Macrobrachium rosenbergii , also known as the giant river prawn or giant freshwater prawn, is a commercially important species of palaemonid freshwater prawn. It is found throughout the tropical and subtropical areas of the Indo-Pacific region.

1. Shellfish Biology

2. Introduction
• Shellfish:
a group of invertebrates and aquatic
organism, is covered by chitinous or
calcareous exoskeleton.
• Shell means an outer covering or layer
which is popularly known as “Khoalos” in
Bengali.
• Shellfishes are belonging to two major
Phylum Arthropoda and Mollusca

3. • . In Bangladesh, there are a wide range of shellfishes
have been found which comprise different groups
such as
Crustaceans (shrimp, prawn, lobster,
crayfish, and crab)
Molluscs (clam, mussel, oyster and
scallop, snails), and others (squid,
Cuttlefish, octopus and, sea
urchins, etc.).

4. Shrimp and prawn
Peneaus monodon
Macrobrachium rosenbergii

5. List of prawn and shrimp species found in
Bangladesh
Sl. Scientific name English name Local name Habitat
1 Macrobrachium rosenbergii.
Giant freshwater
prawn
Golda Chingri F, B
2 M. malcomsonii. Monsoon river prawn
Chotka icha or
Thangua icha.
F, B
3 M. dolichodactylus Goda river prawn
Goda chingri or
Brammhani chingri.
F, B
4 Macrobrachium rude Hairy river prawn Pata chingri B
5 M. villosimanus Dimua river prawn Dimua icha F
6 M. mirabile Latiya icha Shortleg river prawn F, B
7 M. lamarrei Kuncho river prawn
Gura icha or kuncho
chingri.
F, B
8 M. birmanicum Birma river prawn
Shul/thengua/nazari
icha.
F, B
9 M. dayanum Kaira river prawn
Kaira icha or beel
chingri.
F
10 M. idella Slender river prawn Chikna chingri. F

6. Sl. Scientific name English name Local name Habitat
1 Penaeus monodon
Giant /Jumboo tiger
shrimp
Bagda chingri B, M
2 Penaeus indicus Indian white shrimp Chapda chingri or sada icha B, M
3 P. semisulcatus Indian white shrimp Chapda chingri or sada icha B, M
4 Penaeus merguiensis
Banana shrimp/
White prawn
Kola chingri or Bagha
chama
B, M
5 Penaeus orientalis White shrimp Baro chama, Chapda chingri B, M
6 P. canaliculatus White prawn Dora kata chingri. M
7 Penaeus penicillatus Red tail prawn Chama icha/ Lalchama icha. M
8 Penaeus japonicas Kuruma prawn Dora kata /Japani chingri. M
9
Metapenaeus
monoceros
Speckled/Ginger
shrimp
Harina/ Kharkharia chingri B, M
10 Metapenaeus affinis Jinga shrimp Kerani chingri M
11 M. brevicornis Yellow shrimp Honni/saga/ kucho chingri B, M

7. Identifying character of prawn and shrimp

8. No. of rostrum:
Golda- The rostrum is very
prominent and contains 11 to 14
dorsal teeth and 8 to 11 ventral
teeth
Bagda- 6-8 dorsal and 2-4
ventral teeth;
mostly 7 and 3,
respectively.

9. Macrobrachium rosenbergii
• FAO name: Giant river prwan
• English name: Giant Fresh Water Prwan
• Local name: Golda Chingri, Mocha chingri, Mota Chingri
• Synonyms:
Palaemon carcinua rosenbergii ( Oartmann,
1891)
P. whitei (Sharp, 1893)
P. ( Eupalaemon) rosenbergii (Nobili,1899)
P. spinipes (Schenkel, 1901)
P. dachueti ( Sunier, 1925)

10. Taxonomy
• Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Caridea
Family: Palaemonidae
Genus: Macrobrachium
Species: M. rosenbergii

