Development of Aquaculture in Kerala – An Outline 65 65 3 DEVELOPMENT OF AQUACULTURE IN KERALA - AN OUTLINE 3.1 Aquaculture: a conceptual framework 3.2 Development of Aquaculture in Kerala 3.3 Conclusion Aquaculture is an important segment of food producing sector and all over the world it has recorded the fastest growth rate in the field of food production during the last four decades. The average annual growth rate of global aquaculture production was 6.6 per cent during1970 - 2008. The share of aquaculture production in global fish production was 46 per cent in the year 2008 (FAO 2010). It is projected that by 2020 the relative shares of capture and culture fisheries in the world fish production will be reversed, with aquaculture contributing about 2/3 rd of total world fish production (Msangi, Siwa., et al, 2005) 3.1 Aquaculture: a conceptual framework 3.1.1 Definition The term aquaculture is defined in different ways. One of the simple definitions of the term is the “rearing of aquatic organisms under controlled or semi controlled conditions” (Stickney Robert R., 2005). In this definition the word aquatic refers to a variety of water environment including freshwater, brackish water and marine. Aquatic organisms include a variety of plants, invertebrates and vertebrates that can be used as Contents
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Development of Aquaculture in Kerala – An Outline
65 65
3
DEVELOPMENT OF AQUACULTURE IN KERALA - AN OUTLINE
3.1 Aquaculture: a conceptual framework
3.2 Development of Aquaculture in Kerala
3.3 Conclusion
Aquaculture is an important segment of food producing sector and all
over the world it has recorded the fastest growth rate in the field of food
production during the last four decades. The average annual growth rate of
global aquaculture production was 6.6 per cent during1970 - 2008. The
share of aquaculture production in global fish production was 46 per cent in
the year 2008 (FAO 2010). It is projected that by 2020 the relative shares of
capture and culture fisheries in the world fish production will be reversed,
with aquaculture contributing about 2/3rd of total world fish production
(Msangi, Siwa., et al, 2005)
3.1 Aquaculture: a conceptual framework 3.1.1 Definition
The term aquaculture is defined in different ways. One of the simple
definitions of the term is the “rearing of aquatic organisms under controlled
or semi controlled conditions” (Stickney Robert R., 2005). In this
definition the word aquatic refers to a variety of water environment
including freshwater, brackish water and marine. Aquatic organisms
include a variety of plants, invertebrates and vertebrates that can be used as
Cont
ents
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human food. The production of living matter from aquatic medium is
fundamental to all aquaculture activities; aquaculture is based on the
manipulation of the natural or artificial aquatic environment for the
production of the species, which are useful to man and therefore covers all
aspects of the production of living matter in water (Barnabe Gilbert (ed),
1994 & Pillay T V R., 2001) also defined aquaculture in a very wide sense
to include farming of all aquatic animals and plants in fresh, brackish and
marine environments.
Most of the standard definitions of aquaculture emphasised rearing of
aquatic organisms under controlled or semi controlled environment to
enhance production and to ensure adequate supply of desired species in
optimum size at appropriate times for human consumption. But it is pointed
out that many traditional practices of management of wild stocks of fishes
involved similar enhancement techniques. Therefore the FAO included
ownership right also as a criterion to distinguish aquaculture from capture
fisheries. According to the FAO definition “aquaculture is the farming of
aquatic organisms including fishes, molluscs, crustaceans and aquatic
plants. Farming implies some form of intervention in rearing process to
enhance production, such as stocking, fertilising, feeding, habitat
manipulation and protection from predators. Farming also implies
individual or corporate ownership of stock being cultivated” (quoted from
Ackerfors Hans, et al, 1994). Aquatic organisms that are harvested by an
individual or corporate body, who owned them throughout their rearing
period fall within the domain of aquaculture, while aquatic organisms that
are exploitable by the public as a common property resource with or
without licence requirements, are considered to be the subject of capture
fisheries. Though FAO has incorporated ‘ownership right’ in the definition
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of aquaculture for statistical reporting purposes (Ackerfors Hans, et al,
1994), it assumes special significance in the analysis of socio economic
aspects of development of aquaculture. Commercial aquaculture all around
the world is driven by the accelerating demand for fish and prospects of
profit making. It usually requires high capital inputs, technological know-
how and ownership or access to land and water or coastal space. Therefore
the flow of social and economic externalities of aquaculture is closely
related to the ownership of capital and property right on land.
