Shark attacks double in 20 years across densely populated coastlines

The number of shark attacks has doubled in the past two decades in densely populated coastal regions, according to a new global analysis.

However, scientists emphasised that despite this uptick, dangerous interactions with the predatory fish are still very rare, and are in fact declining in many places.

With around 100 unprovoked attacks taking place every year, someone is more likely to be struck by lightning or win an Oscar than faceoff against a shark.

Most attacks are no more serious than a dog bite, and only around six each year prove fatal.

Instead of sharks becoming more aggressive, the increase in attacks across regions like southern Australia and the US East Coast actually reflects the rise in people taking up residence on coastlines and flocking to beaches.

“As development increases along the coast and in beach communities, more residents and tourists frequent these waters,” said Dr Stephen Midway, a fisheries scientist at Louisiana State University.

“With more people in the water, the chance for a shark attack increases.”

However, he noted that many countries saw attacks drop over the same period, and even where they went up numbers were low.

In Australia for example, the rate of attack was around one in four million people in 1995, and increased to roughly one in two million in 2015.

Dr Midway was inspired to investigate shark attacks around the world after a spate of attacked shocked residents of North Carolina.

He wanted to understand whether the sudden increase in attacks was unusual or – in the wider context – to be expected.

“While shark attacks are often reported in numbers, we factored in the regional human populations to determine the rate of shark attacks worldwide,” said Dr Midway.

The scientists concluded episodes like North Carolina were generally the result of a combination of factors including particularly warm summers, fluctuations in prey numbers and surges in beachgoers.

Sharks are under threat around the world, partly as a result of persecution by humans.

Their fearsome reputation has led authorities in Australia, for example to cull sharks off the coast of Queensland in a bid to reduce attacks.

This method has killed nearly 50,000 sharks since the 1960s, and over the same period numbers of vulnerable species like great whites and hammerheads have dropped by over 90 per cent.

Study co-author Dr George Burgess of the University of Florida said people had “always demonised sharks”, but the researchers said they wanted their study – published in the journal Plos One – to contribute to “a more scientifically grounded discussion about sharks”.

“We ought to think of the risk of a shark attack like we would think of the risk of a car accident,” said Dr Midway.

“We don’t assess our personal risk of getting into a car accident by the national statistics on car accidents year over year. We think about our specific car, the weather, the road conditions and other very local factors.”