Plastic and other marine debris are a major environmental concern
Marine debris is a globally recognised environmental issue of increasing concern.
Marine ecosystems worldwide are affected by human-made refuse, much of which is plastic.
Marine debris comes from both land and sea-based sources and can travel immense distances. It can pose a navigation hazard, smother coral reefs, transport invasive species and negatively affect tourism. It also injures and kills wildlife, has the potential to transport chemical contaminants, and may pose a threat to human health.
Plastic production rates are intensifying, and the volume of refuse humans release into marine systems is growing at an exponential rate. Litter impacts wildlife directly through entanglement and ingestion and indirectly through chemical affects. Even toothpaste and personal care products can have plastic microbeads in them. Plastics are mistakenly eaten by a range of marine species.
Building and sharing knowledge on marine debris impact
CSIRO has completed a survey of sites approximately every 100 km along the Australian coastline, representing large scale, integrated, rigorous data aimed at addressing the marine debris issue.
Parts of this research engaged with thousands of students, teachers and Shell employees and has reached millions of people, helping to educate them about, and increase their understanding of, the problems of marine debris.
The CSIRO Marine Debris Team are award-winning national and international leaders in efforts to understand and respond to this global marine challenge. Our engagements have included working alongside government and industry bodies around the world including the Australian Packaging Covenant, the International Whaling Commission, Convention on Biological Diversity and the United Nations.
Our research has shown that approximately three-quarters of the rubbish along the Australian coast is plastic. Most is from Australian sources, not from overseas, with debris concentrated near urban centres. In coastal and offshore waters, most floating debris is plastic. The density of plastic ranges from a few thousand pieces of plastic per square kilometre to more than 40,000 pieces of plastic per square kilometre.
Debris is more highly concentrated around major cities, suggesting local sources. Human deposition is the most important factor in determining how much debris can be found at a site. Water flow (e.g. storm water) and wind contribute to the transport of debris towards marine ecosystems.
Effect on marine wildlife populations
Around the world, nearly half of all seabird species are likely to ingest debris. Balloons are considered to be the biggest plastic killer of seabirds. Birds also eat everything from glow sticks, industrial plastic pellets, hard bits of plastic, foam, metal hooks and fishing line.
CSIRO researchers and colleagues found that 43 per cent of short-tailed shearwaters have plastic in their gut. Young birds were more likely to ingest debris and ate more pieces of debris than adult birds. A global hotspot for seabird impacts exists in the Tasman Sea south of Australia. CSIRO predicts that plastics ingestion in seabirds may reach 95 per cent of all species by 2050, taking into account the steady increase of plastics production.
For turtles, approximately one third of marine turtles globally have likely ingested debris, and this has increased since plastic production began in the 1950s. Most items eaten by turtles are plastic. Smaller oceanic turtles are more likely to ingest debris than coastal foragers; herbivores are more likely to ingest debris than carnivorous species; oceanic leatherback turtles and green turtles are at the greatest risk of ingested marine debris effects; and benthic turtles show a strong selectivity for soft, clear plastic that resembles natural prey such as jellyfish. Recent research has revealed that it takes just one piece of plastic to kill a turtle.
Seabirds, turtles, whales, dolphins, dugongs, fish, crabs and crocodiles and numerous other species are killed and maimed through entanglement. We estimate that between 5,000 and 15,000 turtles have been killed in the Gulf of Carpentaria after becoming ensnared by derelict fishing nets, mostly originating from overseas. For pinnipeds in Victoria, the majority of seal entanglements involved plastic twine or rope, and seals become entangled in green items more than in any other colour. In general, young seals are entangled in greater numbers than adults.
What you can do
Our research shows that people are the greatest contributor to marine pollution, meaning that to make a real difference we need to work together to contribute to solutions, plus help to improve our understanding of the types, amounts and sources of debris PDF (424 KB) that arrive on Australia's coastline. Visit the online national marine debris database.