

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Shark Attack! Flipping the image of our toothy friends in new conservation campaign

2020-03-11 16:45

Sharks have a bad rep. The popular bad guy in many a Hollywood movie, the top ocean predator is used to instilling fear.

But in reality, the seemingly docile cow kills more humans than sharks per year.

On the flip-side, humans kill about 100 million sharks every year, either as bycatch or for their fins.

That's the message behind WILDOCEANS' latest conservation campaign - Shark Attack. Supported by the Shark Conservation Fund, the three-year shark and ray protection effort will focus on improving the status of threatened sharks and ray in South Africa, raising awareness and increasing knowledge about the important marine animals.



It will also involve training and implementation of conservation measures to ensure laws are more than just ink on paper. Through intensified monitoring of the animals and their trade will help inform governmental policies that will help ensure their future.

Judy Beaumont, the deputy director of General Oceans and Coasts at South Africa's Department of Environment, Forestry and Fisheries, is one of many members of the team behind the campaign.

“In South African waters we really are a lifeboat for sharks and rays, globally. This project addresses conservation, fisheries and economic imperatives. We are supportive of this collaborative initiative and believe this is an important conversation to be had.”

Swimmer Achmat Hassiem is another member of campaign tea - someone with an especially personal message about sharks. He lost his leg in Muizenberg to a great white shark, after which he ended up becoming a medalled Paralympian swimmer.

But despite his terrible encounter, he still believes sharks need to be protected, even the one who took his limb.

“Forget Jaws, it’s the sharks that are under attack," adds Karen Sack, CEO and president of international NGO Ocean Unite and part of the WILDOCEANS team.

"As top ocean predators – not to mention lucrative tourist attractions – sharks are worth far more alive than dead; it should not take their extinction for us to figure that out.

"Sharks and rays need local sanctuaries, regional management, international protection, and changing cultural perceptions of products like shark fin soup and ray gill plates if these magnificent animals are to survive.”

Mark Bond, another member of the team and an associate professor of research at Florida University, reiterated the sentiments and highlighted the importance of organisations like the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

“In recent years we have seen an increasing amount of shark and ray species included on CITES to ensure trade in shark or ray products does not threaten their existence in the wild,” said Bond.

“I am excited to help facilitate the use of these CITES listings to work in concert with fisheries regulations to ensure South Africa effectively manages it’s shark and ray populations, maintains its role as a biodiversity hotspot, and continues to be a leader in shark conservation.”

According to the campaign, South Africa is one of the top three global hotspots for shark and ray diversity, harbouring 204 species and one-third of the global fauna, and 69 species are unique to our waters.

They are also important maintaining the delicate balance in the marine ecosystem, something which humanity heavily depends on for resources.

If you want to find out more, visit their website and follow them @sharkattackcampaign on Facebook and Instagram and @SharkAttackSA on Twitter.


"Education is the most powerful weapon which you can use to change the world." Nelson Mandela
The desire for equality must never exceed the demands of knowledge
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