NEW ZEALAND – A new pod of 240 whales beached itself on a remote New Zealand beach at the weekend just hours after weary volunteers managed to re-float a different group of whales following an earlier mass stranding.

In total, over 650 pilot whales have beached themselves along a five-kilometre stretch of coastline over two days on Farewell Spit at the tip of the South Island.

About 335 of the whales were dead, 220 remained stranded on Sunday, and 100 were back at sea.

Department of Conservation Golden Bay Operations Manager Andrew Lamason said they are sure they are dealing with a new pod because they had tagged all the re-floated whales from the first group and none of the new group had tags.

The news was devastating for hundreds of volunteers who had come from around the country to help with the initial group of 416 stranded whales that was found early Friday, many of them already dead.

Rescuers had been hopeful earlier Saturday after efforts to re-float the initial group of whales had gone well, following a frustrating day on Friday.

He said about 100 surviving whales from the initial group were re-floated, and dozens of volunteers had formed a human chain in the water to prevent them from beaching again.

Volunteers were warned about the possibility of stingrays and sharks, he said, after one of the dead whales appeared to have bite marks consistent with a shark - though there had been no shark sightings.

Officials will soon need to turn to the grim task of disposing of hundreds of carcasses.

Lamason said one option was to tether the carcasses to stakes or a boat in the shallow tidal waters and let them decompose.

The problem with towing them out to sea or leaving them was that they could become gaseous and buoyant, and end up causing problems by floating into populated bays.

Arrangements will be made within the next few days about how the bodies will be disposed of, but in the mean time, members of the public are being asked to stay clear of the carcasses beach for health and safety reasons as there is a high risk of them exploding.

DoC spokesman Herb Christophers told the New Zealand Herald: “Because they’re very warm, the decomposition is very rapid in their gut. What happens is their stomach swells up and they do explode.

“I know this from first-hand experience, having seen a sperm whale explode. It’s not a pleasant thing to be around.”

Exactly how many whales became stranded over the last few days would be known some time this week, he said.

But Christophers estimated the total was around the 650-mark. Other media sources say close to 700.

“Of those, I’m guessing nearly 50 per cent of them died. We lost 300 on the first day and a few others had to be euthanised.”

Christophers said authorities and volunteers had been overwhelmed by the support, which created traffic issues in the area over the last few days, something of a rare sight in the Golden Bay area.

They had also received offers of help from people in other parts of the country and as far as Australia and even a person who had contacted them from California, who indicated they were willing to get on a plane if they required more help.

Farewell Spit is a 26km sandbar extending in an arc off the northwest tip of the South Island.

The spit, a sliver of sand that arches like a hook into the Tasman Sea, has been the site of previous mass strandings. Sometimes described as a whale trap, the spit’s long coastline and gently sloping beaches seem to make it difficult for whales to navigate away from once they get close. - PNC sources