How Removing Lost Crab Traps Is Helping Map the Chesapeake Bay

What if everyday work on the water could also help map the seafloor? A partnership between NOAA, William & Mary’s Virginia Institute of Marine Science (VIMS) and Batten School, and Chesapeake Bay crabbers is turning routine vessel activity and lost crab trap removal into a new source of bathymetric data.

The NOAA Marine Debris Program funded pilot surveys in 2005 and 2006 that demonstrated side-scan sonar could identify derelict crab pots in the Chesapeake Bay while enabling large-scale bathymetric data collection. Decades later, William & Mary’s VIMS & Batten School received a 2023 award from the NOAA Marine Debris Program for their Nationwide Trap Removal, Assessment, and Prevention (TRAP) program. In the Chesapeake Bay, the TRAP program equipped commercial crabbers with the proven side-scan sonar equipment to locate and remove lost and abandoned crab traps. Once lost or discarded, these traps can continue to catch and kill wildlife, compete with active fishing gear, and damage important habitats. This effort reduces these impacts while also providing an additional source of offseason income for crabbers.

Although the Chesapeake Bay is the largest estuary in the United States, shallow water depth data is scarce. The same sonar equipment used to find marine debris can also collect valuable information about the seafloor. By turning routine work on the water into usable scientific data, VIMS is building more complete and reliable coastal information where it is needed most.

“By accessing past derelict trap removal depth data and equipping current participants with low-cost sonar units to passively collect bathymetric information, we have generated millions of new bathymetric data points at little to no additional cost,” said VIMS Center for Coastal Resources Management Director, Kirk Havens.

William & Mary’s VIMS & Batten School were recognized by the International Hydrographic Organization (IHO), as a reliable partner for crowdsourced bathymetric data for public use, a status held by only 16 organizations worldwide. 

Data generated from this effort will be publicly available through the NOAA’s National Centers for Environmental Information (NCEI) Bathymetric Data Portal, where it can be used to enhance navigational safety and support coastal commerce. The new dataset will support coastal managers, mariners, and federal agencies working to improve how coastal waters are understood, represented, and leveraged for regional economic growth.

“Accurate, shallow-water bathymetry is the missing puzzle piece for many of our coastal models and navigational charts,” said Rear Admiral (lower half) Chris van Westendorp, director of the Office of Coast Survey, NOAA’s ocean mapping and nautical charting program. “Through harnessing commercial mariners' presence and expertise, we unlock a new data stream and are able to better identify recent seafloor changes in areas notoriously difficult to survey. We look forward to transforming their contributions into actionable knowledge that protects lives and coastal economies."

To access the data as it is released, visit the NCEI Bathymetric Data Viewer. Learn more about William & Mary’s VIMS & Batten School and NOAA efforts to remove crab traps in the Chesapeake Bay and across the nation on the NOAA Marine Debris Program website.