13. Morphology

16. Difference between male and Female

17. BODY
SECTION
SOMITE
#
APPENDAGE NAMES (PAIRS) FUNCTIONS OF APPENDAGES AND RELATED
STRUCTURES
Cephalon front
portion of the
cephalothorax
1 embryonic segment (not visible in
adults)
2 1st antennae tactile and sensory perception (statocyst)
3 2nd antennae tactile
4 mandibles cutting and grinding food
5 1st maxillae (maxillulae) food handling
6 2nd maxillae food handling; water circulation through the gill
chamber (scaphognathite)
Thorax near
portion of the
cephalothorax
7 1st maxillipeds feeding/food handling
8 2nd maxillipeds feeding/food handling
9 3rd maxillipeds feeding/food handling
10 1st pereiopods (chelipeds) food capture
11 2nd pereiopods (chelipeds) food capture; agonistic and mating behaviour
12 3rd pereiopods walking; female gonophores between base of legs
13 4th pereiopods walking
14 5th pereiopods walking: male gonophores between base of legs
Abdomen 15 1st pleopods (swimmerets) swimming
16 2nd pleopods (swimmerets) swimming; copulation in males
17 3rd pleopods (swimmerets) swimming
18 4th pleopods (swimmerets) swimming
19 5th pleopods (swimmerets) swimming
20 uropods propulsion, together with the central telson

24. Moulting and Behaviour Changes
in Freshwater Prawn

25. Moulting and Behaviour Changes in
Freshwater Prawn
The hard chitinous shell of crustaceans is an
extremely efficient protective covering but its
presence prevents any expansion of the body.
What is moulting?
• Moulting is an inherent habit of crustaceans, in which
periodically the old exoskeleton is cast off and a new one is
formed.
• It allows further growth or weight increment.
• Moulting leads to the total replacement of old exoskeleton,
including appendages, with a new exoskeleton.
• The shed exoskeleton is called the exuvium.

26. • In giant freshwater prawns, moulting
generally takes place at night and this
cyclic process continues until death.
• In addition to growth, moulting also leads
to vary changes in the general behaviour
of the prawn.

27. Moult cycle
• The moult cycle in M. rosenbergii has been
defined as
1. pre-moult ,
2. moult,
3. post-moult and
4. inter-moult,
The behavioural differences during different
stages can easily be observed.

28. • The general physiological changes during different stages in a
moult cycle are given below:
i) Pre-moult: (Proecdysis/ Peeler stage)
• This is the stage just before moulting. In this stage, calcium is
reabsorbed from the old integument (outer shell) leading to
enlarged epidermal cells.
There will be clear separation of the old integument from the
epidermis for moulting. Appendages also regenerate.
ii) Moult: (Ecdysis)
• The animal comes out of the old exoskeleton with a newly
formed soft exoskeleton underneath and absorbs water in the
tissue for increase in size.

30. iii) Post-moult: (Metecdysis/ Soft back stage)
• This stage falls a few days after moulting.
• This stage is characterized by hardening of the newly formed
exoskeleton by deposition of calcium and other minerals and
results in the complete formation of a new exoskeleton.
iv) Inter-moult: (Anecdysis)
• This is the stage between successive moults. The prawn in this
stage is called an instar.
• The water taken up during ecdysis is gradually replaced by
tissue growth, enrichment of organic matter and mineral
reserves, resulting in growth of the prawn.
***Moulting is completed in less than 5 minutes.

31. Moult cycle duration
• In M. rosenbergii, the length of the moult cycle varies
depending on the size, sex and age of the animal.
• However, it is not clear what is the exact duration of
each stage.
• In Penaeids generally the moult cycle is short for
juveniles and long for adults.
• Giant freshwater prawn exhibits long (about 30-80 days)
inter-moult periods, short (about 10-12 days) pre-moult
and very short (about 2-6 days) post-moult periods.

32. Moulting

33. Molting Process:
• When a, prawn has accumulated sufficient amount of body
tissue for expansion, a thin , soft and elastic new shell
gradually and steadily is developed right beneath the old
shell.
• During the molting, it starts bending its body and exerts
strong internal pressure which causing a dorsal transverse
split in the membranous part between the carapace and
the abdomen (arthrodial membrane).
• A sudden jerk frees the entire animal, including all the
appendages( by longitudinal splits) from its old shell.
• Frequency of molting depends on the age and the amount
and quality of food taken.

34. Change of behaviour for moulting
• Crustaceans may exhibit extraordinary behaviour
during moulting.
• Shrimps perform intense swimming, walking,
jumping, rolling and rotating movements prior to
ecdysis.
• Immediately after the moult the shrimps were found
to lie on their side for 5 to 30 minutes.
• They do not feed during moulting.
• Immediately after ecdysis, normally they eat the
exuvia, which is rich in chitin. This will compensate
for the loss of minerals due to moulting. Therefore,
addition of any mineral additives should be applied
carefully to avoid hyper-mineralisation in the water

35. Aggressive behaviour
• In farming ponds, the late pre-moult and early post-moult
prawns avoid hard inter-moult and early pre-moult
prawns by burrowing into deep, soft mud.
• The social interaction leads to the emergence of two
groups in the population that can be described as
‘Jumpers’ and ‘Laggards’. Jumpers are the fast
growers, with an increased moulting frequency and
laggards the slow growers, with different behavioural
patterns.
• Jumpers show an almost 6-fold higher weight increment
per moult cycle than non-jumpers.
• Aggressive behaviour has been observed among the
prawns during moult cycle.

