Session Chairs: Mark Borrelli, University of  Massachusetts; Laura Ludwig, Center for Coastal Studies

This session will bring together investigators and project teams that incorporate the use of sidescan sonar and other acoustic techniques to aid in the detection, removal and/or study of derelict fishing gear in coastal environments from shallow nearshore waters to deep ocean fishing grounds and freshwater inland lakes.

The recovery of derelict, lost, abandoned or discarded fishing gear in marine and freshwater environments has become an important tool worldwide for reducing the amount of debris in our waterways and thus mitigating impacts to habitat and living resources. In the US alone, removal efforts have been made in shallow sandy bays, deep rocky canyons, and every strata and substrate in between.

Recovery projects which use sonar to locate targets and assess their habitat impacts require users to interpret acoustic data for effective and efficient removal efforts. With varying operating frequencies, instrument configurations, survey platforms and substrate types, the acquisition and interpretation of acoustic data is often central to a successful recovery effort.

This session will bring together investigators and projects that incorporate sidescan sonar and other acoustic techniques to aid in the detection, removal and/or study of derelict fishing gear in coastal environments, with an examination of the results found in shallow nearshore waters, at great depth, and on differing substrate. Presentations will explore image, signal and data interpretation, efficiency of various methodologies used across a wide range of habitats, ground-truthing efforts, cost-benefit relationships, and lessons learned. Collaborations with fishing industry, technology firms, research teams and federal, regional and state management entities will be highlighted.




Don’t Have a Pot to Ping in: The Efficacy of Using Sidescan Sonar to Detect, Locate and Identify Derelict Fishing Gear.

presenting: Mark Borrelli (University of Massachusetts, Boston, United States); authors: Mark Borrelli (University of Massachusetts, Boston, United States), Laura Ludwig (Center for Coastal Studies), Bryan Legare (Center for Coastal Studies), Theresa Smith (Center for Coastal Studies), Owen Nichols (Center for Coastal Studies)

Acoustic instruments with the ability to rapidly and accurately map the seafloor have long been in use. With increasing frequencies and other technological advances applications for these instruments have broadened dramatically. Several recent projects conducted by the Center for Coastal Studies have used both towed and mounted sidescan sonar instruments to locate and identify derelict fishing gear, particularly abandoned lobster pots. The mounted sidescan instrument used in these studies is a Phase-measuring sidescan sonar which yields co-registered dual frequency, sidescan sonar imagery (op. freq. 550/1600 kHz) and swath bathymetry (550 kHz), simultaneously. These data are also useful for trap assessment and recovery as well as habitat analysis. Examples from projects in Maine and Massachusetts, USA, using both mounted and towed sidescan sonar will be discussed. Gear was mapped over of multiple bottom types from mud and sand to cobble and rock outcrop in water depths ranging from <5m to over 50 m.


Derelict crab trap removal and prevention in southern New Jersey coastal bays: big implications for smaller scale systems

presenting: Mark Sullivan (Stockton University, United States); authors: Mark Sullivan (Stockton University, United States), Steve Evert (Stockton University), Peter Straub (Stockton University), Kaitlin Gannon (Jacques Cousteau National Estuarine Research Reserve), Nathan Robinson (Stockton University), Elizabeth Zimmermann (Stockton University), David Ambrose (Stockton University), Christopher Janiszewski (Stockton University)

Southern New Jersey’s coastal bays provide Essential Fish Habitat and ecological services to numerous mid-Atlantic species that use these areas during coastal migrations or as seasonal nurseries. While small in size relative to Delaware Bay, these bays and rivers account for ~42% of the State’s 10.5 million dollar blue crab fishery. Unfortunately, the dynamic nature of these systems (boat traffic, currents, storms) renders a substantial proportion of crabbing gear lost every year. The negative consequences of this loss are numerous: ecological impacts, navigational hazards, loss of commercial income. Over the past 5 years, Stockton University scientists have engaged local commercial crabbers and restoration groups throughout southern New Jersey to break the cycle of crab trap loss in these diverse coastal bay ecosystems. This work consists of four main objectives: (1) Survey and digitally map derelict crab trap targets via side-scan sonar in coastal bays and rivers covering 36 km of coastline, (2) Recover and recycle or repurpose derelict crab trap gear through the combined efforts of crabbers, scientists, and volunteers, (3) Train coastal bay crabbers on best practices for in-season recovery methods and low cost sonar operation skills, (4) Educate recreational boaters and crabbers on best practices for avoiding crab trap buoys and properly setting their own traps. To date, 2025 pieces of derelict gear have been removed off-season as part of these efforts, supplemented by in-season recoveries aimed at preventing future gear accumulation. Combined results and lessons learned from these NOAA Marine Debris Program-funded projects will be highlighted.


