Updated

Hundreds of tourists at a New Zealand beach watched in horror as a massive Great White shark fatally attacked a swimmer, turning the water crimson and sparking a feeding frenzy that brought as many as four other sharks before police firing shots from a lifeboat and a helicopter chased them off and recovered the dead man's body.

The victim, identified as Adam Strange, a 46-year-old father of one, had been swimming more than 600 feet from shore, according to witnesses who were at Muriwai Beach near Auckland. The attack was 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 Strange struggle against the "huge" shark, estimated at 14 feet. He beckoned the doomed swimmer to nearby rocks, but it was too late.

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

Witnesses told TV3 that they saw other sharks join in on the attack .

“He was attacked in a circle and this poor guy...in maybe five minutes he lost strength, so he just floated," Christian Rasmussen said. "We just stood there and the whole surroundings was crimson.”

Strange was a regular at the Muriwai surf club and was training for a long distance harbor swim, surf club chairman Tim Jago told TV3.

Police Inspector Shawn Rutene said police went out in inflatable surf-lifesaving boats and shot at the shark, but it was not known if the beast was hit.

"It rolled over and disappeared," Rutene said.

Police and Murwai lifeguards spent around a half hour trying to recover the body as two sharks circled it, Stuff.co.nz reports.

About 200 people had been enjoying the beach during the Southern Hemisphere summer at the time of the attack. Police said Muriwai and other beaches nearby have been closed until further notice.

Helicopters will continue to patrol the area until Thursday morning and lifeguards will have a strong presence on beaches, Stuff.co.nz reports.

Jago said authorities have used every available "closed" beach sign to alert people nearby.

Police did not say what species of shark was involved in the attack. Clinton Duffy, a shark expert with the Department of Conservation, said New Zealand is a hotspot for Great White sharks, and other potentially lethal species also inhabit the waters.

But shark attacks in New Zealand are rare. Duffy estimated that only 12 to 14 people have been killed by sharks in the country since record-keeping began in the 1830s.

"There are much lower levels of shark attacks here than in Australia," he said. "It's possibly a function of how many people are in the water" in New Zealand's cooler climate.

He said that during the Southern Hemisphere summer, sharks often come in closer to shore to feed and to give birth, although that doesn't necessarily equate to a greater risk of attack.

"Ninety-nine percent of the time they ignore people," he said. "Sometimes, people get bitten."

Around the world, sharks attacked humans 80 times last year, and seven people were killed, according to the University of Florida's International Shark Attack File. The death toll was lower than it was in 2011, but higher than the average of 4.4 from 2001 to 2010.

The Associated Press contributed to this report.