36. • Overstocking and paucity of food may also cause
cannibalistic behaviour.
• M. rosenbergii exhibits aggressive and social behaviour.
• In M. rosenbergii the removal of claws shortened the
inter-moult period.

37. • Food and feeding habits
• Juvenile and adult prawns are omnivorous, and feed on a wide
variety of food items such as aquatic worms, insects and their
larvae, small molluscs and crustaceans, flesh and offal of fish
and other animals, grains, nuts, seeds, fruits, algae, tender
leaves and stems of aquatic plants.
• They prefer animal sources of food, and sometimes may even
be cannibalistic.
• They also consume their shells which have been shed off as a
result of molting.
• Prawns locate their food mostly by touch with their antennae.

38. Reproduction system

39. External Reproductive organ of Male
Appendix masculina:
• Accessory male organ located on second pair of
pleopods between endopodite and appendix
interna.
• used in copulation or spermatophore transfer.
• The presence or absence of this structure
provides easiest means of distinguishing males
from females; an important taxonomic character
for palaemonids.
• Small branch on inner margin of pleopod 2 of
males, usually rod-like, proximal to appendix
interna

41. • FIgure 22.1 (A) Lateral view of generalized shrimp (after Hobbs and
Jass [218] ). Ai, appendix interna; Am, appendix masculina; As,
antennal spine; B, basis; Bg, branchiostegal groove; Bs,
branchiostegal spine; Cp, carpus; D, dactyl; end, endopod; I,
ischium; M, merus; P, propodus; Sc, scaphocerite; and (B) chela of
second pereiopod with apical tufts of setae; Palaemonias ganteri
Hay (after Hobbs et al. [204] ).

42. Internal reproductive organ of male:
• In males, the internal reproductive structure consists of
- a testis (actually two testes fused together),
- the coiled vasa deferentia (sperm ducts) extending as a
tube and ending in an terminal ampulla.
• The testis is situated dorsally in the carapace and gives rise to
the coiled vasa deferentia which are located anterior to the
heart.
These extend laterally and open at the base of the fifth
pereiopods.

44. Internal reproductive structures of
Macrobrachium rosenbergii. A: male.

45. Female reproductive organ
• In females, the ovaries are located dorsal to the stomach
and hepatopancreas in the carapace cavity.
• When the female is in ripe condition the orange
coloured ovaries are visible through the carapace,
extending from just behind the eyes to the first
abdominal segment.
• An oviduct extends from each ovary (anterior to the
heart) backwards to the gonopore of the third pereiopod.

46. Internal reproductive structures of
Macrobrachium rosenbergii. A: female.

47. Maturity
The maturity stages of females can be
determined by external examination of the
ovary, as follows:
Stage 1 Immature/resting (neuter period). Ovary is tiny, transparent,
confined to the posterior- region of the carapace cavity
Stage 2 Early maturing. Ovary is yellow and occupies about a quarter
to half of the length of the carapace cavity
Stage 3 Maturing. Ovary occupies more than 3/4th of the length of the
carapace cavity and is light orange in colour
Stage 4 Ripe. Ovary occupies entire carapace cavity and is dark
orange in color.

48. Stages of Maturation

49. • Stage I.—In the initial stage of ovarian development, the appearance of the ovary
was semi-transparent, creamy white, and somewhat light pink (Fig. 1A, Table 2). The
ovary appeared thin, small, and rounded, and it remained close to the hepatopancreas.
The size of the ovary in this stage was the smallest of all developmental stages.
• Stage II.—In this stage, the size and thickness of the ovary began to increase, and
changed to creamy white with pale yellowish-green spots (Fig. 1B, Table 2). Sometimes,
two obvious yellowish-green bands along the ovarian lobes were also observed. The
ovary appeared oval-shaped, instead of rounded.
• Stage III.—The ovary was yellowish-green with several green spots or double green
bands along the ovarian lobes(Fig. 1C, Table 2). The size obviously further increased, and
therefore, it covered almost half of the dorsal portion of the hepatopancreas. The
posterior end of the ovary extended to under the heart.
• Stage IV.—In this stage, the ovary had an emerald coloration and had increased in
size to larger than that in stage III (Fig. 1D).