3.1.2 Aquaculture and capture fisheries
Aquaculture is different from capture fisheries in many respects.
Capture fisheries involve hunting and gathering of fishes and other aquatic
organisms from water bodies mostly of the nature of common property
resources. The production process involves search for resources, hunting,
gathering and utilisation of the catch. The search for wild stock requires
vessels and harvesting is done with the help of fishing gears of different
types. Capture fisheries operate in marine and inland water bodies and
range from large commercial concerns to small artisanal fisheries. Quantity
and species composition of the harvest is determined by the environmental
and technological factors, the former being beyond the control of the fish
hunter. Returns from the industry depend on the quantity and species
composition of the catch and the market price. Usually fish species more
preferred in domestic and international markets command attractive prices.
With less control over the environmental factors that determine the quantity
and quality of the catch capture fisheries is characterised by production-
oriented marketing.
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On the other hand aquaculture is the farming of aquatic organisms
like fish, crustaceans, oysters, mussels, seaweed etc using methods that
increase the yield above the level naturally found in environment. The
aquatic organisms are raised in enclosed grow-out systems like ponds, pen,
raft, cages etc owned/hired and controlled by the farmer. Access to land or
water is crucial in the organisation of production under aquaculture.
Cultured species are chosen on considerations like yield, marketability,
price etc. They are stocked in concentrations higher than what is found in
natural environment. The natural food processing system is changed to a
more productive, artificial or manipulated eco system in which, inputs of
energy (feed/manure) are used to increase yield per area. Harvesting is
done either on attainment of optimum size or in times of favourable market
conditions. Since production is confined to an enclosed area, harvesting
involves less effort by man and machine.
The basic elements of production in aquaculture are access to
land/water, external inputs like seed, feed, manure etc and technology.
Depending on the method of farming and technology, the use of these
inputs change in proportion. Under aquaculture, emphasis shifts from
hunting to farming. The production base changes from wild water bodies to
grow-out systems with private property rights for the farmer. Quantity and
species composition of production is the choice of the farmer, which, in
turn is, mostly, market oriented.
To sum up production process in aquaculture is determined by
biological, technological, economic and environmental factors. The farmer
using capital and technology can control many aspects of the production
process. Environmental conditions can be manipulated to a large extent and
harvesting can be timed to ensure continuous supply of fresh product. This is
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in contrast to capture fisheries, which are controlled only through harvesting
regulations, if at all.
3.1.3 Grow-out systems
Aquaculture involves farming of fishes and other aquatic organisms
in a variety of water environments. Different grow-out systems were
devised to provide the necessary controlled or semi controlled water base
for culture that suits the constraints imposed by biological, technological,
social, economic and environmental factors. Commonly used grow-out
systems are briefly explained below.
3.1.3.1 Ponds
Land based ponds- inland freshwater and brackish water ponds-
constitute the main grow-out system of present day aquaculture. In ponds
water management is done with feeder and drainage canals. In tidal fed coastal
ponds water management is facilitated by water control structures like slice
gates and monks, which regulate inflow and out flow of water from the pond
to adjacent natural water bodies. In more intensive systems water management
is done with the help of devices like pump sets, aerators etc. Ponds are
relatively less expensive, but the aquatic environment in ponds is subjected to
many external factors like soil and water quality, environment pollution etc,
over which the farmer has less control. So land based ponds are considered to
be less suitable for intensive aquaculture.
3.1.3.2 Tanks
Tanks are made of different materials like concrete, fibreglass, marine
plywood, metals and other land based materials, which have no toxic effect.
Aquatic environment of tanks can be protected from external influences and
that renders the farmer more control over production. Tanks are grow-out
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systems suitable for intensive farming. The farmer has to make arrangements
for water supply, its aeration and re circulation, the cost of which may be
prohibitive.
