In their research, a team led by Dr Britta Denise Hardesty from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) examined data from nearly 1,000 dead turtles to understand the role plastic played in their deaths.
They found that the youngest turtles appeared to be most susceptible to plastic pollution.
Just over half of the post-hatchling individuals had ingested plastic, and around a quarter of the slightly older juveniles were affected, compared to around 15 per cent of adults.
While the number of plastic pieces in the reptiles’ guts varied wildly from one to over 300, the scientists were able to deduce that turtles have a 50 per cent probability of death after consuming 14 pieces.
The work emerges as another study documents the global decline of turtles and tortoises that has left over 60 per cent of the world’s species either extinct or facing extinction.
Two centuries ago, sea turtles in the Caribbean Sea were estimated to number in the tens of millions, while more recently their numbers were estimated to be in the tens of thousands.
Together with their land-based relatives, these creatures play pivotal roles in shaping global ecosystems.
“We must take the time to understand turtles, their natural history, and their importance to the environment, or risk losing them to a new reality where they don’t exist,” said Mickey Agha, a researcher at University of California, Davis, who contributed to the study. “Referred to as a shifting baseline, people born into a world without large numbers of long-lived reptiles, such as turtles, may accept that as the new norm.