A rescue group says an endangered leatherback turtle that washed up on the shores of Newfoundland died because it ingested a garbage bag.

Wayne Ledwell of the Whale Release and Strandings group said the 300-kilogram sea turtle had likely been dead for weeks when rescuers found its decomposing remains at a beach in Point Lance Tuesday.

Ledwell said after performing an autopsy on the massive reptile, which he estimated to have been around 50-years-old, it was determined the turtle had starved to death after the green garbage bag obstructed its gastrointestinal tract.

"I was almost shocked when we cut open the stomach and (lining) the intestine was this garbage bag," Ledwell said. "It's kind of sad that that's the ending to that animal."

Ledwell said he has seen about a dozen turtles who have suffered similar fates after consuming plastic, but usually the debris is smaller and transparent.

According to the Department of Fisheries and Oceans, scientists believe the turtles may mistake floating plastic for jelly, the main staple of the leatherback diet.

"Leatherbacks are such neat animals," Ledwell said. "To have them in our waters and lose them over some idiotic thing like carelessness ... It's probably a hard way to die."

Marine pollution is a worldwide problem, Ledwell said, but everyone can protect these ancient creatures by keeping their trash out of the ocean.

Leatherback turtles are listed as an endangered species in Canadian waters.