fish hatcheries and its types, different types of hatcheries

Introduction
Needfor hatchery
Roleof hatchery
The various essential componentsof a hatchery
Traditional hatcheries
Modernhatcheries
Planningof hatcheries construction site selection
Essential componentsof hatchery complex
Conclusion
Reference
SYNOPSIS

INTRODUCTION
A hatchery is the most vital component in modern
carp farming. Hatcheries are natural or artificial
confinements used for breeding and hatching the
eggs. Some authors consider the term hatchery in its
enlarged sense as a facility right from fish spawning
to producing fish finger lings for stocking in grow
out ponds ,fish fattening and rearing of brood stock.
But hatchery is indoor facility for fish spawning, egg
incubation, hatching and rearing the hatchings to
spawnstage.

In earlier days availability of fish seed was entirely dependent on wild
catch from rivers and large reservoirs during rainy season, which was
accomplished by several problems and in present time
Quantity of seed is collected from the reveries source is very low .
Fish farmer had to depend only on natural water bodies for their
seed requirements.
Seed they collected constituted mixed variety of different species.
Due to lake of knowledge they reared mixed variety which resulted in
less survival rate.
During the transportation of seed there occurred high mortality of
seed
Thus for these reasons, hatchery construction is so necessary to
overcome such problems and to obtain max quantity of seed in proper
condition.
NEED FOR HATCHERY

ROLE OF HATCHERY
The role of hatchery is vital and it has infect augmented the production of fish seed and
created environment to enable to produce any quality and quantity of seed. State federal
hatcheries are expected to become increasingly important as tools to preserve
biodiversity by maintaining rare,threaded andendangered genotypes.
ESSENTIAL COMPONENTS OF A HATCHERY
Brood fish pond to hold adult fish for spawning donors of pituitary gland and to
accommodate spent male and female fishes.
Nursery ponds for rearinglarvae to fry stage.
Rearing ponds for growing fry to fingerlings.
Ponds for production of fish to supply brood fish ponds and donors of pituitary
glands.

TRADITIONAL HATCHERY
EarthenHatchingPits
The earliest device for hatching carp eggs was the earthen hatching pits employed by the crap breeders. There
are specially designed pit of 3*2*1 dimension. Pits are dug in several rows and the inner walls are plastered
with mud i.e. red soil. The fertilized eggs collected from bund types of tanks are put in to the hatching pits.
Approximately 36000 to 400000 eggs per pit are kept and hatching takes place in about 24 hours. A constant
flow of water is maintained to ensureproperaeration and to reducetheaccumulation of wastes. Afterabout 3
days,when theyolksacistheabsorbedtheavailablespawniscollectedwith a pieceof cloth and istransferred
tonurseries.
EarthenPot Hatchery
This is one of the earlier method adopted for better hatching rates. The fertilized eggs are collected from the
bund and are kept in a number of locally made earthen pots arranged in a particular way , and this furnishes a
flowing current of water, cooled by surface evaporation of the porous earthen pots which the crap eggs
hatched. In this method to some extent the fluctuations of temperature and pH are moderated baked clay,
vessels thoughcheap,easily replaceableandporoushavethedisadvantageof beingopaque.

Earthen Hatching Pits
Earthen Pot Hatchery

•Double Cloth hatching Hapa
It was stated in 1976,in this method there are two rectangular hapas, called outer hapa and inner
hapa. The outer hapa has a size of 2m*1m*1m and the inner hapa of size 1.75m*0.75m*0.5m. the
outer hapa is made of close meshed cotton cloth (4060/mch) and the inner hapa is made of round
mesh mosquito netting cloth. The depth of water maintained in the inner hapa is around 30cm. the
number of gees put for hatching normally is 75000 to 100000 the hatching moves through the mesh
into the outer hapa and after that the inner hatching hapa is removed along with eggs shells and the
spoiled eggs. The hatching in the outer hapa are kept for a period of 48 hour (2to3 days) till the yolk
sacis absorbed.
•Floating Hapa
Floating hapa method is the improved one, in this hapa is mounted on the frames which are made by
joining polytheneoraluminium pipes.Floatsareaddedtofacilitatefloating.

