TỔNG ÔN TẬP THI VÀO LỚP 10 MÔN TIẾNG ANH NĂM HỌC 2023 - 2024 CÓ ĐÁP ÁN (NGỮ Â...
Shrimp hatchery
1. SHRIMP HATCHERY
Name Registration No.
Nazmul Ahmed Oli 12-05-2835
Nusrat Nomary 12-05-2836
Bishwajit Karmakar Sunny 12-05-2837
Rupa Shaha 12-05-2838
Md. Mahfuzur Rahman 12-05-2839
Bilkis Jahan 12-05-2846
Imran Hossain 12-05-2864
Presented By
2. Hatchery:
• A facility where eggs are hatched
• Maintain artificial conditions,
• Especially those of fish or poultry.
Fig: Shrimp Hatchery
3. Shrimp Hatchery
Locations where
shrimp are kept
during their
lifecycle
development
Maintain artificial
condition
On the way to
becoming fully-
formed shrimp for
commercial sale.
Fig: General Layout Of Shrimp Hatchery
4. SITE SELECTION
Location:
• Suitable sites are sandy and
rocky shore because there is
clean, clear and good quality
sea water all year round.
• swamps and muddy shores are
avoided.
Sea water supply
• clean, clear and relatively free
from silt
• stable with minimal fluctuation
in salinity
5. Availability of
spawners
Easily
available
Low cost
Availability of
power source
Sufficient
electricity
supply
Power
generator
(costly)
Freshwater
supply
Salinity
adjustment,
Equipment
maintenance
Domestic
use.
Climate
conditions
Sunlight
available
Suitable in
temperate
region
6. SIZE OF HATCHERY
Small-scale hatchery
Owned and
managed by the
shrimp grower
himself
Space ranging from
a few square meters
up to about 1000
square meters
9. Hatchery facilities
A functional hatchery should have the following
essential components-
Maturation
Tanks
Spawning
tanks
Larval
rearing
tanks
Live food
culture
tanks
Water
storage and
filtration
tank
10. Maturation tanks
• The shape of maturation tanks can
either be circular, rectangular or oval.
• The tank capacity may vary from 5 to
40 tons with depth ranging from 1.2 to
2 meters.
• If the shrimps are kept for less than 5
weeks, bottom substrate is not needed
in the tank.
Spawning tanks
• Spawning tanks should be circular with
a flat or conical-shaped bottom.
• Water holding capacity may vary from
50 liters to 1.5 tons.
A MaturationTank
11. Larval rearing
tanks
Two types of rearing
tanks are being used to
rear the newly hatched
larvae
Larger tanks with a
capacity of more than 50
tons , smaller larval
rearing tanks of about 3
tons capacity
Live food culture
tanks
In mass cultivation of
live food organisms,
size of tanks used
usually ranges from 1
to 20 tons.
Made of either
fiberglass,
polyethylene, marine
plywood or concrete.
Water storage and
filtration tank
Water storage tank is
normally elevated to
effectively distribute
water by gravity to the
hatchery.
normally constructed
out of reinforced
concrete to withstand
the water pressure.
13. • It is necessary for maintaining
sufficient dissolved oxygen
concentration in the water
• For ensuring even water
temperature throughout the water
column through turbulence
• It is provided with a roots blower,
rotary blower or an air compressor
• In culture tanks with depth less
than 2 meters, an air pressure of
about 0.2–0.3 kg/cubic centimeters
and a volume of 4–5
liters/m2/minute is sufficient to
oxidize the dissolved organic
matter in the tanks.
Aeration
Aeration
14. Marine pumps
• Centrifugal pump is more desirable in the big hatchery
because it has a higher total head capacity.
• Small or backyard hatchery, a submersible pump with a
discharge pipe diameter between 1" to 4" and a
discharge capacity of 6–20 tons/litre.
15. • Lay-out of the hatchery should provide a
schematic design of the location and integration
of various facilities such as buildings, broodstock
tanks, larval rearing tanks, nursery tanks,
spawning tanks, pump house, air supply and
power house, laboratory, staff house, piping for
water supply and drainage canal.
Lay-out and
construction
Layout of medium scale hatchery Layout of small scale hatchery
16. PREPARATION OF BROODSTOCK FOR
SPAWNING
Conditioning of brood stock
• The holding tanks should be big enough to provide
proper space and aeration. 60% of the water in the tanks
is changed daily.
• The salinity is decreased by about 4–5 ppt for two days
and then increased to the normal salinity of the seawater.
Mating occurs during this time
Induced maturation
• Complete appendages
• Presence of spermatophore in the thelycum of
females
• Size should at least be 100 gm.
Mature Male and Female
17. Maintenance of broodstock in maturation tanks
Sampling
• Gonadal development of an ablated female is checked 3–5
days after ablation while checking for gravid females is
carried out every other day.
• During sampling, an underwater flashlight, tied to a pole is
held close to the shrimp so that the light strikes
perpendicularly on the dorsal part of the body where the
ovaries are located.
• Only gravid females with stages III or IV ovaries are collected
and transferred to spawning tanks
18. Preparation of facilities for spawning, hatching and
larval rearing
Tank facilities-
• 1.Newly constructed hatchery
• 2.Operational hatchery
Water quality and supply
• The most important factors in hatchery operation.
• Must be regularly monitored for important physico-chemical
parameters.
• Initial water passing through the filter must be drained to prevent
bacterial load.
• Disinfecting and cleaning with chemicals will make the filter neat.
19. Selection of Spawners & Egg Collection
• Spawning time from December to March and June to September.
The criteria used for selecting
spawners from the wild are-
1. Stage IV ovary
2. Presence of
spermatophore
underneath the
thalycum
3. Coloration
4. Presence of appendages
and good health.
