There are growing concerns about Indonesian fishermen illegally killing and eating protected turtles off Australia’s northern coast, with authorities confirming eight animals have been found slit open with their eggs removed.

The green turtles were found on two remote islands north of Broome, during a patrol by the Department of Biodiversity, Conservation and Attractions (DBCA).

The department said in a statement that the carcasses had “what appeared to be man-made slits in the side of their bodies where eggs had been removed”.

“Turtle experts and government agencies are unanimous in their belief that Indonesian fishermen are responsible, given the remote location and method of killing.”

The grim discovery comes amid the biggest spike in illegal foreign fishing in Australian’s northern waters in almost 20 years, which has local boat skippers concerned about the threat of piracy and the impact on marine life.