TECHNOLOGY FOR ARTIFICIAL SPAWNING OF
STIZOSTEDION LUCIOPERCA SPECIES – PIKEPERCH
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TECHNOLOGY DISPLAY
Object
The elaborated technology is after controlled spawning
of Stizostedion lucioperca – pikeperch, towards
redressing its natural populations and inserting it on
aquaculture.
Area of implementation
Implicit costumers of spawning technology are
economical agents that have the main activity fishing
and aquaculture.
Technological system for artificial spawning of
Stizostedion lucioperca – pikeperch
• In correlation with capacity for incubation, technological system will
be constituted by an assembly of earthen ponds: wintering ponds,
standing-wintering ponds, standing-maturation ponds, controlled
spawning ponds, modules for standing and maturation of breeders,
modules for incubation of embrionated eggs and for standing larvae.
• Spawning ponds. These are small surface ponds (0.25 – 0.5 ha),
with continuously supply and discharge of water, hard bottom and
water depth of 0.70 – 0.90 m, rarely 1 – 1.2 m. In these ponds are
fixed pallets (nests) on which breeders will spawn.
• Fixing pallets on spawning
pond is carried out 2 – 3 m
from bank (in order to
observe the moment of
spawning) and the distance
between pallets on the side
of pond is of 8 – 10 m (Fig.
1).
• The installation for incubation of pikeperch eggs is aimed at
achieving optimum condition for incubation of eggs. Is assured
water supply, maintenance of a optimum depth, treatment of eggs
and discharge water individualized from each hatchery.
• Installation constituent
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Installation consists of following subassemblies:
overall preparedness hatching;
installation of water supply for hatcheries;
hatchery;
support for hatcheries;
installation for water discharge.
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Overall preparedness
hatching
Consists of:
installation for technological
water supply;
trays for fertilization;
support frames for eggs;
platform support.
Nucet type hatchery use for
incubation of pikeperch
eggs
Nucet type hatchery is made up
of a metal box with dimensions
60 × 60 × 55 cm in which
introduces a cage made of
Nytal bolt having mesh size of
200 μm and dimensions of 52 ×
52 × 46 cm. Hatchery has a
volume of 180 l and a
maximum incubation capacity
of 1.5 kg of eggs.
• The module for standing of
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breeders is used for breeders
during the period before
spawning.
Composition of unit for
standing of breeders
The module consists of the
following major subassemblies:
parallelepipedous tank with
useful volume of 4.0 m3;
installation of discharge and
adjustment of water level;
installation of water supply.
DESCRIPTION OF TECHNOLOGY
• The technology for controlled-artificial spawning and
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rearing of larvae of Stizostedion lucioperca species
involves travel along following phases:
Assurance of breeders stock;
Evaluation of phenotypic characters and sex
determination;
Standing, pre-maturation of breeders;
Assessment of reproductive condition;
Placing breeders in spawning ponds;
Spawning;
Sampling the pallets;
Incubation of sexual products in specially prepared
enclosures;
Packing and transportation of fry.
• Assurance of breeders stock.
• Pikeperch breeders needed for stations of production and rearing of fry
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come both in natural environments, by catching them in early spring, and
stocks reared in farms especially for this goal.
Preliminary evaluation of breeders
Pikeperch breeders will be assessed immediately after catch for evaluation
of phenotypic characters and determination of sex. Selected breeders have
length of 30 – 50 cm and weight of 1.0 – 3.0 kg.
Breeders must display body integrity, biological qualities and a good
physiological shape.
Assessment of reproductive condition
The method of assessing both the maturation stage and polarity factor
involves collecting a minimum of 5 eggs from posterior part of ovary by
practicing a puncture.
For determination of nucleus or germinal vesicle position, ova will be cut-off
exactly along the axis of animal-vegetal pole. After this operation, nucleus
position will be observed and evaluated.
For determining the polarity factor measured under the stereoscope
distance from the top of germinal vesicle to animal pole and the distance
from animal pole to vegetal pole.
Small values of the coefficient indicated a high degree of polarization for
ova so an advanced stage IV of maturation.
• After evaluating reproductive
condition, females who are in
advanced maturing stage are
selected and populated in
spawning pond, in which are
fixed the pallets. In the pond are
also populated the males that
release a few drops of sperm on
a slight palpation of abdomen. In
a pond of a hectare are release
10 – 12 females and as many
males. The batch has to be more
uniform choosing breeders of
close size.
• Spawning;
• Spawning takes place in the
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early hours of sunny mornings.
The nests with eggs are getting
away from the spawning pond
on the bank, carefully detached
from the pallets and are
carrying in barrows with water
to the spawning station (Fig.
7).
Incubation pikeperch eggs.
The nests with pikeperch eggs
are placed carefully in Nytal
cages from Nucet hatcheries
and ensure continuously water
supply to a flow of 8 l/min.
• Females under the II and III maturation stage are
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hormonal stimulated and spawned artificially
Hormonal stimulation
For hormonal stimulation of pikeperch will be used pituitary extract
of carp. Females are stimulated with 5 – 15 mg/kg of body weight
depending on maturation stage and for males are used 3 – 5 mg/kg
of body weight.
Injection is carried out either in dorsal muscle either on the base of
pectoral fin. After injection, breeders separated on sex are placed in
tanks for maturation on hatchery station. Ovulation can be achieved
after about 48 hours from injection.
Gathering eggs and artificial fertilization. Gathering eggs is
done in females perfectly mature by slightly palpation of abdomen.
From a pikeperch female is gathering a quantity of eggs between
150 and 200 ml.
• Fertilization
• Eggs gather from a single female
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are fertilized individually with a
mixture of sperm from 5 – 6
males. Quantity of sperm used is
2 ml for a portion of 200 ml of
eggs.
The mixture is homogenized then
adds the fertilizer liquid. Time for
fecundation is about 3 – 5
minutes. After passing the three
minutes, eggs are spread on
support frames of Nytal.
• Incubation of eggs
• Incubation of eggs will start with introduction and attach of frames in the
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Nucet hatcheries. Duration of hatching is variable depending on daily mean
temperature: 11 days at 13 0C, 4 – 5 days at temperature of 14 – 15 0C.
For pikeperch, optimal temperature for incubation is 15 0C. Mean duration
of embryogenesis on these values of water temperature is about 5 – 6
days.
The flow of water supply on hatcheries up to gastrulating stage of eggs will
be adjusted for such a way as to create a stream of water that does not
produce displacement of eggs from the frames (3 – 4 l/min). After
gastrulating, the hatchery is increasing the volume of water higher (5 – 7
l/min). During embryogenesis, oxygen level in enclosures of incubation will
be maintained at the minimum values of 5 – 6 mg/l.
Control mould during incubation time will be achieved by bathing eggs with
formalin solution for 15 minutes. The first treatment will be achieved in 24
hours from fertilization, and following at intervals of 12 hours until the
appearance of ocular vesicles.
After hatch, frames out of hatchery, and larvae are kept in hatcheries until
resorption of yolk.