Study estimates more than half of all sea turtles have ingested plastic debris
LINZ — Not long after a team of scientists detailed the extent to which seabirds have been exposed to ocean plastic pollution, another group of researchers say sea turtles face similar threats.
The international study, led by a led by a University of Queensland researcher, shows more than half the world’s sea turtles have ingested plastic or other human trash — perhaps not surprising considering that up to 12 million tons of plastic debris reach the oceans each year.
The study looked at six species of sea turtles and found those living off the east coasts of Australia and North America, Southeast Asia, southern Africa, and Hawaii were particularly at risk due to a combination of debris loads and high species diversity.
“The results indicate that approximately 52 per cent of turtles world-wide have eaten debris,” said Dr Qamar Schuyler. with UQ’s School of Biological Science.
Plastic ingestion can kill turtles by blocking the gut or piercing the gut wall, and can cause other problems through the release of toxic chemicals into the animals’ tissues.
“Australia and North America are lucky to host a number of turtle species, but we also therefore have a responsibility to look after our endangered wildlife,” Schuyler said. “One way to do that is to reduce the amount of debris entering the oceans via our rivers and coastlines.”
A previous study by Dr Schuyler and colleagues showed that plastics and other litter that entered the marine environment were mistaken for food or eaten accidentally by turtles and other wildlife.
The risk analysis found that olive ridley turtles were at the highest risk, due to their feeding behaviour and distribution. Olive ridley turtles commonly eat jellyfish and other floating animals, and often feed in the open ocean, where debris accumulates.
“We now know that both sea turtles and seabirds are experiencing very high levels of debris ingestion, and that the issue is growing,” said Dr Chris Wilcox, who was involved in the study that looked at the rate of plastic ingestion by seabirds. “It is only a matter of time before we see the same problems in other species, and even in the fish we eat.”
The study was published in Global Change Biology, with additional research by scientists with CSIRO Hobart, Texas A&M University, the National Oceanic and Atmospheric Administration in Honolulu, University of New South Wales, and Imperial College London, UK. It was part of an Australian Research Council Linkage project supported by Earthwatch Australia, CSIRO, Healthy Waterways and Australia Zoo.