Use of Sidescan Sonar Imaging for Planning and Implementing Effective Derelict Fishing Gear Recovery Operations in Washington, British Columbia, and Alaska

presenting: Kyle Antonelis (Natural Resources Consultants, Inc., United States); authors: Kyle Antonelis (Natural Resources Consultants, Inc., United States), Joan Drinkwin (Natural Resources Consultants, Inc.), Crayton Fenn (Fenn Enterprises), Paul Rudell (Natural Resources Consultants, Inc.), Kamal Lindoff (Douglas Indian Association)

The effectiveness of sidescan sonar to identify locations of derelict fishing gear in marine waters is well documented. However, when planning subsequent gear removal operations, deeper analysis of the sonar images must be accomplished to maximize efficiency. Here we provide three specific methods to interpret and use sidescan sonar data to plan effective and efficient lost gear removal operations.

In British Columbia waters of Boundary Bay, over 1,800 derelict Dungeness crab pots were identified using sidescan sonar during a transboundary project in 2011. Sonar images were evaluated and targets were categorized as either buried/dilapidated or unburied. Removal operations were then focused only on structurally viable, unburied targets most likely to still be ghost fishing.

In a major effort to identify and remove derelict nets in nearshore waters from the U.S. portion of the Salish Sea, sidescan sonar surveys covered high priority areas identified in models developed by project personnel. Survey targets were analyzed and categorized based on the level of confidence in derelict net presence (1 = high, 2 = moderate, 3 = low). Project cost savings occurred as dive removal teams focused on Category 1 targets while target verification dive teams investigated Category 2 and 3 targets prior to mobilizing full removal teams.

In Gastineau Channel, Juneau, Alaska, sidescan sonar was used to locate lost crab pots in anticipation of a removal by grapple operation. Vessel size and capacity limitations, and the presence of an unburied submarine fiber optic cable, required eliminating targets from the removal plan. Targets were categorized as 1, 2, or 3 by size and additional snag hazards were identified. Areas to avoid were overlain on charts in GIS and navigational software to further refine the targets to be removed.


Using Side Scan Sonar to locate derelict fishing gear to mitigate the effects of ghost fishing in the Upper Gulf of California.

presenting: Ryan Solymar (monterey Bay Diving, United States); authors: Ryan Solymar (monterey Bay Diving, United States), Elizabeth Hogan (World Animal Protection), Jared Berg (Monterey Bay Diving)

The critically endangered (IUCN) vaquita (Phocoena sinus) is the smallest porpoise species in the world, and is endemic to Mexico’s Upper Gulf of California. The illegal totoaba (Totoaba macdonaldi) fishery poses a threat to the survival of P. sinus as abandoned gill nets left behind after the season ends entangle individuals and cause them to drown. monterey Bay Diving (MBD) in partnership with World Animal Protection (WAP) sought to use Side Scan Sonar (SSS) technology to aid in the location of derelict fishing gear in the upper Gulf of California. Working alongside local fishermen coordinated by Dr. Lorenzo Rojas-Bracho and Dr. Armando Jaramillo, on behalf of the International Committee for the Recovery of the Vaquita (CIRVA), they attempted to assist in efforts to mitigate the effect of ghost fishing on P. sinus. An EdgeTech 4125 SSS unit was used at 600 kHz and 1600 kHz simultaneously to locate derelict objects and assess the efficacy of the current technique of dragging hooks along the seafloor to remove derelict gear. The technique being employed was found to be effective at removing derelict fishing gear, and shortcomings in the use of acoustic imagery equipment were noted. Located nets were removed and transported by Parley for the Oceans to Plastix Global, a Danish company specializing in recycling fishing gear for use in other products.