Double Cloth hatching Hapa
Floating Hapa

VERTICAL HATCHERY
GLASS JAR HATCHERIES
istheIndia’sfirsteverhatchery in which thedeveloping eggs can bewatchedin transparentat eyelevel. It
hasa breeding tank, incubation and hatchery unit and spawnery. A fresh water pond or bore well is used
asa water source. Over head tanks with 5500 litters capacity in all are placed connected to hatchery. This
unit consist of a battery of cylindrical shaped glass jar with conical bottom having 6.35 litter capacity.
About50000eggs arehatchedin a single jar.
PLASTIC BUCKET HATCHERY
Plastic hatchery is made of two parts. One is the outer plastic bucket with perforated aluminium bin egg
vessel and other part is galvanized iron sheet spawnery. The plastic bucket having 3 out lets at the top,
theheight is47cmandthediameteris30 cm.waterholding capacityis 45litters.
MODERN HATCHERY

GLASS JAR HATCHERIES
PLASTIC BUCKET HATCHERY

CIRCULAR HATCHERY
Modern carp hatchery CIEF D-80 model
In the year modern crap hatchery CIEF D-80 model was designed. This modern crap hatchery is named
after the name of Ex. Director of CIEF, Dr. S.K. Dwivedi. In this model the efforts have been made to
control the environment parameters like temperature, oxygen, silt, water flow and space for movement
of eggs. The hatchery consist of overhead tank as a source of water supply, cooling tower, hatchery
section, compressor for aeration, vertical hatchery jar, PVC pipes, valves, showers, channels, hatchery
stands and hapas. This type of hatchery has two parts one is incubation tank and the other is egg
collection tank. He is a vertical jar complex of four units, have six funnels. The total capacity of the
hatcherycompleteis50 lakheggs ata time.
Modern Carp Hatchery CIFE D-81 Model
This was the developed in 1981 at CIEF. It is an improved version of crap hatchery Model D-80 and the
entire system works on the principle of D-80. This model D-81 consist of breeding and hatching units
withimprovedwatersprayarrangementsandensuring moreeffectiveaeration.

Operation
Beforeloading of eggswaterisfilledin jarsfromoverhead tank.Theflowof waterisregulated2-3 lit
/jars/min. Eggs are containers are placed in the jar and the aeration is arranged. Eggs are loaded as
per capacity. Once hatching completed flow of water is increased for speedy transfer of hatchings
are transferred in spawnery, the over flowing from jar is stopped. Spray and aeration in spawnery is
keptunderoperationtill yolksacisabsorbed.
Modern Carp Hatchery CIFE D-82 to 85 model
This is a commercial system and workson the principle ofD-81.The main parts of hatcheryare over
head tank, jars, pipelines egg containers spawn collection tank and aeration system. The models are
D-82toD-85and thehatcheryisoperatedin thesamewayasin caseofCIFE D-81model.

CHINESE HATCHERY
The modern eco-hatchery or Chinese hatchery comprises of the
following components:
Overhead tank.
Spawning pool.
Egg collection chamber.
Incubation and hatchingchamber.
Spawn collecting chamber.

CONCLUSION
Quantity of seed is collected from the reveries source is very low
.
Fish farmer had to depend only on natural water bodies for their
seedrequirements.
Seed they collected constituted mixed variety of different
species.
Due to lake of knowledge they reared mixed variety which
resulted in less survival rate.
During the transportation of seed there occurred high mortality
of seed
Thus for these reasons, hatchery construction is so necessary to
overcome such problems and to obtain max quantity of seed in
proper condition.

FISH TRANSPORTATION
DRUGS
The drugs used in transport medium, aimed at
increasing the capacity volume of the transport units
and preventing physiological and health damage to
the fish, constitute an integral part of the complex
problem of fish transport.
They include the use of anaesthetics, water
hardening and oxygen-producing chemicals,
bacteriostatics, buffering and antifoam chemicals.