3.1.3.3 Raceways
Raceways are designed to provide a flow-through system to enable
rearing of much denser population of animals. The system requires an
abundant flow of good quality well oxygenated water to provide respiratory
requirements of cultured animals and to flush out wastes. Raceways are
made of reinforced concrete or cement blocks. Earthen raceways are lined
with plastic material to prevent the loss of water through seepage.
Raceways are smaller in size and occupy much less space than ponds.
3.1.3.4 Cages
Another culture practice is holding or rearing of fish in cages. This is
a traditional practice in some Asian countries and is believed to have
originated in Kampuchea and later spread to Indonesia and Thailand and
other countries (Pillai TVR, 2000). Fishes are held in cages kept in water
bodies and fed till they attain marketable size. Cages usually consists of a
floating unit, framework and a flexible mesh-net under it.
3.1.3.5 Pens
Pens and enclosures are another grow-out system used in aquaculture.
Pens and enclosures are formed by damming a bay, cove, fjord or arm of the
sea, estuary or river. Barriers are constructed across narrow sections to form
the enclosure. Barriers hold sliding screens consisting of vertical aluminium or
galvanized metal bars to allow the free flow of water while holding the fish
stock. Another type of pen is formed by net barriers to partition off areas of an
open water body.
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3.1.3.6 Rafts
Rafts are generally made of bamboo poles or metal rods with buoys at
the top for floating in water. They are used in the culture of oysters,
mussels and seaweeds in open seas.
3.1.4 Classification of aquaculture systems
Aquaculture practices can be classified on the basis of a number of
criteria like species cultured, environment of culture, geographical location
etc.
3.1.4.1 Classification on the basis of species cultured
A wide variety of finfish, shellfish and other aquatic organisms are
cultured throughout the world. The species composition of culture depends
on environmental, biological and economic suitability of cultured items. On
the basis of species selected for culture, aquaculture is classified into
monoculture and poly culture / composite culture. Under monoculture a
single species is cultured in the grow-out system under varying intensities.
In poly culture or composite culture a judicious mix of different species is
made so that cultured animals utilize the full potential of the water column.
3.1.4.2 Classification on the basis of environment
On the basis of aquatic environment, aquaculture can be classified
into fresh water (with very low concentration of dissolved salt) and
brackish water (saltier than fresh water, but not as salty as sea water, like
water in estuaries) aquaculture. Culture of aquatic animals and plants in
open seas, using grow-out systems like cages, pens, rafts etc, is called Mari
culture. The species grown and culture practices differ under these systems
because of the differences in aquatic environment and technology involved.
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3.1.4.3 Classification on the basis of geographical area
On the basis of geographical area of culture, aquaculture practices are
grouped into inland aquaculture and coastal aquaculture. Inland aquaculture
refers to culture of fish and prawns based on freshwater bodies like ponds,
tanks, canals, lakes, rivers, reservoirs etc. Coastal aquaculture means land
based and water based brackish and marine aquaculture practices. The
Coastal Aquaculture Authority Act, 2005, enacted by the Parliament of
India defined coastal aquaculture as “culturing, under controlled conditions
in ponds, pens, enclosures or otherwise, in coastal areas, of shrimp, prawn,
fish or any other aquatic life in saline or Brackish water; but does not
include freshwater aquaculture” (Coastal Aquaculture Authority, 2006).
3.1.4.4 Classification on the basis of intensity of culture
From an economic point of view the most significant criterion is
intensity; i.e., the classification into extensive, semi-intensive and intensive
forms of culture (Asche, Frank., and Fahmida, Khatun., 2006). The term
intensity refers to combination of two variables: the amount of biological
material harvested per unit area of culture system and the degree of
manipulation of natural process (Pillai, T.V.R., 2001). Capital intensity of the
production process is positively related to the degree of intensity of culture
system. Measures of intensity include stocking density, production by area,
feeding regimes, input costs, while the most interesting feature is the degree of
control over the production process. In fact there is a continuum of operation
modes ranging from very high degree of control in intensive aquaculture to
basically no control in traditional extensive systems of culture.
