H. Polet

Institute for Agricultural and Fisheries Research | ILVO · Department of Fisheries and Aquatic Production

The Working Group on Electrical Trawling (WGELECTRA) works on improving knowledge of the effects of electrical or pulse fishing on the marine environment. During the 2023 meeting, the working group considered a discussion on razor clam eletrofishing research trials, the only ongoing research on electrofishing. The final wrap-up of recent research o...

Between 2009 and 2021 almost the complete beam trawl fleet of the Netherlands switched from conventional beam trawls (BT) to pulse trawls (PT) using electrical stimulation to catch sole, Solea solea. Electric fishing, being banned in the EU in 1988, was made possible in 2006 under a derogation. Over the years stakeholders expressed concern about ec...

The Working Group on Electrical Trawling creates a platform for supra-national joint research projects on electro-trawling and scientific publications. The group also reviews all relevant studies on marine electrofishing and discusses the ongoing and upcoming research projects in the light of knowledge gaps. Research areas covered by the group incl...

Ecosystem effects of bottom trawl fisheries are of major concern. Although it is prohibited to catch fish using electricity in European Union waters, a number of beam trawlers obtained a derogation and switched to pulse trawling to explore the potential to reduce impacts. Here we analyse whether using electrical rather than mechanical stimulation r...

The Working Group on Electrical Trawling (WGELECTRA) works on improving knowledge of the effects of electrical or pulse fishing on the marine environment. At the 2020 meeting, the working group considered the Scottish Ensis fishery, ongoing work on shrimp pulse fishery study and analysed the possible contribution of pulse trawling to reducing or in...

This report presents the results of a four year research project “Impact Assessment Pulse trawl Fishery (IAPF)“ on the biological and ecological effects of electric pulse trawls used in the fishery for North Sea common sole (Solea solea).

Ecosystem effects of bottom trawl fisheries are a major concern. We analysed whether the replacement of mechanical stimulation by electrical stimulation may reduce the adverse impacts on the benthic ecosystem in the beam trawl fishery for sole. Although the use of electricity is not allowed to catch fish in European Union waters, a number of beam t...

Abstract Recently, Vibrio tapetis was isolated for the first time from skin ulcerations in wild-caught common dab (Limanda limanda). To further examine its role in the development of these skin lesions, an in vivo experiment was performed. The significance of the skin barrier and in addition the difference between pigmented and non-pigmented side w...

The Working Group on Electrical Trawling (WGELECTRA), works on improving knowledge of the effects of electrical or pulse fishing on the marine environment. In this report the group provide details of ongoing work including preliminary results, upcoming research projects, and possibilities for international collaboration and scientific publications....

In agriculture and livestock farming, big data, advanced analytics and robotics are trending. There is an increased need to fuse multiple data sources and deploy advanced algorithms that require parallel execution. The H2020 project CYBELE (IA, 2019-2021, grant nr. 825355) aims to demonstrate how the convergence of high performance computing (HPC),...

Tickler-chain SumWing and electrode-fitted PulseWing trawls were compared to assess seabed impacts. Multi-beam echo sounder (MBES) bathymetry confirmed that the SumWing trawl tracks were consistently and uniformly deepened to 1.5 cm depth in contrast to 0.7 cm following PulseWing trawling. MBES backscatter strength analysis showed that SumWing traw...

Despite electric pulse fishing being regarded as a promising environmentally friendly fishing method, very little is known about possible negative effects on early life stages of bottom‐dwelling species such as Sole Solea solea. Electrotrawling for brown shrimp Crangon crangon is increasingly used in shallow coastal zones and estuaries of the south...

The capture fishing sector causes direct and indirect impacts on benthic habitats and associated fauna and flora. Effectiveness of new mitigation measures depends on fishermen's perceptions; their acceptance of, and compliance to, those measures. Accordingly, by means of Advisory Councils (ACs), fisheries stakeholders are encouraged by the Common F...

BENTHIS developed the scientific basis to quantify the impact of bottom trawling on the seafloor and the benthic ecosystem. Based on insight in how fishing gear affects the seafloor, an assessment framework was developed that provide indicators of impact and seafloor status on a continuous scale that can be applied in the context of the MSFD. The m...

Skin ulcerations rank amongst the most prevalent lesions affecting wild common dab (Limanda limanda) with an increase in prevalence of up to 3.5% in the Belgian part of the North Sea. A complex aetiology of these ulcerations is suspected, and many questions remain on the exact factors contributing to these lesions. To construct the aetiological spe...

