how dangerous is ocean plastic? insights from global experts on the greatest threat to marine wildlife
Over the course of the 30-year history of the International Coastal Cleanup, volunteers have removed over 200 million items from beaches and waterways around the world. The top-ten list of items removed includes items like plastics bottles, plastic bottle caps, aluminum cans, cigarette butts, derelict fishing gear and a range of disposable plastic goods and food packaging. The scientific literature is replete with anecdotal information of marine wildlife impacted by these marine debris items. Indeed, over 690 species (from the smallest of plankton to the largest of whales) have been documented to be negatively impacted by marine debris.
But until now, the consequence of different marine debris items to populations of these animals – and the mechanism by which they do so – has been far less clear. Experimentally testing the impact of plastic items to whole populations of marine wildlife is technically challenging (if not impossible) and for species that are of threatened or endangered status, legally prohibited as well as morally questionable. But we have just published a paper in Marine Policy along with our colleagues Drs. Chris Wilcox and Denise Hardesty at Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia that uses elicitation techniques to overcome these challenges. Our analysis provides key insights into the relative threat of different debris items to a healthy ocean that should provide additional impetus to decision makers to tackle this growing problem.