In intensive system of aquaculture, aquatic organisms are reared in
grow-out systems like land based ponds, tanks, pens, raceways etc in which
the eco system is manipulated, using capital and technology, and managed to
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entail a high degree of control over the growth of bio mass. Intensive
aquaculture systems are characterized by high inputs of energy (balanced high
energy feed/ manure/ water quality), selective stocking of seeds exclusively
procured from hatcheries, high-density stocking, short-term food chains with
low energy losses and high yield per unit area.
The eco system under intensive culture is highly manipulated, not
natural. It serves only one ecological function, consumption – to gain
maximum body weight per unit of food intake. All other ecological functions
such as decomposition of wastes, exchange of gases,, and production of
oxygen are accomplished artificially, by mechanical aeration and flushing. As
a result the possibility of environmental degradation and pollution is higher
under intensive system of aquaculture. In other words intensive systems of
aquaculture attempt to reap maximum internal economies, while giving rise to
many externalities that may prove to be counter productive.
Under the extensive system of aquaculture, intensity of culture practices
is very low. It involves very low degree of control over the environment,
nutrition and yield. Stocking is not selective. Very often fishes from the wild
are stocked and it may contain both desired and undesired species and are
allowed to grow to marketable size. The proportion of high-energy input used
is very low or nil and output per unit of area is very low. The traditional
practices of aquaculture are operated on an extensive basis as farmers do very
little to control growth of biomass.
Under extensive system of culture the eco system is very similar to
the natural one and the degree of manipulation is very low. As capital and
technology employed are of very low levels, output under extensive system
depends on the natural productivity of water bodies and area of land used
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for culture. However, as the eco system is better placed to serve its natural
functions, the possibility of environmental degradation and pollution is
very low under extensive systems aquaculture. In other words, extensive
systems of aquaculture are more sustainable in nature.
The semi-intensive systems of aquaculture are production modes that lie
between intensive and extensive systems of culture. They are characterized by
some degree of environment manipulation that entails a higher degree of
control over production than in extensive systems of culture. Semi-intensive
systems are characterized by selective stocking of species with hatchery seeds
at comparatively higher densities, supplementary feeding, and water quality
management. The yield per unit of area will also be higher than under
extensive systems.
3.1.4.5 Integrated aquaculture
Integrated aquaculture is yet another culture practice that gained
wider acceptance among farmers on grounds of higher productivity, larger
income and sustainability. Integrated farming involves a sequential linkage
between two or more farming activities. In integrated fish farming, fish
becomes the major commodity. Integrated fish farming can be of two types
(Pillai, N.G.K., and Katiha, P.K., 2004):
a) Systems with no by-product utilization from one to other sub
system, but with optimum utilization of farming space and time.
E.g., Paddy cum fish culture and
b) Systems, where by-product, i.e., waste from one sub system is
being utilized for sustenance of the other. E.g., Fish cum pig/
poultry / duck / cattle farming.
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3.2 Development of Aquaculture in Kerala
Kerala occupies a very prominent position among the states in India,
particularly with regard to the development of brackish water aquaculture in
the country. The state has 3rd position in the country with regard to area under
shrimp culture and production of cultured shrimp. Table 3.1 give details of
shrimp culture in major cultured shrimp producing states in the country.
Table 3.1: State wise details of Shrimp Production in India
Sl. No State
Area Developed
(ha)
2009 - 10 Productivity (MT/ha/yr)
Area Utilized
(ha)
Production (MT)
1 West Bengal 51659.00 47488.00 33685.00 0.71
2 Orissa 13843.00 4769.00 6149.00 1.29
3 Andhra Pradesh 58145.20 33754.00 39537.00 1.17
4 Tamil Nadu 6109.33 2381.49 2702.38 1.13
5 Kerala 15099.39 9544.84 7096.00 0.74
6 Karnataka 3708.84 1484.00 1581.00 1.07
7 Goa 867.00 272.00 319.00 1.17
8 Maharashtra 1329.56 650.86 1243.79 1.91
9 Gujarat 2214.48 1915.79 3605.72 1.88
Total 1,52,975.80 1,02,259.98 95,918.89 0.94
Source: Annual Report 2010-11, MPEDA, Kochi
In the case of freshwater prawn culture the state has 3rd rank with
regard to area under culture and 4th rank with regard to production among
the states in India. Table 3.2 gives state wise details freshwater prawn
culture in the country.
