DOWNLAOD THE ASSIGNMENT HERE:
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BIOLOGY TOPICS:
rDNA TECHNOLOGY:
https://www.sciencearena.in/2025/06/recombinant-dna-technology.html
EUGLENA:
https://www.sciencearena.in/2025/05/euglena.html
MONOCYSTIS:
https://www.sciencearena.in/2025/05/monocystis.html
PARAMECIUM:
https://www.sciencearena.in/2025/05/paramecium.html
CO- ENZYME AND CO- FACTOR:
https://www.sciencearena.in/2025/06/co-enzyme-and-co-factor.html
Animal Breeding and Culture
Prawn Fishery
Some aquatic crustaceans are among the fisheries of economic
importance and constitute food for persons from various parts of the world.
Prawns form highly nutritive diet and tasty food for human beings. Prawn fishery
in India is next to USA in the world.
Prawn fishery can be studied under the following four heads:
1. Shallow Water
Prawn Fishery: This includes fishing prawns on the west coast including
Malabar coast and Kerala. The fishing is restricted to shallow coastal water
upto a depth of 18 metres.
2. Estuaries and
Backwater or Saline Lake Prawn Fisheries: Its principal areas of production
are back waters extending along the southern half of Kerala coast and mouths of
numerous hill streams in Malabar area. Ennur, Pulicat, Collair, Chilka Lake and
Estuaries of river Ganges and Brahamputra are important prawn-fishing areas.
3. Freshwater Prawn
Fishery: Freshwater species of prawn are caught from rivers, ponds and
lakes. Some species can be found in brackish water lakes when their salinity is
low during rainy season.
4. Marine Prawn
Fishery: Prawns caught from Indian Ocean belong chiefly to family
Peniaeidae. Three genera are more common. These are Penaeus, Metapeneus and
Parapenaeus. These live in shallow sea.
Species of Prawn
A number of species of Prawn are found in wide-spread waters
in India. But only those prawns are of commercial value which are of good size
and good taste, are available in plenty and are easily culturable. These
varieties belong to families Penaeidae, Pandalidae, Hippolytidae, Sergestidae and Palaemonidae. The edible prawn genera and
species are:
(a) Penaeus indicus
and P.monodon
(b) Metapenaeus
affinis
(c) Parapenaeopsis
sculptilis
(d) Palaemon
fluminicola
(e) Macrobrachium
carcinus and M. mirabilis.
Culture of Freshwater Prawn
Macrobrachium rosenburgi is a big sized, palatable
freshwater prawn found abundantly in rivers, ponds, fields, and low salinity
areas of estuaries.
Reproduction
1. Spawning: For
maintaining stock breeding a fully mature male and female, 1.c. one pair of
Prawns are kept in an aquarium of 60 litre capacity. About 24 hours after
mating female starts laying eggs.
For commercial purpose spawning is planned and spawning tank
of 200x 100x40 cm or 300 x 150 x 50 cm sizes are constructed.
2. Hatching: For
proper development of eggs, marine water is mixed with freshwater. The eggs
hatch into larvae. These are immediately transferred to cemented tanks 200-300
x 50 x 25 cm.
The temperature of tank water is maintained between 24-30°C
and pH between 7 to 8. The larvae are fed 4-5 times a day with steamed egg
custard, fish ball and fish egg. The feeding begins from 2-3 days after
hatching to their metamorphosis.
After about 60 days when larvae are about 5 cm long, these
are transferred to fresh or slightly brackish water at 22°C to 32°C in proper
oxygenated ponds. The size of the pond should be 50 x 10 x 1.5 metre. The ponds
should be kept clean and free of vegetation and predators.
The natural food for proper growth of prawns in their
natural habitat includes 200 kg cow dung mixed with 10 kg lime per hectare per
month. Gentle circulation of water stimulates proper growth of prawns.
Under normal conditions, prawns grow up to 20 cm in length
and about 100 g in weight within 6 months. Two crops of prawn per year can
easily be harvested.
Fishing of Prawns from Sea and
Estuaries
Prawn fishing requires gears, crafts, trollers and nets and
other devices like hooks or traps.
