Tourists have been advised not to swim or surf in the water of an idyllic island near the coast of Madagascar as it is home to many sharks.
Ten people have been killed around Réunion in recent years – a paradise in the Indian Ocean in an area known as the “Shark Highway”.
French territory now has the highest number of deadly shark attacks in the world and authorities have banned swimming or surfing outside of its relatively safe coral lagoon for fear of further attacks.
Since 1913, around 30 people have been killed and 56 attacked while swimming off Réunion – with eleven deaths since 2006 and ten since 2011.
The death rate averages three deaths per million people – more than three times that of South Africa and much higher than Australia and the United States.
Experts believe this is partly because the island sits on a shark highway between Australia and South Africa and that it is drawn to its active volcano Piton de la Fournaise, The Sun reported.
Ninety percent of the attacks are said to have been carried out by bull sharks. These are considered to be the deadliest for humans due to their aggressive tendencies and ability to migrate up rivers.
Bull sharks prefer shallow water, live near high population areas, and have the best ability to move around in fresh water – especially large coastal rivers and lakes. This behavior puts them in more contact with humans than most other species of shark, making them responsible for biting more people fatally.
Recent attacks on Réunion include 44-year-old Briton Richard Martyn Turner, whose severed hand was found in a shark in November 2019.
In May of that year, 28-year-old Kim Mahbouli, a French tourist, was attacked and killed by a shark while he was surfing in an area where swimming was prohibited.
Fisherman Floris Huet also died in January 2019 after a shark tore off his left leg. There were 57 shark attacks on the island in 2020, the deadliest year since 2013, with ten unprovoked bites resulting in death.
The island’s government has tried to make the waters safer by culling and investing in anti-shark studies. However, scientists are still unsure what drove the increase in attacks. Therefore, surfers and swimmers are banned from the area for the time being.
Professor Erwann Lagabrielle has studied shark activity in the waters around Réunion to see why they are so dangerous 9News.
His previous research has shown that the likelihood of being attacked by a shark in Réunion has increased “by a factor of 23” since the 1980s.
Prof. Lagabrielle was inspired to do the research after seeing his friend attacked by a two meter long bull shark in 2015.
“It was like a horror movie,” he said.
He had swum in Saint-Leu with Rodolphe Arriéguy, who was attacked just 20 meters away from him.
“The water was white foam and then the white turned pink and the pink turned red,” recalled Prof. Lagabrielle.
“I swam to my friend’s and that was the scariest part – I swam against my own instinct.”
Arriéguy, 45, had been bitten on the arm and Prof. Lagabrielle used his surfboard leash to make a makeshift tourniquet and stop the bleeding before swimming him back to shore.
Arriéguy was taken to the hospital and survived but lost his arm.
“The next question is what can explain this increase.” Said Dr. Lagabrielle and discussed the continuation of his studies on the increasing number of shark attacks.
“It’s either an increase in the shark population or a change in their behavior.
“These can be explained by other factors such as changes in water temperature and fishing for shark populations.”
Dr. Blake Chapman, a marine biologist who studied shark neuroscience for her PhD, said Guardian Australia that some multiple bite attacks suggested that the sharks might purposely hunt humans.
The cloudy water created by sediments from the volcano would also make the conditions ideal for the sharks to sneak up on their prey.
Dr. Chapman said, “If they bite more than once, the more likely they are fatal as more blood is lost.”
Bull sharks are one of the largest requiem sharks, measuring 11 feet in length and weighing up to 315 kg. They are very aggressive predators and eat a wide variety of prey including various types of bony fish and also small sharks, some mammals, sea birds and sea turtles. Large, adult bull sharks do not have natural predators.