Marine Debris
Greater Farallones

bird skull with fishing line wrap through the beak
Inappropriately discarded fishing line is a type of marine debris and can entangle and kill seabirds and marine mammals. Credit: Beach Watch, GFNMS, NOAA

Why is it a concern?

Levels of debris in both the ocean and at the land-sea interface are of growing concern. Marine debris poses a growing threat to marine life in the sanctuary and various types of debris are known to have adverse effects on marine species.

Sources of plastic waste within the sanctuary are both land and ocean-based. Land-based sources of marine debris include: litter washed into the bay through storm drains and outflow from combined sewer treatment systems; garbage from landfills; shoreline recreational activities; improper handling of garbage in transport and on-site storage; and plastic resin pellets discharged from plastics manufacturing facilities into storm drains and nearby waterways. Ocean-based sources generally include lost fishing gear and dumping of garbage at sea by vessels and oil platforms. Estimates show that approximately 30,000 crab pots are abandoned or lost in the sanctuary each year (Z. Grader, Pacific Coast Federation of Fisherman's Associations, pers. comm.). This derelict gear impacts sanctuary resources by altering the seabed and continues to unintentionally ensnare marine life in the trap in perpetuity.

Plastic waste has also been shown to entangle marine wildlife in the Greater Farallones and elsewhere. From 2001 to 2005, the cause of death for 0.7 percent (n = 8,475) of the bird carcasses documented during sanctuary Beach Watch surveys was entanglement in marine debris. Based on Beach Watch surveys of dead seabirds, an estimated 200 birds are killed every year in the Greater Farallones due to entanglement in fishing gear and other plastic debris. Small plastic fragments and pellets in the ocean and inland waterways have been found to adsorb pollutants from the marine environment – most notably, persistent organic pollutants. When marine life mistake these pellets for food, they are likely to ingest a wide array of contaminants, posing the threat of PCB accumulation and the increased likelihood of starvation. Another negative consequence of plastic fragments in the marine environment is that they have been found to attract marine organisms such as bacteria, diatoms, algae, barnacles, hydroids, tunicates and bryozoans that attach to and “raft” on them, which can contribute to the spread of invasive species.

Overview of Research

The Greater Farallones National Marine Sanctuary is actively seeking research partners to conduct work connected to Marine Debris as a sentinel issue.

Science Needs and Questions

The best available science is used by Sanctuary scientists and managers working to address priority resource conservation and management issues. As priorities change and new issues emerge, each Sanctuary develops new science needs and questions and works with partners to address them.

  • Within the sanctuary, what are the types and accumulation rates of marine debris from land based sources vs. ocean-based sources?
  • Are certain areas more or less susceptible to marine debris accumulation and/or impacts?
  • Are there critical habitat areas that should be prioritized for marine debris removal efforts?
  • What are the entanglement rates for marine mammals, prioritizing endangered and threatened species?
  • How can we reduce the co-occurrence of marine mammal foraging hotspots and derelict (out of season) crab pots?

Education and Outreach Material

NOAA's Marine Debris Program is a cross-NOAA collaboration that is undertaking a national and international effort focusing on identifying, removing, reducing and preventing debris in the marine environment.

NOAA's Coastal Nonpoint Pollution Control Program is a joint program between NOAA and the U.S. Environmental Protection Agency that ensures that coastal states have the tools to address polluted runoff. Under the program, states must implement measures to promote recycling and proper waste disposal at marinas and encourage litter control to reduce the amount of trash that enters our coastal waters.

NOAA's Clean Marina Initiative is a voluntary, incentive-based program that encourages marina operators and recreational boaters to engage in environmentally sound operating and maintenance procedures, such as recycling and proper waste disposal that will reduce the amount of marine debris.

The International Pellet Watch project is a global monitoring program of persistent organic pollutants using beached plastic resin pellets. Participants collect plastic resin pellets on nearby beaches that are then sent to a lab for analysis.


Chin, J.L. and A. Ota. 2001. Disposal of dredged materials and other wastes on the continental shelf and slope. In: Karl, H.A., J.L. Chin, E. Ueber, P.H. Stauffer, J.W. Hendley, J.W. (eds.) 2001. Beyond the golden gate—oceanography, geology, biology, and environmental issues in the Gulf of the Farallones. U.S. Geological Survey Circular 1198. 84 pp. Electronic document available from: