Olive Ridley turtles with varying levels of injuries were found washed ashore here along Arcottuthurai-Maniantheevu stretch on Thursday.
Over 10 Olive Ridley turtles, all female, were found dead with injuries primarily caused by propellers of fishing boats.
The Forest Department had carried out autopsies to ascertain the cause of death, it was said.
The turtles that were found dead have been believed to have suffered these injuries to their skull at least a few nautical miles off the coast.
The eastern coast provides favourable nesting habitats to Olive Ridley turtles, and the period from December up to March witnesses large influx of turtles that come out for nesting in this region.
The Forest Department has set up hatcheries from Porayar to Kodiakkarai to facilitate the nesting and caring of young turtles.