Australian rescuers on Friday struggled to refloat the last surviving pilot whales from a mass stranding that killed nearly 200 of the animals on a surf-ravaged beach in Tasmania.

Fewer than 10 of the glossy black mammals still live on Ocean Beach in Tasmania’s remote west, state wildlife services said.

About 30 of the animals were released into the ocean on Thursday, but some had stranded again, said Brendon Clark, incident controller at the Tasmania Parks and Wildlife Service.

Under a cool drizzle, marine wildlife experts began to complete a complex, day-long rescue operation that began with a large pod of the animals, which are part of the dolphin family, stranding on the beach in midweek.

Three pilot whales had yet to be reached due to their remote location on shore and difficult tidal conditions, Clark told reporters at the scene.

“The priority remains the rescue and release of these remaining animals and anyone else that we identify in this re-beach,” he said.

Next, Clark said, comes the task of disposing of the carcasses.

Wildlife workers used a forklift to line up whale carcasses along the beach, their tails pointing out to the cold ocean.

A small, young calf was seen tethered alongside the larger adult pilot whales.

A long white leash was looped around the tails of dozens of the animals so they could be towed en masse for disposal at sea.

Weather forecasts suggested the “best opportunity” for the operation would be on Sunday, Clark said.

If left in shallow water or on the beach, the carcasses could attract sharks and transmit disease.

“We are currently making every effort to consolidate the carcasses in one place and then bring them offshore,” said Kris Carlyon, operations manager at the State Wildlife Services.

Once in the water, the carcasses can attract predators or become a collision risk, Carlyon said, but experts hoped the winds and currents would drive them out to sea, and some were expected to sink.

Two years ago, Macquarie Harbor was the scene of the country’s largest ever mass stranding, involving nearly 500 pilot whales.

More than 300 pilot whales died during the event, despite the efforts of dozens of volunteers who struggled for days in Tasmania’s freezing waters to free them.

Scientists still don’t fully understand why mass strandings occur.

Some have suggested that pods go off track after feeding too close to shore.

Pilot whales – which can grow up to six meters long – are also very sociable, allowing them to follow their fellow occupants if they find themselves in danger.

This sometimes happens when old, sick, or injured animals swim ashore and other members of the group follow them, trying to respond to the trapped whale’s distress signals.

Others believe gently sloping beaches like those in Tasmania confuse whales’ sonars and make them think they’re in open water.

The latest stranding came days after a dozen young male sperm whales were reported dead in a separate mass stranding on King Island – between Tasmania and mainland Australia.

State officials said the incident could have been a case of “accident”.

Strandings are also common in nearby New Zealand.

According to official figures, around 300 animals strand there every year, and it is not uncommon for groups of 20 to 50 pilot whales to run aground.

But numbers can run into the hundreds when a “super pod” is involved. In 2017, nearly 700 pilot whales were mass stranded.