Following the success of our pilot surveys in Boothbay Harbor last autumn, the General Oceans Foundation returned to Maine in May 2026 for a two week field campaign across Penobscot Bay. Working alongside OceansWide, we expanded side-scan sonar surveys to new locations, provided hands-on training to help build local survey capability, and carried out initial trials using remotely operated vehicles (ROVs) to inspect and support the recovery of ghost fishing gear identified on the seabed.
Why ghost gear matters
Ghost gear refers to fishing equipment that has been lost, abandoned, or otherwise discarded in the marine environment. Although lobster traps are designed with biodegradable escape panels intended to stop them from continuing to fish indefinitely, OceansWide has found that around 66% of the ghost traps that they recover from the seabed are still actively trapping marine life, with lobsters and crabs most commonly found inside.
Large accumulations of lost gear, often known as gearballs, can form when traps, ropes, and other fishing equipment become tangled together over time. These dense masses present hazards not only to marine life but also to commercial fishers and recreational boaters, while becoming increasingly difficult to recover as they grow in size.
Expanding the search
Surveys were carried out around Vinalhaven, North Haven, Rockland, Matinicus, and Owls Head using a Klein System 4900 side-scan sonar, generously loaned by Klein Marine Systems. Survey locations were selected using a combination of local knowledge from the OceansWide team and the fishing community, together with a gearball density model developed by researchers Andrew Goode and Damian Brady at The University of Maine. This combination of local experience and scientific modelling helped prioritise areas most likely to contain concentrations of lost fishing gear.
Building local capability
Building local survey capability was a key objective of the project. Training combined a one day classroom course on side-scan sonar, led by sonar expert and volunteer Vince Capone of Black Laser Learning, with hands-on field experience during the surveys. This equipped the OceansWide team with the skills needed to independently conduct future side-scan sonar surveys, strengthening local capacity to identify and remove ghost fishing gear across the region.
The project also welcomed a number of visitors on board throughout the surveys, including local fishers, a representative from the Vinalhaven Land Trust, and researchers from the University of Maine, helping to share knowledge and strengthen local collaboration around ghost gear removal.
From sonar targets to underwater inspection
For several days of the project, Strategic Robotic Systems joined the survey team with their Fusion Hybrid ROV. After side-scan surveys identified targets of interest, the ROV was used to relocate them using its onboard sonar before inspecting their condition and the surrounding environment with its camera. This additional information will help determine the most appropriate retrieval method and improve planning before divers enter the water.
The team also carried out initial trials using different ROV attachments, including Reach Robotics Alpha robotic arms, to remotely attach a clamp and recovery line to ghost traps. While divers remain the most efficient recovery method in shallow water, robotic solutions could become increasingly valuable for recovering gear in deeper environments where diving becomes more challenging.
What the surveys revealed
Around the Vinalhaven and Fox Island Thorofare area, approx. 1.7 km² (or 170 hectares) of seabed was surveyed using side-scan sonar, revealing over 1,800 traps. The surveys identified one confirmed gearball and another potential gearball that will require further investigation.
Not every target identified in the sonar imagery can be confirmed as ghost gear from side-scan sonar data alone. Although some active fishing gear was present, the surveys were conducted early in the season when the number of active traps was still relatively low. Many of the areas where we identified dense concentrations of traps on the sonar had no corresponding surface buoys visible during the survey.
Turning data into action
“All of these highlighted spots and areas of high trap concentration are going to assist our dive team in being more efficient underwater. Instead of surveying with divers and spending that time, we can just put our divers right on top of a pile of traps in a high concentration area so we can get those traps out of the water as quickly and efficiently as possible.”
- Matt Lewis, Vice CEO and Lead Dive Instructor, OceansWide
The data collected during the surveys will now be used by OceansWide to plan dive recovery operations over the coming months. The survey results from around Vinalhaven will also be used by researchers at the University of Maine to validate and refine their gearball density model. In addition, the dataset is being shared with groups developing AI-assisted tools for automatically detecting ghost fishing gear from side-scan sonar imagery, with the aim of speeding up future data processing, target selection, and mapping.
Reflecting on the project, Buzz Scott, President and Founder of OceansWide, said the survey data had been "extremely useful", adding that side-scan sonar "changes the way we will do our work" by reducing dive time, increasing the number of traps the team can recover, and minimising the need for divers to search for gear on the seafloor.