20. Procurement and transportation of spawners
1. Live fish holding compartment in the
boat with running water system
2. Holding tank with aerated seawater at
controlled temperature (22–24°C) using ice.
3. Plastic bags injected with oxygen and
packed in styrofoam boxes.
4. Bamboo or PVC tubes
Fig: Transportation in polyethene bag.
21. Treatment of
spawners
•Spawners are usually treated with either (a) Treflan (trade name),
0.5–1 ppm (b) KMnO4, 3ppm or (c) Formalin, 25 ppm for 10–15
minutes.
Spawning activity
•Spawning usually occurs while swimming with the spermatophore
in the thylecum and eggs are released from the genital pore.
•sperms are likewise discharged into the water through an
apperture at the base of the fourth pereiopod
Egg collection and treatment
•After spawning, the animal is removed from the tank the
following morning.
•During the cold season, fungus and bacteria are likely to infect
the eggs during incubation.
22. Hatching and Transportation of nauplii
Eggs of most species of shrimps within 12–18 hours
after fertilization at temperature and salinity range of
26–30°C and 30–23 ppt.
Determination of hatching rate
Transportation of nauplii
Plastic containers - Only strong and healthy larvae should be
transported. Survival rate is above 50%.
Plastic bags - Each bag containing about 6–8 liters of water can
be stocked with 200,000 nauplii. Survival rate is 80-90%.
23. Larval rearing
1. Larval rearing in small indoor tanks
This is a critical stage of
larval rearing.
The larvae at this stage
start feeding on
microscopic algae like
skeletonema, tetraselmis
etc.
Microencapsulated algae
can be used.
The use of these types of
The larvae at this stage
will start feeding on
rotifers (Brachionus
plicatilis) or brine
shrimp naupli.
Each mysis larvae
consumes about 100–
200 rotifers or about
20–50 Artemia nauplii
per day
25. 2. Larval rearing in large nursing tanks
The initial water level in the 40-ton
nursery tanks during stocking is 100
cm.
The nauplii density is usually about
20–50 per liter.
Technical grade fertilizers can be
used directly to enhance algae
growth.
It is pertinent to monitor the types
and density of algae in big tanks to
ensure that the optimal density is
maintained. Fig: Schematic diagram of prawn
production from hatchery to grow-out
27. Maintenance of water quality
-Salinity
-Temperature
-Dissolved oxygen
-pH and nitrogenous compound
Feeds and feeding schemes
Monitoring
ROUTINE HATCHERY MANAGEMENT
28. MAINTENANCE OF WATER QUALITY
Salinity
• Salinity in spawning grounds normally ranges from 30 to 36 ppt.
• seawater salinity in spawning tanks should be maintained at 30–32 ppt to ensure good hatching rates.
Temperature
• In penaeid shrimps, eggs do not hatch at temperatures lower than 24°C.
• The optimum temperature is 26–31°C.
• molt to mysis stage within 4 days at temperatures ranging from 28°C to 31°C,
• however, molting takes 6 days when temperature drops to 24–26°C.
Dissolved
oxygen
• Dissolved oxygen is a critical factor in larval rearing.
• High mortalities can occur if aeration stops even for only one hour.
pH and
nitrogenou
s
compound
• Normal pH of seawater ranges from 7.5 to 8.5.
• NH3 and NH4 ratio in water is pH dependent.
29. • The approximate density sufficient for
larvae in the rearing tank is 50,000/ml for
Chaetoceros sp.
• Brachionus must be maintained at 20
individuals/ml and Artemia at 50 grams for
every 100,000 post-larvae.
Feeds and feeding
schemes
• Environmental parameters such as water
temperature, salinity and pH should be
checked twice daily.
• Count larvae in three 1-liter samples for
small tanks and 10 times for big tanks.
Monitoring
30. NURSERY OF POST LARVAE
• Concrete tanks
-Ideal stocking density of the larvae is about 50/cubic meter of water.
• Earthen pond
-Nursery pond size ranges from 500 to 20002 and water depth at 40–70 cm.
-P9-P10 are suitable sizes for stocking in the nursery ponds.
-Stocking density is 100–150 individuals per square meter.
• Nursery cages
-Postlarvae (p6–7) is suitable for stocking in cages at a stocking density of
1000–2000 per cubic meters of water.
Figure: Nursery
Figure: Nursery Cages
(stationary cages & floating
cages)
31. HARVEST AND TRANSPORT OF LARVAE
• P21-P25 is suitable for harvesting from nursery tanks because this size can be stocked
directly to the pond and easily be transferred.
• The postlarvae can also be harvested with a scoop net, dip net or seine net after 2/3
of the tank water has been drained.
Methods of transporting post-larvae
Tanks
-Post-larvae can be transported in plastic, fiberglass or canvass tanks of a suitable
transport size (500–1000 liters) and provided with aeration.
Plastic bag
-post-larvae are transported in polyethyelene bags provided with oxygen.
-The bag (60 cm × 40 cm) is first filled with 6–8 liters of fresh seawater and then
packed with 3000–5000 post-larvae.
32. GUIDELINES — SHRIMP HATCHERIES
Community property rights and regulatory compliance
Community-community relations
Community-worker safety and employee relations
Environment-ecosystem protection
Environment-effluent management
Food safety, drug and chemical management
Environment storage and disposal of hatchery supplies
Comments:Shrimp hatcheries may require some facilities, such as pipe -lines, to be
located on public land. Where this is the case, hatcheries shall ensure that local
communities are consulted, approval is granted by pertinent authorities and adequate
precautions are taken to prevent the facilities from being a hazard, nuisance or eyesore.
