2. Introduction
Giant Tiger Prawn (P. monodon, also known as "black tiger
shrimp") occurs in the wild in the Indian Ocean and in the
Pacific Ocean from Japan to Australia.
The largest of all the cultivated shrimp, it can grow to a
length of 36 cm and is farmed in Asia. Because of its
susceptibility to white spot disease and the difficulty of
breeding it in captivity, it is gradually being replaced by L.
vannamei since 2001.
3. P. Monodon Taxonomy
Kingdom : Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostracea
Order: Decapoda
Suborder: Dendrobranchiata
Family: Penaeidae
Genus: Penaeus
Species: P. Monodon
4. Biological Features
The shell is smooth, polished and glabrous.
The rostrum extends beyond the tip of the anntennular
peduncle, is sigmoidal in shape and possesses 6-8 dorsal
and 2 ventral teeth, most 7 and 3 respectively.
The carapace is carinated with the adrostal carina almost
reaching the posterioi margin of the carapace.
The gastro orbital carina occupies the posterior one-third
to one half distance between the post-orbital margin of the
carapace and the hepatic spine.
5. Cont…
The hepatic carina is prominent and almost horizontal.
The antennular flagellum is subequal to or slightly longer
than the peduncle.
Europods are present on the first four pereopods but
absent in the fifth.
The abdomen is carinated dorsally from the anterior one-
third of the fourth, to the posterior end of the sixth
somites.
The telson has a median groove but w/o dorso-lateral
spines.
6. Life Cycle
The eggs are demersal and tend to sink while larvae are
Planktonic.
Prawn larva thrives mainly offshore and undergoes three
main stages: nauplius, protozoea, and mysis.
At the postlarval and juvenile stages, the prawn migrates
toward the estuary.
As it grows, it starts moving to the shallow coastal waters.
The adult prawn inhabits the open sea.
7. Cont….
Sexes are separate and can be easily distinguished through the
external genitalia located at the ventral side. The thelycum in
females and petasma in males.
During mating, the male deposits the spermatophore inside the
thelycum of the female.
Mating can only occur between newly molted females and
hard-shelled males.
Spawning tanks place throughout the year. The eggs are
fertilized in the water after the female simultaneously extrudes
the eggs and the spermatophore. The number of eggs released
by a single spawner varies from 248,00 to 811,000.
8. Eggs
The eggs are small, spherical, and vary from 0.25 to 0.27
mm in diameter.
The developing nauplius almost fills up the entire space
inside the egg.
At 28-30°C, the eggs hatch 12-17 h after spawning.
9. Nauplius Stage
Stage after eggs have hatched.
The prawn nauplius is very tiny, measuring from 0.30 to 0.58
mm in total length.
It swims intermittenly upward using its appendages in a “bat-
like” manner.
It is attracted to light and in aerated tanks, it will concentrate
in the most lighted areas if aeration is stopped.
The nauplius molts through each of six sub stages for a total of
about 1.5-2 days.
The substrates differ from each other mainly on the furcal
spine formula. The latter indicates the number of spines at each
side of the furca.
10. Protozoea Stage
• Its body is more elongated and measures from 0.96 to 3.30 mm
in total length.
• It consists of the carapace, thorax and abdomen.
• It can also be distinguished by its movements, it swims
vertically and diagonally forward towards the water surface.
• The protozoea undergoes three sub-stages. The paired eyes of
protozoea I can be obscured as two dark spots in the upper
portion of the carapace.
• These eyes become stalked at protozoea II.
• At protozoea III, the dorsal medain spine at the sixth abdominal
segment first appears.
11. Mysis Stage
Shrimp-like with the head pointing downward.
Its body measures from 3.28 to 4.87 mm in total length.
The telson and uropods are developed.
The mysis swims in quick darts accomplished by bending
the abdomen backwards.
For mysis sub-stages, the most prominent change is the
development of pleopods.
The pleopods appear as buds at Mysis I, which protrude
at Mysis II and finally become segmented at Mysis III.
12. Postlarval Stage
The post larval resembles an adult prawn.
At postlarva I the rostrum is straight and exceeds the tip
of the eye.
