Pulse fishing in Europe

Fishery Overview Sophisticated DC pulse discharge systems Fisheries for flatfish and shrimp ( different stimuli) Dutch, Belgian, German and UK vessels using systems Electrical systems replacing beam trawls with heavy ground gear and tickler chains. Up to 10% of Dutch fleet ( 80 vessels) may be derogated in future to use systems. (Predominately flatfish) Presently 42 Dutch, 1 Belgian, 5 German, 3 UK licences.

WGELECTRA Contributors IMARES, & LEI, Netherlands Thuenen Institute, Germany ILVO & University of Ghent, Belgium Marine Laboratory, Scotland

Reported work (2014) Effects on Sole (adult, egg and larval stages), Plaice, Dab, Cod, Brown Shrimp, Ragworm, Armed Bullhead, Bullrout and enis (Scotland). Investigation of impact on benthic invertebrates on going. Comparison of catch rates, discards, bycatch etc in traditional and pulse shrimp trawls Reduction in by catch by modifying bobbin sizes on shrimp trawls Monitor economic performance of pulse fishing vessels Initiate survey of stakeholders views on pulse fishing

Dutch trawler with tickler chains

Sumwing ( contactless) “beam” trawl Image courtesy of Dr. Daniel Stepputtis Thuenen Institute, Germany

Financial benefits (Energy) Country Vessel class [hp] Flatfish Flatfish + shrimps ShrimpsSum Total by nation Fuel consumption [M litre/year] Fuel cost [M €/year] Fuel saving [M litre/year] Fuel cost reduction [M €/year] CO2 reduction [M kg/year] Netherlands> ≤ Germany> ≤ United Kingdom> ≤ Belgium> ≤ Total> ≤ Totals VariableValueDimension Fuel saving large50% Fuel saving small35% Fishing weeks large40weeks Fishing weeks small35weeks kg CO2 per litre2.6kg/litre Fuel cons large30000litre/week Fuel cons small15000litre/week Fuel costs per litre0.65€/litre Data courtesy of B. V. Marlen IMARES, Netherlands

Conclusions ( Flatfish trawling) Lower fuel consumption (40-50%) Smaller landings (60-80%) Fewer discards (30-40%) Higher net earnings (150%) Conclusions ( Shrimp trawling) Increased catch rate (23%) Reduced by catch (9%) Less flat fish ( 13%) Less benthic fish (29%) Less discards (67%) Reduced bottom pressure (75%)

Dutch proposed ensis fishery Target species is E. Ensis ( E. Siliqua in Scottish work) Stimulus 24 volts 45 amps Proposed airlift dredge system penetrating 5cm Tank trials elicited emergence in 40 – 60 seconds Tow tank trials 90 seconds Too slow to allow vessel to manoeuver Future work to elicit faster response: Increasing voltage and current, partially burying electrodes.