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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 StepputtisThuenen Institute, Germany
Financial benefits (Energy)
CountryVessel class [hp]
FlatfishFlatfish + shrimps
Shrimps SumTotal 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 > 300 25 25 30.0 19.5 15.0 9.8 39.0 ≤ 300 13 1 3 17 42 8.9 5.8 3.1 2.0 8.1Germany > 300 3 3 3.6 2.3 1.8 1.2 4.7 ≤ 300 1 0 1 2 5 1.1 0.7 0.4 0.2 1.0United Kingdom > 300 3 3 3.6 2.3 1.8 1.2 4.7 ≤ 300 0 0 0 0 3 0.0 0.0 0.0 0.0 0.0Belgium > 300 0 0 0.0 0.0 0.0 0.0 0.0 ≤ 300 0 0 1 1 1 0.5 0.3 0.2 0.1 0.5Total > 300 31 0 0 31 37.2 24.2 18.6 12.1 48.4 ≤ 300 14 1 5 20 51 10.5 6.8 3.7 2.4 9.6
Totals 47.7 31.0 22.3 14.5 57.9
Variable Value DimensionFuel saving large 50% %Fuel saving small 35% %Fishing weeks large 40 weeksFishing weeks small 35 weekskg CO2 per litre 2.6 kg/litreFuel cons large 30000 litre/weekFuel cons small 15000 litre/weekFuel costs per litre 0.65 €/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 AC @ 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.