Rescuers have been unable to save the last surviving sperm whale from separate mass-strandings in Australia and New Zealand that have seen 91 whales die since the weekend.
Though whale strandings are relatively common in both countries, the past few days have been particularly tough for conservation authorities.
In all, 24 sperm whales and two minke whales died in a stranding on and around remote Ocean Beach in Tasmania. In an equally remote New Zealand location, the tip of Farewell Spit in the South Island, 65 pilot whales died.
Australian authorities were trying to guide the last surviving sperm whale to open water from Macquarie Harbour when the whale died late Wednesday. They had earlier managed to free two sperm whales from the harbor, which is located near Ocean Beach.
"We did everything possible to save this whale," said Liz Wren, a spokeswoman for the Tasmania Parks and Wildlife Service. She said the whale appeared to be swimming strongly before it died at about 7 p.m.
Paradoxically, mass-strandings in most cases appear to be triggered by the survival strategy of a single whale, said Anton van Helden, a marine mammal expert at New Zealand's Te Papa museum. When a whale is sick or injured, it will often seek shallower water to recover, he said, so it doesn't have to swim so far to reach the surface and breathe.
Unfortunately, he said, a sick whale will often become beached as it tries to recover. It will then send a distress signal to other whales in its pod and they will join it as part of the group's strong social cohesion.
"The key thing about life in the ocean is that whales are highly dependent on one another to deal with any ailment," van Helden said.
He said Farewell Spit provides a "classic whale trap" because it has long, shallow beaches that can confuse whales into thinking they are in open ocean, as well as large tidal variations which can strand whales. The peak time for strandings in the South Pacific is between October and February, van Helden said, as conditions change and whales move closer inshore.
He said that one of the worst mass-strandings in New Zealand occurred in 1918 when about 1,000 pilot whales were beached on the Chatham Islands.
In general, worldwide whale populations have been slowly recovering since major nations agreed to a ban on commercial whaling in 1986. However, some species of whale remain endangered and Japan's practice of hunting whales for what it says are scientific purposes continues to cause controversy.