An apparent increase in shark attacks may well have a human cause, with low-cost air travel but also over-fishing and possibly global warming among the hidden suspects, experts say.

Recently headlines were grabbed by a decision to close beaches in the Seychelles after a shark savaged a British honeymooner before the horrified gaze of his spouse, in the second fatal attack there in 15 days.

In Russia's Pacific coastal region of Primorye, a shark mauled a 16-year-old boy a day after a man lost his forearms defending his wife. In the Caribbean, a woman vacationing in Puerto Rico received a 30 cm shark bite as she swam in a tourist haunt, the bioluminescent bay of Vieques.

According to the International Shark Attack File (ISAF), compiled at the University of Florida, 79 unprovoked shark assaults occurred around the world in 2010, six of which were fatal. This was the highest number in a decade, amounting to an increase of 25 percent on 2009, when there were 63 attacks with six fatalities, and 49 percent over 2008, which had 53 recorded attacks, four of them mortal.

So far this year, there have been six deaths and seven cases of injuries, according to an unofficial toll compiled from news reports.

Compared to deaths from smoking, road accidents, lightning strikes or even from other animals, the risk is minute, experts say.

"The attention from shark attacks is completely overblown," says Agathe Lefranc, a scientist with a French group, the Association for the Study and Conservation of Salachians (APECS), a category that includes sharks and rays.

Marine biologists say there is little research into the causes of shark attacks but point to several possibilities, all linked to humans.

No 1 is quite simply the growth in mobility, with cheap air travel and package vacations enabling people to swim, snorkel, surf or dive in places that previously had no human presence.

"The growth in shark attack numbers does not necessarily mean that there is an increase in the rate of shark attacks," ISAF says.

"Rather it most likely is reflective of the ever-increasing amount of time spent in the sea by humans, which increases the odds of interaction between the two affected parties."

One case that stands out occurred in the Egyptian resort of Sharm el-Sheikh, where sharks made five attacks in a week in November-December in 2010, one of which was fatal.

The finger of blame was pointed at a passing livestock transport ship that had dumped sheep carcasesses overboard and at operators who illegally fed sharks to thrill the tourists.

Another question - but again, lacking sufficient data to answer it - is the impact on shark behavior from overfishing and from global warming, which affects ocean temperatures and currents.

Agence France-Presse