Most Endangered Baby Turtles Found to Have Eaten Plastic in Pacific Ocean

Most young marine turtles from the Australian Pacific coast featured in a new study contained plastic in their bodies, researchers have found.

For the study, published in the journal Frontiers in Marine Science, the authors examined a total of 121 juvenile sea turtles—ranging from hatchlings to those with a shell measurement of up to 50 centimeters (around 20 inches).

The turtles had washed up ashore on either Australia's west coast or east coast, or had been caught by fishers in the adjacent Indian and Pacific oceans respectively.

The turtles represented five of the world's seven species: green, loggerhead, hawksbill, olive ridley and flatback. Greens, loggerheads and hawksbill turtles are all classified as endangered.

The scientists, from various institutions in the United Kingdom and Australia, found that the proportion of turtles containing plastic was significantly higher on the Pacific coast.

Figures from the study show that 86 percent of loggerheads, 83 percent of greens, 80 percent of flatbacks and 29 percent of olive ridleys from this region contained plastic.

Among the turtles from Australia's Indian coast region, meanwhile, 28 percent of flatbacks, 21 percent of loggerheads and nine percent of green turtles contained plastic.

None of the hawksbill turtles that were found on either coast contained plastic, but only seven were included in the study as a whole, which is a small sample size.

While all marine turtle species have been documented ingesting plastic, the researchers said in the study that small juveniles are thought to be most at risk, due to their feeding preferences and overlap with areas that are abundant in plastic waste.

Sea turtles hatch on beaches but spend their early years in the open ocean. During this period they can accumulate large amounts of plastic when they feed near the surface, due to what the researchers have dubbed an "evolutionary trap."

"Juvenile turtles have evolved to develop in the open ocean, where predators are relatively scarce," Emily Duncan, lead author of the study from the Centre for Ecology and Conservation at the University of Exeter in the U.K., said in a statement. "However, our results suggest that this evolved behavior now leads them into a 'trap'—bringing them into highly polluted areas such as the Great Pacific Garbage Patch."

"Juvenile sea turtles generally have no specialised diet—they eat anything, and our study suggests this includes plastic. We don't yet know what impact ingesting plastic has on juvenile turtles, but any losses at these early stages of life could have a significant impact on population levels."

The researchers also observed a difference in the type of plastic found in the turtles depending on their location. The plastic found in the turtles from the Pacific was mostly hard fragments, which could have originated from a vast range of man-made products.

The plastic in the turtles from the Indian Ocean, meanwhile, was mostly fibers, which likely originated from fishing ropes or nets. The most widely ingested polymers among all the turtles in the study were polyethylene and polypropylene.

"These polymers are so widely used in plastic products that it's impossible to pin down the likely sources of the fragments we found," Duncan said. "Hatchlings generally contained fragments up to about five millimeter to 10 millimeter in length, and particle sizes went up along with the size of the turtles."

"The next stage of our research is to find out if and how plastic ingestion affects the health and survival of these turtles. This will require close collaboration with researchers and veterinarians around the world."

A loggerhead sea turtle
Stock image showing a loggerhead sea turtle. A study of juvenile sea turtles has found that many contain plastic in their bodies. iStock