SHRIMP HATCHERY

Hatchery:

• A facility where eggs are hatched

• Maintain artificial conditions,

• Especially those of fish or poultry.

Fig: Shrimp Hatchery

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

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

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

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

Medium-scale hatchery

larger than the small-scale

hatchery

More labour required

Annually 10–20 million post-

larvae produced.

Large-scale Shrimp Hatchery

Mainly for commercial

purposes

national agencies or cooperative

projects

More labourrequire

More cost

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

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 Maturation Tank

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.

Spawning tanks Artemia culture tank

Water Storage Tank

• 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

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.

• Lay-out of the hatchery should provide a schematic design of the location and integration of various facilities such as buildings, broodstocktanks, 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

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

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

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.

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 spermatophoreunderneath the

thalycum

3. Coloration

4. Presence of appendages and good health.

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.

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.

• Dipping the eggs in1 ppm of methylamene blue or 0.5 ppm of malachite green for 10 minutes or 3 ppm KMnO4 for 30 minutes to prevent.

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%.

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 feed

can reduce production cost

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

Fig: Small nursery tank

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

ponds

Fig: large nursery tanks

Maintenance of water quality

-Salinity

-Temperature

-Dissolved oxygen

-pH and nitrogenous compound

Feeds and feeding schemes

Monitoring

ROUTINE HATCHERY MANAGEMENT

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.

• 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 bechecked twice daily.

• Count larvae in three 1-liter samples for small tanks and 10 times for big tanks.

Monitoring

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

Pond

Figure: Nursery Cages (stationary

cages & floating cages)

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-larvaeTanks

-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.

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.

THANKS TO

ALL