This document discusses techniques for induced breeding of carp species in hatcheries. It describes the collection of pituitary glands from brood fish and injection of hormones like HCG to stimulate breeding. After conditioning, brood fish are weighed and injected, then placed in hapas or tanks. Water temperature between 25-28°C and oxygen levels of 5-9 mg/L promote successful spawning. Eggs are incubated in glass jars or Chinese circular hatcheries consisting of overhead tanks, spawning tanks, incubation tanks, and receiving tanks, and fry are reared in earthen ponds.
2. INTRODUCTION
The commonly cultivated six species - Catla (Catla catla)
Rohu (Labeo rohita), Mrigal (Cirrhinus mrigala) Silver
carp (Hypothalmichthys molitrix), Grass carp
(Ctenopharyngodon idella) and Common carp (Cyprinus
carpio) are considered to be the best cultivable species
of fishes in the inland water system. These fishes
originally belong to riverine environment and when
cultured in standing water bodies such as ponds and
tanks, they attain maturity but normally do not breed
under confined conditions. Special attempts are
therefore made to breed them by artificially creating
riverine conditions and stimulating there endocrine
system.
3. The technique of breeding fish by other than its
natural course is known as INDUCED BREEDING.
Induced breeding techniques has been developed for
production of quality fish seed of cultivable
varieties. It is one of the most dependable methods
of producing pure seed of desired species of fish.
Further this technique has helped to produce fish
seed in those areas where natural collection of fish
seed was not possible.
4. METHOD OF INDUCED BREEDING:
HYPOPHYSATION
The technique of breeding the fish by administering
pituitary gland extract injection is known as induced
breeding or hypophysation. The pituitary gland secretes
several hormones of which Gonadotropin is the most
important for breeding.
The increasing demand of fish pituitaries have now
been solved to some extent by the introduction of
HCG, now readily available in the market. The HCG is
now increasingly becoming popular due to its low
cost. A mixture of HCG and pituitary hormone
extract in definite proportion are employed
successfully for breeding fish.
5. COLLECTION OF PITUITARY GLAND:
Glands are collected from ripe fish by removing the
upper part of the skull (scalp) by a sharp knife or a bone
cutter. After removing the scalp, the brain is exposed
which is then cut from the posterior end and lifted up
anteriorly. As soon as the brain is lifted the gland can be
seen located in the cavity covered by a thin membrane.
It is carefully picked up with the help of tweezers and
kept immersed in a cavity block or a Petri dish in
absolute alcohol under cover.
6. BREEDING TECHNIQUES:
After selection of brood fishes from the segregated
brooder ponds they are kept in the hapas at fish
farms or in fish seed hatcheries for about 6-7 hours
for conditioning. After proper conditioning the
individual brood fish is weighed in a hand net using
a spring balance. The breeders are then ready to
receive injection.
7. BREEDING ENVIRONMENT :
Success of spawning by hypophysation depends on
the hydrological and climatic conditions.
Temperature is one of the most important factors. It
has been observed that 250-280C is most conducive
for breeding. However, spawning could be induced
at or below this temperature range. The percentage
of fertilization and hatching under uncontrolled
conditions is not very satisfactory. Circulation of
fresh water containing 5-9 mg/liters of oxygen
promotes better success in spawning, higher
fertilization of eggs and higher recovery of
hatchlings from fertilized eggs.
9. THE GLASS JAR HATCHERY COMPLEX IS A SELF
CONTAINED UNIT , CONSISTS OF….
1. WATER SUPPLY SYSTEM
In order to supply water to the hatchery unit an over-
head tank connected with the G.I. Pipe line with a water
capacity of 5500 lit. The height of the OHT is 4mt. From
the ground level for supplying water through gravity to
hatchery unit.
10. 2. BREEDING TANK
A breeding tank of 2.0 X 1.0 X 1.o m in dimensions
provided with shower and outlet to drain excess water.
The no. of breeding tanks depends on target seed
production.
11. 3. GLASS JAR INCUBATORS
The incubators are made of good quality transparent
glass and jars is set up vertically on the wooden table.
The jars are conical in shape being open at the top and
gradually tapering towards the bottom.
The capacity of each jars is 6.35 lit.
Top of the jar is fitted with a G.I. rings having a beak
which serve as an outlet for water coming out from the
jars.
At end jars connected with rubber tubing's.
12. 4. THE SPAWNERY
The spawnery is a hapa of synthetic materials which is
fitted on a frame placed inside a cement cistan.
An Over head shower is provided from the above to
spray water over the developing hatching in the hapa.
A cement cistan of the size 1.8 X 0.9 X 0.9 m which can
accommodate about 10 lacs of spawn for 3 days..
16. CHINESE HATCHERY :-
It is also known as Eco-Hatchery or Circular Hatchery.
The hatchery complex consists of an
1. Over head tank,
2. Spawning tank,
3. Incubation tank &
4. Spawn receiving tank.