PhD students within fisheries technology

PhD students within the research area Fisheries Technology.

Morteza Eighani in front of remotely controllable otter boardsMorteza Eighani


Title of PhD project

The development of low impact and fuel efficient fishing gears

Supervisors

Barry O’Neill & Junita Karlsen

Background of the project

Towed bottom fishing gears can cause widespread disturbance to the seabed of shallow shelf seas. The physical impacts can have environmental and ecological consequences that affect primary production and threaten the biological sustainability and economic viability of fisheries, whereas the energy requirements will have global consequences associated with emissions of CO2 and NOX gases. In Denmark, demersal trawls are widely used and to ensure the long-term sustainability of these fisheries and to reduce their environmental impact there is a need to develop and design fishing gears that have a reduced impact on the seabed and that are more fuel-efficient.

About the project

This project will focus on developing methods for the assessment of the physical impact and drag of demersal trawls and the evaluation of low impact gears that are being developed by the fishing gear manufacturing industry. A specially designed sledge that tows individual gear components will be used to investigate the depth to which these components penetrate the seabed, the hydrodynamic turbulence they create and the associated quantity of sediment they mobilise into the water column. Small-scale modelling trials in a flume tank will be used to get a better understanding of the hydrodynamics of the trawl gear components and to extend the results of the sledge trials. Additionally, there will be full-scale trials to assess and compare the physical impact and fishing gear performance of a conventional otterboard with a remotely controllable otterboard that is being developed by a commercial trawl door company.

Perspective

This project will ensure that towed gear fisheries will be biologically sustainable, environmentally friendly and economically viable. It will allow policy makers and fishery managers to implement the EU Common Fisheries Policy (CFP) and contribute to the Danish Government’s sustainability target or reducing CO2 emissions by 70% by 2030.

 

Zita Bak-JensenZita Bak-Jensen 


Title of PhD project

Shifting from single to multi-species methods when evaluating fishing gear performance

Supervisors

Bent Herrmann, Valentina Melli, Jordan Feekings & Juan Santos

Background of the project

Several demersal fisheries are by nature mixed species fisheries because of abundance of several species simultaneously in the fishing ground. In the capture some species are target species while others should be avoided or at least minimized as much as possible. Therefore, there has been focus on developing gear solutions that can address the mixed-species challenge. In the Baltic Sea the challenge is having an effective fishery targeting flatfish species while avoiding or at least minimizing the capture of cod. Traditionally,  the approach of dealing with gear development has typically been towards single species, where the selectivity for each species is evaluated individually, but is in this PhD project shifting to a multi-species approach. 

About the project

With the demersal trawl fisheries being used as case studies, this PhD project will focus on developing and testing new approaches and data frameworks that bring the currently used method from single to multi-species assessments in evaluating fishing gear performance. A special focus will be on cod avoidance in the demersal trawl fishery in the Baltic Sea targeting flatfish species such as plaice and flounder. 

Perspective

The aim is to develop a new approach and data framework for evaluating the performance of the selectivity in multi-species fisheries making selection and selectivity models more adequate when dealing with multi-species fisheries. Even though this PhD project will focus on cod in the Baltic Sea the method will be extrapolatable to much larger scaled mixed-species fisheries.

 

Mette Svantemann LyngbyMette Svantemann Lyngby

Title of PhD project

Developing real-time decision support tools for commercial fisheries to facilitate a more dynamic fisheries management

Supervisors

Ludvig Ahm Krag, Fletcher Thompson & Esther Savina

Background of the project

Today’s limited insight into what is occurring throughout fishing processes means that commercial fishing is still mainly undertaken in the blind. Consequently, current commercial fishing practices result in unnecessary bycatch and environmental impacts, carbon dioxide outputs, all while reducing the economic competitiveness of the sector. DTU Aqua has developed a cable-based real-time camera to be applied in fishing operations such as bottom trawling. The camera will provide the fishermen with a stable real-time video of the process and enable them to observe catch items that enter the trawl. DTU Aqua has undertaken development work to improve the camera observation scene in the trawl to accurately monitor the entire catch and the species composition passing towards the codend. 

About the project

This PhD project will use the established data stream from the newly developed and installed real-time trawl camera system. The focus of the PhD project will be to quantify the system’s performance and its overall effect on both the ecological and economic sustainability in selected trawl fisheries. The project will further develop new AI-based solutions to automate the extraction of important information from the real-time UW observations to improve catch efficiency and specific bycatch avoidance.

Perspective

Such real-time catch descriptions will allow fishermen, for the first time, to continuously monitor catch volumes and compositions and actively improve the catch composition in the ongoing fishing process. This new technology has significant news value, both nationally and internationally, and will contribute to the development of a technology-based fishery where fishermen in real-time will know what is being caught and have the opportunity to direct the ongoing catch compositions towards the quotas available.

