JO*4
f OR TORSK
ELECTRICAL TRAWLING FOR BROWN SHRIMP'
ARFAÇ
Department of Morphology, Faculty of Veterinary Medicine, Ghent University,
Salisburylaan 133, 9820 Merelbeke, Belgium
2 Institute fo r Agricultural and Fisheries Research (ILVO), Animal Sciences - Fisheries,
Ankerstraat 1, 8400 Oostende, Belgium
3 Departm ent of Pathology, Bacteriology & Poultry Diseases, Faculty of Veterinary
Medicine , Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
4 Department of Comparative physiology and biometrics, Faculty of Veterinary
Medicine, Ghent University, Salisburylaan 133 , 9820 Merelbeke, Belgium
5The Norwegian Institute of Food, Fisheries and Aquaculture Research
(NOFIMA), Muninbakken 9-13, 9291 Troms0, Norway
\-Jk A Q U A
«HS E X C E L
IMPACT ON YOUNG LIFE STAGES
IN NURSERIES & SPAWNING
Desender Marieke1'2, Chiers Koen3, Verschueren Bart2, Polet
Hans2, Duchateau Luc4, Velmurugu Puvanendran5
Mortensen Atle5, Decostere Annemie1
o f i m ai
■ e u r o p a s f i s h e r ie s f u k u ]
f
c
f
t
t
S
T
M
E
N
fI
N
I M
l
%
T
A
J
f
A
A
I
I
iI M
Ü
M
In
i
l
S
vTtvo
mm
INTRODUCTION
THE FACULTY HAS BEEN
Catching shrimp without touching the
seafloor by electrical stimulation results in:
Discard reduction 65%
Less bottom contact 80%
No immediate effects on
adult fish!
fÆ
ounger life stages?
,
5-10
10-15
15-25
25-50
50-100
100-200
>200 V/m
Simulation electrical field
RESULTS
EMBRYONATED EGG STAGES
Survival Stage
■Exposed
■Control
0
0
Survival Stage
£ 60
o
5
10
25
No significant difference
in survival over all egg stages
No significant difference in
Hatching rate between control
and exposed groups
Survival Stage
A
50
5
10
o
10
15
20
Cod (Gadus morhua)
eggs, larvae and
juveniles
Expose for 5 seconds
to 150V/m
Count survival after
1 week
0
0
MATERIAL & METHODS
25
Day 0
Fertilisation
1DPF
Early cleavage
5DPF
Epiboly
Days after exposure
Days after exposure
LARVAL & JUVENILE STAGES
Survival larvae & juvenile stages
r ------------- \
li
Developmental stage
Handling effect of stage
Mortality is significantly higher
in the exogenous stage
(OR 1.94 p<0.0014)
No difference in survival
between exposed and control
groups in the other larval
stages or the juvenile stage
Sample during
further
development
TPIate shaped Electrodes
creating a homogeneous
electrical field of 150V/m
'S! Development of cod
18DPF
Heart is beating, eyes
are pigmented
hatch
500pm
'*ts
Feeding on
rotifers but the
yolk is still
present
REPEAT THIS EXPERIMENT
ON SOLE (Solea solea)
A flatfish with a special
metamorphosis
4000pm
»
.
f
«
V
No yolk, need to
chase prey
2000pm
Development of 3
dorsal fins, digestive
T
Feeding on
the yolk
V
After 4 Years
Adult
rd
Morphological analysis:
Differences in yolk resorption,
length, g ro w th ,...
Deformations
Organogenesis
fertilisation
FUTURE RESEARCH
THE EXOGENOUS LARVAL STAGE
Development
germ layers
1000pm