In the remote town of Strahan, rescuers had been scramble to save the survivors among what are believed to be 270 pilot whales on Monday, a beach and two sandbars.
However, another 200 stranded whales were seen from the sky on Wednesday, less than 10 km south of them, according to Nic Deka, director of the Tasmanian Parks and Wildlife Service.
“From the air, they didn’t appear to be in a condition that would warrant a rescue,” Deka said. “Most of them looked dead. ”
Crews will be sent to the creatures by boat, to assess whether or not they can be saved, Deka added.
Rescuers moved around 30 of the stranded whales from their original position to the high seas, but many of them found themselves stranded.
Authorities estimate that about a third of the original group of whales had died on Monday evening, with a further update expected later on Wednesday.
The Australian island is the only part of the country prone to massive whale strandings, the current one being the first since 2009 to involve more than 50, and the largest on record by the government.
Pilot whales are a species of oceanic dolphin that reach seven meters in length and can weigh up to three tons.
Getting them back to the sea can include physically pushing the animals or using specialized tarps and pontoons to drag them to deeper water. Rescuers try to keep the whales upright to avoid disorientation.
Scientists don’t know why whales, which travel together in pods, sometimes get stranded but they are known to follow a leader and congregate around an injured or distressed whale.