It usually has one dorsal rostral oine w/o any ventral
spine.
Plumose hairs are present on the swimming legs.
13. Reproduction
P. Monodon is heterosexual.
The female attains a relatively larger size than the male.
The sexually mature prawn can be distinguished by the
presence of the external genital oragans: joined petasma, a
pair of appendix masculina on the exopods of the second
pleopods, and a genital opening on the coxa of the fifth of
pereopod for the female.
In females, the thelycum is situated between the fourth
and fifth pereopod w/ the genital opening on the coxa of
the third pereopod.
14. Male Genital Organ
The internal reproductive organ of the male consists of
paired testes, vasa deferentia, and terminal ampoules
located in the cardiac region dorsal to the hepatopancreas.
The testis is translucent and composed of six lobes, each
connected in the inner margins leading to the vas deferens.
The vas deferens consists of four porions, namely: the
short narrow proximas vas deferens, and the muscular
portion referred to as terminal ampoule.
The terminal ampoule contains the terminal
spermatophore and opens at the base of the coxopod of the
fifth pereopods.
15. Cont…
The spermatozoa are minute globular bodies composed of
the head of about 3 microns in diameter and a short spike.
The petasma is a pair of endopods of the first pleopods
formed by the interlocking hooklike structures.
The appendix masculina is oval and is located on the
endopod of the second pleopod.
16. Female Genital Organ
Consists of paired ovaries and oviducts.
Ovaries are bilaterally symmetrical, partly fused and
extend almost the entire length of the mature female.
It is composed of the anterior lobe located close to the
esophagus and the cardiac region of the stomach; the
lateral lobes located dorsal to the hepatopancreas; and the
abdominal lobe w/c lies
17. Hatchery Facilities
Larval and Postlarval Tanks:-
Rubberized canvas, marine plywood, fiberglass, or
concrete.
These can either be circular, oval or rectangular,
depending on the operator’s preference or financial
capability.
The capacity of each tank may be from 1-20 t but 10-12 t
tanks are more economical and practical
Depth should only be about 1m because tanks w/c are too
deep are difficult to manage.
18. Algal tanks
Minute plants (phytoplankton) are needed as food for the
early life stages of prawn.
Algal tanks must be shallow (ideally 0.5 m deep) to allow
sufficient light prevention.
19. Spawning Tanks
It is advantageous to have smaller tanks w/ volumes
ranging from 0.25 to 1 t where egg washing is done
20. Artemia Hatching Tanks
Artemia or brine shrimp is a protein-rich live food
organism given to prawn larvae starting at the Mysis
stage.
Artemia is available in cyst form w/c has to be hydrated
and incubated in tanks for at least 18-24 h.
21. Aeration System
Aeration is necessary in hatchery operations to keep food
particles and algal cells in suspension and to maintain
sufficient dissolved oxygen levels.
Continuous aeration is essential during operations. A
standby generator will be very useful during power
interruptions.
22. Preparation of Spawning, Larval,
and Nursery Tanks
To prevent disease outbreak, the hatchery should be
totally dried after several production runs.
Tanks and facilities in the hatchery must also be cleaned
well prior to a hatchery run.
New tanks need to be filled w/ fresh or seawater for at
least a week to avoid mortalities due to toxic effects of
chemicals used during construction of the tanks.
23. Selection and Stocking of
Spawners
Nauplii to be reared to the fry stage can come from
a) broodstock – wild or pond-reared immature females
induced to mature by unilateral eyestalk ablation.
b) Wild spawners – female prawns caught from the sea w/
developed ovaries.
The number of spawners needed for a hatchery runs is
dependent of the nauplii requirement.
24. For every million nauplii about 4-5 wild spawners or 7-8
m female broodstock are needed.
Spawner procured as nauplii source must be carefully
selected to obtain high fertilization and hatching rates of
eggs.
Stage of maturity should not be used as the basis for
selection.
Spawners must also be disease free. To ensure
development of the eggs, females should be mated to
ensure release of sperm cells necessary for fertilization.
25. Stocking of Nauplii
During stocking and throughout the culture period, prawn
must not be exposed to abrupt changes in environmental
conditions.
