Sydney, Mar 23 (IANS): A shark alert was issued on Friday in southwestern Australia after more than 150 pilot whales were stranded on a beach, with over half of them already dead.

A group of experts and volunteers went to Hamelin Bay, around 315 km south of Perth, to assess the situation and attempt to rescue around 50 whales still alive on the beach and another 25 stuck in shallow waters, Efe news reported.

"The strength of the animals and the windy and possibly wet weather conditions will affect when and where we attempt to move them out to sea," incident controller Jeremy Chick said in a statement issued by the department of bio-diversity and conservation of the state of western Australia.

Authorities have closed down the beaches in the area and issued an alert over the possible presence of sharks, which occasionally attack humans in this part of the country.

The short-finned pilot whales measure between four and 5.5 metres in length and inhabit tropical and subtropical waters in groups of around 100 members, often becoming stranded en masse on beaches due to moving in large groups.