Marine debris is a major problem for Australia's sea life, with plastic fragments regularly causing serious injuries to turtles and birds. Now Australian researchers are participating in an international conservation project to survey marine debris and determine exactly what impact it's having.Our reporter Li Dong has the details.

The coastline around Ballina in New South Wales is close to the country's most easterly point. Its waters are home to a rich variety of marine life, including birds and sea turtles.

But the local wildlife rescue organization has found itself caring for a large number of creatures that have been injured by marine debris, particularly plastic.

The Australian Seabird Rescue Centre cares for around 600 birds and 80 turtles each year. Keith Williams, Projects Manager at the organization, says that plastic marine debris is responsible for most of the injuries among birds and sea turtles in the area.

"Plastic is the single greatest cause of why we see wildlife at our hospital here. In birds it's entanglement in plastic, particularly fishing line, but for turtles, ingestion of plastic is the single greatest cause of them coming to our sea turtle hospital, and that's a horrifying thought. It's not something that was a problem for turtles 50 years ago. There wasn't plastic in the oceans. So this is a new threat, and it's a very major threat for sea turtle populations worldwide."

Williams explains how plastic fragments affect turtles.

"The problem for turtles and plastic is that when they eat it, it eventually becomes lodged in the intestine. The intestine finds it very difficult to move plastic. It's not breaking down; it's not behaving like normal food, and it gets lodged there. Food builds up behind it, and for the turtles what happens is that they begin to float. They build up gas inside their body. And once that happens, they're really in trouble. Once they're floating on the surface of the ocean, all their food is down at the bottom,. They can't eat. They just start to starve and become weaker."

The researchers often trawl for an hour, covering a distance of around four kilometers. But even on a shorter 250-meter trawl, Williams and his colleague, Kathrina Southwell, find numerous pieces of plastic from wrappers, animal feed sacks and plastic bags.

Southwell is the Marine Debris Project Coordinator at the Australian Seabird Rescue Centre. She says the problem is much worse than previously thought. She believes this region's easterly position means that marine debris is carried to the waters here by the east Australian current.

"Although it's a long way away from the South Pacific gyre and everything, it's all still one ocean, so it's affecting the whole world, this problem of plastic debris. And because we have the east Australian current running so close to us, which is one of the most easterly points in Australia, that's why we think maybe we're seeing so many animals being affected by it in this area."

Williams believes that the severe impact plastic is having on marine life means society needs to reassess its reliance on the material and find new, safer methods for its disposal.

"Plastic can't be a disposable commodity. It's too dangerous to actually be a disposable commodity—particularly dangerous for wildlife. But I think in the longer term, the buildup of plastic in our environment is a danger for humans. We really need to think and rethink our way of treating plastic. We can't just dump it as we have been."

For CRI, I am Li Dong.