Whales stranded on island

Sydney - More than a dozen large sperm whales may have died in a beaching incident on Australia's southern island state of Tasmania, local wildlife rangers said on Monday.

A pod of 19 sperm whales became stranded in rough weather on Tasmania's west coast and poor conditions hampered rescue efforts, said district ranger Chris Arthur.

"We know that the majority of the whales are dead and that they are in the surf zone," Arthur said.

He said the whales ranged in size from seven to 14 metres in length and weighed up to 45 tonnes.

"These are not small animals, these are quite large animals," Arthur said on ABC radio.

Authorities learned of the stranded whales early on Monday but severe weather had hampered efforts to fly to the area to see if any of the animals could be saved.

"The weather is incredibly difficult," he said.

In November, 117 pilot whales and dolphins died after a mass stranding on Tasmania's east coast.

Scientists have long been puzzled about why the ocean mammals become beached in groups.

Theories range from diseases that upset internal navigation systems to herd behaviour in which large numbers of whales blindly follow a leader into trouble.

Others believe they may follow stocks of food such as crayfish too close to the shore.