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Table 3.2: State wise Freshwater Prawn Production in India
Sl. No State
Area Developed
(ha)
2009 - 10 Productivity (MT/ha/yr)
Area Utilized
(ha)
Production (MT)
1 West Bengal 4825.00 3325.00 1725.00 0.52
2 Orissa 3786.00 447.61 1724.07 3.85
3 Andhra Pradesh 10913.00 2823.00 1759.14 0.62
4 Tamil Nadu 465.60 161.98 111.97 0.69
5 Kerala 2594.17 1378.83 398.74 0.29
6 Karnataka 285.00 0.00 0.00 0.00
Total 22989.26 8153.00 6567.92 0.81
Source: Annual Report 2010-11, MPEDA, Kochi
Development of aquaculture in an area depends on natural resource
endowment and availability of external inputs and technology. In regions
where extensive system of aquaculture is widely practiced availability of
natural resources is the key determinant.
3.2.1 Resource endowment
Kerala occupies foremost position among the maritime states of the
country with regard to fishery resources. The state has a coastline of 590
km (10% of the coast line of the country), which provide habitats to many
species of fishes, invertebrates, plants, algae and other aquatic organisms.
In addition the state is endowed with rich resources of fresh and brackish
water bodies suitable for aquaculture.
3.2.1.1 Fresh water resources
The state has a total fresh water area of 1,58,358 ha consisting of
reservoirs, private ponds, tanks, rivers etc (Kerala Fisheries at a Glance
2007). The state has 41 west flowing rivers and 3 east flowing rivers,
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together contributing nearly 54 % of freshwater resources of the state.
Reservoirs account for 27 % and ponds and tanks contributing 17 % of the
area under freshwater. Details of freshwater resources suitable for
development of aquaculture in the state are given in Table 3.3. Out of the
total area of 1,58,358 ha , 32,000 ha is readily available for freshwater
aquaculture, but actual utilization is less than 1/3rd of the potential (Director
of Fisheries, GOK, 2007).
Table 3.3: Freshwater Resources of Kerala
Sl No. Item Number Area (ha)
1 Private ponds 35763 21986
2 Panchayat ponds 6848 1487
3 Quarry ponds 879 341
4 Holy ponds 2689 480
5 Village ponds and other water holds 185 496
6 Irrigation tanks 852 2835
7 Public sector freshwater fish farms 13 85
8 Freshwater springs 7 …
9 Freshwater lakes 9 1620
10 Water falls 11 …
11 Rivers 44 85000
12 Reservoirs 53 42890
13 Check dams 80 259
14 Bund/Barrier/Anicut/Shutter water holds 70 879
Total 158358
Source: Inland Fisheries Statistics of Kerala 2005, Dept. of Fisheries.
3.2.1.2 Brackish water resources
A very important geographic feature of the state that contributes to its
brackish water resource potential is the existence of a large number of
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backwaters bordering the coastline, into which open many rivers flowing
west from Western Ghats. The chain of backwaters is separated from the
Arabian Sea by a narrow strip of land, composed of sand and black clay or
silt. Very often backwaters and sea come close that only the sand beach
separates them. There are also frequent communications between sea and
backwaters, either through perennial openings, which allow free admixture
of salt and freshwater or through periodical openings, which allow flow of
water from one to another only during certain seasons of the year. In
several places the sand bank that separates sea and backwater is so shallow
as to allow the water flow from the former to the latter during high tide.
Owing to these factors and ‘brine percolation’ through the coastline the
backwaters contributes to the formation of brackish water zones extending
over a wide area in association with low lying lands, paddy fields and the
network canals. According to conventional estimates the total brackish
water area of Kerala is 2,42,600 ha. Due to various reasons the area available
for brackish water aquaculture is only 65,000 ha (Director of Fisheries,
GOK, 2007), details of which are given in Table No: 3.4
Table 3.4: Brackish Water Resources of Kerala
Sl No Item Number Area (ha)
1 Backwaters 53 46129
2 Prawn filtration fields 234 12873
3 Public sector brackish water fish farms 12 227
4 Estuaries 84 …
5 Mangrove area … 1924
Total brackish water area … 65213
Source: Inland Fisheries Statistics of Kerala 2005, Dept. of Fisheries.
