Hundreds of the long-finned pilot whales have been found beached on Tasmania's west coast since Monday (21 September).
Around 270 were first spotted by rescuers at the beginning of the week, but today (23 September) a helicopter found a further 200 whales nearby. It is believed they were all part of the same pod, with officials saying the second group may have been washed in with the tide.
Rescuers were able to save 50 at the time of writing and are continuing to help the remaining 30 animals, but sadly the majority of the animals weren't so lucky.
Tasmania Parks and Wildlife Service Manager Nic Deka said in a statement issued earlier today: "From the air most of the additional whales detected appear to be dead, but a boat has headed over there this morning to do an assessment from the water.
"We believe the group has been detected now for a range of reasons - one is that they are seven to ten kilometres away so it's a good distance from where we have been working and not necessarily a place that is obvious for a stranding.
"We certainly searched up and down the coast. In that part of the harbour the water is a very dark tannin colour so we think potentially they stranded, washed back into the water and then have been washed back into the bay, so that made it more difficult for them to be detected earlier in the piece."
Deka said rescue crews will be sent out to the creatures by boat to see whether or not more can be saved - with efforts being affected by a strong tide that ended up bringing some of the freed whales back to shore.
"Our focus is on those animals that are still alive," Deka added.
"The mortality has increased, but there are a significant number that are alive so we will continue to work with those."
Marine and Conservation Program wildlife biologist Dr Kris Carlyon said the stranding has been the biggest in Tasmania.
Dr Carlyon said: "Globally there has been some much bigger events than this, twice the size and over for example in New Zealand.
"In Tasmania, this is the biggest we have recorded.
"There is little we can do to prevent this occurring in the future."
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