Great white enigma: In search of the Mediterranean’s giant sharks

Few species thrill (or chill) like the great white shark. Yet little is known about the population inhabiting one of the world’s busiest seas – except that they’re there, and they’re big.
Photograph by Shutterstock / National Geographic Creative

A YOUNG BOY sits atop a fishing rig on a small boat, the rod arced under tension. The film cuts, and we see the boy turn to his father with a victorious balled fist as he regards his catch – a small thresher shark – lashed to the side of the boat. In the background a local pop tune croons out of a radio, mingling with the sounds of the sea below and seagulls above.  

Then the camera catches something in the water beyond: a fin the colour of soot, tracking the boat. Seconds later a black head the shape of a torpedo breaks the water and attacks the fisherman’s prize. The water becomes a chaos of foam and blood as the creature shears its head from side to side, tearing the catch to pieces, its eye a white cue ball. Off-camera, the boy’s father – urgency in his voice – says, ‘uno squalo bianco:’ white shark.    

It could be a scene from any shark fright-fest but of course, it’s real: footage captured by fisherman Stefano Catalani whilst sport fishing with his son, Nicola, in 1998. His identification leaves little doubt: the animal tearing the catch from their boat is indeed a great white shark, probably the most formidable – and demonised – apex predator in the world.
 


The shark is huge, too: estimates at the time put the shark around six metres in length, close to the record for a species commonly spotted making short work of sea lions off the coasts of Australia, South Africa and California. The Catalani film, however, was shot 15 miles off the coast of Rimini, Italy. It was thought to be the first great white shark filmed alive in the Mediterranean – but it is in fact only a minor milestone in the species’ long history in one of the busiest waterways in the world. (Read: how the ultimate shark photo went viral.)

Are there great white sharks in the Mediterranean? Yes. Little is known about them, but they have probably been there for a very long time. And there was once probably a lot more of them. 

Ancient sea devils

Given the resplendent civilisations that sprung up around the coastlines of this sea, wedged between Africa and Europe – from the Ancient Greeks, to the Ottomans and the Ancient Egyptians – it’s hardly surprising that their seafarers noticed sharks.

What is believed to be the first documented shark attack of any kind was in the Mediterranean, recorded on a vase found in Naples and dated to 725 BC. Greek historian Hetrodotus’s infamous account in The Histories describes 300 Persian ships, commanded by the invader Mardonius, being wrecked against the cliffs of Mount Athos, and the crews being dispatched by ‘sea monsters’.

The Maltese used to refer to the silfjun, a ‘whale sized shark,’ and a local 17th century nobleman named Giovanni Francesco Abela wrote of ’a terrifying marine monster with double rows of teeth’ that washed ashore on the island. All of which paints a portrait of sharks not only being noticed, but abundant – and human-shark conflict, too.

An image from the Icones Animalium, published in Rome in 1560, shows what is believed to be a stricken seafarer being attacked by sharks, and a giant ray. Images of sharks from ancient times to the middle ages show a chequered approach to the perception of sharks, with many drawings distorted or inaccurate. But even the most ancient accounts reveal conflict between sharks and humans in the Mediterranean – which has been surrounded by seafaring nations since the dawn of modern civilisation – dating back to 725 BC.

Photograph by Olaus Magnus / Icones Animalium

The grisliest case came in 1908, when a 4.5-metre female great white was caught off Capo San Croce in eastern Sicily, with three human corpses in its stomach. But as damning a picture as this paints, these remains – of a man, a woman and child – were thought to have been victims of a recent tsunami caused by the Messina earthquake, and not necessarily victims of a shark. In addition, the creature was found to contain the remains of a dog and a cow.

Overall, the broader picture of shark attacks in modern times in the Mediterranean is notably low – particularly given the relatively small volume of water and the huge numbers of people who use it for recreation and utility. Whatever the status of any shark in the sea, it’s therefore unlikely humans have much to fear. With over 100 million sharks killed by humans for every four humans killed by sharks every year, (2020 saw the latter spike to an unusually high ten, none of which were in the Mediterranean) it’s invariably the sharks that suffer. But the presence of the most notorious one of all off the costas is still a spine-tingling thought. Even if, on the whole, we don’t know much about them. And our chances are probably dwindling, as the consensus amongst experts are the populations of this demanding predator are – like many other species in the Mediterranean – likely in decline.

You’re going to need a bigger screen. Tune in to the biggest SharkFest ever, spanning July. The 9th annual SharkFest starts Monday, July 12, at 8PM on National Geographic with the one-hour marquee doc special Shark Beach With Chris Hemsworth.

