Updated

Marine biologists said Wednesday that they are trying to understand why 23 endangered Franciscana dolphins have showed up dead on several beaches.

Gloria Veira, spokeswoman for the Mundo Marino foundation, told The Associated Press that the animals were found last week.

Veira said the majority had strange markings on their snouts. She said they were found on beaches south of Buenos Aires, such as La Lucila, Aguas Verdes, Santa Teresita and Las Toninas.

Specialists were struck by the number and that they died at the same time, Veira said.

She said marine biologists so far believe climate change or large-scale fishing could be factors.

The Franciscan is an endangered species recognized by its long, slender beak. It is only found in waters off Argentina, Uruguay and Brazil.