PhD students

Zita Bak-Jensen 

Title of the 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. 

Perspectives
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 Lyngby

Title of the 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.

Perspectives
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 Nielsen

Title of the 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.

Perspectives
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 Diernæs 

Title of the 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.

Perspectives
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 Huda

Title of the 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.

Perspectives
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. 

Sissel Kolls Bertelsen

Title of the PhD project
Electronic monitoring and new management structures for facilitating innovation within fisheries

Supervisors
Jordan Feekings, Marie Storr-Paulsen & Bent Herrmann

Background of the project
The Common Fisheries Policy (CFP) aims to ensure sustainable fish stock exploitation and eliminate discards. To achieve this, the EU has implemented the Technical Measures Regulation, outlining complex restrictions to e.g. fishing gear and area. The complexity and prescriptiveness of the TMR restricts fishers' ability to adapt their fishing practices according to changes in the fishery. Presently, however, emerging technologies such as electronic monitoring can potentially facilitate automatic catch registration, and thereby provide fully documented fisheries. Thus, by providing fully documented fisheries, electronic monitoring could increase the data input to stock assessments, enhance enforcement of regulations, replace time consuming control procedures, and potentially render large parts of the Technical Measures Regulation redundant.

About the project
The overall aim of this PhD is to understand whether the implementation of new technologies for catch monitoring and reporting can facilitate a simpler and more flexible management framework, while ensuring improvements in the environmental and economic performance of fisheries. The project will be made in close collaboration with the fishing industry and the Danish Fisheries Agency and contribute to the EU Horizon project EveryFish.

Perspectives
Simplifying the management framework may act as an incentive for the fishing industry to adopt electronic monitoring. Additionally, this project will explore fisher’s perceptions of electronic monitoring, to understand challenges and advantages related to this from a fisher’s perspective. Finally, the project will investigate how information from electronic monitoring data can be made useful for fishers to increase the efficiency of the fishing process. Hence both management, technical, and social aspects related to the implementation of electronic monitoring are considered in this project.  

Cristina Fernandez Garcia

Title of the PhD project
Using hydrodynamics to modify the performance of towed fishing gears

Supervisors
Barry O’Neill & Valentina Melli

Background of the project
Demersal fishing gears, particularly beam trawls, lead to significant negative impacts on the seabed and benthic communities. Heavy gear components are used to mechanically lift target catches into the net, damaging benthic habitats, causing alterations in sediment composition and disrupting marine ecosystems. Overall, these effects contribute to reduced biodiversity, altered species composition, resuspend sediments, and nutrients, and release CO₂ that was sequestered in the seabed, compromising the overall marine ecosystem health.

With increased awareness towards sustainability in recent years, there is significant demand for innovative technologies that can be both less aggressive towards the seabed and selective for the target species with high commercial value, thereby reducing bycatch. Fishing gear development, specifically the modification of towed gear design to enhance fisheries sustainability and optimize fishing performance, therefore, has great potential for mitigating environmental impacts.

About the project
This PhD project will start building on the results of a recent study in the Limfjord sea star fishery, where it was demonstrated that the turbulence in the wake of a beam towed close to the seabed can replace the mechanical gear components to raise sea stars from the seabed. This new data constitutes the foundation to investigate further modifications of the beam design and the project will shed light on the understudied behavioral responses of several demersal target and bycatch species in response to hydrodynamic flow.

Perspectives
By leveraging this innovative gear modification, this project aims to explore new possibilities for sustainable fishing practices which, in turn, strive to make cost-effective technology readily available to fishers enhancing their efficiency and sustainability practices, with a focus on minimizing environmental impacts and reducing bycatch in various highly impactful fisheries.

Previous PhD students within the research area Fisheries Technology (since 2020)

Morteza Eighani
Developing low impact and fuel efficient towed demersal fishing gears
(link awaits publication of thesis)

Karen Baastrup Burgaard
Using hydrodynamics to improve the selectivity of towed fishing gears

Maria Sokolova
Development of an optical catch monitoring tool for demersal trawl fisheries