Reasons Still Unclear For Massive Dolphin Deaths In Peru
April 23, 2012

Reasons Still Unclear For Massive Dolphin Deaths In Peru

Environmentalists and local authorities are working together to discover why nearly 900 dead dolphins have washed up on the northern coast of Peru so far this year.

Gabriel Quijandria, Deputy Environment Minister of Peru told the Associated Press (AP) in an interview that their investigation is still underway but their hope is to complete research by the end of this week.

About 90% of these 877 washed up dolphins were the common, long-nosed varieties, while the rest were Burmeister porpoises.

“The most probable hypothesis is the possibility of an infection with a virus,” Quijandria said in the interview.

“There are scientific articles about the incidence of morbillivirus, a type of distemper, in cetaceans in Peru, and that can be ruled out or proven next week.”

Quijandria also said more than 80% of the dolphins washed up on shore were in an advanced state of decomposition, making it difficult to identify the causes of their deaths.

Last week, the Peruvian government put together a group from different ministries to analyze a report from the Peruvian Sea Institute (IMARPE). These officials concluded the mass deaths have not been caused by lack of food, interaction with fisheries, or pollution.

Some are looking to the oil exploration being carried out off the northern shore as the cause of the deaths.

Quijandria said his officials do not believe these deaths are caused by seismic oil exploration work being conducted off the Peruvian shore by Houston, Texas-based company BPZ Energy.

BPZ´s manager in Peru, Rafael Zoeger, told AP the seismic studies were carried out as ships fired compressed air at the sea floor. Such studies are common and are used to send out under-water pulses. Zoeger does not believe the dolphins have died in part to these explorations.

Sue Rocca, a marine biologist with the Whale and Dolphin Conservation Society, thinks something more traumatic may be the cause for these deaths. In an interview with CNN, Rocca said, "When you have something this large, my gut would tell me that there's something traumatic that happened.”

"More investigation needs to be done," she told CNN.

Dr. Carlos Yaipen Llanos, Lima-based director of the marine mammal rescue organization, ORCA Peru, has been performing research on the deceased animals and has noticed damage to the periotic bones (inner ear) of the dolphins he has investigated. This damage could have come from the seismic blasts, though there was no significant skin damage, which would have happened should the seismic blasts have been loud enough. According to a report by Huffington Post, Dr. Llanos didn´t find any evidence of fishery interaction in the stranded dolphins. Therefore, this possibility is likely to be ruled out.

Peru isn´t the only coast the dolphins have washed up upon. Hundreds of dolphins have washed up in other parts of the world, including Brazil and the United States. This is the largest episode of dolphin die-offs in Peru´s history, according to Quijandria.

He adds Peru hopes the US National Oceanic and Atmospheric Administration (NOAA) will lend some help in determining just how the dolphins died and if some sort of virus is to blame.

As for the air guns used in seismic studies, researchers outside of Peru are investigating the effects of these guns on marine animals.