USE OF FISH TRANQUILIZERS
⚫ During transport, sedation of the fish is desirable, since
oxygen consumption and CO2 and NH3 production are
all decreased. However, deep sedation is undesirable
because the fish may fall to the bottom, pile up and
smother.
⚫ If pumps are used, the fish may be pulled into the
screen, the air may move the deeply sedated fish about
and cause a loss of scales.
⚫ It is best to sedate the fish in the holding facility for 30
min before loading and then to continue exposure to a
lower concentration of sedative during transport.

⚫ The use of anaesthetics should not be relied on for increased
load carrying capacity. Other methods are safer and
dependable.
⚫ The use of anaesthetics on food fish that will be consumed
soon after exposure is not legal. Consideration should always
be given to the legal status of a chemical and possible
consequences to the consumer.
⚫ Anaesthesia usually applies only to transported brood fish.
⚫ In practice, the fish are first tranquilized with the normal dose
and put into the transport tank, where original concentration is
diluted by 50 percent by adding the same amount of fresh
water. The brood fish will remain tranquillized well in that
diluted solution.

⚫ MS-222 is a very mild tranquilizer and fish easily recover
from its effects even after a long stupor.
⚫ MS-222 to water at the rate of 20 mg/l for carp and
grass carp, 10 mg/l for silver carp, and 35 mg/l for
bighead carp or sheatfish. At these concentrations the
fish can still hold their natural position but their
respiration and motility are significantly decreased.
⚫ When applying this anaesthetic, the mass of transported
fish in a unit volume can be increased by 50–150
percent, but it is best to test it before application.

⚫ Quinaldine (2–4 methylchinolin) is a toxic liquid and must,
therefore, be handled with care. The fish are usually treated
with it when they are held in a large volume of water, such as
a large tank.
⚫ Apart from these two tranquilizers, other drugs are to be
used. Phenoxyethanol is another chemical that has recently
come into use as a fish tranquilizer. It is milder and less
effective than MS-222, but it is far cheaper; 30–40 cm3 of
phenoxy-ethanol are mixed with 100 litres of water for the
treatment.

APPLICATION OF SODIUM CHLORIDE
AND CALCIUM CHLORIDE
⚫ Handling stress and delayed mortality of fish can be
decreased by the addition of sodium cloride (NaCl) and
calcium chloride (CaCl2) to the transport water.
⚫ The sodium ion tends to “harden” the fish and reduce slime
formation, and the calcium ion suppresses osmoregulatory
and metabolic disfunction.
⚫ Calcium chloride may not be needed in hard water already
containing high concentrations of calcium.
⚫ Recommended the addition of 0.1 to 0.3 percent salt and 50
mg/l calcium chloride.

⚫ Some of the fishes that tolerate wide ranges of salt in the
water, such as striped bass, tilapias, carp, can benefit from
as much as 0.5 percent salt.
⚫ Addition of 0.2 percent salt is recommended also by
Johnson (1979).

DRUGS AS OXYGEN SOURCES
⚫ Use of hydrogen peroxide on transported carp fry and
found that one drop (1 ml = 20 drops) of hydrogen
peroxide (6 percent concentration), applied to 1 litre of
water, increased the oxygen content by 1.5 mg/l when
the temperature was 24°C. CO2 content and water pH
were not influenced by the addition of hydrogen
peroxide.
⚫ Dissolved oxygen was measured by the Winkler
method.

BACTERIOSTATIC
CHEMICALS
⚫ Antibacterials are also used to check the
development of bacteria in transport units.
⚫ Antibacterials may strengthen the resistance of
fish, but they are probably of little value as
bacterial checks in transport tanks.
⚫ Rare exception would be in the case where a
superficial infection of an antibacterial-
susceptible bacterium was in progress.

BUFFERS
⚫ Among other chemical additives, buffers such as “tris-
buffer” (tris-hydroxylmethyl-amino methane) are helpful in
controlling pH at a favourable value of 7 to 8.
⚫ The accumulation of carbon dioxide in bag transport
allows for a decrease in pH, because carbon dioxide is an
acid.

