Orcas die trapped in ice

Eleven killer whales were declared dead on Wednesday after being trapped between ice floes and concrete blocks on the northern Japanese coast, but one managed to escape badly wounded back into the ocean.

The 12 giant mammals were found trapped in floating ice off the town of Rausu on the Shiretoko Peninsula, about 1 050km northeast of Tokyo, on Monday.

One female whale, though seriously hurt, broke through the ice on Tuesday and returned to the Pacific as the others grew feeble and lifeless.

"We confirmed 11 are dead today," said Satoshi Mizuguchi, an environmental official in the town.

Television footage showed floating bodies of whales with their fins up and tetrapods smeared with blood next to a wall where a message was etched in the snow, "Whales, hold out."

"We had been trying to rescue the whales but it was difficult because ice was clustering too much and the waters were too shallow to send a rescue ship," Mizuguchi told AFP by telephone.

The 4m-female whale "escaped by herself but she's badly wounded", he said.

"I am a bit worried if she can survive in the ocean."

The town will collect the bodies of the dead whales and hand them over to universities and other institutes for research.

The tragedy was believed to have been caused when low pressure off Shiretoko brought about northern winds which sent the floating ice crashing into the peninsula, trapping the whales.

Killer whales, also called orcas, can live for up to 80 years and grow to nine tons.

They can swim in families at more than 50km/h and are at the top of the ocean food chain, preying on other animals including seals, turtles and even lesser whales and dolphins.

Japan has been at odds with much of the international community over its insistence on hunting whales, whose meat is traditionally eaten here, but the main whales killed are of the smaller Minke variety.