MBNMS Marine Debris Final Report 2023
Various human activities contribute to marine debris that can threaten sanctuary wildlife. Photo: Claire Fackler/NOAAMarine debris on the shoreline of Monterey Bay National Marine Sanctuary:
An assessment of behaviors contributing to marine debris, categories & composition, spatial distribution, and predictor variables
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All marine debris comes from people and can threaten wildlife. Shorelines are the interface between the land and sea; thus, they represent an important geography for monitoring and assessing marine debris. Globally, approximately 80% of marine debris is transported to the ocean by rivers. It can enter waterways and the ocean from land through littering, poor waste management practices, storm water discharge, and extreme natural events. From the ocean, marine debris can be washed ashore by wind, currents, waves, upwelling, and tides.
Thus, shoreline litter provides insight regarding the types of marine debris likely to be prevalent in the nearby ocean environment. Because shorelines are accessible, carry high debris loads, and are easier to study than marine debris found in the ocean and on the seafloor, beach litter surveys can provide a large and robust dataset for understanding predominant types of marine debris in a region. Analyzing the distribution and density of marine debris on beaches, transport mechanisms, and sources of marine debris can inform and provide direction to preventative and corrective management measures.
This report identifies prevalent types of marine debris on MBNMS shoreline and their distribution in order to assess potential sources and transport mechanisms. The data analyzed was collected by five citizen science programs along the entire 276 miles (444 kilometers) of MBNMS shoreline over a five-year period from January 1, 2017 to December 31, 2021, providing a total of 4,725 survey points collected by more than 37,000 volunteers.
5 Citizen Science Data Sets analyzed:
NOAA Marine Debris Monitoring and Assessment Project (MDMAP)
Debris Tracker
Trash Information and Data for Education and Solutions (TIDES)
Save Our Shores
Surfrider Foundation
Downtown Streets Team Santa Cruz
The report also includes possible strategic actions by individuals, municipalities, agencies, researchers, and organizations who could influence and reduce marine debris on MBNMS shoreline.
Citizen scientists involved in beach cleanups play a major role in preventing marine debris from being transported from the beach to the sanctuary. Photo: Karen Grimmer/NOAAKey findings:
- Most trash collected on MBNMS beaches come from human activities on the land, with more than 50% of trash items tied to smoking, eating and drinking. Cigarette butts alone made up 23% of items picked up during MBNMS beach cleanups.
- About 73% of the marine debris on MBNMS beaches is composed of plastic material, including foam, which may fragment into smaller and smaller pieces and never fully go away. Plastic fragments, no longer identifiable as an object, made up more than a quarter of all items collected during beach cleanups.
- Marine debris is not always deposited directly onto the beach by beachgoers. It can enter the ocean and waterways from land through poor waste management practices, storm water discharge, and extreme natural events. Debris can also come from ocean-based sources, such as fishing vessels, stationary platforms used for offshore oil and gas, cargo ships, and other large vessels. Therefore, prevention efforts must include all land-based and ocean-based human activities.
- Marine debris can be reduced or prevented if we take an active role in proper trash disposal and follow the five Rs: Reduce, Refuse, Reuse, Recycle, and Replace. Collective action taken on the part of individuals, plastic producers, governments, and non-profit organizations are needed to reduce marine debris in an expedient and coordinated way.
- Citizen scientists involved in beach cleanups play a major role in preventing marine debris from being transported from the beach to MBNMS. More volunteers helping with beach cleanups, more frequent and extensive beach cleanups, and accurately tracking the debris collected will help efforts to reduce marine debris in the environment.
Thanks to funding from the NOAA Marine Debris Program, this report was created in partnership with California Marine Sanctuary Foundation, Monterey Bay Aquarium Research Institute, NOAA Marine Debris Monitoring and Assessment Project, Ocean Conservancy, Surfrider Foundation, Save Our Shores, Downtown Streets Team Santa Cruz, Trash Taxonomy Tool developers, Saber Consulting, and to the more than 37,000 citizen science volunteers who contributed important marine debris data for continued research and analysis to better understand source contributions and transport processes.