AMMONIA CONTROL
⚫ To control ammonia concentration in the transport bags
when the transport is expected to be long, it is
recommended to use clinoptilolite, a zeolite mineral.
⚫ The doses of 10–40 g/l ; the concentration of non-
ionized ammonia nitrogen never exceeded 0.017 mg/l
in bags containing even the lowest dose of clinoptilolite,
whereas concentrations as high as 0.074 mg/l were
recorded in the control bags left without clinoptilolite.

Drug Name Dose
MS-222
20 mg/l for carp, grass carp<br>10 mg/l for silver
carp<br>35 mg/l for bighead carp or sheatfish
Phenoxyethanol
30–40 cm³ of phenoxyethanol mixed with 100 liters of
water for treatment
Sodium Chloride and Calcium Chloride 0.1 to 0.3 percent salt<br>50 mg/l calcium chloride
Hydrogen Peroxide 1.5 mg/l
Ammonia 10–40 g/l

VARIOUS DRUGS USED IN TRANSPORTATION
Fish Drug Common Name Typical Dose
Tranquilizers Tricaine methanesulfonate (MS-222) 50-100 mg/L
Antibiotics Erythromycin 10-50 mg/L
Tetracycline 5-10 mg/L
Enrofloxacin 2-5 mg/L
Antiparasitics Formalin 10-100 mg/L
Praziquantel 2-5 mg/L
Copper sulfate 0.1-1 mg/L
Potassium permanganate 1-2 mg/L
Anesthetics Benzocaine 10-20 mg/L
Lidocaine 5-10 mg/L
Propoxur 5-10 mg/L

DRUGS USED IN BREEDING
FINFISH & SHELLFISH

FISH BREEDING
To control In fish breeding, drugs are
sometimes used to induce spawning and
enhance reproductive success.
The use of drugs to enhance spawning and
reproductive success in fish breeding should be
done under the guidance of experts and in
accordance with applicable regulations. Here is
a general overview of how drugs can be used
to enhance spawning and reproductive
success:

In fish breeding, drugs are sometimes used to induce
spawning and enhance reproductive success. Here are a few
drugs commonly used in fish breeding:
Hormones
Hormones are often used to induce spawning in fish species
that do not naturally reproduce in captivity or to synchronize
the reproductive cycle of fish. Common hormone
preparations include synthetic versions of the naturally
occurring hormones such as gonadotropin-releasing hormone
analogs (GnRHa), luteinizing hormone-releasing hormone
analogs (LHRHa), and human chorionic gonadotropin (hCG)

Antibiotics
Antibiotics are used in fish farming to prevent and treat
bacterial infections. They are administered to fish through
medicated feed or by adding them to the water. Examples of
commonly used antibiotics include oxytetracycline, florfenicol,
and erythromycin.
Parasiticides
Parasiticides are drugs used to control and treat parasitic
infections in fish. They can be added to the water or applied
topically. Common parasiticides include formalin, malachite
green, and praziquantel.

Anesthetics: Anesthetics are used during fish handling and
surgery to minimize stress and pain. They are used to sedate or
immobilize fish temporarily. Commonly used fish anesthetics
include tricaine methanesulfonate (MS-222) and benzocaine.
It's important to note that the use of drugs in fish breeding
should be carried out under the guidance of a veterinarian or
fisheries professional to ensure proper dosages and minimize
any potential negative impacts on the fish and the environment.

