MEXICO CITY, Aug. 29 (Xinhua) -- More than 300 vulnerable olive ridley sea turtles have been found dead off the Mexican coast, authorities said.

Mexico's Federal Attorney for Environmental Protection (PROFEPA) said in a statement that the dead turtles were found in the ocean off the coast of southern state Oaxaca on Tuesday.

The turtles were entangled in illegal fishing nets used for riparian fishing on riverbanks rather than fishing in the ocean, the Federal Attorney's office said.

Officials took the turtles' remains ashore, buried them in two pits and will inform local fishermen about the risks posed by illegal nets.

The endangered olive ridley turtles descend on various Mexican states to lay their eggs from May to September. "Their vulnerable status comes from the fact that they nest in a very small number of places, and therefore any disturbance to even one nest beach could have huge repercussions on the entire population," according to the World Wildlife Fund.

A similar incident happened earlier this month when 102 olive ridley and some other turtles were found dead in a sanctuary in Chiapas, another Mexican state. The possible cause is still being investigated, PROFEPA said.