Mud crab culture

Introduction:
• Among the marine edible crustaceans, crabs
occupy third position by virtue of its delicacy,
demand and price.
• Genetic studies shows that there are four
Scylla species distributed from red sea to
Indo-Pacific region.
• Scylla serrata, S. olivacea, S. tranquebarica, S.
paramamosain.

Global distribution
• S. serrata : South Africa, French Polynesia,
Japan, and Australia.
• S. tranquebarica and S. olivacea is limited to
the South China Sea, extending into both the
Indian Ocean and western Pacific.
• S. paramamosain is the most restricted
species found only in the Java and South China
Seas.

• The species of the genus Scylla, are widely
used for aquaculture purpose in the Indo-
West Pacific region.
• Thailand, Malaysia, Indonesia, Philippines,
Singapore and Taiwan, mud crab farming is
practiced on commercial scale

• There are only two species of mud crabs
occurring in most of the Indian brackish water
areas and inshore seas.
• Scylla tranquebarica: maximum size of 2.3 kg.
• Scylla serrata: maximum size of 0.7 kg.

Scylla serrata Scylla tranquebarica

Biology:
• The males growing to larger sizes than
females.
• omnivorous and they feed on shrimps, crabs,
bivalve molluscs and fish.
• The females S. tranquebarica reach sexual
maturity at a size of about 12 cm (CW) and
• In S. serrata 8.5 cm in the brackish water or
sea.

Mating:
Male cradling female Scylla
serrata
Mating of Scylla serrata with male
uppermost and female turned upside
down

12-day-old eggs (≈ 330 μm diameter) attached to
setae, showing pigmentation of eyes and body

Newly hatched first zoeal stage (Z1) of
S. serrata next to unhatched egg.
The fifth zoeal stage (Z5) of S. serrata.

Megalopae metamorphose from the
Z5 stage, developing large claws.
The first crab stage (C1) of S. serrata,
after metamorphosis from the megalopal
stage

Farming of Mud Crabs:
• Desirable water quality parameters:
 Salinity 10-34 ppt.,
 Temperature 23-30°C,
Dissolved oxygen above 3 ppm and
pH 8.0-8.5.
• Commercial mud crab farming is done by two
methods.

Grow-out method:
• Juvenile crabs are grown to marketable size in
earthen ponds for a period of 3-6 months.
• In India, crabs formed secondary crop along with
shrimp in pokkali fields of Kerala, bheries of west
Bengal, and Khazan lands of Karnataka.
• Crab farming in earthen ponds is done either in
monoculture or in polyculture with other
organisms. (milkfish, penaeid prawns and
seaweeds).

• small ponds (0.3 to 0.5 ha) with sandy or
sand-covered muddy bottom and a water
depth of 1.5 m are ideal for crab farming.
• Crabs are capable of climbing over the bunds,
which is prevented by fixing overhanging
fences on dykes.
• The height of the fencing ranges 0.5-1.0 m
above the dykes.

• The seed crabs collected from the wild are
stocked in the ponds after acclimatization.
• Stocking density @2 to 5/m2 for monoculture.
• Feeding with bivalve meat or trash fish @ 5 to
10 % of body weight.
• The juvenile crabs attain marketable size of
200-300 g in a period of 5-6 months

Fattening:
• The medium sized or large sized crabs, preferably
post-moult crabs, are reared in cages, pens or
ponds for about 20 to 30 days till the shells are
hardened with additional gain in weight.
• Immature female crabs are hold until their
gonads develop and fill the mantle cavity.
• In countries like India, newly moulted crabs of
sizes above 550 g and about 15 cm CW are
obtained alive from commercial catches and
subjected to fattening in ponds, cages or pens.

• The stocking density is normally 1 crab/ 1 to 3 m2.
• In addition to fattening in ponds, cages made of
areca nut palm are also used increasingly in the
open backwaters in States like Kerala.
• The crabs are harvested after the shell becomes
sufficiently hard and before next moulting takes
place.
• Crab fattening/hardening is done profitably by
repeated stocking and harvesting.

• Taiwan: small ponds (50-600 m2 ).
 Female crabs measuring 8-12 cm CW are stocked @ 2-
4/m2 or 1/m2 during summer.
• Thailand : ponds and pens. (Surat Thani )
stocking size of about 415 g, for a month
six crops are taken a year.
• Malaysia: Floating cages.
 Crabs are stocked at 10/m2
The market size is 300-500 g, although they may reach 1
kg.
• Fattening of crab is profitable, Because of low operating
cost, high survival rate due to control of cannibalism and
short rearing period and good market demand for finish
product.

Crab fattening pen in a crab-growing pond at
Bone, South Sulawesi, Indonesia

Individual crab fattening in a basket in the Mekong Delta, Vietnam.
Trash fish is added for crab feed.