In this paper we examine the response of the Belgian beam trawl fishery after the implementation of a spawning closure in the Celtic Sea. It was observed that fishing effort was mainly reallocated in time, resulting in a short-term “race for fish” immediately after re-opening of the fishery. The rationale of this behavior was examined by analyzing...

This article builds on earlier work that found that real-world decision makers did not learn from playing with a high-complexity simulation model designed as a learning laboratory for their decision-making domain. The absence of clear learning effects was sought in the absence of collaboration with others during participants' interaction with the s...

The application of electrical pulses in fishing gear is considered a promising option to increase the sustainability of demersal trawl fisheries. In the electrotrawl fishery for brown shrimp, an electrical field selectively induces a startle response in shrimp. Other benthic organisms remain mainly on the seafloor and escape underneath a hovering t...

share link: https://authors.elsevier.com/a/1U0ji_WA32OY1 Pulse fishing may pose a promising alternative for diminishing the ecosystem effects of beam trawling. However, concerns about the impact on both target and non-target species still remain, amongst others the possible damage to the electro-receptor organs, the Ampullae of Lorenzini, of elasmo...

Pulse trawling is the most promising alternative to conventional beam trawls targeting Sole Solea solea (also known as Solea vulgaris), but due to the electric fields created by electrotrawls spinal injuries are reported in gadoid round fishes such as Atlantic Cod Gadus morhua. This study aimed to investigate the variability in the occurrence of el...

Pulse trawling is currently the best available alternative to beam trawling in the brown shrimp Crangon crangon and Sole Solea solea (also known as Solea vulgaris) fisheries. To evaluate the effect of repetitive exposure to electrical fields, brown shrimp were exposed to the commercial electrodes and pulse settings used to catch brown shrimp (shrim...

Under the “high survival” exemption of the European landing obligation or so-called discard ban, monitoring of the vitality and survival of European flatfish is relevant in the discard-intensive (Belgian) beam trawl fishery. Quantifying post-release survival of European plaice (Pleuronectes platessa) has been given priority, because plaice is frequ...

We examine whether the landing rates of Belgian beam trawlers in the Southern Bight of the North Sea were affected through competitive interactions with the Dutch beam trawler fleet and whether the development of a pulse trawler fleet has altered competitive interactions between both fleets. Effects of competition were investigated through a natura...

This newsletter deliverable contains a collection of news items that have been, or will be published individually on the BENTHIS website (www.benthis.eu) and/or on social media such as Facebook (https://www.facebook.com/Benthis-405411256222122/timeline/, during the year 2015. These news items will also be bundled into an online news letter by Febru...

This study assesses the seabed pressure of towed fishing gears and models the physical impact (area and depth of seabed penetration) from trip-based information of vessel size, gear type, and catch. Traditionally fishing pressures are calculated top-down by making use of large-scale statistics such as logbook data. Here, we take a different approac...

A framework to assess the impact of mobile fishing gear on the seabed and benthic ecosystem is presented. The framework that can be used at regional and local scales provides indicators for both trawling pressure and ecological impact. It builds on high-resolution maps of trawling intensity and considers the physical effects of trawl gears on the s...

A framework to assess the impact of mobile fishing gear on the seabed and benthic ecosystem is presented. The framework that can be used at regional and local scales provides indicators for both trawling pressure and ecological impact. It builds on high-resolution maps of trawling intensity and considers the physical effects of trawl gears on the s...

The Belgian fishing sector is under pressure to demonstrate the sustainability of its fishing methods. First, the beam trawl (which accounts for 80% of the landings) is contested due to its low selectivity and significant disturbance of the sea bed. Second, the Belgian retail market has committed to sourcing sustainable seafood. However, converting...

Vibrio tapetis is primarily known as the causative agent for brown ring disease in bivalves, although it has been isolated from cultivated fish during mortalities on farms. Here we describe the first isolation of V. tapetis from wild-caught and subsequently captive-held Dover sole (Solea solea). Pathological features consisted of multifocal circula...

In a previous paper, Review of habitat dependent impacts of mobile and static fishing gears that interact with the sea bed (2014) we offered definitions for benthic habitat, fishing gear and fisheries management and a way of thinking about the challenge of understanding best practices for measuring, monitoring, managing and mitigating benthic impac...

In an effort to improve the selectivity of beam trawls targeting flatfish, codend size selectivity of three flatfish and two roundfish species were compared testing 80 mm diamond-shaped mesh (T0), versus 80 mm mesh turned 90⁰ (T90). The results demonstrate that the T90 codend significantly increased size selectivity for the two roundfish investigat...

Beam trawling causes physical disruption of the seabed through contact of the gear components with the sediment and the resuspension of sediment into the water column in the turbulent wake of the gear. To be able to measure and quantify these impacts is important so that gears of reduced impact can be developed. Here we assess the physical impact o...

