Puzzled scientists are investigating the death of some 175 whales and dolphins which swam on to three beaches of  southern Australia and New Zealand over the weekend.

According to Australian officials, 97 whales and dolphins died Sunday after beaching on King Island near Tasmania.

On Monday, 43 whales were found beached on Maria Island, some 450 km away. Local residents and officials struggled overnight to save 24 that were found alive by dragging the huge creatures-each weighing at least a ton, back into the sea.

In New Zealand, rescuers were able to save 20 of the 73 pilot whales beached at Opoutre, near Auckland, on Sunday. However, some of those rescued are unlikely to survive the ordeal, said officials supervising a mass grave for the 53

dead animals.

As explanations--ranging from changing weather patterns, the availability of mackerel close to the coast to 'sound bombing' by oil companies scouring the deep seas—started coming in to explain the mass deaths, the Australian government announced the establishment of a national database on whale strandings.

"We are not sure why these tragedies happen but it's important that we coordinate existing scientific work to establish the reasons why these creatures become stranded," said Environment Minister Ian Campbell.