Plastic Ingestion Killing Shearwaters
But not for the reason you might think.
Every spring it’s a grim scene on the beaches of Lord Howe Island, off Australia’s east coast. Dozens of dead flesh-footed shearwater chicks litter the shoreline, their stomachs full of plastic. While starvation likely contributes to the birds’ demise, new research suggests that a secret ingredient may also be taking a toll: trace metals that glom onto bottle caps, toothbrushes, and other bits of flotsam.
Jennifer L. Lavers, a wildlife ecologist at Monash University in Melbourne, who has been studying the island’s shearwaters for nearly eight years, recently uncovered the connection. Most of the chicks she’s collected had plastic in their stomachs, fed to them by parents that mistook the junk for food. Those findings, combined with a growing number of studies showing that metals bind onto plastic debris, led Lavers to investigate whether metals were a culprit. So she sampled the feathers and stomach contents of 38 fledglings. Ninety percent of the birds had plastic in their systems (an average of 17 pieces but as many as 276); the greater the trash load, the lower the birds’ body mass and the higher the concentrations of chromium and silver.
“Whether you have six small pieces or you have 276 large pieces in an animal, the plastic does the same thing—it introduces contaminants,” says Lavers, who published her findings in the April issue of the journal Environmental Pollution. “Having even one piece of plastic in an animal could potentially be quite detrimental.” Heavy metals can cause stomach ulcerations, liver damage, and neurological and reproductive problems.
This May, Lavers will visit Lord Howe Island for the 11th time. What she is discovering is helping to draw solid links between plastic and recent declines in shearwater populations. Her findings could build support for policies that help stem the flow of plastics into the sea. And that would benefit not just flesh-footed shear- waters and scores of other seabirds but also a range of species around the globe, from tiny plankton to sea turtles.
This story originally ran in the May-June 2014 issue as "Junk Food."