Research

Ghost Trackers

Derelict crab pots – Impact assessment and removal

Personnel: Art Trembanis (UD), Kate Fleming (DSG), Ed Hale (UD)

Students: Jen Repp (UD)

Derelict crab pots are lost or abandoned pots that are no longer tended to. Left on the bay floor, they may engage in ghost fishing, cause habitat scouring, and pose hazards to navigation or dredging. Through side-scan sonar surveys of over 500 acres so far, derelict crab pots are present with densities greater than 1 pot per acre in the creeks and coves of Delaware’s Inland Bays.

The goal of this two-year project by the University of Delaware and Delaware Sea Grant, funded by the NOAA Marine Debris Program, is to remove one thousand of these pots and study their impact on the ecosystem. Project components include:

  1. Mapping 1000 acres in Indian River Bay using high-frequency side-scan sonar (Humminbird Solix) and an Autonomous Surface Vessel (Seafloor Systems Echoboat) 
  2. Monitoring the impact of derelict crab pots on recreational fishing 
  3. Removing derelict crab pots from Indian River Bay via volunteer recovery roundup events in January 2021 and 2022 (see https://www.deseagrant.org/derelict-crab-pots). Our 2021 effort successfully removed 74 derelict crab pots in 1.5 days.
  4. Characterizing sediment using machine learning and GIS analysis 
  5. Automated object detection of derelict crab pots

Interested in helping? 

  • If you have a boat and are interested in helping remove derelict crab pots from Indian River Bay in January 2022, contact Kate Fleming, Delaware Sea Grant Coastal Ecology Specialist, at kfleming@udel.edu.
  • If you have a high-frequency side-scan sonar unit (e.g. Humminbird Helix, Solix) and are interested in recording data, especially if you are in an area where crab fishing is common, contact Art Trembanis at art@udel.edu and view our demo on how to record side-scan sonar data on the Humminbird Solix here: https://youtu.be/LcjwTNCSNVY
  • For more information about data processing and analysis, contact Jen Repp at jrepp@udel.edu.

Acoustic images of derelict crab pots:

Ocean Infinity Shallow Water Survey Desktop Study

Personnel: Art Trembanis (UD), Grant Otto (UD)

Description: Ocean Infinity and UD are working on their first collaborative effort to  select sonar, magnetometer, and sub-bottom sensors for their new Armada Fleet in a desktop study.  The study is scheduled to be finished by April 2020, after which field testing will begin. Photo by Ocean Infinity.

Ocean Infinity Yellow Boat Program

Personnel: Art Trembanis (UD), Grant Otto (UD)

Description: Ocean Infinity will be delivering “Seaworker 2”, a L3Harris Seaworker 8 for sensor testing and development, to the University of Delaware in early April 2020. This is an 8 m Unmanned Surface Vessel that has sonar mapping capability as well as positioning capability for an Autonomous Underwater Vehicle. The CSHEL lab will be doing preliminary sensor testing for Ocean Infinity as well as using these sensors for time series mapping efforts to study shipwreck and reef scour as well as coastal sediment transport.  Photo by L3Harris.

Carolina Bays

Personnel: Art Trembanis (UD)

Students: Mark Lundine (UD)

Description: These are round, rimmed, and sandy depressions found on the Atlantic Coastal Plain, which means they are on land, not in the ocean!  Carolina bays can be marshy or swampy or sometimes they can be drained and just collect water after it rains (sort of like a natural detention pond).  Here are several LiDAR images of some bays found in Delaware near Slaughter Beach, northern Kent County, and the eastern shore of Virginia:

Contrary to popular belief, these features are NOT impact scars of any kind (meteor, comet, or ice), they likely originated due to a combination of their poorly drained underlying sediment, intense winds, and after significant ponding of water, waves.  Carolina bay sediment deposits date between 120,000 years and within the last few thousand years, but sediment transport activity today seems to have ceased due to a lack of significant amounts of ponded water, less intense winds, and stabilization from vegetation.

Chincoteague Inlet Modeling Study Phase I (CIMS-I)
Personnel: Christopher Hein (VIMS), Arthur Trembanis (UD), Michael Fenster (RMC), Ioannis Georgiou (UNO)

Students: Kaitlyn McPherran (UD), Justin Shawler (VIMS)

Description: Deploy sensors to measure in situ hydrodynamic parameters including waves, tidal currents, turbulence, and bottom roughness in sites distributed within the Chincoteague Inlet system in order to characterize the forces that affect sediment transport. This time series data of hydrodynamic properties will inform and validate the numerical modeling effort of the inlet system dynamics.

Integrated Barrier Island System (IBIS) Management Project Phase I: Sediment Fluxes and Trapping Dynamics around Fishing Point, Southern Assateague Island, VA

Personnel: Christopher Hein (VIMS), Arthur Trembanis (UD), Michael Fenster (RMC)

Students: Kaitlyn McPherran (UD), Justin Shawler (VIMS)

Description: Quantification of sediment fluxes, rates of sand bypassing and trapping, and mechanisms of sand delivery to and trapping within Fishing Point in order to investigate the hydrodynamics and sediment transport of the Chincoteauge-Assateague-Wallops (CAW) system. These data will provide insights into possible future behavior of the CAW system in response to climate change and serve as tool for coastal management efforts.

Bedform Parameterization and Object Detection from Sonar Data

Personnel: Arthur Trembanis (UD), Doug Miller (UD), Larry Mayer (UNH), Jonathan Beaudoin (UNH)

Students: Carter DuVal (UD), Trevor Metz (UD)

Description: The long-range goals of this research are to improve our ability to characterize the seabed geometry and texture in energetic inner-shelf/bay mouth settings composed of heterogeneous sedimentary material and possessed of dynamic seabed ripples.  Our purpose is to improve our understanding of bedform dynamics and spatio-temporal length scales and defect densities through the application of a recently developed fingerprint algorithm technique (Skarke and Trembanis, 2011) in the vicinity of manmade seabed objects and dynamic natural ripples on the inner shelf utilizing high-resolution swath sonar collected by an AUV and from surface vessel sonars in energetic coastal settings with application to critical military operations such as mine countermeasures.