Wildlife officials in Peru are struggling to explain a mass dolphin death along the country's northern shores.
Since the beginning of the year, hundreds of dolphins have washed ashore dead on Peru's beaches, according to officials there, who said that more than 400 dead dolphins have been found this year.
About 220 dead dolphins were found in the last week of January and at least 200 more were found in the preceding three weeks, according to The Associated Press, which cited the Peruvian Sea Institute, also known as Imarpe.
The dolphins were found in the Lambayeque region on the northern coast, not far from the border with Ecuador.
The mass of dolphins deaths occurred along the same stretch of beach as a 2012 mass dolphin death where more than 870 of the animals were found dead. Autopsies of the dead dolphins from the 2012 event were inconclusive, the AP reported, noting that the cause of death could have been anything from seismic testing, to poisoning from biotoxins in the sea to an unknown.
Additionally, more than 1,500 birds, mostly brown pelicans and boobies, died between February and May 2012 in Peru. Officials said there was no link between the bird deaths and the dolphin deaths, according to The New York Times.
"It is odd indeed," Gabriel Quijandría, Peru's deputy environment minister, told the Times. "But they are not related."
A report by Fox News Latino said that tissue samples taken from the dolphins that dies in the recent episode revealed that they did not die from poisoning or from the effects of "extractive activities" in the region.
Autopsies currently underway will focus on the dolphins' lungs, kidneys and livers, the AP reported, adding that it will take two weeks for results to come in.
Jaime de la Cruz, the head of Imarpe's Lambayeque office, speculated that the dolphins could have died from ingesting toxic algae, Fox reported, citing a local newspaper.