 

Martin Mathias NielsenMartin Mathias Nielsen


Title of PhD project

Unravelling the potential of electronic monitoring data for facilitating innovation within demersal trawl fisheries 

Supervisors

Jordan Feekings, Tiago da Veiga Malta & Marie Storr-Paulsen

Background of the project

Electronic monitoring (EM) was introduced into demersal fisheries in Europe in 2008. The EM cameras were installed to produce video footage of the fishing operations on-board with the objective to verify declared catches to attain a fully documented fishery. Since then, it has become clear that these data have much wider applications than merely control and enforcement. A key challenge in utilizing these data has been the reliance on manual reviews for analyzing the EM footage, which today is processed on land by trained humans. This procedure severely limits the application of the data as only a fraction of the collected data is getting analyzed due to the workload involved, and since the analysis is not conducted in real-time. 

About the project

In this PhD project, the application of new computer vision methods is investigated to address some of the existing challenges in automatically documenting catch compositions in terms of species identification and length distributions. This new data can potentially challenge conventional fisheries management practices, provide fishers more insight into their fisheries, and change the way fishing gears are developed, tested, controlled and monitored – which will be investigated to further incentivize the adoption of EM.

Perspective

Besides being a control and enforcement tool to verify declared catches, this new data has the potential to significantly increase the 1 percent catch coverage from observer programs today. This data can, among others, support more accurate stock assessments, identify bycatch hotspots, help fishers avoid choke situations, and provide insights into interactions with protected species, mammals, and birds.

 

Laura DiernæsLaura Diernæs 

Title of PhD project

Observing and quantifying fish behaviour in relation to active fishing gear

Supervisors

Junita Diana Karlsen, Stefan Neuenfeldt & Bjørn Krafft 

Background of the project

Trawl gears are responsible for a large portion of unwanted catches, globally. Consequently, there is a large focus on improving their environmental sustainability while ensuring that the fisheries remain economically viable. Animal behaviour is one of few main components that are decisive for the efficiency and selectivity of commercial trawl gears and so, the amount of unwanted catches retained. Behaviour of marine animals is typically studied using underwater cameras attached to the fishing gear. This technology has however limitations in the operational conditions during which observations can be obtained. 

About the project

Recent technological developments, such as high frequency acoustics, as well as alternative platforms for collecting data, such as remotely operated vehicles, provide new ways to quantitatively study fish behaviour in relation to fishing gear. This project focuses on using hydroacoustic to develop methods for optimal identification and tracking of individuals. Such tracking enables detailed observations of animal behaviour during the capture process with trawls.

Perspective

Using hydroacoustic techniques to observe detailed animal behaviour facilitates the understanding of the behavioural mechanisms involved when animals respond to fishing gears. This information will reduce the huge knowledge gap found for many commercial species and has the potential to support the development of more sustainable trawl designs.

 

Nurul HudaNurul Huda

Title of PhD project

The scale modelling of towed demersal fishing gears 

Supervisors

Barry O’Neill, Jens Peter Kofoed & Emilio Notti 

Background of the project

In recent years there have been increasing concerns regarding demersal trawl physical impacts on the seabed, which can give rise to (i) increased fuel consumption, (ii) the release of carbon sequestered in the seabed, (iii) habitat modification and (iv) benthic mortality. In order to promote the environmental and economic sustainability of towed demersal fisheries, we must reduce the physical impacts of these gears when they are towed across the seabed. One of the main approaches in the design and development of fishing gears is small scale model testing in recirculating flume tanks. These approaches are based on maintaining the ratio of the gravitational and hydrodynamic drag forces, (characterised by the Froude and Reynolds numbers) so that the observations at the small scale can be extrapolated to the full scale. The current approaches do not account for bottom contact forces, and hence are not particularly suitable for designing demersal gear which are towed across the seabed.

About the project

This project will focus on developing generic scale-modelling rules for demersal trawls that balance the gravitational, hydrodynamic drag and contact forces acting on a trawl gear. The theoretical framework will be established based on the fundamental relationships between these forces. This will be done by analysing the geometry and force measurements on different scale representa-tions of a given trawl gear. Small scale trials will take place in a flume tank and full-scale trials will take place at sea, using a research vessel.

Perspective

The resulting scale modelling criteria will allow small-scale experiments on demersal fishing gear, which are carried out in flume and towing tanks, to be scaled up and extrapolated accurately to full scale. This will permit the design and development of low impact, fuel efficient fishing gears that will help ensure the environmental and economic sustainability of towed demersal fisheries. 


Previous PhD students (since 2020)


Karen Baastrup Burgaard

Using hydrodynamics to improve the selectivity of towed fishing gears
Go to DTU Orbit to download thesis

Maria Sokolova

Development of an optical catch monitoring tool for demersal trawl fisheries
Go to DTU Orbit to download thesis