VARIOUS DRUGS USED IN
BREEDING
Fish Drug Purpose Recommended Dose
Formalin Parasite control 25-50 mg/L for 1-2 hours
Malachite Green Fungal and external parasite control 0.2-0.5 mg/L for 1-2 hours
Methylene Blue Fungal infections, egg fungus 1-3 mg/L for 1-2 hours
Praziquantel Flukes and tapeworms 2 mg/L for 24 hours
Copper Sulfate Parasite control 0.2-0.5 mg/L for 24 hours
Acriflavine Bacterial and fungal infections 2-5 mg/L for 1-2 hours
Oxytetracycline Bacterial infections 10-50 mg/L for 5-7 days
Metronidazole
Protozoan and anaerobic bacterial
infections
100-200 mg/L for 5-7 days
Kanamycin Bacterial infections 50-100 mg/L for 5-7 days
Erythromycin Bacterial infections 50-100 mg/L for 5-7 days
Levamisole Internal parasite control 2 mg/L for 24 hours
Dimilin Gill flukes and anchor worms 2 mg/L for 24 hours
Salt External parasite control 1-3 grams/L (depending on species)
Hydrogen Peroxide External parasite control 10-100 mg/L for 5-30 minutes
Formaldehyde/Malachite Green
Combination
Parasite control
10 mg/L formaldehyde + 2 mg/L
malachite green for 1-2 hours

Fish brood stock management
and transportation of brood fish

Management of broodfish ponds
• Broodfish - prerequisite for all induced breeding programmes
• Good broodstock - better breeding responses, increased fecundity, fertilization,
hatching and larval survival rates and more viable fish seed
Carp broodfish pond:
• Carp broodstock ponds - large (0.2-2.5 ha), 1.5-2.5m deep, rectangular, seasonal
or drainable and earthen in nature
• Water inlet and outlet - simulate riverine/fluviatile conditions
INTRODUCTION

Source of broodfish:
• No reliable source
• Hence the source of future brood fish is stock ponds from the same farm or
different farms or live adult of different species procured from capture fishery
waters like rivers, lakes or reservoirs

Care of brood fish:
• Recommended stocking density of carp broodfish is 1,000-3,000 kg/ha
• While rohu and mrigal are stocked at a higher rate, catla is stocked at a lower rate
since it requires more space for proper gonadal development
• Stocking rates are manipulated to permit individual and collective care of broodfish,
enabling them to get nutritional and environmental advantages for onset of right
degree of maturity

• A gravid fish when held by hand with tail up should practically ooze milt and also
ova
• Carp broodfish fed with a traditional diet consisting of rice bran and oil cake (1:1)
at a feeding rate of 1-2% body weight daily
• In addition to the artificial feed the grass carp is also given tender aquatic
weeds/terrestrial grass.

• Common carp demand their separation from other carp species due to their
natural breeding in ponds with aquatic vegetation
• The common carp broodfish is segregated sex-wise and stocked in separate ponds
to prevent accidental spawning in pond
• Catla, in particular, needs to be separated from the rest of the species as it shows
poor response to hormonal injection when stocked with other species
• It is believed that catla broodfish need special care and diet such that deposition of
mesenteric fat in the maturation phase does not hinder gonadal development of
the species.

Broodstock management practice in Karnataka State
• Described by Basavaraja et al. (1999)
• The number and quality of eggs produced are significantly affected by the
conditions under which the broodstock is maintained
• The quality of broodstock diet, feeding regime, the quality of broodstock and water
management are the principal factors that influence the condition of the
broodstock
• Most seed farms raise broodstock in their own farm (there are instances of
inbreeding depression, as reported by Eknath and Doyle (1985) and maintain them
in ponds at a density of 1,000-2,500 kg/ha.

• The earthen broodstock ponds vary in area from 0.2 to 1.0 ha, with depth ranging
from 1 to 2 m
• The main basic steps in the preparation of broodstock ponds are :
– control of aquatic weeds, which in done manually;
– eradication of unwanted fish by applying mahua oilcake at 2,000-2,500 kg/ha
– pond liming at 100-200 kg/ha depending on the pH of soil and water

• Fertilizing the pond with cattle dung, at 15,000-20,000 kg/ha/yr or poultry manure
at 5,000-10,000 kg/ha/yr to enhance heterotrophic food production
• 200-400 kg/ha/yr NPK mixture is applied in split doses at fortnightly or monthly
intervals
• The initial dose of organic manure is reduced by half if mahua oil cake is used as
piscicide

• After stocking the pond with carps that are one-year-old or more, they are fed with
a conventional feed containing a mixture of groundnut oil cake and rice bran (1:1
or 1:2 ratio) at 1-2% b. w., once daily
• To ensure better and timely development of gonads, fish breeders use a special
broodstock diet (protein : 25-30%) prepared using locally available cheap
ingredients
• This diet is nutritionally superior, advances maturation and spawning by one or
two months and results in increased fecundity and better seed quality.

