TECHNOLOGY FOR ARTIFICIAL SPAWNING OF STIZOSTEDION LUCIOPERCA SPECIES

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TECHNOLOGY FOR ARTIFICIAL SPAWNING
OFSTIZOSTEDION LUCIOPERCA SPECIES PIKEPERCH

• 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.

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Technological system for artificial spawning
ofStizostedion 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.

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• 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).

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• 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
• 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.

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• The module for standing of breeders is used for
  breeders during the period before spawning.
• Composition of unit for standing of breeders
• The module consists of the following major
  sub-assemblies
• parallelepipedous tank with useful volume of 4.0
  m3
• installation of discharge and adjustment of water
  level
• installation of water supply.

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DESCRIPTION OF TECHNOLOGY

• The technology for controlled-artificial spawning
  and 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.

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• Assurance of breeders stock.
• Pikeperch breeders needed for stations of
  production and rearing of fry 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.

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• 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.

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• Spawning
• Spawning takes place in the 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.

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• Females under the II and III maturation stage are
  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.

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• Fertilization
• Eggs gather from a single female 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.

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• Incubation of eggs
• Incubation of eggs will start with introduction
  and attach of frames in the 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.