Heavy Lifting: Marine Debris Removal in Flower Garden Banks National Marine Sanctuary
Photo credit: Sierra Sarkis/NCCOS
Every successful field mission requires planning, teamwork, and the ability to adapt. These three qualities were on display during a recent expedition in Flower Garden Banks National Marine Sanctuary, where a multifaceted group of partners came together to remove about 1,700 pounds of marine debris from the seafloor. It was a significant step in restoring mesophotic, or “middle light,” coral habitats in the Gulf, as marine debris can physically damage and smother corals, entangle marine life, leach chemicals into the water, and introduce new pollutants that cling to it. This mission built on years of data about the type and location of marine debris in the sanctuary, the best methods to remove it, and the importance of restoring seafloor habitats.
The expedition, funded by the National Marine Sanctuary Foundation through a grant from the National Oceanic and Atmospheric Administration (NOAA) Marine Debris Program, used commercial divers and a crane to carefully remove derelict fishing gear from Stetson Bank. The mission ran 24-hour operations, with divers entering the water in shifts every few hours and diving as deep as 190 feet. On a dive, a diver would locate and rig a piece of derelict gear to a crane line, allowing the debris to be pulled to the surface. The proficiency of the divers, combined with expert coordination on deck, meant the team brought debris to the surface on nearly every dive.
Photo credit: Sierra Sarkis/NCCOS
A successful mission is the result of a lot of planning. The work to identify the right targets–pieces of marine debris that were a threat to the habitat and could be safely removed–began long before the team went to sea.
The groundwork began with a comprehensive inventory published in 2023 of known marine debris compiled from years of seafloor surveys within the marine sanctuary.. Experts completed these surveys by driving camera-equipped remotely operated vehicles (ROVs) above the seafloor, capturing videos that can be analyzed later for habitat type, coral and fish sightings, and more. After 570 ROV dives during 38 cruises in and around the marine sanctuary across two decades, the team documented almost 500 pieces of debris.
The next step was to evaluate some of the known debris sites to determine which pieces should be removed. Since debris removal takes a lot of time, money, and people power, the team wanted to prioritize debris that poses a threat to the habitat and could be removed without causing any damage to the seafloor. Experts from the Mesophotic and Deep Benthic Communities (MDBC) portfolio, a coordinated effort to restore deep habitats in the Gulf after the Deepwater Horizon oil spill, analyzed the data and identified some select targets for removal. On an expedition in 2024, the MDBC team removed some of the debris and conducted reconnaissance on other items–an important step to make sure the historical location data was accurate. They came out of that mission with new data, new imagery, and a new plan to target fishing debris.
Photo credit: Sierra Sarkis/NCCOS
The decision to focus the June 2025 removal efforts on Stetson Bank was a result of this new plan and a strategic analysis of previously-collected data. Stetson Bank contained the highest concentration of debris in the sanctuary, 73% of which was derelict fishing gear, a high priority for removal due to its direct threat to mesophotic habitats.. Although it was closed to most commercial fishing when Stetson Bank was added to the marine sanctuary in 1996, it’s still a popular destination for recreational anglers. By concentrating the debris removal mission’s resources on this single, high-yield area, the team could maximize their time on the seafloor to help restore the habitat.
Photo Credit: Sierra Sarkis/NCCOS
The information gathered during the reconnaissance phase allowed the dive team to drop directly onto the targeted derelict fishing gear, maximizing every minute of their limited bottom time. In poor visibility conditions, a difference of a few meters can determine the success or failure of finding the target debris. Plus, in a collaborative effort, experts developed a new decision-making flow chart that helped the team determine which pieces of debris to target, considering safety and efficiency for divers. Once a diver determined a piece of gear was safe to remove, they would rig the derelict gear to a line from the ship’s crane. Then, the powerful crane would begin the slow, careful process of lifting the debris while the diver remained below, watching for any snags on the seafloor and ensuring the extraction caused no harm to the surrounding coral habitat.
Once on deck, the recovered debris became the focus of the science team. Aquarists from Moody Gardens and Georgia Aquarium were ready to provide expert care in case any organisms were found attached to the debris. Each piece of debris was carefully inspected, and any associated organisms—including small crabs, sponges, and other invertebrates—were removed. Following protocols for animal care and data collection, most mobile animals were returned to the seafloor on a subsequent dive. Non-mobile (or “sessile”) organisms, like a particular species of black coral that had settled on the nets, were either preserved as scientific samples or, if still viable, were “outplanted” by divers back onto suitable habitat nearby.
A small “hitchhiker” who was brought up with the marine debris and then returned to the sea floor. Photo Credit: Chris Ledford
This mission’s success is measured not just in the approximately 1,700 pounds of debris removed from the seafloor, but also in the effective model it provides for future restoration work. It showcases how years of historical data, targeted reconnaissance, and the combined expertise of scientists, commercial divers, and other partners can lead to a direct and meaningful impact. By meticulously planning and adaptively managing the operation, the team did more than just remove some derelict gear; they actively restored it, contributing to the long-term recovery and resilience of the Gulf.
This mission was funded by the National Marine Sanctuary Foundation through a grant from the NOAA Marine Debris Program in partnership with Flower Garden Banks National Marine Sanctuary, Moody Gardens, and the Deepwater Horizon Mesophotic and Deep Benthic Communities Restoration projects.