“Great white sharks were, without a doubt, at one time much more abundant in the Mediterranean than they are presently,” says Alessandro De Maddalena, Adjunct Professor of Vertebrate Zoology at the University of Milano-Bicocca, shark researcher and author of Mediterranean Great White Sharks: A Comprehensive Study, in an email.

“This is not only true for white sharks, but there is also evidence showing that many species of sharks have suffered a strong decline in the past 50 years, [becoming] uncommon or rare as a consequence of overfishing either the shark or its prey.”

Logging sharks is a tricky business, beset with the difficulties of any quantitative analysis that relies on qualitative sources. To aid research for his book, De Maddalena created the Italian Great White Shark Data Bank, an ongoing project which aims to catalogue every witnessed appearance of the shark in the Mediterranean, from the Middle Ages to the present.

Typically these were sightings of sailors, fishermen, divers, researchers and military personnel – but also included more lateral sources of public record, such as bounties paid for the shark, paintings depicting altercations or other evidence of its presence – such as bite marks in whale carcasses. These were then cross-checked against the morphology and behaviour of the shark to rule out mistaken identity, and fortified with records from other sources, such as the Global Shark Attack File (GSAF) based in Princeton, New York. The databank’s records today stand at 640 – of which, according to De Maddalena, “80 are doubtful.”

A sign warning bathers of the presence of great white sharks off Lighthouse Beach, Cape Cod, Massachusetts. In 2020 the U.S. had the most unprovoked shark attacks, with 33 recorded – of which three were fatal. Australia had 18 unprovoked attacks – but six fatalities. 

Photograph by Rusty Watson / Unsplash

“There may be some doubt over the exact identity of the species, the record may be a copy of another record with wrong or inexact details, the source may not be 100% reliable...” he says. “Obviously when a case is highly doubtful it is not included in the database at all.”

‘Monster’ sharks

Another consideration with room for doubt, is size. Reports of specific great whites caught by anglers – either on purpose, or by accident – in the Mediterranean over the years form a key part of the log. And while many are subject to pride-inflated dimensions by those who caught them, several specimens have been measured reliably enough to suggest the sharks in the Mediterranean are particularly hefty by great white standards. And the reason may not be down to an abundance of prey.

“The Mediterranean Sea is an important area for reproduction, with the Strait of Sicily being the primary parturition ground for female white sharks – and also a fundamental nursery area for the newborn and pups,” says De Maddalena. “Therefore it's normal that in the area there have been so many observations of sexually mature great white sharks, which may sometimes attain huge sizes.”

Of the confirmed specimens De Maddalena believes to be reliable, the biggest was likely a female estimated at 6.6-6.8 metres caught off Marseille, France, on 15 October 1925; a shark of near identical size caught off Filfla, Malta in 1987; and three more females, with measurements estimated between 6 and 6.2 metres, caught off Sicily in 1961, Majorca in 1976 and Halkidiki, Greece, in 1985.  

He cautions these are based on photographic evidence, but reasons that “from Mediterranean specimens, there is solid evidence that great white sharks attain 6.6 meters in total length.”

A great white shark caught in a tuna net off Favignana, Italy, by fishermen taking part in the annual Mattanza fishing festival off Italy. (Year unknown.) Sharks are known to breed in the waters of the Strait of Sicily due to the tuna populations there. 

Photograph by Jeff Rotman / Alamy

Another resource De Maddalena found invaluable for compiling his data was artefacts preserved in museums around Europe preserved from specimens through the ages – over 100 pieces from some 50 institutions. Of the sharks caught that can still be measured, the largest is a stuffed specimen in the Museum of Zoology in Lausanne, Switzerland – a female caught off Maguelone, France, on October 13, 1956. “The 589 cm female great white shark mentioned above was accurately measured at the time of capture and is still measurable from the cast,” says De Maddalena, “making it the largest specimen ever reported with a size that cannot be disputed.”

If nothing else, these landed sharks demonstrate the range of the species distribution: Malta, Greece, France, Sicily, Majorca, and recently in Tunisia - and they’re just the specimens that were caught. What’s harder to make sense of is the range and number of the sharks still out there.

A question of identity

With its squat, triangular teeth, short snout, black eyes and chunky fins, the squalo blanco is typically an unmistakeable shark when presented with a specimen – particularly when combined with its prodigious size. But in the water, it can be trickier to determine. A gunmetal topside that blends with the water from above, and a snowy white belly – a colouration pattern known as ‘countershading’ – they can be hard to spot near the surface both by prey, and interested observers. The other Mediterranean mackerel sharks of the family Lamnidae, namely the porbeagle and longfin mako shark, be bear enough of a resemblance to their more infamous cousin to be grouped together under a collective name by fishermen and observers that didn’t know any better.

