AquaDebris: An assessment of marine debris from shellfish aquaculture using drone technology in north carolina

Shellfish farming is one of America's oldest and most beloved aquaculture industries. Shellfish farmers and their families are often regarded as sentinels for the environment with an abiding respect for protection of water quality and natural resources. Shellfish aquaculture has become one of the fastest growing coastal zone industries in the U.S. with some states such as Virginia reporting over 30% growth per year. Development of aquaculture is a national priority in order to meet growing seafood demand, address U.S. food insecurity, and revitalize working waterfronts and water-dependent coastal economies. As the footprint for shellfish aquaculture continues to increase, so will the requirement to ensure sustainability including siting and planning, monitoring of environmental impacts, addressing user conflicts for space, and mitigation of impacts on habitat and public trust resources. Marine debris is a recognized stressor in aquatic ecosystems and is a highly visible warning for a wide range of environmental contaminants. Marine debris originating from aquaculture has become an important issue with industry expansion and development of sophisticated technology to intensify production. In many states, there is growing evidence to suggest that significant amounts of marine debris in estuarine and coastal environments is attributable to the aquaculture industry.

Aquaculture debris is a known hazard for marine organisms and can directly cause entanglement, be ingested, or cause fatal injuries or health problems. Aquaculture gear is different from commercial fishing gear in that aquaculture gear is concentrated in one location and may occupy a large footprint (many acres). After storms, debris lost from farms can build up along shorelines and within sensitive habitats such as saltmarsh, seagrass, and oyster reefs. A pilot study conducted by NOAA in partnership with Duke University Marine Laboratory used drones to digitally photograph and characterize marine debris associated with an abandoned and derelict shellfish farm located near Harkers Island, North Carolina. Decommissioning of the aquaculture operation and restoration of the site did not occur with lease closure. The abandoned aquaculture equipment has resulted in a high level of marine debris that over the years has been deposited onto neighboring shorelines and salt marshes and SAV habitats during intense storms and hurricanes common to North Carolina. Drone surveys of the 30-acre site revealed a large debris field with roughly 250 cubic meters of debris. Imagery from the surveys is being used to assess habitat damage and recovery and inform planning for removal.