Are shark attacks on the rise – and should I be worried?
The number of 'unprovoked' attacks worldwide has been rising steadily over the past century
Last week a body surfer was attacked and killed by a shark in the waters off Cape Cod in the first fatal attack seen in the US state of Massachusetts for more than 80 years.
The 26-year-old Brazilian, Arthur Medici, was treated on Newcomb Hollow beach but was pronounced dead later in hospital having suffered multiple bite wounds to the legs. The beach was closed as experts tried to identify the species of shark. As of now, according to Gregory Skomal, a researcher from the state Division of Marine Fisheries, the “highest probability is that it was a great white”.
In the months leading up to the tragedy, there had been a number of reported sightings of great whites along the picturesque coastline, famous for its lighthouses and windswept beaches, and one other attack. William Lytton, a 61-year-old neurologist, was bitten on the leg in August off Truro, 6.4km from Newcomb Hollow. He survived but is still recovering.
Should we be concerned?
There does appear to have been a rise in shark sightings along the outer Cape this summer. The National Park Service, which covers the area, said it closed beaches about 25 times this year, for at least an hour at a time, equating to more than double the annual average, local media has reported.
And the number of “unprovoked” shark attacks worldwide has been rising steadily over the past century.
Florida Museum’s International Shark Attack File (ISAF) has data on shark attacks that stretch back to the 1900s. In the first decade of the 20th century, 39 unprovoked attacks were recorded. One hundred years later, between 2000 and 2009, that number had climbed to 661.
But it’s important to keep two things in mind. First, that our research continues to advance in leaps and bounds, and our figures are far more comprehensive in modern times. Second, there is a direct correlation between the number of shark attacks and the number of beachgoers who enter their domain each year.
“As the world population and interest in aquatic recreation continues to rise, we expect the incidence of shark attacks to increase as well,” states the ISAF’s latest report, covering 2017.
In short, the more people who swim, surf and otherwise paddle around in known shark hunting grounds, the more are likely to fall prey.
There were 88 unprovoked attacks listed last year worldwide, compared with 81 the previous year, but not as high as it was in 2015, when 98 attacks were listed.
“The ISAF does not assign too much significance to these short-term trends as annual fluctuations in shark-human interactions are to be expected,” the report states. “Year-to-year variability in oceanographic, socio-economic and meteorological conditions significantly influences the local abundance of sharks and humans in the water and therefore the odds of encountering one another.”
The spike in attacks during 2015 is a notable example. Increased activity in North and South Carolina, for one, caused panic to break loose. The neighbouring states, which see one or two shark attacks per year on average, reported eight (none fatal) in July alone.
“We know the water temperatures got warmer earlier this year,” George Burgess, director of the Florida Programme for Shark Research, said at the time. “There’s been a lack of rainfall, which means there’s less fresh water entering the sea, so it’s more saline along the coastline.
“There are abundant schools of herring-like fish that are particularly favoured by sharks and other predators, and it’s sea turtle nesting season, when the sea turtles leave the water to lay their eggs and come back in, which is a favourite meal for some large sharks.
“All of those things mean it’s good to be a shark right now in those waters.”
Moreover, the presence of more people in the water during the school holidays increased the likelihood of encounters.
“What you have is a combination of lots of people, lots of sharks, and lots of food in one area, which is a formula for shark attacks,” said Burgess.
Where do most attacks occur?
The US has for a long time had the most attacks, this year accounting for more than 60% of the worldwide total, with 53. It’s followed by Australia (14), Reunion Island (3) and (each with only two attacks last year) Ascension Island, the Bahamas, Costa Rica, Indonesia and SA.
Countries that listed one attack in 2017 include the UK, Japan, New Zealand, the Maldives, Brazil, Egypt, Cuba (the only death) and the Canary Islands. Of the 88 unprovoked attacks worldwide, five were fatal.
SA’s relatively low number of attacks is interesting. Its two, non-fatal attacks in 2017 were slightly lower than its annual average of four total shark attacks and one fatality. But considering SA, and in particular Gansbaai, is often referred to as the great white shark capital of the world, such are their numbers around the Cape, you’d be forgiven for expecting more.
It’s perhaps because the surfers who take to these waves daily in SA are more alert to their presence, tend to avoid the times of days when great whites are most likely to be hunting (dawn and dusk), and have a strong aerial patrol presence (plenty of helicopters that monitor sightings and issue alerts accordingly).
Wilfred Chivell, CEO of Marine Dynamics and the Dyer island Conservation Trust, based in Gansbaai, said: “We have been working and researching great white sharks for more than a decade and we are just not on the shark’s menu.
“These occasional incidents that happen are usually mistaken identity due to various factors. It is a tragic event when a life is lost and we send our condolences to the family of the victim in Massachusetts, but this is inevitable as more people spend time in the shark’s natural habitat.
“Depending on the type of coastline, programmes such as Shark Spotters in False Bay are incredibly helpful. It is important to find ways to mitigate interactions and respect their territory. White shark numbers are of concern and we need to protect this very necessary apex predator.”
Who is most likely to fall victim?
Overwhelmingly, surfers. Florida accounts for nearly 60% of all shark attacks off US shores, and of these 2017 attacks, 59% involved surfers, 22% swimmers, 9% snorkellers and 2% scuba divers.
Why? Because from beneath the surface surfers most closely resemble seals, and on rare occasions are mistaken for the favourite great white prey. It should be noted that great whites do not appear to enjoy the taste of humans, typically only biting once.
Is the number of sharks increasing?
Far from it. “The sombre truth is that the world’s shark populations are actually in decline, or exist at greatly reduced levels, as a result of overfishing and habitat loss,” says the ISAF.
“On average there are only six fatalities that are attributable to unprovoked shark attacks worldwide, each year. By contrast about 100 million sharks and rays are killed each year by fisheries.”
What about the UK?
There are already more than 30 species of shark currently found in British waters, says marine conservation charity Shark Trust, “including some of the fastest, rarest, largest and most highly migratory sharks in the world”. But none that pose any real danger to humans.
This could change, however, according to recent research that indicates that climate change could be responsible for the appearance of some new, more deadly species to our shores in the future.
What has climate change to do with it?
A study published in April, carried out by Dr Ken Collins, senior research fellow at the University of Southampton and a former member of the UK Shark Tagging Programme, has warned that dangerous sharks including great whites and oceanic white-tips could be swimming off the beaches of Cornwall within the next 30 years.
It found that rising sea temperatures will encourage more exotic predators that have previously avoided the chilly coastline.
At least 10 new species are predicted to become regular visitors to Britain’s waters by 2050, including black tips, sand tigers and hammerheads, which are currently found no further north than the coasts of Spain and Portugal. At the end of June a great white was sighted near the island of Majorca for the first time in 40 years.
– © The Daily Telegraph