Otter boards for trawl. Photo: Morteza Eighani

PhD defence on development of low impact and fuel efficient demersal trawl

On 23 May 2024, Morteza Eighani will defend his PhD thesis. The defence can be followed online or attended in person at DTU Hirtshals Campus.

Demersal trawling is a widespread fishing technique used around the globe. It plays a crucial role in ensuring food security, driving economies, and sustaining coastal communities. However, it is also one of the leading human-induced disturbances to the seabed, threatening marine ecosystems, reducing the sustainability of fish populations, and indirectly contributing to climate change through CO2 emission.

During his PhD at DTU Aqua, Morteza Eighani examined the performance of a novel self-adjusting, semi-pelagic otter board (SAO) system, which can maintain a given height above the seabed, aiming at reducing seabed contact. The SAO has two adjustable flaps, which are controlled by onboard altimeters and actuators, modifying their lift and drag and altering their position in the water column. The actuators are governed by a feedback system, which uses the altimeter data to maintain the otter boards at a preset target height above the seabed.

Morteza Eighani’s research demonstrates that the reduced hydrodynamic drag and reduced contact drag of the SAO system not only minimizes the impact on seabed habitats but also reduces fuel consumption. The results thereby contribute to the economic and sustainable development of demersal fisheries. The tested technology is relevant mostly for fisheries targeting demersal species such as cod, haddock, plaice, shrimp and Norway lobsters.

About the defence

Morteza Eighani will defend his PhD thesis, Developing low impact and fuel efficient towed demersal fishing gears, on Thursday, 23 May 2024, at 13:00.

The defence can be followed online or in person at DTU, Willemoesvej 2, 9850 Hirtshals. Find more information below.


  • Jordan Feekings, DTU Aqua (chair)
  • Paul Winger, Marine Institute of Memorial University of Newfoundland, Canada
  • Matthew McHugh, Bord Iascaigh Mhara, Ireland

Chairperson at defence

  • Senior Researcher Junita Karlsen, DTU Aqua


  • Principal supervisor: Professor Barry O'Neill, DTU Aqua
  • Co-supervisor: Researcher Tiago Veiga Malta, DTU Aqua
  • Co-supervisor: Researcher Valentina Melli, DTU Aqua
Learn more

A copy of the thesis is available for reading at DTU Aqua. Please contact PhD Coordinator Susan Zumbach Johannesen,

How to attend the defence

In person

Everybody is welcome to attend Morteza Eighani's PhD defence at DTU, Willemoesvej 2, 9850 Hirtshals.



The defence can be followed on Teams using this link
Please, enter the meeting 10 minutes prior to the defence proceedings are scheduled to start. All participants are muted per default, but we ask you to double check that your microphone is turned off at all times. 



Thursday, 23 May 2024 at 13:00.