Ghost Gear Haunts the Maine Coast: Leveraging Technology for Recovery Efficiency

An estimated 30,000 to 40,000 lobster traps go missing in Maine’s coastal waters every year—a staggering loss rate that exceeds any other North American fishery. This "ghost gear" places a significant burden on marine ecosystems, waterfront communities, the food supply, and the fishing industry. For years, these lost traps remained an unseen and largely ignored problem.

Previously, conventional wisdom suggested that lost gear simply created additional submerged habitat. However, scientists and fishermen now realize that ghost gear has a profound, detrimental impact. Unlike old-style wooden traps, modern plastic-coated wire traps can persist for decades; traps from as early as the 1990s have been found still "fishing" today. Tens of thousands of traps are lost annually, resulting in a significant accumulation over many years of coated-wire trap use.

OceansWide Inc., a local Maine company, has been working with lobstermen to recover, recycle, and properly dispose of these traps. This past fall, I collaborated with Hayley Craig of the non-profit General Oceans Foundation and the Oceanswide team to demonstrate how technology can significantly improve recovery efficiency.

While side-scan sonar has been used to detect lobster and crab traps for decades

Old Klein Side Scan Sonar Image of Fish Traps on a Delaware artificial Reef circa 2002. Courtesy Vince Capone Private Collection

, several questions remained:

• Could this equipment be integrated into local efforts without requiring expert sonar operators?

• Would the equipment cost and survey time improve collection efficiency?

• Could the operation become more cost-effective on a per-trap-recovered basis?

In the Fall of 2025, the General Oceans Foundation—in cooperation with Klein Marine Systems, Inc. and Oceanswide—conducted a pilot survey in Boothbay Harbor, Maine. Serving as the volunteer operations manager and sonar operator, we found that:

• Range & Identification: Traps were clearly identifiable at sonar ranges up to 75m in outer harbor areas. However, the inner harbors required shorter ranges to filter out "surface-return clutter" and improve the ability to distinguish traps from mooring blocks and other bottom debris.

• Diver Productivity: By focusing dive time on identified clusters rather than searching blindly, divers recovered significantly more traps per dive than they could without sonar data.

  
  

While any competent operator can detect traps, Maine remains a challenging environment for towed side-scan operations. Active traps pose entanglement hazards, and rapidly changing depths create steep-terrain risks for the equipment.

The next phase of our work will determine if this technology can be operated effectively by new users under these conditions without ongoing technical assistance. There are three primary skill sets to be mastered:

Equipment/Software Operation: This basic level of training is relatively easy and can be accomplished onshore in the classroom.

Field Operations: Field operations can be divided into two distinct skills; the first is interacting with the vessel. The sonar operator must coordinate with the vessel helmsman, adjusting speed and course to maintain proper altitude and coverage. Turns can be tricky as the towfish will dive unless the turn radius and speed are properly managed. Second, adjust sonar parameters according to environmental conditions. Parameters such as range, altitude and image adjustments need to be tailored to the mission environment. These skills tend to be acquired only through experience. As more operators shift to unmanned vehicles like the art of sail, the art of towing a side scan is slowly disappearing from operational requirements.

Data Analysis & Target Identification: Data analysis was always thought of as a black art. The one analyst possesses mystical powers that can detect targets under all conditions. Having taught hundreds of EOD sailors sonar data analysis, I can most definitely say it is a learned skill, not a mystical power. To help newcomers learn techniques, Black Laser Learning has a new short video on the basics of side-scan sonar analysis.

(The trailer is available on YouTube (https://youtu.be/filUUgBSIv8? si=UdDKWuBuEeCPLLCY) or on Vimeo at blacklaserlearning.vhx.tv)

With machine learning and artificial intelligence, automatic target detection (ATR) for simple targets is now feasible and is being used by the University of Delaware and others to detect crab traps.

Our future efforts will focus on transferring this technology to local firms and on developing techniques for searching deep, rugged terrain.

Until next time,

Vince Capone

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