FISH FARMING TECHNOLOGY: Cage culture in Indian reservoirs: Present status and prospects

1. FISH FARMING TECHNOLOGY
Cage culture in Indian reservoirs: Present status and prospects
T
he growing and production of farmed aquatic organisms in caged enclosures has
been a relatively recent aquacultural innovation. The cage aquaculture sector has
grown very rapidly during the past two decades and is presently undergoing rapid
changes in response to pressures from globalization and growing demand for
aquatic products in both developing and developed countries.
Potential for
reservoirs
Reservoirs,
or man-made
lakes are huge water bodies that are
created primarily for irrigation, power
generation and other water resource
development purposes. India has 19,
370 reservoirs spread over 16 states and
this is expected to increase due to the
execution of various water projects in
the country.
The reservoirs of India have a
combined surface area of 3.25 million
hectares, mostly in the tropical zone,
which makes them the country’s most
important inland water resource, with
huge untapped potential.
Cage culture is an alternative to inland
pond culture, whereby existing water
resources are used to increase fish
production, and the fish are enclosed
in a cage allowing the water to pass
freely between the fish. The young fish
and other aquatic species are kept, fed
and grown to marketable size in these
cages, which are made of high-density
polyethylene.
Now cage fish farming started in the
reservoirs of states like Tamil Nadu,
Jharkhand, Himachal Pradesh, Kerala,
Odessa, Karnataka, West Bengal,
Chhattisgarh, Assam, Tripura, Manipur,
Bihar, Srinagar (J&K), Uttar Pradesh,
Andhra Pradesh, as well as Telangana, to
name but a few.
Present status
In India cage culture in inland water bodies was initiated for the first time in air breathing fishes in
swamps, for raising major carps in running water in Jamuna and Ganga at Allahabad and for raising carps,
snakeheads and tilapia in lentic water bodies of Karnataka. Thereafter, the cages have been used for rearing
fry in many reservoirs and floodplain wetlands to produce advanced fingerlings for stocking main water
bodies.
The Central Inland Fisheries Research Institute (CIFRI), Barrackpore, Kolkata has taken lead role in
popularising fish rearing in net cages in freshwaters especially in reservoirs as well as wetlands in the
country.
Cage culture is an
emerging technology,
through which fishes
are reared from fry to
fingerling, fingerling
to marketable size
while captive in an
enclosed space that
maintains the free
exchange of water
with the surrounding
water body. A cage
is enclosed on all
sides with mesh
netting made from
synthetic material
that can resist
decomposition in
water for a prolonged
period of time.
46 | March | April 2016 - International Aquafeed

2. FISH FARMING TECHNOLOGY
There is an enormous diversity of types, size, shape, and design of this cage; so they have been developed to suit the
varying demands of the fish growers in open waters. In India, cages are constructed using locally sourced materials
like bamboo poles, GI pipes, iron/plastic drums, synthetic ropes and nets etc. These cages are mostly rectangular and
rarely round in shape. But, cages made of revolutionary HDPE Modular Floating Buoys, which are more durable, are
now replacing the conventional cages.
These HDPE buoys are cubical in shape and modular in nature that enables easy assembly and dismantling of cages.
Being modular in nature, they can be easily arranged to form a cage frame of any size. The cage net shall be of custom
size provided with GI pipe lower frame of 0.5” diameter at the bottom to maintain shape and resist the water current.
Various cage net options are available. Standard netting materials used are welded polymer square mesh of 15 mm, 8
mm and 6 mm and also nylon nettings of various mesh sizes.
Culture practices
Species cultured: The choice of species depends to a large extent on availability of fish seed, feed and market
demand. However, the main desirable characteristics of the candidate species for cage culture are potential for fast
growth, high survival, capacity to withstand overcrowding, rapid adoption to artificial feeds, high-feed conversion
rate, quality flesh and resistance to diseases. At present, cage farming in India predominantly includes the farming of
sutchi catfish, Pangasius hypophthalmus and Nile tilapia, Oreochromis niloticus.
Stocking density: The number of fishes that can be stocked in cage is variable and depends on carrying capacity of
the water, water exchange, species of fishes and quantity and quality of supplementary feed input. In each cage (6m
x 4m x 4m size) 5 000 fingerlings are stoking and allow them to grow for 8 – 10 months period by adopting proper
management methods. Depending on the farmer’s choice, some cages allow for tilapia fish culture and some cages
allow for pangas catfish to be cultured separately.
Feed & feeding methods: Floating pellet feed is given to the fish that are grown in cages. The feed is in different
sizes i.e. starter, grower and finisher with varying crude protein levels. Feeding is done twice a day i.e. morning and
evening.
Production level: At the end of the culture period, which ranges from eight to ten months, three to five tonnes of
fish are produced just from one cage compartment i.e. 6m x 4m x 4m size. Generally each battery consists of 12 cage
Images: Reservoirs,
or man-made lakes
are huge water
bodies that are
created primarily
for irrigation, power
generation and
other water resource
development
purposes. India has
19, 370 reservoirs
spread over 16 states
and this is expected
to increase due
to the execution
of various water
projects in the
country.
International Aquafeed - March | April 2016 | 47

3. compartments. But it varies from place to place and
reservoir to reservoir.
Role of NFDB
National Fisheries Development Board (NFDB)
currently supports several initiatives in cage culture
in reservoirs; first introduced in Jharkhand (Chandil
Reservoir), later in Chhattisgarh (Kabirdham) and Assam
(Samuguri Beel). Now it is spread to many states of the
Indian reservoirs.
Cage culture proved to be highly successful, increasing
fish production and productivity from open water bodies
on one hand and improving income and livelihoods of
local fishers on the other.
NFDB is also providing financial assistance to Fisheries
Research and Training Institutes for capacity building
to fisher folk and fishery officials on cage fish farming
system in reservoirs of the country.
Prospects
The commercial prospects for cage farming are so good
in India. Though the many species of fish are suitable for
cage culture, picking the fish species that will do well in
cages in the particular location is important.
There must be a multidisciplinary approach in the
selection of a species for cage culture and therefore the
species introduced have to be selected under economic
and biological limitations, such as the existing and
potential markets; which should precede the selection of
species for cage culture.
Knowledge of the biology and culture requirements
of each species is crucial in optimising production from
cages. The species chosen for culture is usually based on
a number of biological and economical criteria, as well as
the prevailing conditions of the culture site.
The success of the adoption of any innovation or new
technology lies in its economic performance. The rate of
financial return on investment is the economic indicator
that guides the investor to choose a particular enterprise
or practice.
It is essential of cage culture in inland open water
is stocking of reservoirs and culture of economically
important fishes for augmenting fish production. Stocking
with the right fish species, using seed of appropriate
size and introducing it at the right time are essential
to optimising fish yield from reservoirs. The success
demonstrated at different localities in the country has
paved way for thinking of cage culture as one of the
investments for enhanced fish production and livelihood
in the country.
About the author
Dr B. Laxmappa,
Fisheries
Development
Officer, Department
of Fisheries,
Mahabubnagar – 509
001, Telangana,
India. E-mail:
laxmappaboini@
gmail.com
FISH FARMING TECHNOLOGY
The National Fisheries
Development Board
(NFDB) currently
supports several
initiatives in cage
culture in reservoirs
48 | March | April 2016 - International Aquafeed

4. FISH FARMING TECHNOLOGY
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