How to survey marine debris on a US shoreline

Picking up litter and measuring litter are related jobs, but they are not identical. A cleanup aims to remove as much material as safely possible. A monitoring survey holds the site, search area and method consistent enough to compare observations over time.

NOAA's Marine Debris Monitoring and Assessment Project—MDMAP—is its flagship shoreline monitoring initiative. It provides protocol documents, field data sheets and public data tools for partner groups and volunteers. If the goal is a defensible trend rather than an event total, start there.

Decide which question you are asking#

An opportunistic count can answer: “What did our volunteers remove today?” A standardized survey can help answer: “Is debris abundance or composition changing at this defined shoreline segment?”

Neither is automatically better. Problems begin when an event count is presented as a trend even though the number of volunteers, searched distance, tide, season and time spent all changed.

Choose a repeatable site#

NOAA's detailed protocol governs formal MDMAP work, including site criteria and sampling design. At a practical level, a monitoring site needs safe public access, boundaries that can be relocated, and a shoreline form compatible with the chosen method. Avoid quietly adapting the method and still calling the result MDMAP data.

Photograph fixed landmarks and record coordinates. Note conditions that affect detectability: tide stage, recent storms, wrack, snow, vegetation and unusually heavy public use.

Build the field team#

Assign roles before reaching the sand:

• protocol lead who controls boundaries and decisions;
• item counters or collectors;
• recorder who checks categories and metadata;
• safety lead watching water, weather and hazards;
• photographer documenting the site consistently.

Review the item guide together. If everyone invents categories in the field, the spreadsheet will not become standardized later.

Keep natural material in place#

Driftwood, seaweed, shells and other natural wrack provide habitat and are not ordinary litter. Do not strip the strandline to make a photograph look cleaner. Human-made material entangled with wildlife, large fishing gear, cylinders, hazardous containers and disaster debris may require the land manager or NOAA regional contact.

Never enter surf, climb unstable logs or pull heavy netting alone. A complete count is not worth an injury.

Preserve the metadata#

The empty fields on a data sheet are not administrative clutter. Date, segment, survey type, team, elapsed time and environmental conditions explain what a number means. Enter data promptly and retain the original field sheet or digital export.

For local storytelling, publish a dated shoreline photo set and keep the scientific record linked, not replaced. Map a recurring accumulation zone with access and waste-type notes when it needs a separate removal project.

Turn observations into prevention#

Repeated counts can reveal patterns: food-service items near an access point, fishing line at a pier, debris deposited after winter storms, or fragments accumulating in one wrack zone. The response might be a bin redesign, outreach, gear collection, storm-drain work or a targeted cleanup.

That is the real value of monitoring. It makes the next action more specific than “plastic is a problem,” while a cleanup makes the shoreline immediately safer. A mature program does both and is honest about which dataset came from which activity.