Hundreds of whales stranded on Tasmania’s West Coast, second event in the State this week

A mass stranding of about 230 whales has occurred at Macquarie Harbour near Strahan on Tasmania's west coast, just a say after a separate mass stranding event on King Island and two years since a similar event in the area.

The Tasmanian Department of Natural Resources and Environment (DNRE) has confirmed that the whales, which appeared to be pilots whiles were stranded on Ocean Beach, known as “Hells Gates”. Some animals are also stranded on a sand flat inside Macquarie Harbour.

The department said that about half of the animals are still alive. A team of marine wildlife experts heading to this area are assembling whale rescue gear, “the experts will assess the scene and the situation to plan an appropriate response.”

The event comes exactly two years after Australia’s worst ass whale stranding on record occurred in the same location. On 21 September 2020, 470 long-finned pilot whales were found beached on sandbars. A week-long rescue effort saved 111 whales, but authorities had to dispose of more than 350 carcasses.

Yesterday, there was a separate stranding on King Island in the Bass Strait, north of Tasmania, where 14 whales died and washed ashore. It appeared all the whales were "young males".

Researchers are unsure as to why whales beach themselves. Some possible explanations include a leading whale “mis navigating” the waterway, a sense of adventure leading the group astray, or the animal leading the pod getting frightened and taking evasive action.

Prof Karen Stockin, an expert on whale and dolphin strandings at Massey University in New Zealand, said the west coast of Tasmania, including Strahan, Ocean Beach, and Macquarie Harbour, appears to be “a hotspot” for a type of oceanic dolphin known as the pilot whale.

She said there were multiple reasons that may lead to marine animals stranding, including changes in water temperatures like in a La Niña or El Niño, with the animals coming closer to shore than usual.

“In pilot whales, they are highly social and cohesive and if one is debilitated or comes too close to shore, hundreds can follow.” Prof Stockin explained.

Wildlife biologist Kris Carlyon said the Tasmania state's "quite complex" coastal topography "can often act as a bit of a whale trap".

"Our coast is very close to the shelf edge where it drops off, and a lot of these species forage in the deeper waters off the shelf edge. The most common cause of stranding is simply misadventure. The animals get themselves into trouble in a complex bit of coast or are caught out in a low tide."

Dr. Carlyon worried there were few feasible ways to remove or bury the bodies. The rocky coastline restricts access to machinery, and towing the carcasses out to sea could see them "wash up somewhere, probably more problematic".

"The preference for us is to let them decompose naturally," Dr Carlyon said, "All that nutrient then goes back into the ecosystem and feeds a whole bunch of other animals."

Earlier this week, Stockin led a study that found as members of the public pressured rescuers to help whales, this could lead to negative outcomes for stranded animals, prolonging their suffering.

DNRE confirmed that staff from the Tasmania Parks and Wildlife Service and Tasmanian Police would assist in rescuing the stranded whales, as the situation is complex, “If it is determined there is a need for help from the general public, a request will be made through various avenues.

David Midson, general manager of the Australia West Coast Council, urged well-meaning public members to stay clear.

"The most important thing, if you're not invited by parks or one of the organizations helping, is to stay away. Having extra people can really hinder how they go about their rescue efforts."