More than 100 whales and dolphins have died in two separate beachings in islands off Tasmania in Australia.
It is not known what caused the beachings
Ninety-seven pilot whales and bottlenose dolphins died off King Island over the weekend, and several others have died off Maria Island.
Volunteers have been trying to prevent others from suffering the same fate, by carrying them back to deeper waters.
Scientists have flown in to try to establish why so many of the mammals have died.
Tasmanian wildlife officer Shane Hunniford said about half of the 53-strong pod of whales off Maria Island had already died, and efforts were under way to save the other beached animals.
"As I'm looking out to sea now, I can see seven people holding rescue whales and beyond that there's a police launch out there, and there's a mother and calf out there, so we've had a good success rate, we're pretty happy," Mr Hunniford told reporters.
"In terms of degrees of health, some are good, some are not so good. If things keep going the way they're going now we're doing alright," he said.
The BBC's correspondent in Sydney, Phil Mercer, says just why so many have become stranded on the beaches remains a mystery.
In the past, scientists have speculated that predators such as killer whales may have forced them onto land.
Other researchers have suggested that they are attracted by high levels of nutrients in the water, or that they become disorientated by the noise of oil and gas installations.