• This diet is given at 2% b.w. daily, starting in December
• At some farms about a third of the broodstock will be injected with a low dose of
HCG at 6-7 mg/kg body weight every 20 days, starting from mid-February for
advancing maturation so as to induce spawning by the end of May
Ingredients %
Rice bran 25
Groundnut oil cake 25
Fish meal 10
Maize 10
Broken rice 10
Horse gram 10
Blackgram 10
Table : Feed ingredients and their contribution to broodstock diet

• At some seed farms, a few vitamin E tablets are mixed, in the diet to facilitate
gonad development
• Algal blooms and oxygen depletion -common problems in broodstock ponds
• Overcome by frequent water exchange
• Infestation by Lernaea and Argulus on catla are common - manual removal of adult
specimens, followed by a dip treatment in a mild solution of potassium
permanganate
Lernaea Argulus

Transportation of broodfish
• Transport of bigger fingerlings/yearlings and broodfish in small packing containers-
not economically feasible
• Truck mounted open tanks with facilitates for mechanical aeration and/or
circulation were initially used quite successfully (Hora and Pillay, 1962; Mammen,
1962)

• Open canvas containers (1m x 1m x 1.25m) are used in Punjab and Madhya
Pradesh for transporting major carp breeders
• In those States galvanized iron drums of 180 l capacity are also used
• In India, two successful models of closed system of live-fish carrier were designed.
One is due to Mammen (1962), which he called `Splashless tank’.

• The later model of the splashless tank is of a petrol tanks design of 1,150 l capacity
with an autoclave-type lid
• It has a built-in aeration system for supplying compressed air, which works on a
belt driven by the engine of the transporting vehicle
• An oxygen cylinder is carried only as a stand by for emergency
• The inner surface of the tank is lined with U-foam which prevents physical injury to
live fish during transport
• A total weight of about 250 kg live fish can be transported at a time in the
splashless tank, as also 90,000 carp fingerlings
• The load ratio of fish to water in this type of carrier in about 1 kg of fish per 4.5 l
water

Fiberglass transport tank with four compartments, each with an electric aerator (arrow). Additional oxygen is provided through carbon
rods or micropore tubing on the bottom of the tank (Piper et al., 1982)
Installation of transport tanks on a truck. The transport capacity of the truck is about 8 000 litres; when the truck is combined with a trailer,
the volume of the fish tanks is about 15 000 litres

• Patro (1968) developed a tank which has an outer chamber of 120 cm diameter
open from top and a slightly smaller one closed from top; the latter, during
transport, fits inside the former
• The top of the inner chamber is provided with an air vent and an oxygen valve
• The outer chamber serves as a storage tank and is initially filled with water along
with fish to be transported
• The inner chamber, which is shipped from the upper open end of the water serves
as an oxygen holding chamber at its top and is lined throughout with U-foam to
prevent fish from sustaining injury during transport
• This double-barrel type carrier as stated by Patro can transport a total weight of
100 kg of live fish at a time

Multiple spawning
• Refers to spawning fish, female in particular, more than once in a season
• This is particularly important in carps as they have narrow captivity breeding
season and are difficult to bring them to maturity to maturity in captivity.
• Resulted in the successful spawning of major carps up to four times in a season

Factors that facilitate multiple spawning of carps are :
1. Manipulation of water quality
2. Manipulation of diet
3. Use of ready-to-inject spawning agents
4. Use of circular spawning and hatching tanks

Broodstock management
• Spent brooders of the previous season are preferred as initial broodfish for
multiple breeding.
• They are fed with a protein-rich diet, having a protein content of % and fat content
of %.
• Water exchange - 30-40% every month.
• Minimum handling of brooders.
• Disinfection of spent brooders
• Rearing of spent brooders with special care.