The prawn must be given time to gradually adapt to new
conditions to avoid stress and mortalities.
26. Feeding
Nauplii subsits on the yolk stored in their bodies.
Larvae start to feed at the first protozoeal sub stage (
diatoms like Skeletonema or Chaetoceros)
Larvae at the second protozoeal sub stage may be fed
Tetraselmis.
At the Mysis Stage, some fish protein must be present in
the diet.
27. Newly hatched artemia nauplii and microparticulate diets,
most commonly used protein source w/c contain about 45-
50% protein.
When they reach the postlarval stage, egg custard, trash
fish, mussel meat or ground dried acetes (small shrimp or
alamang) can be given to supplement the Artemia nauplii
diet.
28. Water Management and Treatment
The quality of the rearing water in larval tanks deteriorates
after sometime due to the accumulation of feces, and
decomposition of uneaten food and dead larvae.
The resulting water temp. and salinity after water change must
not differ by more than 1°C or 2ppt.
In high density cultures by more (100 nauplii/liter) water
change is done daily starting at the second protozoeal substage.
About 30% of the water volume is changed at the protozoeal
stage and 50% at the Mysis stage.
At lower density (50-80 nauplii) water change is done only
after all the prawn in the tank have metamorphosed to the post
larval stage.
29. The latter water mngt. Scheme and lower stocking densities
result to better survival rates because of lesser stress due to
water change.
Water for rearing is treated w/ 5-10 ppm hypochlorite.
Treated water can be neutralized by strong aeration until all
chlorine residues are evaporated or by addition of sodium
thiosulfate.
Hypochlorite kills are retards the growth of possible harmful
microorganisms. However, it is also toxic to larvae or
postlarvae so water must be neutralized.
Water should also be treated w/ 5-10 ppm EDTA (ethylene
diamine tetracetic acid) to chelate heavy metals.
High survival rates could also be obtained when water is
allowed to stand about 3 days after neutralization before this
used for culture.
30. Harvest, Transfer, Packing, and
Transport
Proper procedures must be observed for harvest, packing,
and transport to ensure high survival of prawn fry.
The number of fry loaded per bag will depend or the size
and age of fry, travel time, distance, and means of
transportation.
During extended transport periods, water temperature
must be reduced to decrease molting and metabolic rates
and the incidence of cannibalism among prawn fry.
However, there is no need to lower water temperature in
transport bags when transporting at night or during cool
weather.
31. Seawater Quality and Quantity
Seawater w/ minimum seasonal fluctuation in quality is
most desirable.
It should not be affected by inland discharges containing
agricultural runoff or industrial wastes.
Turbidity should be as low as possible.
Adequate volume of seawater should be available when
needed.
32. The best method to determine the suitability of seawater for
larval rearing is to conduct preliminary larval rearing
experiments using pails or small tanks on the site.
The production of post larvae w/ reasonable survival rate
from eggs in a series of at least three runs would indicate
the likelihood of success.
33. Source of Spawners
Whether the spawners to be used in the hatchery are
matured by means of eyestalk ablation in tanks, cages or
pens, or caught from the wild, it is most desirable for a
hatchery site to be near the source of spawners for a
constant supply.
Although there are existing techniques of transporting
spawners over long distances, the quality of eggs may be
greatly affected by the transport stress.
34. Road Accessibility
The hatchery should be accessible by road for
convenience in transporting supplies and other necessities
for the hatchery operation.
This can also minimize transport problems in the
distribution of the post larvae to be reared in ponds far
from the hatchery.
36. Fresh Water Source
The need for fresh water is minimal but an adequate
supply is essential for miscellaneous activities and
personal needs of hatchery staff.
37. Availability of Technical Staff
The technical expertise necessary for hatchery
management at this stage is still rare.
38. Harvesting
Harvesting is done by first draining out threefourths of the
volume of water in the tank. A strainer is used to prevent
the fry from being drained out. The drain valve is then
opened slowly and the contents discharged into a 150-L
harvesting box. The upper one-fourth portion of the walls
of the harvesting box is fitted with plastic screen to allow
the water to overflow while retaining the fry inside.