of Giant Fresh Water Prawn
Meena*., A. K. Sahoo*., Debabrata Panda* and B.K Bahera*.
Inland Fisheries Research Institute, Barrackpore, Kolkata, 700 120
Dharmendra Kumar Meena
Email : firstname.lastname@example.org
commonly known as giant
freshwater prawn and forms a priced commodity among the species from
freshwater aquaculture. The species distribute in the major river
systems of the country, while many estuaries form a high potential
ground for the breeding. Till past few decades the species was being
cultured traditionally with the seed collection from the natural
river resources. But in the recent years the culture of giant
freshwater prawn has expanded significantly both in area under
culture i.e 43,395 ha from 12,022 ha and number of hatcheries
established, as the onset of white spot diseases in tiger shrimp.
addition to the disease resistance to white spot, the species has
many advantages such as i) high growth rate compared to other
freshwater prawn ii) can be cultured under freshwater to saline zone
upto 10 ppt iii)
be cultured as monoculture or mixed culture with carp fishes iv)
rate is always higher compared to fishes.
Fresh Water Prawn
general external anatomy of the freshwater prawn M. rosenbergii, and
provides some notes on the function of various major parts of the
body. Internal morphology (circulatory, respiratory, digestive,
excretory, reproductive and nervous systems) is not covered in this
manual, which concentrates on farming, but further information is
available in the references cited in the introduction to this
prawn eggs of this species are slightly elliptical, with a long axis
of 0.6-0.7 mm, and are bright orange in colour until 2-3 days before
hatching when they become grey-black. This colour change occurs as
the embryos utilize their food reserves.
scientists accept that the larvae go through 11 distinct stages (Uno
and Kwon 1969) before metamorphosis, each with several distinguishing
features which are described and illustrated in Annex 1. However,
from stage VI onwards their size is variable, which has led to some
workers, notably Ling (1969) to describe only eight stages. Stage I
larvae (zoeae) are just under 2 mm long (from the tip of the rostrum
to the tip of the telson). Larvae swim upside down by using their
thoracic appendages and are positively attracted to light. By stage
XI they are about 7.7 mm long. Newly metamorphosed postlarvae (PL)
are also about 7.7 mm long and are characterized by the fact that
they move and swim in the same way as adult prawns. They are
generally translucent and have a light orange-pink head area.
body of postlarval and adult prawns consists of the cephalothorax
('head') and the abdomen ('tail'). The bodies of freshwater prawns
are divided into twenty segments (known as somites). There are 14
segments in the head, which are fused together and invisible under a
large dorsal and lateral shield, known as the carapace. The carapace
is hard and smooth, except for two spines on either side; one (the
antennal spine) is just below the orbit and the other (the hepatic
spine) is lower down and behind the antennal spine. The carapace ends
at the front in a long beak or rostrum, which is slender and curved
upwards. The rostrum extends further forward than the antennal scale
and has 11-14 teeth on the top and 8-10 underneath (Figure 1). The
first two of the dorsal (top side) teeth appear behind the eye socket
front portion of the cephalothorax, known as the cephalon, has six
segments and includes the eyes and five pairs of appendages. The
final three of these six segments can be seen if the animal is turned
upside down and the appendages of the thorax (see below) are moved
aside. The cephalon segments therefore support, from the front of the
first antennae, which each have three-segment peduncles (stalks)
from which three tactile flagella emerge;
second antennae, which each have five-segment peduncles and a
single, long flagellum;
which are short and hard and are used to grind food;
first maxillae, which are plate-like (lamelliform), hidden below the
second maxillae, and used to transfer food into the mouth; and
maxillae, which are similar to the first maxillae but have an
additional function. Part of these appendages are constantly
beating, thus producing a current of water through the gill chamber
to promote the respiratory function of the latter.
two pairs of antennae are the most important sites of sensory
perception; the peduncles of the first antennae contain a statocyst,
which is a gravity receptor. The mandibles and first and second
maxillae form part of the six sets of mouthparts (see below).
rear portion of the cephalothorax, known as the thorax, consists of 8
fused segments which have easily visible pairs of appendages. These
appendages consist of 3 sets of maxillipeds and 5 pairs of
pereiopods, as follows:
first and second maxillipeds are similar to the first and second
maxillae and function as mouthparts (see above);
third maxillipeds, which are also mouthparts but look rather like
and second legs (pereiopods), which have pincers (chelae). These
pincer-ended legs are also called chelipeds. The first legs are
slender but the second pair bear numerous small spines and are much
stronger than any other leg. The second chelipeds are used for
capturing food, as well as in mating and agonistic (fighting)
fourth and fifth legs (pereiopods), which are much shorter than the
second cheliped, have simple claws (not pincers), and are sometimes
called walking legs. Eggs are extruded from oval gonopores in the
base of the third pereiopods of females, which are covered with a
membrane. In males, sperm is extruded from gonopores which are
covered by flaps, situated in the base of the fifth pereiopods.
