Enormous

A shark possibly four metres long killed a swimmer near a popular New Zealand beach on Wednesday, then disappeared after police attempting to save the man fired gunshots at the enormous predator.

Muriwai Beach near Auckland was closed after the fatal attack, one of only about a dozen in New Zealand in the past 180 years.

Pio Mose, who was fishing at the beach, told The New Zealand Herald he saw the swimmer struggle against the “huge” shark. He told the man to swim to the rocks, but it was too late.

“All of a sudden there was blood everywhere,” Mose said. “… I was shaking, scared, panicked.”

Mako

South Australian Research and Development Institute (SARDI) environment and ecology program research scientist Paul Rogers said mako sharks were known to travel vast distances and several tagged as part of the current program had followed the same route.

"He is the fourth shark that has been up there in the past five years," he said.

"It is a fairly consistent pattern we are starting to detect with this species. It does tend to happen in late winter, but there have been sharks that have broken that pattern."

Mr Rogers said Morry weighed about 80kg when tagged and is believed to be aged between eight and 10 years old.

While the reason for their passage north was not yet known, the sharks were following a consistent pathway along the slope of the Continental Shelf until they were off Cape Leeuwin, the most southerly point of WA.

They then ventured into ocean waters, possibly visiting sea mountains and mid-ocean ridges to navigate and locate food.

Another mako tagged off Port MacDonnell in May 2009 swam 24,700km before its tag stopped transmitting in November 2010.

Unprovoked

Shark attacks in the U.S. reached a decade high in 2012, while worldwide fatalities remained average, according to the University of Florida's International Shark Attack File report released today.

The U.S. saw an upturn in attacks with 53, the most since 2000. There were seven fatalities worldwide, which is lower than 2011 but higher than the yearly average of 4.4 from 2001 to 2010. It is the second consecutive year for multiple shark attacks in Western Australia  and Reunion Island  in the southwest Indian Ocean, which indicates the localities have developed problematic situations, said George Burgess, director of the file housed at the Florida Museum of Natural History on the UF campus.

“Those two areas are sort of hot spots in the world – Western Australia is a function of white shark incidents and Reunion is a function most likely of bull shark incidents,” Burgess said. “What I’ve seen in all situations when there’s been a sudden upswing in an area is that human-causative factors are involved, such as changes in our behavior, changes in our abundance, or an overt shark-attracting product of something that we’re doing.”

Eighty unprovoked attacks occurred worldwide, slightly more than 2011. Four attacks were recorded in South Africa, three of which resulted in death, which is higher than its recent average of one fatality per year. Australia had an average year with 14 attacks and two fatalities, despite the media attention regarding incidents in Western Australia that resulted in a government-sanctioned culling hunt for endangered white sharks.

Drones

Drones with infra-red technology and high-tech cameras could be used to spot sharks off WA beaches, which have been ranked as a global hotspot for fatal attacks, according to a Perth shark expert.

Surf Life Saving WA statistics show 101 sharks have been seen from the metropolitan helicopter this season, including nine great whites, 57 tiger sharks, two bronze whalers, 11 hammerheads and a whale shark.

But there could have been more than 500 sharks off the metropolitan coast, with a NSW Department of Primary Industries report finding helicopter surveys spotted only 17.1 per cent of sharks.

Wildlife Marine founder and director William Robbins, who wrote the report while working for the NSW Government, said people in helicopters struggled to spot sharks that were more than 2.5m below the surface or more than 250m from the aircraft.

Dr Robbins said it would be worth investigating whether aerial drones, such as those used by the military, could be equipped with infra-red sensors to look further into the water than human observers.

"White sharks in particular, they actually have a body temperature that's slightly higher than the surrounding water that they're swimming in," he said.