Werner and his colleagues then stayed on the scene to monitor the six animals until they swam into deeper water. But by Wednesday, five of the six dolphins left alive had also re-stranded, per Newshub, forcing agency veterinarians to put them down as well.
The one remaining whale is believed to still be offshore.
"I can confirm that the remaining pygmy killer whale has not been seen since Wednesday afternoon," Project Jonah general manager Daren Grover told IFLScience.
"Regarding strandings, New Zealand has one of the highest stranding rates in the world but thanks to our organisation and well-trained members of the public, we also have one of the highest success rates," he continued. "Whales and dolphins can strand for many reasons, whether they may be old or sick, or in unfamiliar waters and caught our by some of our geography (gentle sloping beaches with a large tidal range that can catch out whales close to shore)."
"They might also be chased close to shore by other ocean predators or confused by underwater sounds including those made by humans. There are other human-caused (anthropogenic) reasons including; eating plastics in the ocean and becoming emaciated, increased pressures on food caused by over-fishing, increased ocean temperatures caused by climate change, and being caught and injured in fishing nets."