DOCUMENTATION OF TECHNOLOGICAL TRANSFER OF TECHNOLOGY
FOR ARTIFICIAL SPAWNING OF ESOX LUCIUS SPECIES – PIKE
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TECHNOLOGY DISPLAY
Object
The elaborated technology is after controlled spawning of Esox lucius –
pike, 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.
TECHNICAL CONDITIONS OF APPLYING TECHNOLOGY
2.1 Technological system for artificial spawning of Esox lucius
• Technological system for artificial spawning must include the following
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buildings, installations and facilities:
ponds for pre-maturation;
ponds for maturation;
station for incubation;
Such constructions are recommended to be located as close to one another
in order to enable fast evolve of works.
Technological system will be apportion depending on production capacity
agreed by costumer, and will ensure by its capacity the spawning of
minimum 50 families, in order to insure maintenance and conservation of
genetic biodiversity of species.
Ponds for pre-maturation (Fig. 1) are intended for standing pike breeders in
the period November – March.
• These are earthen ponds made
by digging, usually have
rectangular form, surface of
1000 – 2000 m2, maximum
3000 m2, depth of 2.0 m and
flow of water supply 3 – 5
l/sec/ha.
• Ponds for maturation used
for standing of breeders after
administration pituitary
injection are build on Earth
made in cut and have surface
of 20 – 30 m2 and depth of 1
m (Fig. 2).
• Station for hatching is so constracted
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that can ensure a constant temperature and
can be adjusted and used to reproduce
several species of fish. Construction
dimensions are determined by the number
and type of hatcheries and by the size of
tanks used to rearing larvae. Usual length
of hatching hall is 40 – 50 m and width is
10 – 12 m.
Small laboratory;
Platform for carrying out work on the
collection of sexual products and
fertilization;
Devices for hatching;
Modules for standing, maturation of
breeders;
Tanks for standing and rearing larvae;
System for supplying, distributing, adjusting
and discharging technological water.
• Device for hatching pike eggs is aimed
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to achieving some optimum conditions for
hatch and rearing larvae during
postembryonic development.
System consists of two concrete tanks
located in a pilot station provided with
pipeline network for supplying,
distributing and discharging technological
water, platform for apportion and
fertilization of eggs, support frames for
hatching eggs, modules for antifungal
treatment of eggs.
Concrete tanks have a useful volume of
120 m3 and dimensions of 30 × 4 × 1.2
m (Fig. 6). These are supplied with pond
water through lateral pipelines with a
diameter of 100 mm on which are fitted
as many as 7 taps. The maximum flow
rate provided by the 7 taps on each pipe
is about 70 l/min, generally working flow
rates being smaller (50 l/min).
• Support frames for
hatching pike eggs (Fig. 9).
This type of frame is like a box
opened at the top, having the
dimensions of 34 × 40 cm,
margins of 5 – 6 cm, made of
wood from brad. On the long
side present a slot with
dimensions of 10 – 15 cm
which allow to eliminate the
excess of spermatozoids and
after hatch allow larvae to
escape in the concrete tank
where they will start rearing
cycle.
DESCRIPTION OF TECHNOLOGY
• The technology for artificial breeding and rearing of Esox lucius
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larvae imply the passing through of following phases:
Assurance of breeders stock;
Evaluation of phenotypic characters and sex determination;
Standing, pre-maturation of breeders;
Assessment of reproductive condition
Induction of sexual cells maturation;
Gathering sexual products;
Fecundation;
Incubation of sexual products in special installed enclosures;
Sacking and transportation of larvae;
Rearing larvae up on achieving adult-like phenotypic characters;
Bagging and transportation of fry.
Assurance of breeders stock
• Having regard to the fact that pike reproducing early spring, when
water temperature is of 8 – 10 0C, breeders are separated by sex
and standing in ponds of pre-maturation on fishing in autumn,
such as wintering coincides with pre-maturation time.
• Stoking density on pre-maturation ponds is of 500 – 600 ex/ha.
• Pike breeders will be examined immediately after fishing for
evaluation of phenotypic characters and determination of sex.
Breeders with length of 50 – 60 cm and width of 1.5 – 2 kg are
selected. Fish hit or affected by parasitic or infectious diseases are
not accepted.
Maturation of breeders
• At the end of winter – usually in early March, when water
temperature reaches 5 – 6 0C, breeders are transferred in
maturation ponds separated by sex, in which is ensure continuous
stream of water.
Hormonal induction
• Is accomplish when water temperature is situated around the value
of 10 0C. For hormonal induction will be used extract of carp
pituitary. Females are induced to spawn with 3.5 – 4 mg/kg of body
weight, depending on maturation stage, and for males is
administered 1.5 – 2 mg/kg of body weight.
• Gathering sexual produces is accomplished after about 72 hours.
Gathering eggs and artificial fertilization
• Gathering eggs is made from
perfect sexually matured
females. At the time harvesting
eggs, the fish is hold by rolling
up with a towel of mull around
the head and tail, is hold by
head with left hand in position
with tail down so that by
gently palpation of abdomen,
eggs to fall in jar prepared
(Fig. 10).
• Sperm is milks directly on the
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eggs or pipette (using the same
type of pipette as for carp
fertilization) and then doped on
the eggs.
Hatch on frames in tank for
postembryonic rearing.
Comparatively with classic
technology in which pike eggs
were subjected to operation of
desizing and incubation in ZugWeiss hatcheries, at CCDP Nucet,
it has develop a more efficient
method for incubating eggs, on
frames, in tanks where is also
accomplished postembryonic
development after hatching time.
Rearing larvae
• In the first stage of development, larvae can be reared
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inside of hatching station, in special tanks for
postembryonic development with following sizes: 30 × 4
× 1 m. Tanks are provided with an enclosure of filtering
to the discharging side to prevent escape of larvae or
fries.
Water supply is made gravitationally from subsiding tank
where filters are fixed on each column that filling
spawning stations.