1. Institute for Agricultural and Fisheries Research www.ilvo.vlaanderen.be Agriculture and Fisheries Policy Area Institute for Agricultural and Fisheries Research SG Electra Presentation PhD-research Drs. Ir Maarten Soetaert UGhent - ILVO

2. 2 Content ‘Safety Margin’ for a selection of marine species – Determine the injury dose (ID 50) – Determine the lethal dose (LD 10) Optimalisation of startle pulse for sole – At ≠ frequency, field strength, waveform, wavelength, pulse type Effect of startle pulse for sole on marine species Effect of electrical pulses on fish quality

3. 3 Safety Margin (I): idea Goal: determine the injury dose (ID) and lethal dose (LD) for a selection of marine organisms: – Sole: target species – Cod: top predator, sensitive to pulses – Shrimp: target species – Sandworm: model species for polychetes Starting from startle pulse for Crangon crangon At 50 & 100 V/m: 5 Hz → 180 Hz invertebrate vertebrate

4. 4 Safety Margin (II): What? Injury Dose x% (IDx): frequency at which x % of the exposed animals shows extra injuries Lethal Dose x% (LDx): frequency at which x % of the exposed animals dies In this example: ID25 = 25Hz LD50 = 45 Hz

5. 5 Safety Margin (III): How? Homogeneous Field – Exposure (3s) 2 plate-shaped electrodes Orientation: – Euthanasia after 14 days – Autopsy Macroscopic: hemorrhages, color, spots, deformation, … Rontgen photos (lateral & dorsal) Histology: dorsal muscle, kidney, liver, spleen, intestine, gills, heart

6. 6 Safety Margin (IV): Why? What can we learn out of it? – Difference in sensitivity between 4 species – Effect of field strength on effects (injury/mortality) – Effect of frequency on effects (injury/mortality) – Kind of injuries function of frequency? – Is there a ‘safe’ range of pulse parameters in which we can apply pulses in justifiable way? – Pulses of Hovercran/Pulskor/Pulswing in safe zone?

7. 7 Content ‘Safe Zone’ for a selection of marine species – Determine the injury dose (ID 50) – Determine the lethal dose (LD 50) Optimalisation of startle pulse for sole – At ≠ frequencies, field strengths, waveforms, wavelengths, pulse types Effect of startle pulse for sole on marine species Effect of electrical pulses on fish quality

8. 8 Startle Pulse for Sole: idea 25 % of sole jumps out of sediment during exposure to startle pulse for shrimp (Chiers et al., 2011) Is there a ‘safe’ startle pulse that makes the majority of the sole jump out of the sediment ? Varying different parameters: frequency, field strength, pulse form, pulse duration, pulse type Chiers et al., 2011, ‘Short-term effects of low frequency pulsed direct current on captive-housed sea fish’, submitted

9. 9 Startle Pulse for Sole: parameters Frequency: Field strength: Pulse form: Pulse duration: 0,1 to 0,5 ms Pulse type: Time of exposure: 1 to 2 s Within Safety Margins

10. 10 Startle Pulse for Sole: how? Video tracking of reaction during exposure at specific pulse, quantification & comparison Parameter Effect score (A) Weight (B) Total (T) 321= A x B 1. Hight upbove bottom (cm) > 155 - 15< 53T1T1 2. Swimming speed (% of max) < 7525 - 50< 251T2T2 3. Recovery time (s) > 33 - 1< 12T3T3 TOTAL “EFFECT NUMBER” (= assesment number of observed startle response) T 1 + T 2 + T 3

11. 11 Content ‘Safe Zone’ for a selection of marine species – Determine the injury dose (ID 50) – Determine the lethal dose (LD 50) Optimalisation of startle pulse for sole – At ≠ frequency, field strength, waveform, wavelength, pulse type Effect of startle pulse for sole on marine species Effect of electrical pulses on fish quality

12. 12 Startle Pulse for Sole: Effects Video tracking of reaction after exposure at optimal sole startle pulse – Feeding response – Behavior Euthanasia & autopsy (cfr ID & LD): – Macroscopic – Rontgen photos – Histology sole & cod shrimp & sandworm

13. 13 Content ‘Safe Zone’ for a selection of marine species – Determine the injury dose (ID 50) – Determine the lethal dose (LD 50) Optimalisation of startle pulse for sole – At ≠ frequency, field strength, waveform, wavelength, pulse type Effect of startle pulse for sole on marine species Effect of pulses on fish quality

14. 14 Effect of pulses on fish quality Is there an effect on the sole quality? ≠ in appearance? Pulse fisherman is getting a better price: why? What/how big is the difference with beam trawl? ≠ in filet quality? Do electric pulses have an effect on fish decay? (QIM) f.e. faster or slower decay ≠ in filet taste?

15. Institute for Agricultural and Fisheries Research www.ilvo.vlaanderen.be Agriculture and Fisheries Policy Area Institute for Agricultural and Fisheries Research Thanks for your attention! Questions?