For years we’ve heard about the North Pacific Gyre (or Garbage Patch) where there is up to 40x more plastic in the ocean than plankton. We’ve seen tragic photos of thousands of Laysan Albatross chicks that have died as a result of ingesting plastic on remote islands in Hawaii. And have watched eminent speakers like Captain Charles Moore and Professor Richard Banati speak to captivated audiences about our plastic addiction.
But what most people don’t realize is the North Pacific Garbage Patch is not the only one of its kind. There are at least five others, fed by more than 20 million items that enter the world’s oceans each and every day (~6.4 million tonnes of plastic per year) (a recent study suggests there are FIVE TRILLION pieces of plastic already in the surface layer of the ocean, as of 2014). The wind and wave patterns that lead to the development of Gyres (some with more than 26,000 pieces of plastic per km2) redistribute this plastic around the globe, so that one country’s garbage washes up in anothers backyard. Its time to reconsider the infamous quote “Garbage Patch the size of Texas” and start thinking outside the box. Unlike Texas, ocean basins do not have boundaries. Our garbage is everywhere. Even in Antarctica.
So its not just the Laysan Albatross that comes into contact with plastic floating in the ocean. More than 690 marine species are known to ingest plastic, including fish and other animals at the very base of the marine food chain. This plastic accumulates toxins such as polychlorinated biphenyls (PCBs) at more than 100x the surrounding seawater concentrations. Once ingested, plastic can block or rupture the digestive tract and leak contaminants into the bird’s blood stream resulting in stomach ulcerations, liver damage, infertility, and in many cases, death. Here in Australia, 90-100% of Flesh-footed Shearwater Ardenna carneipes adults and chicks contain plastic (Lavers & Bond 2016). In 2011, one chick was found to have more than 275 pieces of plastic in it’s stomach (equivalent to an average human ingesting 10kg of plastic; Lavers et al. 2014). Recent data (see Publications) indicate this species is one of the world’s most heavily contaminated seabirds and chicks that ingest large amounts of plastic have poor body condition and likely suffer reduced juvenile survival. Not surprisingly, Flesh-footed Shearwater populations on Lord Howe Island and in New Zealand have declined significantly over the past few decades.
To address this serious issue, we are utilising 16 years of existing data combined with experimental trials to identify characteristics of plastic that may influence the birds willingness to ingest it as well as determine whether certain techniques can be used to safely remove plastic (and therefore contaminants) from seabird stomachs, providing a management tool for numerous species at risk from the ingestion of plastic at sea.