Schedule of multiple spawning:
First spawning (March-April) - Spawn yield :
Interval 40-45 days
Second spawning (May-June) – spawn yield :
Interval 40-45 days
Monsoon spawning (June-July) – Spawn yield :
Interval 40-45 days
Fourth spawning (August-September) – Spawn yield

Advantages of multiple spawning :
1. Increase period of seed availability, i.e. seed will be available over a longer period
2. Number of broodfish (female) to be maintained gets reduced
3. Seed production potential of the farm could be improved.
• Recent studies conducted at CIFA, Bhubaneswar show that rohu could be induced
bred even in the month of January

Distribution and importance:
• Groupers belong to the family Serranidae and Order Perciformes.
• Important species are Epinephelus tauvina and E. malabaricus.
• E. tauvina is found mainly in the east coast of India
• Can be cultured in brackishwater and marine waters.
• They are demersal, highly carnivorous and highly predatory, cannibalistic when
food is scarce.

• An important foodfish, commands high price (up to Rs. 400/- per kg)
• Suitable for culture in net cages as well as in ponds.
• Grows to 500- 800 g in 6 months, maximum size recorded is 100 cm.
• Spends the growing phase in shallow brackishwater, estuaries and rivers.

Identifying characters:
• Elongate and compressed body, with a deep caudal peduncle.
• Head is pointed with a concave dorsal profile , becoming convex in front of the
dorsal fin.
• Mouth large, slightly oblique and the lower edge of the pre-opercle is serrated,
with a strong spine.
• Adults are greenish or bluish above and silvery below.
• Eyes are bright pink, glowing at night.

Food and feeding:
• Highly predatory, feeding on small fish and crustaceans.
• Juveniles are omnivorous.
• Fry feed on zooplankton, while fingerlings prefer small crustaceans, worms,
mollusks, etc.

Breeding season:
• Spawning season is November – May.
• It migrates to deeper waters for breeding.
• Is a protogynous hermaphrodite (functions first as female and then turns to male
after spawning, i.e. natural sex-reversal).
• Fish in the weight range 2 – 3.5 kg are females, whereas those in the size range 3.5
– 5.0 kg are males.
• Three to four year-old fish show 1:1 (M:F) sex ratio.
• Males mature at 25 cm length.

Breeding of E. tauvina :
• E. tauvina is a protogynous hermaphrodite, females when they reach 650-700 g,
change to male.
• natural males are difficult to get.
• female groupersare artificially transformed to sexual males by male hormone 17α
–methyltestosterone (17 α –MT).
• Oral administration of 17 α –MT at 1 mg/kg b.w. given 3 times a week for 2 months
is effective.

• Natural females and sex-reversed males have to be maintained separately.
• Spermiation occurs within 4 months and lasts for at least 4 months after
implantation.
• Females with egg diameter of 0.4 mm are selected and injected with 2 doses of
HCG at 250 IU/kg and a third injection of HCG at 100 IU/kg + salmon pituitary
extract at 10 mg/kg at one day interval.
• Full maturation occurs 52-54 hours after injection.
• Fertilization is carried out artificially using dry method.
• Eggs hatch after 24 hours at 27-300C.

Larval rearing:
• The hatchlings are small with extremely small mouth opening and hence cannot
feed on rotifers.
• The first feed can be egg custard (55-60 um particle size) and trochophore larvae
(60-80 um) of green mussel.
• The larvae are obtained by subjecting the mussel to temperature shock treatment.
• CIBA, Chennai is developing a technique for brood-stock development, breeding
and larval rearing of this species.

fish hatcheries and its types, different types of hatcheries

More Related Content

Similar to fish hatcheries and its types, different types of hatcheries

More from IrfanBhat44

Recently uploaded

fish hatcheries and its types, different types of hatcheries