found there was a one in five chance of death for a turtle who consumed
just one item - rising to 50% for 14 pieces.
team found that younger turtles are at a higher risk of dying from
exposure to plastic than adults.
authors say their research raises concerns over the long term survival of
some turtle species.
never ending surge of plastic into the world's oceans is taking an
increasing toll on iconic marine species.
it has been relatively straightforward for researchers to document the
threat to animals who become entangled in plastic and drown, determining
the impact of consumed plastic is much harder.
authors of this study estimate that around half of all the sea turtles on
the planet have ingested plastic - this rises to 90% among juvenile green
sea turtles off the coast of Brazil.
determine how this exposure was impacting the species, the researchers
looked at post mortem reports and animal stranding records relating to sea
turtles in Queensland.
that information they were able to deduce the role of plastic in causing
death - if an animal had ingested more than 200 pieces of plastic, death
pieces meant a 50% chance of dying - while one piece gave a 22% chance of
of their digestive tract, they don't regurgitate anything," lead author Dr
Britta Denise Hardesty from Australia's Commonwealth Scientific and
Industrial Research Organisation (CSIRO), told BBC News.
it ends up in the wrong place, even one little thin, filmy piece of
plastic can block that canal and mean that nothing can pass and ultimately
the blockage can result in death."
well as causing blockages, harder pieces caused internal injuries which
often lead to death as well.
research team also found that younger turtles were taking in far more
plastic than adults. Around 23% of juveniles and 54% of post-hatchling
turtles had ingested plastic compared to 16% of adults. The scientists say
that this greater susceptibility is down to where they live and how they
small turtles actually drift and float with the ocean currents as does
much of the buoyant, small lightweight plastic," said Dr Hardesty.
think that small turtles are less selective in what they eat than large
adults who eat sea grass and crustaceans, the young turtles are out in the
oceanic area offshore and the older animals are feeding in closer to
sea turtles can live until they are about 80 and reproduce for decades,
researchers are concerned for the longer term impact of so many juveniles
consuming so much plastic.
know that disproportionately finding it more in younger animals who won't
make it to the reproductive state will have long term consequences for the
survival of the species," said Dr Hardesty.
experts in this field say the new study is an important step towards
quantifying the scale of the threat that plastic poses to the lives of sea
authors offer a very defensible framework for allowing us to measure the
mortality risk resultant from plastic ingestion," said Prof Brendan
Godley, from the University of Exeter, who wasn't involved with the study.
also points to the likelihood that plastic may be a key threat to the
smallest life stages. This is of particular concern as pieces of plastics
and baby turtles are both likely to be aggregated together in similar
authors of the new study want to raise awareness among consumers and
political leaders about the threat from plastic and to encourage creative
solutions to the issue. One option may well be a plastic tax or deposit
rethink our relationship with plastic," said Dr Hardesty.
put a true cost on plastic so they have a similar value to aluminium cans
which we don't find lost in the environment, they get picked up and they
don't get mismanaged and find their way out into the ocean," she added.
has been published in
the journal Scientific Reports.