Two massive pods totaling up to 145 pilot whales beached and died after washing up on an hard-to-reach sandy beach in New Zealand. Half of the stranded mammals died when the help arrived, the rest were put down.

New Zealand's Department of Conservation (DoC) has released daunting footage showing dozens of pilot whales sprawled helplessly across a serene sandy beach in Mason Bay on the west coast of Stewart Island, NZ, with no help in sight.

The officials said that the pilot whales were first spotted by a hiker on Saturday evening, who reported the discovery to a field base.

Since the beach is isolated, it's unclear how long the creatures had been stranded before they were discovered. Department official Ren Leppens said that half of the animals were already dead when they were found.

Arriving at the scene, there was not much the conservationists could do, and they were forced to make a tough call.

The whales were in a miserable condition, and there were not enough resources to try and re-float what was left of the two pods, so it was decided to put them down, Leppens said.

"Sadly, the likelihood of being able to successfully re-float the remaining whales was extremely low. The remote location, lack of nearby personnel and the whales' deteriorating condition meant the most humane thing to do was to euthanize," she said in a statement, describing the call as "heart-breaking."

The pods washed ashore some two kilometers [1.2 miles] apart from each other.

A stranded whale is not a rare sight in New Zealand, where some 85 incidents are being reported every year. However, the majority of the reports concern sole whales that are way easier to refloat than pods consisting of dozens of animals, each weighing up to 2,300kg.

Mass strandings are less common but still happen regularly in Australia and New Zealand. Prompt assistance is a crucial factor in saving the beached mammals. In one of the largest whale strandings in decades last February, volunteers working together with officials helped to refloat some 100 whales out of 650 that washed ashore on a South Island beach in New Zealand. Some 350 died, while 200 were able to swim away by themselves.

While the phenomenon still remains a mystery, there have been several theories as to what might cause the whales to swim to their deaths, with the loss of orientation, illness, bad weather and extreme tidal fluctuations being named among the possible reasons.

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