Sharks killed twice as many swimmers and surfers last year than in 2010, with the increase due largely to a growth in tourism and changing shark patterns due to global warming.

There were 12 deaths in 46 shark attacks in 2011, a mortality rate of more than 25 percent compared to an average of under seven percent in the last 10 years, according to statistics from the University of Florida.

Countries that recorded shark attack deaths included Australia with three fatal out of a total of 11 attacks; South Africa, two fatal out of five; the French island of Reunion, two deaths in four attacks; and Seychelles with two attacks both of which ended in death.

Other countries with non-fatal shark attacks included Indonesia (3), Mexico (3), Russia (3) and Brazil (2).

Three locations not normally associated with high numbers of shark attacks -- Reunion, Seychelles and New Caledonia -- registered a total of seven attacks with five fatal outcomes, according to Burgess. "Those areas were not traditional area for tourism in recent years," the scientist explained.

"Over the last decade, more and more tourists have been going there... So we are getting more people coming to places where there are sharks, and the local communities are not prepared for the number of people going into the water at this time."

He added that medical facilities in these areas may not be developed enough to provide treatment in emergencies of this type.

In addition to the influx of tourists, the effects of global warming has meant sharks migrating to regions where they were not normally seen.

Last August, authorities even in the far east Russian reported three non-fatal shark attacks in the Primorye region -- not a normal location for the predator.

The United States experienced the most shark attacks last year with a total of 29 out of 75 reported around world, but suffered no fatal cases, George Burgess, an ichthyologist from the University of Florida, which published the "International Shark Attack File," told AFP.

"In the US and in Florida, where the most shark attacks occur in the US, we have seen a decline over a 10-year period," he said of the fatalities

According to Burgess, this could be a result of the economic crisis of recent years, which has reduced the number of tourists coming to Florida beaches.

He noted that the United States had done a "good job" to ensure safety in areas where sharks and humans get together.

Burgess said the reduction in the number of fatalities had been made possible due to good beach safety personnel, reliable emergency care, and the availability of many good hospitals and other medical facilities.

"As a result, when trauma occurs, when there are serious injuries in the water, we can get the people to the hospital quickly," he said.

Still, the number of fatal shark attacks remains very low compared to other causes of death, Burgess observed.

The number also appears lower still compared to the 30 million to 70 million sharks killed by humans each year, noted the scientist. The shark killing, he said, was a "tragedy."

A third of all shark species, including the Great White, are threatened with extinction because of overfishing and demand in Asia for their fins, to which people wrongly attribute aphrodisiac properties.