11/02/2017 16:59 GMT | Updated 11/02/2017 17:07 GMT

Pilot Whales Stranded In New Zealand Rises To 650 As Intensive Rescue Effort Continues

About 335 of the whales have died.

Rescuers in New Zealand were faced with a grim discovery on Saturday as hundreds more pilot whales became stranded, bringing the total number to more than 650 in less than a week.

On Saturday about 240 more pilot whales arrived at Farewell Spit, at the top of the South Island, in what has become one of the worst whale strandings in the country’s history.

It comes after about 400 whales beached themselves on Thursday.

Anthony Phelps / Reuters
Volunteers try to assist some more stranded pilot whales that came to shore in the afternoon after one of the country's largest recorded mass whale strandings, in Golden Bay, at the top of New Zealand's South Island, February 11, 2017.

Scores of volunteers have been working to save the animals after they beached themselves on Thursday and rescuers tried to form a human chain to prevent the animals they returned to the sea from swimming back to shore.

But that unfortunately did not prevent a fresh pod coming inland on Saturday.

About 335 of the whales are dead, 220 remain stranded, and 100 are back at sea, the Associated Press reports.

Anthony Phelps / Reuters
Hundreds of whales became stranded in New Zealand's South Island.
Anthony Phelps / Reuters
Volunteers try to guide some of the stranded pilot whales still alive back out to sea.

It is hoped the new arrivals who survived can be moved back out to sea during the next high tide in daylight on Sunday.

Project Jonah, an organisation working to save the stranded animals, said that the incoming tide and frequent sightings of stingrays and sharks led volunteers to cease today’s rescue. 

Rescuers said they will return on Sunday morning.

Volunteers took turns pouring water over the beached whales to try and keep them cool, while school children sang to soothe the distressed animals, Reuters reports.

Anthony Phelps / Reuters
Volunteers try to assist some the stranded pilot whales.

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 refloated whales from the first group and none of the new group had tags.

About 20 of the new group were euthanised by conservation workers because they were in poor condition and more would likely need to be killed Sunday.

Lamason said improved weather and crystal clear water had helped with the rescue attempt.

Anthony Phelps / Reuters
A dead pilot whale lies on a sandbank after one of the country's largest recorded mass whale strandings.

The Department of Conservation has faced criticism for not reacting quicker to the tragedy. 

The department first received reports of the stranded pod on Thursday at about 8pm but did not send a rescue team until 5.30am the following morning because it said it was too dangerous to attempt to rescue the whales at night, the New Zealand Herald reports.

Anthony Phelps / Reuters
Volunteers attend to some of the hundreds of stranded pilot whales.
Anthony Phelps / Reuters
Volunteers try to guide some stranded pilot whales back out to sea.

Farewell 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.

It is not yet known why these whales beached themselves.

New Zealand has one of the highest rates of whale strandings in the world, and Friday’s event was the nation’s third-biggest in recorded history.

The largest was in 1918, when about 1,000 pilot whales came ashore on the Chatham Islands. In 1985, about 450 whales stranded in Auckland.

Pilot whales grow to about 7.5 meters (25 feet) and are common around New Zealand’s waters.