1. Crafts (Boats):
Boats used in prawn fishing depend on flow and depth of water, habit of prawn,
flora and fauna of water reservoir.
Boats used in different parts of India are:
(a) Vallom (8.3
to 10.6 metres) is used in Kerala.
(b) Thanguvallom
(12.6 to 14 metres) is also operated in Kerala.
(c) Masula (8.5
to 12 metres) is used from Kakinada to Machilipatalan.
(d) Nava (6.4 to
10.7 metres) is also used in Kakinada.
(e) Machwa (9 to
14 metres) is used in W. Bengal.
(f) Nauk
(10.5-13.5 metres) is used in W. Bengal.
2. Gears: Devices
used for catching prawns are nets, trope and hooks.
3. Nets: Nets are
usually made from cotton, nylon, hemp or any combination of these. Nets are
prepared in such a way that adult prawns are retained and young ones escape
back in the water.
Preservation and Processing of Prawns
Prawns after fishing are taken to the markets for local
consumptions as soon as possible by keeping them in ice layers. For the supply,
prawn are frozen in different forms as given below for the purpose of export.
The preservation of prawns is of following types:
1. Peeling and
Deveining: The freshwater prawns are beheaded, peeled, deveined and washed
thoroughly with water kept in freezer at 30°F to 40°F for about 3 to 4 hours.
If prawns are frozen in trays the sticky hard matter obtained is dipped in ice
water for glazing because glazing protects the frozen material from
dehydration, oxidation, etc. and is performed at 10°F to 15°F
2. Cooking and
Peeling: In this method, fished prawns are cooked in 7 to 10% boiling brine
for about 2 to 3 minutes, then cooled in ice-cold water containing 3 to 5%
salt. After cooling, prawns are peeled and washed in 20 ppm chlorinated water.
The washed material is then placed in cardboard or trays, frozen and glazed
with 50 ppm chlorinated water.
3. Peeling, Deveining
and Cooking: First of all, the prawns are peeled, deveined and washed with
water and cooked in 3% to 5% brine for about 3 to 5 minutes. After cooking,
they are cooled and placed in trays.
4. Headless
(Shellon): In this method of prawn preservation, only the head of the
prawns are removed and the rest of the body, covered with its shell is
preserved.
Export of Prawn
The prawns have become an important source of earning
foreign currency because of their export to various parts of the world. They
are exported in the form of frozen prawns, canned prawn, dried prawn, prawn
pickles, prawn powder, prawn bits, prawn curry and prawn meal.
Thus, it is clear if India can produce more and good quality
of Prawns and prawn products, it would be a very good source e raising the
economy of the Nation as foreign currency earner.
Economic
Importance:
Food
Source: Prawns are a popular and highly
nutritious food source, rich in protein and essential minerals.
Foreign
Exchange Earnings: Prawns are a major export product,
particularly for countries like India, generating substantial foreign exchange.
Aquaculture
Industry: Prawn farming is a growing industry,
providing livelihoods for millions of people and contributing to economic
growth.
Rural
Economy: Freshwater prawn farming provides
income opportunities for small farmers and can boost the rural economy.
Employment
Generation: The prawn industry creates jobs in
farming, processing, and distribution.
Market Demand: Prawns are in high demand both
locally and internationally, making them a valuable commodity.
Uses of Prawns:
Food: Prawns are
consumed globally as a delicious and nutritious seafood dish.
Aquaculture: Prawns are
farmed extensively for commercial purposes.
Exports: Frozen prawns
are a major export product for many countries.
Local
Markets: Prawns are also sold in local markets for consumption.
Scientific Research: Prawns are sometimes used in scientific
research, particularly in studies related to aquaculture and nutrition.
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BIOLOGY TOPICS:
EUGLENA:
https://www.sciencearena.in/2025/05/euglena.html
MONOCYSTIS:
https://www.sciencearena.in/2025/05/monocystis.html
PARAMECIUM:
https://www.sciencearena.in/2025/05/paramecium.html
rDNA TECHNOLOGY:
https://www.sciencearena.in/2025/06/recombinant-dna-technology.html
CO- ENZYME AND CO- FACTOR:
https://www.sciencearena.in/2025/06/co-enzyme-and-co-factor.html