RIO DE JANEIRO -- Brazilian environmentalists are trying to figure out why more than 80 dolphins have been found dead in a bay west of Rio de Janeiro.

Eighty-eight dead dolphins have been retrieved from the Bay of Sepetiba, about 45 miles from Rio de Janeiro, in the last 18 days, Leonardo Flach, a biologist and the chief coordinator of the Boto Cinza Institute in Mangaratiba, Brazil, told ABC News today. That’s about 10 percent of the dolphin population that live in the bay, he said.

The cause may be bacteria or a virus, Flach said.

"We've never experienced this before. It’s a tragedy," Flach said. "Every day we are finding four or five dolphin carcasses."

He added, "One day we will find dolphin corpses that are male and adults, and the next day, female and puppies. But most of them are skinny and with deep skin lesions. I've never seen anything like that."

If the dolphins are dying because of the presence of bacteria in a uncontrolled environment, the only solution would be to create a marine refuge to allow the dolphins to survive, Flach said.

"The bay of Rio is extremely polluted, and unfortunately you have illegal dolphin hunting," Flach said, referring to the waters near Rio de Janeiro. "They are an endangered species, but with now this unknown disease, we hope to be able to put more pressure on the officials to help us to save the dolphins. Otherwise it will be very quick."

Several nongovernmental organizations, including the Boto Cinza Institute and SOS Botos, are joining efforts to conduct a full examination of the dolphin carcasses – including their skin, blood, and bones – in a university laboratory to unravel why these dolphins, or "botos" in Portuguese, are dying. They should have results by the end of the month, according to the Boto Cinza Institute.