50. • Stage V.—The ovary was olive-green, and was characterized by the greatly
increased size and the presence of visible oo¨cytes (Fig. 1E, Table 2). The ovary
had expanded in size, and not only fully occupied the space under the carapace
but also covered the entire dorsal portion of the hepatopancreas and about half
of the stomach. The posterior end of the ovary extended further into the first
Abdomen of the prawn.
• Stage VI.—After mature oo¨cytes had ovulated, the ovary was obviously
reduced in size, and became thinner and irregular-shaped (Fig. 1F, Table 2). This
stage was identified as the final stage of ovarian development. Because of the
lack of mature oo¨cytes, the ovary appeared translucent. Sometimes, a few
yellow residual oo¨cytes that had not ovulated were also observed.

51. Reproductive process
• Females generally become reproductively mature at 6 months
of age.
• Mating can occur only between hard-shelled males and soft-
shelled females, i.e., females who have just completed a pre-
mating or prenuptial molt.
• The male deposits sperm into a gelatinous mass that is held
underneath the body of the female, between her fourth pair of
walking legs.
• Eggs are laid within a few hours after mating and are fertilized
by the sperm contained in the gelatinous mass attached to the
outside of the female’s body.

52. • The female then transfers the fertilized eggs to the underside
of the abdominal (tail) region, into a “brood chamber,”
where they are kept aerated and cleaned by movement of the
abdominal swimming appendages (pleopods).
• Eggs remain attached to the abdomen until they hatch (about
3 weeks).
• Females carrying eggs are termed “berried females.”

53. Life History
• The number of eggs produced at each spawn is directly
proportional to the size of the female
(Fecundity-5000-20,000).
• As long as water temperature exceeds 70°F, multiple spawns
per female can occur annually
The bright-yellow to orange color of newly spawned eggs
gradually changes to orange, then brown, and finally gray about
2 to 3 days before hatching.
• At a temperature of 28- 30°C, the eggs hatch approximately 20
to 21 days after spawning.
• Newly hatched freshwater prawns enter into a larval phase of
growth and metamorphosis

54. Early and Ripe stage of egg
Berried female

55. Stages of M. rosenbergii:
Larvae Post larvae (PL) Juvenile Adult
Larvae
• After hatching, larvae are released and swim upside down and
tail first.
• The larvae cannot survive in freshwater beyond approximately
48 hours and thus survive best in brackish water with salinities
of 9 to 19 ppt.
• As larvae grow they become aggressive sight feeders and
feed almost continuously, primarily on
- small zooplankton,
- worms, and
- larval stages of other aquatic invertebrates.

56. • Larvae undergo 11 molts, each representing a
different stage of metamorphosis. Following the
last molt, larvae transform into postlarvae.
• Transformation from newly hatched larvae to
postlarvae requires 15 to 40 days, depending
upon food quantity and quality, temperature,
and a variety of other water quality variables.
• Optimum temperatures for growth are about 28
to 31oC

57. • Table 1. Key for identification of larval stages of
Macrobrachium rosenbergii.
• Larval stage Age (days) Recognized characters
• I 1 Sessile eyes
• II 2 Stalked eyes
• III 3-4 Uropods present
• IV 4-6 2 dorsal teeth
• V 5-8 Telson narrows and elongated
• VI 7-10 Pleopod buds present
• VII 11-17 Pleopods biramous
• VIII 13-20 Pleopods with setae
• IX 15-22 Endopods of pleopods with
appendices internae
• X 17-23 3-4 dorsal teeth on rostrum
• XI 23-35 Teeth on half of upper dorsal margin
• PL 23-35 Adult behaviour

58. Larval
stages
of
M.
rosenbergii

59. Postlarva to adult
• After metamorphosis, the PL settle to the bottom to become
crawlers.
• PL now change to bottom-feeders, and will pick up and eat
pieces of clam, snail or squid meat, shrimps and fish flesh,
and a variety of formulated pellet feeds.
• The PL need freshwater. In nature they would migrate from
coastal waters back to rivers and grow into adults.
• The PL, known as juveniles as they grow older, have five
horizontal lines on the carapace, which are characteristic of
the species.
• PL are whitish, grey and brownish in colour and gradually
change to light brown and bluish as they grow into juveniles
and to adults.

60. Life cycle