Spring sperm whale deaths in 'hotspot' for strandings

Scientific samples from sperm whales that beached on a remote island in Bass Strait could play a part in unpacking the mysteries of mass strandings.

Five of the mammals died at Marshall Bay Beach on the northwest coast of Tasmania's Flinders Island after being spotted ashore on Sunday.

There have been several major whale strandings in early spring in Tasmania in recent years.

In September 2020, more than 400 pilot whales got into trouble at Macquarie Harbour on the state's west coast in the biggest recorded stranding in Australia.

Roughly 230 of the same species stranded at the same spot two years later.

In September 2022, 14 sperm whales also died on King Island, another remote Bass Strait outpost.

"Tasmania over the years has become, in some people's opinion, a stranding hotspot," wildlife scientist Vanessa Pirotta said.

"One of the reasons is its geographical location. It is on the doorstep of the Southern Ocean."

Dr Pirotta said sperm whales, which routinely dive hundreds of metres below the surface, prefer deep ocean but do enter Australian waters.

"They may have been swimming together in a social unit," she said.

"It could have been a group that were transiting through, perhaps feeding ... or maybe they hang out there more than we think."

The reasons for strandings remains a mystery but drone footage of pilot whales from Tasmania and Western Australia has shed light on pre-beaching behaviour.

Whales were observed huddling together and creating tight group formations in shallow water before getting stuck.

"There is a group of international scientists and myself chatting about what this could mean," Dr Pirotta said.

"We haven't solved the problem yet but we are slowly piecing together the puzzle."

It is speculated the Macquarie Harbour strandings were because the area's shallow and sloping underwater topography played havoc with the whales' echo-location.

Dr Pirotta said it wasn't clear why the mass strandings in Tasmania had occurred around the same time of the year.

Tasmania's Parks and Wildlife Service was able to provide palliative care to two of the whales on Flinders Island before they died.

"Staff will collect valuable samples to enable research to better understand the species and why they strand," an environment department spokeswoman said.

The beach has been closed, with people warned the carcasses may attract sharks.