Pike-perch by linzhengnd

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									        TECHNOLOGY FOR ARTIFICIAL SPAWNING OF
     STIZOSTEDION 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.
          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
•   Installation consists of following subassemblies:
•   overall preparedness hatching;
•   installation of water supply for hatcheries;
•   hatchery;
•   support for hatcheries;
•   installation for water discharge.
•   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
    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.
                  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.
• 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.
• 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
    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
    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
    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
    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.

								
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