Impacts of pulse fishing for flatfish on the ecosystem

What effects does the flatfish fishery using the pulse technique have on marine organisms? What are the effects on the benthic ecosystem? These are the core questions of a multi-annual research programme.

Pulse fisheries for flatfish

The traditional beam-trawl fishery for flatfish uses so-called tickler chains to startle fish like common sole and plaice and make them leap into the net. The chains are dragged over the seabed, disturbing the sediment and causing mortality of organisms in the trawl track. In the fishery using the pulse technique, the tickler chains have been replaced by electric pulses to make the flatfish leap into the net. European regulations prohibit the use of electricity in marine fisheries. As part of the decision-making process on whether or not to allow pulse fisheries, the impacts of the gear on the ecosystem will have to be investigated. Fishers who use the pulse gear are currently fishing based on a derogation.

The research questions

This four year impact assessment programme has 3 key elements:

  1. Effects on marine organisms
  2. Effects on the benthic ecosystem
  3. Upscaling the effects to fleet and ecosystem level

Effects on marine organisms

PhD candidate Pim Boute of Wageningen University (Chair Group Experimental Zoology) investigates the response of selected marine organisms representing different groups of fish and invertebrate species (such as roundfish, flatfish, rays and sharks, bivalves, crustaceans, polychaetes) to the exposure by a range of pulse parameters representative for the commercial pulse trawls. Based on the results, a predictive model on the distribution of the electrical field within these organisms and the effects on their activity and survival will be developed.

Read more about modelling the effects of electrical pulse stimulation on marine fishes and invertebrates.

Effects on the benthic ecosystem

Phd candidate Justin Tiano of the Netherlands Institute for Sea Research (NIOZ) investigates the effects of electrical pulses on the benthic ecosystem, and in particular its biochemical characteristics. For this study field experiments will be carried out and pulse exposure data of the North Sea sediment will be collected. Based on the results, a predictive model on the short and long term effects of pulse exposure on the North Sea benthic ecosystem will be developed.

Upscaling impacts to fleet and ecosystem level

Wageningen Marine Research will bring the studies carried out as part of this research programme as well as of other research projects together and will upscale it to the level of the fishing fleet and the North Sea. What is the effect of pulse trawling on the fish stocks and the benthic ecosystem at the scale of the North Sea? Does a transition in the flatfish fishery from conventional beam trawling to pulse trawling contribute to a reduction in bycatch and adverse impact on the benthic ecosystem? Through a modelling approach, the impacts of pulse fishing on the functioning of the ecosystem will be mapped.

International scientific advisory committee

An international scientific advisory committee (ISAC) guides the multi-annual impact study. ISAC is responsible for the scientific quality of the research (so-called scientific peer-review). ISAC members are prof. Michel Kaiser (chair; University of Bangor, United Kingdom), Dr Chris Zimmerman (Thune Institute, Germany), Dr Dave Reid (Marine Institute, Ireland) and Dr Allynne Delaney (University Aalborg, Denmark).