The reformed Common Fisheries Policy (CFP) does away with the practice of throwing back unwanted catch (‘discarding’) via the introduction of a ‘landing obligation’ (also called ‘discard ban’). This will make it obligatory to bring ashore every individual of a certain species. It will be introduced gradually, between 2015 and 2019 for all commercia...

Brown shrimps are caught with bottom trawls, as is the case for 90% of all demersal fish, shell and crustacean landings in the North Sea. These demersal trawl fisheries are known to produce large amounts of discards and to disturb the seafloor habitat of benthic organisms. This results in severe ecosystem damage and the indirect reduction of quota...

Pulse trawling is currently the most promising alternative for conventional beam trawls targeting sole and shrimp, meeting both the fisher's aspirations and the need for more environmentally friendly fishing techniques. Before electrotrawling can be further developed and implemented on a wider scale, however, more information is needed about the ef...

Beam trawling causes physical disruption to the seafloor through physical contact of the gear components on the sediment and the resuspension of sediment into the water column in the turbulent wake of the gear. Recently Dutch beam trawlers have replaced tickler chains by electrodes as alternative stimulation for catching flatfish. It is claimed tha...

Originally published as a single report, this paper presents part one of a two-part publication that focuses on best practices in measuring, managing and mitigating the impact of fishing on benthic habitats. Here the authors review the classification of fishing gears in relation to their likely environmental disturbance on a range of habitat types...

In dit rapport worden de effecten van visserij met sleepnetten op de zeebodem en bodemdieren bestudeerd. Een BACI - ontwerp experiment werd gebruikt om de effecten van een traditionele boomkor en een pulskor te onderzoeken. In de afgelopen jaren is als gevolg van lagere brandstofkosten en goede tong vangsten het gebruik van de pulskor techniek onde...

Publicly reported statistics on the production of fisheries refer to 'landings' as opposed to 'catch'. However, well-informed decisions and evaluation of the impacts of fisheries on ecosystems must be based on total removals, so including the part of the catch that is discarded at sea or not reported as landings. Total removals by Belgian fisheries...

In trawl fisheries, beam trawls with tickler chains, chain mats or bobbin ropes are used to target flatfish or shrimp. High fuel consumption, seabed disturbance and high discard rates are well-known disadvantages of this fishing technique. These shortcomings are increasingly gaining international public and political attention, especially with the...

Visserijbeheerders zetten alles in het werk om kabeljauwvangsten in de Noordzee te verminderen, zodat het kabeljauwbestand zich kan herstellen. De Nederlandse overheid vroeg IMARES om een overzicht van maatregelen, die in verschillende landen rond de Noordzee in gebruik zijn voor het verminderen van kabeljauwvangsten. De beheerder is specifiek geïn...

Depestele, J., Vandemaele, S., Vanhee, W., Polet, H., Torreele, E., Leirs, H., and Vincx, M. 2011. Quantifying causes of discard variability: an indispensable assistance to discard estimation and a paramount need for policy measures. – ICES Journal of Marine Science, 68: 1719–1725. Fishery-dependent data underpin the scientific advice given to fish...

This study examines the heterogeneity of the Belgian fishing fleet based on “strategic groups”, a concept borrowed from the field of strategic management. Its objectives are: (1) to define strategic groups within the Belgian fishing fleet; (2) to examine the performance differences among these strategic groups; (3) to examine whether firms (i.e., v...

The environmental impact of fishing is still a widely discussed issue with conflicting opinions. There is, however, ample scientific evidence that fisheries can compromise the structure and functioning of marine ecosystems although the specific characteristics of the fishery will determine the nature and intensity of the impact. Discussions on the...

Thirteen participants worked together to develop new gears/fishing techniques that have a lower impact on benthic habitats, to quantify the potential reduction of the physical impact as well as the negative effects on benthic communities, to weigh the socio-economic consequences of these changes against those of alternative management measures, e.g...

This article was submitted without an abstract, please refer to the full-text PDF file.

This article was submitted without an abstract, please refer to the full-text PDF file.

Even with the rapid changes in the level of complexity and the uncertainty of the environment in which Belgian sea fisheries operate, fisheries management in Belgium is still mainly based on restrictive policy instruments founded in the biological approach of fisheries management science. Since they will continue to play an important role, this pap...

Since there is no doubt about the huge impact high fuel prices currently have on the performance of European fleets, researches start to wonder about the future. This paper contributes to this recently emerging discussion. It evaluates the effect of three fuel price scenarios on Belgian fleet dynamics. These scenarios are tested using a microeconom...