As society has developed new uses for plastics, the variety and quantity of plastic items found in the marine environment has increased dramatically. These products range from common domestic material (bags, Styrofoam cups, bottles, balloons) to industrial products (strapping bands, plastic sheeting, hard hats, resin pellets) to lost or discarded fishing gear (nets, buoys, traps, lines).
Examples of common plastic marine debris items.
Photo courtesy of J. Burger, PMRF.
These materials are similar to plastic in that they are used for a wide range of products. While they can be worn away-broken down into smaller and smaller fragments, they generally do not biodegrade entirely. As these materials are used commonly in our society, their occurrence as marine debris is overwhelming.
Derelict fishing gear (DFG) refers to nets, lines, crab/shrimp pots, and other recreational or commercial fishing equipment that has been lost, abandoned, or discarded in the marine environment. Modern gear is generally made of synthetic materials and metal, and lost gear can persist for a very long time.
Examples of types of derelict fishing
gear including a net, trap, and rope.
Thousands of abandoned and derelict vessels litter ports, waterways and estuaries, creating a threat to navigation, recreation, and the environment. Many vessels end up sinking at moorings, semi-submerged in the intertidal zone, or stranding on shorelines, on reefs or in marshes, and breaking apart. In protected harbors and bays these vessels may persist for years, while in open, exposed coastal environments the debris from disintegrating vessels may be widespread along shorelines and across underwater habitats.
Derelict vessel in American Samoa.
Photo courtesy of D. Helton, NOAA.