pereiopods include chemoreceptor cells, which are sensitive to
aqueous extracts of food and to salts (and may therefore be involved
in migratory and reproductive processes). The left and right second
legs (chelipeds) of M. rosenbergii are equal in size, unlike some
other Macrobrachium spp. In adult males they become extremely long
and reach well beyond the tip of the rostrum..
tail (abdomen) is very clearly divided into 6 segments, each bearing
a pair of appendages known as pleopods or swimmerets (as this name
implies, they are used for swimming, in contrast to the walking
legs). The first five pairs of swimmerets are soft. In females they
have attachment sites for holding clusters of eggs within the brood
chamber (see below). In males, the second pair of swimmerets is
modified for use in copulation. This spinous projection is known as
the appendix masculina. The sixth pair of swimmerets, known as
uropods, are stiff and hard. The telson is a central appendage on the
last segment and has a broad point with two small spines which
project further behind the point. The telson and the uropods form the
tail fan, which can be used to move the prawn suddenly backwards.
between male and female Giant
Fresh Water Prawn
male prawns are considerably larger than the females
have Second chelipeds are much larger and thicker than female.
head of the male is also proportionately larger, and the abdomen is
narrower. The head of the mature female and its second walking legs
are much smaller than the adult male.
ripe or 'ovigerous' female can easily be detected because the
ovaries can be seen as large orange-coloured masses occupying a
large portion of the dorsal and lateral parts of the cephalothorax.
have three morphomites whereas incase of female there is no such
are situated at the base of 5th
pereopods incase of female it is at 3rd
pair of pereopds.
Male has central
lump on fisrt abdominal somite but female does not.
Male has appendix
masculina but female has brood chamber.
For culture of
giant freshwater prawn, more focus should be given on the following
selection and farm construction:
of suitable site is pre-requisite for establishing a prawn farm.
Farming site should be connected to approachable road for
transportation of seed, fertilizers, feeding materials, farm
equipment. Soil and water testing may be carried out before farm
construction for assessing the productivity status, water holding
capacity of the soil. Sandy-clay or sandy loam soil is suitable. For
establishing the prawn farm the pond should be prepared in such a way
that entire water may be drained out. The pond size can ideally vary
between 0.1 and 1 ha area. Since prawns are migratory in mature, they
try to migrate from one pond to other during rainy days and cool
construction with appropriate depth and dyke height
the bund height of the pond should be at least 0.5 m above the water
level. While the depth of pond should not be more than 1.5 m, as it
affects the growth of prawn. Layering the bottom of the pond with
sand or small pebbles with hide outs helps in movement and shelter to
the prawn, leading to the increase in production capacity.
kill the unwanted fishes Mahua oilcake is applied @ 2,500 kg/ha.
Alternatively combination of urea @ 100kg and bleaching powder @ 200
kg/ha can also be used, with urea applied 18 h before the bleaching
powder application. In a newly excavated pond 5-7 tonnes cow dung/pig
manure and 200-500 kg lime/ha should be applied. To maintain the
planktonic population in the pond, organic and inorganic fertilizers
like poultry droppings, pig and cow manure may be applied after
stocking of juveniles at periodical intervals. In prawn farming
Calcium form an important component in moulting process. Therefore
after a heavy shower calcium level in the water may decrease which is
signaled by lowering of water pH. If the pH decreases below 6.5, the
molting process is arrested. For this purpose, 50 kg lime/week should
be applied to maintain calcium balance in water.
morphotypes of M. rosenbegii
are cannibalistic in nature and having territorial behavior. During
starvation they attack the weaker members of their own group. To
prevent such situations special arrangements may be made by providing
hide outs during moulting time. Water hyacinth can be kept in the
pond under bamboo frame. Apart from this large palm leaves, plastic
pipes, small asbestos sheets can also be used.
of postlarvae in nursery:
is observed that releasing the post-larvae directly into the pond
results in poor survival, emphasizing raising the PL in nursery pond
tanks for nursery phases
tanks are usually used for nursery cycle. Complete drainage of water
from such nursery tanks helps for easy harvesting of the juveniles.
Earthen ponds are not suitable for nursery rearing as continuous
aeration makes the water muddy, beside wastage of feed through mixing
with the mud and its further decomposition leading to decrease in
dissolve oxygen levels and microbial infection. As soon as the
postlarvae becomes juveniles, they should be reared in low saline
water of 3-7%0. Before stocking of juveniles in rearing ponds
physic-chemical parameters of the water like Dissolve oxygen,
temperature, pH, NH4,
, and Mg+2
should be analysed and need to be kept within desire limit. Depending
upon the water volume 5-10 PL/lt should be stocked for 2-4 weeks.
