Institute for Agricultural and Fisheries Research
SG Electra
Presentation PhD-research
Drs. Ir Maarten Soetaert
UGhent - ILVO
Institute for Agricultural and Fisheries Research
www.ilvo.vlaanderen.be
Agriculture and Fisheries Policy Area
Content
• ‘Safety Margin’ for a selection of marine species
– Determine the injury dose (ID50)
– Determine the lethal dose (LD10)
• 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
2
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
vertebrate
invertebrate
• Starting from startle pulse for Crangon crangon
• At 50 & 100 V/m: 5 Hz → 180 Hz
3
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
Logistic Regression (example)
100%
In this example:
ID25 = 25Hz
LD50 = 45 Hz
75%
# with injuries
# mortalities
50%
25%
0%
0
20
40
60
Frequency (Hz)
80
4
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
5
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?
6
Content
• ‘Safe Zone’ for a selection of marine species
– Determine the injury dose (ID50)
– Determine the lethal dose (LD50)
• 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
7
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
8
Startle Pulse for Sole: parameters
• Frequency:
Within Safety Margins
• Field strength:
• Pulse form:
• Pulse duration: 0,1 to 0,5 ms
• Pulse type:
• Time of exposure: 1 to 2 s
9
Startle Pulse for Sole: how?
• Video tracking of reaction during exposure at
specific pulse, quantification & comparison
Parameter
Effect score (A)
Weight
Total (T)
2
1
(B)
=AxB
5 - 15
<5
3
T1
25 - 50
< 25
1
T2
3-1
<1
2
T3
3
1. Hight upbove
bottom (cm)
> 15
2. Swimming
speed (% of max)
< 75
3. Recovery time(s) > 3
TOTAL “EFFECT NUMBER”
(= assesment number of observed startle response)
T1 + T2 + T3
10
Content
• ‘Safe Zone’ for a selection of marine species
– Determine the injury dose (ID50)
– Determine the lethal dose (LD50)
• 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
11
Startle Pulse for Sole: Effects
• Video tracking of reaction after exposure at
optimal sole startle pulse
– Feeding response
– Behavior
sole & cod
• Euthanasia & autopsy (cfr ID & LD):
– Macroscopic
– Rontgen photos
sole & cod
shrimp & sandworm
– Histology
12
Content
• ‘Safe Zone’ for a selection of marine species
– Determine the injury dose (ID50)
– Determine the lethal dose (LD50)
• 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
13
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?
14
Institute for Agricultural and Fisheries Research
Thanks for your attention!
Questions?
Institute for Agricultural and Fisheries Research
www.ilvo.vlaanderen.be
Agriculture and Fisheries Policy Area