“In some local languages, a single common name was widely used for a very long time,” says De Maddalena. ”Words like pescecane in Italian and haifisch in German were used for centuries to refer to all species of sharks of the family Lamnidae.” This, he says, was likely due to unfamiliarity with the bigger shark, due to its relative rarity. “The great white shark was common in some areas of the Mediterranean only a long time ago, while nowadays close encounters with humans in the entire Mediterranean are rare.”

“From Mediterranean specimens, there is solid evidence that great white sharks attain 6.6 meters in total length.”

Alessandro De Maddalena

And while such confusion can lead to supposed great white sightings being misreported, this mistaken identity can work the other way round, too. According to De Maddalena, “even experienced fishermen often mistake young white sharks for similarly sized porbeagles and shortfin makos. This is the main reason why most captures of juvenile white sharks go unnoticed.”

The numbers game

So how many are there? Perhaps the more pertinent question is, what conditions are likely to be needed for the sharks to thrive in number – and what could cause those numbers to plummet?

“The main thing it would need is sufficient food source and for the waters to have the right conditions, such as temperature.” Says Yannis Papastamatiou, a shark behavioural ecologist and National Geographic Explorer – who highlights the sea’s status as a conservation hotspot. “The Mediterranean is a fairly oligotrophic sea, and has been overfished so there is likely a lot less prey than there once was.”

A great white shark attacks a seal by ambushing from below off the coast of South Africa. Sharks are known to congregate around seal and sea lion colonies during breeding season, but when the mammals are unavailable, are experts are recruiting other sources of food. 

Photograph by Shutterstock / Nat Geo Creative

The State of World Fisheries and Aquaculture (SOFIA) report commissioned by the United Nations in 2018 identified the Mediterranean as the world’s most human-depleted sea, with 62% of fish stocks categorised as overfished.  

Trends of mammal populations in the Mediterranean could also run parallel with those of the sharks, as great whites in particular are known to frequent areas with high concentrations of seals and sea lions. But according to Papastamatiou, they can be opportunists, too. “We know that white sharks eat marine mammals like seals but that’s not their only prey. They will also eat a variety of fishes, turtles and other sharks. They may take advantage if they can find large pelagic teleosts, like tuna. For example they are reportedly seen off Sicily, where there is bluefin tuna fishing.”

(Read: why are we afraid of sharks? There's a scientific explanation.)

As for absolute numbers of the sharks, there is little to go on. A 2018 assessment by the IUCN listed the shark as ‘vulnerable’ worldwide, but – despite quoting a 2016 study based on ‘anecdotal records and limited fisheries data’ estimating a population drop of 80% over the 69 years from 1947 to 2016 – ultimately assessed the Mediterranean population was showing signs of increasing in the region since protection was established. This protection takes the form of a number of international mechanisms, ranging from habitat conservation, to fishing bans and illegal trade in body parts, which can be lucrative. But ignorance and the complexity of international waters around the Mediterranean makes regulation difficult, and the shark continues to be caught, by accident or otherwise, in the waters of countries such as Tunisia and Libya.  

Watch a great white shark hunting seals
A female great white sharks demonstrates her hunting tactic near a colony of sea lions. 

A 2019 study estimated a more modest reduction of 61% in population and 58-72% in range during the second half of the 20th century. The same report also observed the eastern Mediterranean as being a ‘suboptimal habitat for adult endothermic white sharks… [and] by contrast the colder and productive western sectors could represent resource hotspots for the species,’ adding that the physical oceanographic and ecological characteristics were more amenable to the shark, and created a population that was highly fragmented. The same study gave perhaps the pithiest summary of the great white’s presence in the Mediterranean: that the shark was ‘rare, but persistent.’ 

The population source is critical when it comes to this persistence. Some have speculated that current white shark populations in the Mediterranean are the result of a few (probably pregnant) individuals that swam astray, possibly hundreds of thousands of years ago. Other theories state the white shark’s presence is transient, due to habitual migrations through the strait of Gibraltar – possibly to breed – from the Atlantic. However, preliminary results from a project led by the Save Our Seas foundation found the present population had ‘little or no contemporary immigration from the Atlantic,’ effectively putting the predator in an ecological pressure cooker that ‘made it extraordinarily vulnerable.’

Trends aside, information on absolute numbers just doesn’t exist. “It’s just impossible to know,” says De Maddalena. “There may be a few dozen, or a few hundred.”

Further knowledge of this formidable creature will therefore likely rest of more sightings, more images of them strung up by their tails – and more snatched videos of dramatic encounters like that of the Catalanis. It seems the Mediterranean great whites are destined to remain as elusive as they are enigmatic.

SharkFest starts on the National Geographic Channel on 12 July. 

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