Video report by ITV News Correspondent Martha Fairlie
Some 380 whales have died in Tasmania in the largest mass stranded ever recorded in Australia.
In recent days, nearly 500 pilot whales have become stuck near the remote coastal town of Strahan.
An estimated 270 whales were found on Monday on a beach and two sandbars near Strahan.
While another 200 stranded whales were spotted from a helicopter on Wednesday - less than 10 kilometres (six miles) to the south. Despite the best efforts of rescue teams, all 200 had died by late afternoon.
"They were among 380 whales that have so far died overall, 30 that were alive but stranded and 50 have been rescued since Tuesday," Tasmania Parks and Wildlife Service manager Nic Deka said.
"We’ll continue to work to free as many of the animals as we can," Mr Deka said.
Adding: "We’ll continue working for as long as there are live animals."
About 30 whales in the original stranding were moved from the sandbars to open ocean on Tuesday, but several got stranded again.
Why the whales ran aground in the first place remains a mystery.
Tasmania is the only part of Australia prone to mass strandings, although they occasionally occur on the Australian mainland.
The latest mass stranding is the largest in the country's history.
Before this incident, the largest Australia had seen was when 320 pilot whales became stranded near the Western Australia state town of Dunsborough in 1996.
The latest stranding is the first involving more than 50 whales in Tasmania since 2009.
Marine Conservation Programme wildlife biologist Kris Carlyon said the latest mass stranding was the biggest in Australia "in terms of numbers stranded and died".
As to why the whales came ashore in the first place, Mr Carylon suggested the pod may have been drawn into the coast to feed or by the misadventure of one or two whales, which led to the rest of the pod following.
"It’s really likely this was the one stranding event of a big group. This would have been one big group offshore," he said.
Marine scientist Vanessa Pirotta said there were a number of potential reasons why whales might become beached, including navigational errors.
"They do have a very strong social system, these animals are closely bonded and that’s why we have seen so many in this case unfortunately in this situation,” Ms Pirotta said.
Rescuing them does not always work “because they are wanting to return back to the pod."
She continued after becoming stranded the whales are often "disoriented and in this case extremely stressed, and just probably so fatigued that they in some cases don’t know where they are," she added.
In neighbouring New Zealand, more than 600 pilot whales washed up on the South Island at Farewell Spit in 2017, with more than 350 dying.