More than 130 dolphins die in mystery beach stranding

Volunteers drag some animals back out to sea but many return

Authorities in the Cape Verde islands are waiting for experts from Spain to help discover why the dolphins washed ashore (AP)

More than 130 dolphins have died after a mysterious mass stranding on a west African beach.

About 200 melon-headed whales – mid-sized dolphins – were found on a beach at the Cape Verde Islands.

Officials, residents and tourists managed to drag some of the animals back out to sea, but many returned.

Bulldozers buried 136 dead dolphins, local media reported.

Shortly afterwards, off the US east coast, about 26 pilot whales beached themselves on an island off Georgia, leaving 15 dead. It was the species’ second mass stranding along the state’s coast since July.

Vets from Spain are preparing to travel to Boa Vista Island off west Africa to carry out tests to investigate why the animals died.

A volunteer environmental group in the former Portuguese colony said it took samples from 50 dolphins, and that the local council placed four others in a deep freeze.

Experts say factors that could contribute to mass strandings include sickness, navigational error, a rapidly falling tide, being chased by a predator and extreme weather.

In the first three months of the year, more than 1,100 mutilated dolphins washed up in south-western France. Experts said most of the deaths were caused by the animals being captured by industrial-sized fishing nets.

Last year around 150 short-finned pilot whales stranded themselves on Australia’s western coast south of Perth.

If marine mammals land on solid surfaces, their chest walls start to compress their internal organs because they are no longer supported by the weight of the water.