Marine debris is a global environmental issue of increasing concern. Marine ecosystems worldwide are affected by human-made refuse, much of which is plastic. The potential impacts of waste mismanagement are broad and deep. 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, can transport chemical contaminants and may pose a threat to human health.
Marine debris includes consumer items such as glass or plastic bottles, cans, bags, balloons, rubber, metal, fibreglass, cigarettes and other manufactured materials that end up in the ocean and along the coast. It also includes fishing gear such as line, ropes, hooks, buoys and other materials lost on or near land, or intentionally or unintentionally discarded at sea.
The Australian government has recognised marine debris as a key threatening process, because of the potential harm it poses to wildlife. In 2003, ‘injury and fatality to vertebrate marine life caused by ingestion of, or entanglement in, harmful marine debris’ was listed as a key threatening process under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act). A key threatening process is defined as one that ‘threatens or may threaten the survival, abundance or evolutionary development of a native species or ecological community’. Under the EPBC Act, the Australian government implemented the Threat Abatement Plan (TAP) which focuses on strategic approaches to reduce impacts and injuries to marine fauna and ecological communities.
CSIRO’s national marine debris project set out to address knowledge gaps identified in the TAP. The project engaged with young Australians while collecting robust, scientific data relevant to the global marine litter problem. To understand the patterns and sources of marine debris and assess the potential harm posed to Australia’s marine fauna, our research sought to address four questions:
1) What are the sources, distribution, and ultimate fate of marine debris?
2) What is the exposure of marine wildlife to debris?
3) When wildlife are exposed to debris, what factors determine whether animals ingest or are entangled by debris?
4) What is the effect of ingestion or entanglement on marine wildlife populations?