Marine Debris: Understanding, Preventing and Mitigating the Significant Adverse Impacts on Marine and Coastal Biodiversity.

Marine debris is recognized as a globally significant stressor on the marine and coastal environment, with impacts on marine biodiversity having been reported over the last four decades. There are also socioeconomic impacts, as debris can be a health and safety hazard and can also affect commercially significant resources. The vast majority of marine debris is made up of various forms of plastic that are highly persistent and often contain toxic chemicals or acquire them from the surrounding seawater. The fragmentation of plastics produces large numbers of microplastic particles that are easily taken up by a wide range of marine organisms. Plastic production has grown exponentially since the 1950s and is expected to continue at an increasing rate over the coming decades. According to current estimates, between 4.8 and 12.7 million tonnes of plastic waste entered the marine environment in 2010. This document provides an update to the review of the impacts of marine debris that was previously undertaken by the Scientific and Technical Advisory Panel of the GEF (GEF-STAP) in collaboration with the Secretariat of the Convention on Biological Diversity (SCBD), and published as CBD Technical Series 67 in 2012. This document follows a similar format and should be referred to in combination with the aforementioned document. The first chapter of this document reviews the state of knowledge of the various impacts of marine debris on marine and coastal biodiversity. It provides an update of the total number of species known to be affected by marine debris, which is now almost 800 (including effects of ghost fishing reported in recent years). The proportion of cetacean and seabird species affected by marine debris ingestion has risen substantially to 40 per cent and 44 per cent, respectively. The latest research on the physical and toxicological effects of microplastic is summarized along with evidence of trophic transfer in planktonic food chains in the laboratory and direct uptake of microplastics by invertebrates in the marine environment. Results of studies of plastic marine debris as a novel habitat for unique microbial communities and a potential vector for disease are also provided. The report also addresses the ability of large macrodebris items to transport invasive alien species across oceans, based on evidence from recent records of tsunami debris stranding along the west coast of North America. The impacts of lost, abandoned or discarded fishing gear on marine biodiversity, including long-term effects of ghost fishing and habitat degradation mainly from plastic-based gear, are also discussed. Recent estimates of the socioeconomic costs of marine debris are also provided to complement the information available in CBD Technical Series 67. The second chapter provides a review of policy options and approaches that are in place or have been proposed to address the impacts of marine debris. This includes a summary of the latest research to monitor and model the distribution and abundance of debris in the marine environment. The responses of management and regulatory bodies at the global or regional level indicate that the issue of marine debris is gaining recognition as a significant ecological and socioeconomic problem that may also have implications for human health. Different types of policy approaches and research needs to tackle predominantly land-based sources of marine debris are described.