LIMA, (Reuters) – The mystery surrounding the deaths of at least 877 dolphins in Peru deepened yesterday as the government said human activity was not to blame but failed to pinpoint a natural cause for the massive die-off.
A final report from the Peruvian government’s Ocean Institute, which manages one of the world’s richest marine ecosystems, said the dolphins did not die from a lack of food, hunting by fishermen, poison from pesticides, heavy metal contamination, an infection or a virus.
It also said there was no conclusive evidence that linked seismic offshore exploration by oil companies to the deaths of the long-beaked common dolphins along the Andean country’s northern coast.
But it did leave open the possibility that abnormally warm surface water temperatures and high levels of algae may have played a role, saying further analysis would be needed to determine if any red and brown plankton species in the sea were toxic.
“The dolphins were killed by natural causes and not due to any human activity – that is what you might say is the major conclusion,” said Minister of Production Gladys Triveno, who oversees the government’s Ocean Institute.
However, ORCA, a local NGO, says the deaths occurred after seismic events – which locals attribute to exploration by oil companies – damaged the ears of the sound-sensitive mammals and caused them to surface too rapidly.
“We found cells that had injuries due to bubbles that are associated with decompression sickness,” said Carlos Yaipn-Llanos, director of ORCA.
The government and many independent scientists say it is impossible to prove the bubbles were caused by decompression sickness, known by divers as the bends.
Houston-based BPZ Resources Inc has said it conducted seismic surveys starting on February 8 in part of the area but that it adheres to strict environmental standards and that the first deaths happened before it began exploration work.
Another company, Savia Peru, has said it was not working on its concessions in the area at the time of the deaths.
Both companies have said seismic exploration technology is used widely around the world and has never been linked to massive die-offs.
