The 90 out of the approximately 150 that were deemed to have a chance of survival if they could be returned, will now be put down, according to the country's public service channel ABC.
The personnel who came to rescue the animals and return them to the sea gave up after several failed attempts with two of the stranded dolphins.
We failed due to the sea conditions preventing the animals from being able to get out, says Shelley Graham from the park and nature conservation agency PWS to ABC.
They were constantly being washed back onto land by the sea and the weather conditions are expected to persist in the coming days.
Why did the dolphins swim up onto land? That is the million-dollar question – extremely difficult to answer. Mass strandings occur from time to time, for various reasons.
An individual that is sick or lost can lead the rest of the group onto the beach, says Kris Carlyon, also from the park and nature conservation agency.
The agency believes that the animals had been on the beach, near the mouth of the Arthur River, for between one and two days before they were discovered.
