Over hundred dolphins were found dead on an island off the coast of Mozambique.
Eighty-six carcasses were found on Bazaruto Island, north of the capital Maputo on Tuesday, after a first group was washed ashore on Sunday.
The cause of the deaths is still unknown, the country’s environment ministry said, and more experts are heading to the site.
Last week’s Cyclone Guambe caused unrest in the waters off the island of Bazaruto. Authorities were investigating if the cyclone contributed to their deaths.
Dolphins are known to follow their leader to shore when they are in danger, Bazaruto Archipelago National Park, Tomás Manasse said.
The autopsy did not conclusively find problems with the skin, tongue or intestines, he said, however, more samples have been sent to a laboratory in Maputo.
Last year, 52 dead dolphins were found on the coast of the Indian Ocean island of Mauritius.
Campaigners blamed a ship which had run aground and spilled vast amounts of oil. But later an investigation found an abrupt change in pressure in sea waters was the reason. Factors such as use of military sonar, an underwater earthquake, explosives or a volcanic eruption affects pressure.