Crab fattening cages in a tambak (brackish-water pond) at Timbulsloko,
near Semarang, Central Java, Indonesia

Constraints:
• Crab farming will remain small-scale until
hatchery techniques are developed and
improved.
• Low survival and heavy cannibalism are the
problems in larvae-culture.
• The inadequate supply of seed at desired time
has been considered as limiting "factor in crab
farming.
• Destruction of nursery grounds and increased
fishing activity may damage the resource
potentials.

References:
• Suseelan, C., (1996). Crab Culture and Crab
Fattening, In: Bull. Cent. Mar. Fish. Res.
Inst., 1996, 48: 99-102.
• Marichamy, R., (1996). Crab Farming Potential
India. Proceedings of the Seminar on
Fisheries – A Multibillion Dollar Industry,
Madras, Aug 17-19, 1995. pp. 115-122.
• S. Kulasekara pandian et al., (2009). Training
manual on Mud Crab Breeding and Culture.
CIBA

Culture of Lobster:

Culture Of Lobster:
• A highly priced seafood delicacy.
• Demand for both live and whole-cooked
lobster in the South East Asian countries.
• The potential for increasing the yield from the
wild fisheries is limited, as the stock is
subjected to extreme fishing pressure.
• Hence, the best management strategy is
increasing the production through population
enhancement and aquaculture.

Commercially important species of spiny
lobster
• Panulirus polyphagus (mud spiny lobster):
- Maharashtra and Gujarat coasts
• P. homarus (scalloped spiny lobster):
–Along Kerala and Tamilnadu coasts.
• P. ornatus (Ornate spiny lobster):
- The southeast coast of India.

Panulirus polyphagus
P. homarus
P. ornatus

Biology:
• In tropical waters spiny lobsters do not have a
particular breeding season.
• Fecundity varies from 1 to 15 lakhs.
• Nocturnal feeders, with specific predatory
feeding habit.
• The eggs hatched out as phyllosoma larvae.

Life cycle:

Lobster farming:
• Farming can be done by two methods i.e. Farming and
fattening.
• In India, lobster culture has become popular in
Bhavnagar, Gujarat.
• Juvenile lobsters are caught using stake net from
shallow coastal waters they are grown in small ponds
covered with nylon nets in the intertidal region of the
beach.
• Lobsters of over 500 gm are exported live to the
Southeast Asian countries.
• The smaller lobsters are either frozen or whole-cooked
for export.

Optimum water parameters:
• Temperature : 26-33ᴼC,
• Salinity: 25-35 ppt
• pH: 6.8-8.5
• dissolved oxygen: > 3.5 ppm.
• Ammonia < 0.1 ppm and
• Nitrate < 0.1 ppm

• Stocking density: for farming in indoor grow out
system would be 10-15 lobsters/m2 and
for fattening: 5 numbers/m2.
• Feeding with molluscan meat, trash fish,
compounded feed, etc.
• Experimental studies show that growth is
enhanced by eyestalk ablation and mono-sex
culture.
• Disease is generally not a serious problem in
lobster farming, but sudden fluctuation in
environmental conditions causes Moult Death
Syndrome (MDS).

Cage culture:
• Panulirus polyphagus stocked in two cylindrical
floating net cages.
• In cage I 1000 juveniles of weighing 80-120gm
(Group I).
• Cage II 1500 juveniles of weighing < 80gm (group
II).
• Result shows that smaller animals in cage II
showed higher growth rate than the larger
animals in Cage- I which suggests higher growth
performance of smaller animals at high stocking
density compared with larger animals.
Mojjada, et al., (2012)

References:
• Manisseri,, K . Marry (1998). Crab and lobster
culture. In: Kadalekum Kanivukal (Bounties of the
Sea). Ravindran, K and Srinath,
Krishna and Kunjipalu, K K and Sasikumar, V,
(eds.) CIFT, Cochin, pp. 71-75.
• Mojjada, s.k., i. Joseph., k. Mohammed koya., k. R.
Sreenath., g. Dash., s. Sen., mahendra., d. Fofandi.,
m. Anbarasu., h. M. Bhint., s. Pradeep., P. Shiju., g.
Syda rao., (2012) Capture based aquaculture of
mud spiny lobster, Panulirus polyphagus (Herbst,
1793) in open sea floating net cages off Veraval,
north-west coast of India. In: Indian J. Fish.,
59(4): 29-34, 2012.

• RADHAKRISHNAN, E. V., (1996). Lobster farming
in India. In: Bull. Cent. Mar. Fish. Res. Inst.,
1996, 48: 96 – 98.
• Vjayakumaran, M., and E. V. Radhakrishnan.,
(1998) Lobster culture and live transport. In:
Proceedings of the Workshop National
Aquaculture Week. Sakthivel,
M and Vivekanandan, E and Rajagopalan,
M and Meiyappan, M M and Paulraj,
Rand Ramamurthy, S and Alagaraja,
K,(eds.) The Aquaculture Foundation of India,
Chennai, pp. 97-103

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