A group of foreign scientists discovered at least 20 dead sei whales beached along Chile's southern coast on the Gulf of Penas and reported them to the National Fisheries Service.

A statement from Chilean officials on Friday said there were around 20 whales, while the scientists said they counted more than 30.

The International Union for Conservation of Natures lists the sei as an endangered species and the whales are no longer supposed to be hunted commercially.

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A group of scientists discovered at least 20 dead sei whales on Chile's southern coast on the Gulf of Penas

The sei whale is an endangered species and the mammals are no longer supposed to be hunted commercially

The sei became endangered when it was heavily hunted after the stocks of blue and fin whales became depleted and it now has a population of about 12,000, according to the WWF.

It's not unusual to find beached whales along Chile's 2,400-mile coast, however it's the first time sei whales have been found beached in the country, the Fisheries Service said.

There is a military base several miles from the fjord where the whales were found.

Adults can be longer than 50 feet and weigh 20 tons or more.

The whales, which were rotting when they were discovered, measured about 33 feet in length.

Officials are trying to determine how the whales died and what caused the mammals to wind up on the beach

German biologist Vreni Haussermann, who was leading the group that found the whales, said:

'They were everywhere, none were injured, so we thought they suffered from a red tide [algal bloom] or a virus.

'I think they were swept away by the currents.

'In my 15 years in the area I never saw something like that.'

Officials said they were trying to determine how the whales died and what caused them to wind up on the shore.

Bad weather is hindering the investigation.