Threat and Impact of Marine Debris

turtle stuck in a net


The threat and impacts of marine debris have long been ignored. Perhaps it is the perceived vastness of ocean and lack of visibility of marine debris to most people that has allowed society to dismiss the problem as a serious threat. However, recent research demonstrates that quantities and impacts of marine debris are significant and increasing. The Algalita Marine Research Foundation’s investigation of plastic in the North Pacific Central Gyre of the Pacific Ocean showed that the abundance of plastic pieces was six times greater than zooplankton floating on the water’s surface. This study is one of many that demonstrate that our oceans have become the virtual garbage can for the developed and developing world.

Most of the marine debris in the world is comprised of plastic materials. The average proportion varies between 60 to 80% of total marine debris. In many regions, plastic materials constitute as much as 90 to 95% of the total amount of marine debris. Nearly 80% of marine debris comes from land-based sources. Most of the land-based debris is conveyed to oceans via urban runoff through storm drains. The main sources of plastic and other types of anthropogenic (human-made) debris in urban runoff include: litter (mostly bags, packaging and single-use disposable products), industrial discharges, garbage transportation, landfills, construction debris, and debris from commercial establishments and public venues.


Barreiros, J.P. and J. Barcelos. 2001. Plastic ingestion by a leatherback turtle Dermochelys coriacea from the Azores (NE Atlantic). Marine Pollution Bulletin 42(11): 1196-1197.

Bugoni, L., L. Krause, and M.V. Petry. 2001. Marine debris and human impacts on sea turtles in southern Brazil. Marine Pollution Bulletin 42(12): 1330-1334.

Bullimore, B.A., P.B. Newman, M.J. Kaiser, S.E. Gilbert, and K.M. Lock. 2001. A study of catches in a fleet of ”ghost-fishing” pots. Fishery Bulletin 99(2): 247-253.

Donohue, M.J., R.C. Boland, C.M. Sramek, and G.A. Antonelis. 2001. Derelict fishing gear in the Northwestern Hawaiian Islands: Diving surveys and debris removal in 1999 confirm threat to coral reef ecosystems. Marine Pollution Bulletin 42(12): 1301-1312.

Gregory, M.R., Ryan, P.G. 1997. Pelagic plastics and other seaborne persistent synthetic debris: a review of Southern Hemisphere perspectives.. In Coe, J.M., Rogers, D.B. (Eds.), Marine Debris- Sources, Impacts, Solutions. Springer-Verlag, New York, pp.49-66.

Henderson, J.R. 2001. A pre- and post-MARPOL Annex V summary of Hawaiian monk seal entanglements and marine debris accumulation in the northwestern Hawaiian Islands, 1982-1998. Marine Pollution Bulletin 42(7): 584-589.

Moore, C.J., S.L. Moore, M.K. Leecaster, and S.B. Weisberg. 2001. A comparison of plastic and plankton in the North Pacific central gyre. Marine Pollution Bulletin 42(12): 1297-1300.

Moore, S.L., D. Gregorio, M. Carreon, S B. Weisberg, and M. K. Leecaster. 2001. Composition and distribution of beach debris in Orange County, California. Marine Pollution Bulletin 42(3): 241-245.

Nagelkerken, I., G.A.M.T. Wiltjer, A. O. Debrot, and L.J.P.P. Pors. 2001. Baseline study of submerged marine debris at beaches in Curacao, West Indies. Marine Pollution Bulletin 42(9): 786-789.

Tomas, J., R. Guitart, R. Mateo, and J. A. Raga. 2002. Marine debris ingestion in loggerhead sea turtles, Caretta caretta from the Western Mediterranean. Marine Pollution Bulletin 44(3): 211-216.

Thompson, R. C., Y. Olsen, R. P. Mitchell, A. Davis, S. J. Rowland, A. W. G. John, D. McGonigle, A. E. Russell. 2004. Lost at sea: Where is all the plastic? Science Vol. 304, page 838.

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