During these period provision of shell strings has to be made so that
they can hide while moulting. Groundnut oilcake, small mussel,
chicken feed, fish meal with 30-40% protein may be used as feed.
Juveniles attain 40-60mm within a rearing period of 2-4 weeks,
of M. rosenbergii
which can be
transferred to the grow-out ponds. Starting from breeding to larval
rearing one complete cycle requires around 2-3 months.
into grow-out ponds:
arrival at the pond bank utmost care should be given to acclimatize
the juveniles to the temperature by floating the transport bags in
the pond for 15 minutes before emptying them into the water (as shown
in figure). Severe mortalities can be caused not only by thermal
shock but also by sudden changes in pH. If the water pH is more than
0.5 pH units different from the pH in the juvenile holding tank or
the nursery ponds, acclimatize the juveniles to this pH level slowly
(over a one-day period) in nursery before transporting and stocking
them at the grow-out pond. Generally for better growth in
semi-intensive, stocking rates vary between 4 and 20 PL/m2 (40
000-200 000/ha). In stagnant water where facility for water exchange
is is not available stocking density should be kept between 30,000 to
50,000 juveniles/ha. During these period 30-40% crude protein out of
which 50 % should be from animal origin and 50% from plant origin is
given as diet. The feed is provided @ 3-10% of the standing
biomass/day in two rations during morning and evening.
with pond water temperature and release of juveniles into grow-out
addition to feed, suitable water conditions also required for better
growth and survival i.e temperature 26-320C,
pH 7-8.5, DO > 2.5 ppm, total hardness 100-150 ppm, calcium 30-80
ppm, phosphorus 0.01-0.9 ppm and nitrogen 0.05-0.5 ppm. Any imbalance
of these parameters affects the growth as well as production. Prawn
being a bottom dwelling animal, the optimum growth and development
depends upon the pond soil, which should be alkaline. Therefore to
make soil fertile, fused lime should be applied.
culture practice of M.
may be categorized as i) monoculture ii) polyculture iii) integrated
stocking rate of about 4 juveniles/ m2 (40 000/ha) is recommended for
the monoculture of Macrobrachium
are some advantages in using larger juveniles for stocking. For
example, it has been demonstrated that increasing the average
stocking weight at 4 animals/m2 from 0.17 g to 0.75 g increases
production at harvest by nearly 30%. However, this stocking size
advantage does not apply indefinitely; research has shown that
stocking 3 g animals did not improve production because the animals
matured too rapidly. In addition, grading nursed juvenile prawns
before stocking also has significant advantages under monoculture
practice. It has been found to increase average harvest size and
total pond production. Size grading is a way of separating out the
faster growing prawns and lowering the suppression of growth that
they cause to other prawns; it can also result in improved
feedconversion ratios (FCR). Another means of improving in production
freshwater prawn culture is to place artificial substrates in the
ponds, which makes it feasible to increase stocking rates above the
level recommended earlier for ponds without substrates. PVC fencing.
The above points are more effective in increasing the higher
production under monoculture.
of M. rosenbergii:
exist of the polyculture of various Macrobrachium
in combination with single or multiple species of fish, including
tilapias, common carp, Chinese carps, Indian carps, ,mullets,
ornamental fish. Other combinations may be feasible. The inclusion of
freshwater prawns in a poly-culture system almost always has
synergistic beneficial effects, which include:
dissolved oxygen levels
consumption of fish faeces by prawns), which increases the
efficiency of feed
greater total pond
productivity (all species) and the potential to increase the total
value of the crop by the inclusion of a high-value species.
culture with M. rosenbergii:
wastewater from ponds containing prawns being reared in monoculture
or polyculture with fish can be used for the irrigation of crops.
Prawns can also be reared in paddy fields, without depressing rice
production. This has proved especially valuable in Viet Nam, where it
has been shown that the income from prawns in integrated rice-prawn
culture can be two or three times as great as that from the
cultivation of rice. The introduction of freshwater prawns reduces
the area devoted to rice paddy (because deeper areas where prawns can
shelter when the rice field is dry have to be provided). It also
reduces weeding costs (prawns eat weeds) and fertilization costs.
being a high value commodity and possessing great potential for
export offer greater scope for their larger scale adoption both under
monoculture and polyculture. In India, MPEDA is providing incentives
and technical assistance for the development of prawn farming,
greater R&D interventions and credit support given in recent
years is expected to boost the growth of prawn seed production and
farming in the country.