Two pods of pilot whales stranded off the south coast of New Zealand's South Island have died.
A camper found more than 140 whales stranded in Mason Bay on Stewart Island on Saturday night. They hiked to a nearby field base to report the stranding to the New Zealand Department of Conservation.
Half the whales were already dead when they were found, the department's Rakiura operations manager Ren Leppens said in a statement on Monday.
The decision was made to euthanise the remaining living whales due to their deteriorating condition and the "remote, difficult to access location".
"Sadly, the likelihood of being able to successfully re-float the remaining whales was extremely low," Leppens said. "However, it's always a heartbreaking decision to make."
The department has notified Ngāi Tahu iwi [the local Māori tribe] and is working together on next steps.
The department said marine mammal strandings were relatively common on New Zealand's shores, and it responded to an average of 85 incidents a year, mostly of single animals.
"Exactly why whales and dolphins strand is not fully known but factors can include sickness, navigational error, geographical features, a rapidly falling tide, being chased by a predator, or extreme weather," the department said in the statement.
"A number of strandings occurred on New Zealand shores over the weekend, however these events are unlikely to be related."
On Sunday 10 pygmy killer whales also stranded at 90 Mile Beach, on New Zealand's North Island. Two have since died and attempts to re-float will be made on Tuesday.
A 15-metre-long sperm whale beached in Doubtful Bay in Northland, North Island, on Friday died overnight on Saturday. A dead female pygmy sperm whale also washed up at Ohiwa on the North Island over the weekend.