FOR years a remote patch of the north Pacific has served as a benchmark of global marine plastic pollution - and now it appears we have our own.
Seabirds that forage in the Tasman Sea are mistaking plastic for food, eating it and perishing on Lord Howe Island.
''The problem is here - in our backyard,'' zoologist Jennifer Lavers said.
Staggering amounts of plastic are being recovered from flesh-footed shearwaters on Lord Howe. In the latest survey, one bird's stomach contained more than 200 pieces, Dr Lavers told The Saturday Age.
The sharp-edged fragments tear internal organs and toxic substances bind to the plastic. Mercury, which is toxic to birds at four parts per million (ppm), was found in these shearwaters at up to 30,000 ppm.
The birds' numbers are plummeting on Lord Howe. Dr Lavers, of the Tasmanian Museum, said in this April's survey 95 per cent of nesting shearwaters had some plastic in their stomachs and it was hard to find living chicks.
The first clear evidence of the scale of the problem came with the discovery of the North Pacific Garbage Patch - a gyre, or giant circular current, north of Hawaii where Asian and North American plastics gather.
Most of the marine life that dies there falls to the sea floor unchecked, but laysan albatross brought plastic back to island nests, where both adults and their chicks died.
Dr Lavers joined Lord Howe naturalist Ian Hutton in 2007 for surveys and and has been returning annually. ''It's just so heartbreaking to go back year after year and see the problem gradually get worse,'' she said.
Just this week a giant petrel floundered ashore at Lakes Entrance in eastern Victoria and died. Bairnsdale vet Jason Wong said he found a piece of plastic blocking its crop, and styrofoam in its stomach. He said he routinely found plastic in other dead seabirds.
The UN Environment Program has called for intensified research on its impacts, and Birds Australia warns it must be treated as a serious threat.
In its 2011 yearbook, the UN program has flagged marine plastics as a toxic time bomb.