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Ernakulam district alone accounts for nearly one fourth of the
brackish water area in the state. District wise distribution of brackish water
resources in the state is presented in Table No: 3.5. The low lying paddy
fields, known as ‘pokkali’ fields in central Kerala and ‘kaipad’ fields in
northern Kerala, constitute the major part of wetland resources used for
traditional seasonal shrimp filtration.
Table 3.5: District wise details of Brackish Water Area in Kerala (including Backwaters and Canals)
Sl. No Name of District Area (ha) Percentage
1 Kasaragod 3248.25 4.98
2 Kannur 5944.10 9.11
3 Kozhikode 4162.44 6.38
4 Malappuram 1796.26 2.75
5 Thrissur 4271.94 6.55
6 Ernakulam 6212.71 24.86
7 Kottayam 4326.74 6.63
8 Alapuzha 5222.92 3.34
9 Kollam 8603.62 13.39
10 Thiruvananthapuram 1423.98 2.18
Total 65212.96 100.00
Source: Inland Fisheries Statistics of Kerala 2005, Dept. of Fisheries, GOK.
3.2.2 History of Aquaculture in Kerala
Scientific aquaculture in the state is hardly three decades old, but on
traditional lines it has a long history. Paddy fields and low lying areas in
flood plains and those connected to estuaries and estuarine creeks became
the cradle of aquaculture, where, inundation caused by monsoon rain or
tidal waters brought natural seeds of finfish and shellfish, which
automatically got trapped after the water receded. This eventually gave rise
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to the practice of ‘trapping and holding’ till the attainment of optimum size.
This marked the beginning of aquaculture in the state and other parts of
India. The ‘trapping and holding’ method was in vogue in the ‘Pokkali’
paddy fields of Kerala, the ‘Bheris’ of West Bengal, the ‘Gheris’ of Orissa,
‘Khar’ lands of Karnataka and ‘Khazam’ lands of Goa. (Pillai SM,
et. al.,2002).
The traditional practice of shrimp filtration, locally known as
‘chemmeen kettu’ or ‘chemmeen vattu’ in central parts of Kerala and
‘chemmeen kandi’ in northern Kerala, is widespread in the coastal wetlands
of the state. The industry is more than a century old. First descriptive
account of the traditional prawn culture in Kerala was given by Panikkar
(1937). As per his account, “ the industry first flourished in the backwaters
adjoining Parur taluk. Owing to an increasing demand for prawns and to
high prices prawns began to fetch, the industry rapidly spread to the
adjoining taluks of Sherthalay and Vaikom and several places in the Cochin
state. This became more or less a regular occupation of fishermen
inhabiting the banks of the Vembanad Lake and several industrial
establishments sprang up for the collection and preservation of prawns for
the market”. The activity was sustained mainly on export of dried prawn
kernels to markets in Rangoon, Singapore, Colombo, Hong Kong and
Mauritius. The traditional practice of shrimp culture is still practiced,
except for some minor modifications, in various parts of the state. Under
the traditional system shrimp filtration is practiced as a rotational crop in
paddy fields, during the period November – April, when paddy cultivation
is impossible due to increased salinity of water and soil.
Aquaculture on modern, scientific lines in the state is of recent origin.
While fresh water aquaculture of fin fishes still remains largely
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unorganized and stagnant, aquaculture of prawns (fresh water) and shrimps
(brackish water) has made rapid progress in the recent past. Attempts to
commercialize the activity prompted the farmers to introduce scientific
methods of selective stocking at relatively higher densities, supplementary
feeding, protection from predators and diseases, water management etc.
However, the degree of intensity attained in culture practices in the state is
very low, as reflected in the fact that farms in state belong to ‘traditional’ or
‘improved traditional’ and ‘modified extensive’ category, employing