More than 3,000 dolphins have been found dead on beaches in Perú this year, and environmentalists are so far stumped as to what could be the cause, Perú 21 reports.
One theory is that powerful waves caused by oil exploration ships could have resulted in internal damage for the mammals, Carlos Yaipen Llanos, science director of the marine mammal rescue group Organización Científica para Conservación de Animales Acuáticos (ORCA), told the Peruvian news source, according to Discovery News.
The first hundred dolphins washed up on the shores in February. At that time, some hypothesized they had consumed toxic fish, though testing was unable to confirm this was the case.
Yaipen Llanos told MSNBC he believes acoustic testing produced a "sonic blast" which caused internal bleeding and loss of equilibrium for the dolphins, though he has "no definitive evidence" of this.
"It is a horrifying thought that these dolphins would die in agony over a prolonged period if they were impacted by sonic blast," Hardy Johns, head of the conservation group BlueVoice.org, said in an statement obtained by MSNBC.
According to the Associated Press, the U.S. has paused similar acoustic testing for fear that it was having a fatal impact on the dolphin population.
In addition to the dolphins, MSNBC reported thousands of anchovies have also been found dead on Peruvian beaches.