"One piece of plastic" can kill sea turtles, study finds

A new study suggests that ingestion of a single piece of plastic can be deadly for sea turtles.

The researchers found that there was a one in five chance of death for a turtle that consumed only one item – reaching 50% for 14 pieces.

The team found that young turtles are at a higher risk of dying from plastic exposure than adults.

The authors state that their research raises concerns about the long-term survival of some turtle species.

The endless surge of plastic in the world's oceans is weighing more heavily on iconic marine species.

Although it has been relatively simple for researchers to document the threat to animals that get entangled in plastic and drowning, it is much harder to determine the impact of the plastic consumed.

The authors of this study estimate that nearly half of marine turtles in the world have ingested plastic, or 90% of juveniles off the coast of Brazil.

To determine the impact of this exposure on the species, researchers examined post mortem reports and animal stranding recordings of Queensland marine turtles.

From this information, they could deduce the role of plastic in death – if an animal had ingested more than 200 pieces of plastic, death was inevitable.

Fourteen coins meant a 50% chance of dying, while one coin gave a 22% chance of dying.

"Because of their digestive tract, they do not regurgitate anything," said BBC News senior author, Dr. Britta Denise Hardesty, of the Commonwealth Scientific and Industrial Research Organization of Australia (CSIRO). .

"If it ends up in the wrong place, even a small piece of thin, filmed plastic can block that channel and mean that nothing can pass and that blockage can lead to death."

In addition to blockages, harder parts cause internal injuries that often result in death.

The research team also found that younger turtles absorbed a lot more plastic than adults. About 23% of juveniles and 54% of post-hatchling turtles had ingested plastic, compared with 16% of adults. Scientists say that this greater susceptibility depends on where they live and how they feed.

"Young small turtles drift and float with ocean currents, much like much of the light floating plastic," said Dr. Hardesty.

"We believe that small turtles are less selective in what they eat than large adults who eat seagrass and shellfish, young turtles are in the oceanic offshore and older animals are feeding closer to the shore. . "

While sea turtles can live up to about 80 years old and breed for decades, researchers worry about the long-term impact of so many juveniles consuming as much plastic.

"We know that finding it disproportionately in young animals that fail to reproduce will have long-term consequences for the survival of the species," said Dr. Hardesty.

"It's very disturbing."

Other experts in this field say that the new study is an important step in quantifying the threat plastic poses to the life of sea turtles.

"The authors propose a very defensible framework to enable us to measure the mortality risk resulting from the ingestion of plastic," said Professor Brendan Godley, of Exeter University, who n & # 39; 39; was not involved in the study.

"It also highlights the likelihood that plastic may pose a major threat to smaller life stages, which is of particular concern because plastic pieces and baby turtles are likely to be clustered in similar areas. . "

The authors of the new study want to educate consumers and political leaders about the threat of plastic and encourage creative solutions to this problem. An option may be a plastic tax or a deposit system.

"Rethink our relationship with plastic," said Dr. Hardesty.

"Let's put a real cost on plastic so that they have a similar value to aluminum cans that we do not find lost in the environment, they are collected and they are not managed and end up in the ocean "she added. added.

The study was published in the journal Scientific Reports.