1. Penaeus Monodon
Hatchery Management

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 whitespot
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.

5. • 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.
• The hepatic carina is prominent and almost
horizontal.
• The antennular flagellum is subequal to or
slightly longer than the peduncle.

6. • 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.

9. 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.

10. • As it grows, it starts moving to the shallow
coastal waters. The adult prawn inhabits the
open sea.
• 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.

11. • 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.

12. 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.

13. 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.

14. • 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.

15. 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.

16. • 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.

17. 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.

18. • The pleopods appear as buds at Mysis
I, which protrude at Mysis II and finally
become segmented at Mysis III.

19. 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.

20. 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.

21. • In females, the thelycum is situated between
the fourth and fifth pereopod w/ the genital
opening on the coxa of the third pereopod.

22. 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.

23. • 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.

24. • 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.

25. 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

26. Hatchery Facilities

27. 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

28. • Depth should only be about 1m because
tanks w/c are too deep are difficult to
manage.

29. 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.

30. Spawning Tanks
• It is advantageous to have smaller tanks w/
volumes ranging from 0.25 to 1 t where egg
washing is done

31. 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.

32. Reservoir
• Storage tank is necessary for chlorination and
holding of filtered and treated water for daily
use.
• This must have a total capacity of at least
50% total larval tank volume.

33. 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.

34. 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.

35. 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.

36. • The number of spawners needed for a
hatchery runs is dependent of the nauplii
requirement.
• 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.

37. • 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.

38. 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.

39. 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.

40. • 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.

41. 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.

42. • 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.

43. • 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.

44. • 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.

45. 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.

46. • However, there is no need to lower water
temperature in transport bags when
transporting at night or during cool weather.

47. 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.

48. • 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.

49. 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.

50. 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.

51. Availability of Electric Power
• Electric Power is necessary for the life system
in the hatchery.

52. 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.

53. Availability of Technical Staff
• The technical expertise necessary for
hatchery management at this stage is still
rare.

54. 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.

55. Questions?