At least 300 sea turtles have washed up dead on Mexico's Pacific coast.
Preliminary exams suggests that the olive ridley turtles (Lepidochelys olivacea) drowned, an official with Mexico's environment ministry said.
The official said they had probably become tangled in illegal fishing nets in the high seas or in abandoned nets known as "ghost nets".
Olive ridley turtles are listed as vulnerable by the International Union for the Conservation of Nature (IUCN).
The IUCN says that their population is decreasing and that they are listed as vulnerable because they only nest in a small number of places.
The turtles were found washed up on Morro Ayuta beach in Oaxaca, on Mexico's western coast. The beach is one of the sites where olive ridley turtles come to lay their eggs.
All of the dead animals were females, turtle expert Ernesto Albavera Padilla told local media.