Hatchery production prawn seeds

Sameer G. ChebbiIndustrial Fish and Fisheries

Dept. of ZoologyKarnatak Science College, Dharwad

Introduction • India has 1.24 million hector of brackish water area suitable for fish

and shrimp culture of which some area is exclusively under shrimp farming.

• A rapid development appears in Indian in shrimp culture.• For this rapid changing scenario, requirement of shrimp seed has

become many folds increased.• Natural collection of shrimp seed is also limited, which big gap

between the demand and supply of seeds from natural water bodies.

• This leads to establish commercial hatcheries for production of more seed under controlled environment.

• The Andra Pradesh Shrimp Seed Production Supply and Research Centre (TASPARC) at Mangamaripeta near Visakhapatnam and Orissa Shrimp Seed Production Supply and Research Centre (OSPARC) at Gopalpur in Oridsia state were the first two commercial shrimp hatcheries started functioning in India.

• By the 2000, in India there 100 hatchereis producing seeds in mass scale.

• Many maritime states of India has now more than 1500 hatcheries producing the seeds of prawn and fishes.

Introduction• Hatchery, as an initial phase in prawn culture, has

become an indispensable step to meet the growing fry requirement of the industry.

• The first larval rearing techniques were adopted from the Japanese method utilizing large tanks (Shigueno 1975).

• The use of small tanks was later introduced following the Galveston method (Mock & Murphy 1971).

• Through the years, considerable progress in the development of a prawn hatchery technology has been achieved.

• A much improved and simplified technology which could be easily adopted by prawn growers was in recent year by developed at SEAFDEC(AQUACULTURE DEPARTMENT SOUTHEAST ASIAN FISHERIES DEVELOPMENT CENTER).

• The techniques may be modified depending on the problems encountered in a specific site.

Brackishwater of India

• The number of shrimp hatcheries in India increased rapidly from the late 1980s to the early 2000s. 

• In the 2002–2003 production year, approximately 300 hatcheries, mostly in the state of Andhra Pradesh, used an estimated 200,000 broodstock to produce 10 billion postlarvae.

Number and Production Capacity of Shrimp Hatcheries in India by State

State Penaeus monodon Macrobrachium sp. Total

  NumberCapacity

(in millions)

NumberCapacity

(in millions)

NumberCapacity

(in millions)

Andhra Pradesh 148 7,882 43 1,453 191 9,335

West Bengal 2 100 9 66 11 166

Orissa 13 455 2 20 15 475

Kerala 22 484 7 53 29 537

Tamil Nadu andPondicherry

73 2,863 8 215 81 3,078

Karnataka 13 301 0 0 13 301

Gujarat 2 45 0 0 2 45

Goa 1 20 0 0 1 20

Maharashtra 6 325 2 20 8 345

Totals 280 12,457 71 1,827 351 14,302

• Although there are 30 shrimp hatcheries in Andhra Pradesh equipped with PCR laboratories, only a few screen the broodstock for whitespot. 

• Random checking is performed by selecting one or two individuals from a batch of 50–60 broodstock.

•  Wild-caught broodstock is the only source of shrimp seed. 

• Studies indicate that about a quarter of wild-caught spawners are infected with the whitespot virus. 

• Moreover, quality appears to vary with the season, and there are some indications that average size has become smaller and quality poorer.

Shrimp Farming Potential, Usage and Production in India

State Potential Area for Shrimp FarmingArea Under

CultureProduction

(Metric Tons)Production

(Metric Tons Per Hectare Per Year

Andhra Pradesh 150,000 69,640 53,124 0.76

West Bengal 405,000 49,925 29,714 0.60

Orissa 31,000 12,116 12,390 1.02

Kerala 65,000 14,029 6,641 0.46

Tamil Nadu andPondicherry

56,800 3,214 6,070 1.91

Karnataka 8,000 3,085 1,830 0.59

Gujarat 376,000 1,013 1,510 1.49

Goa 18,500 963 700 0.73

Maharashtra 80,000 615 981 1.60

Totals 1,190,900 154,600 112,780 0.73

Site Selection for Hatchery

Layout of a small-scale hatchery system.

Site selection criteria for a hatchery

• Careful evaluation of various criteria should be conducted before deciding on the site of a hatchery. The principal criteria are the following:

• 1. Seawater quality and quantity. Seawater with 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. The best method to determine the suitability of sea water for larval rearing is to conduct preliminary larval rearing experiments using pails or small tanks on the site. The production of postlarvae with reasonable survival rate from eggs in a series of at least three runs would indicate the likelihood of success in actual operations.

• 2. 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.

• 3. Road accessibility. The hatchery should be accessible by road for convenience in transporting supplies and other necessities for the hatchery operations. This can also minimize transport problems in the distribution of the postlarvae to be reared in ponds far from the hatchery.

• 4. Availability of electric power. Electrical power is necessary for the life support system in the hatchery. Although an independent generating unit is desirable as a standby, it is cumbersome for the hatchery staff to operate on a continuous basis.

• 5. 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.

• 6. Availability of technical staff. The technical expertise necessary for hatchery management at this stage is still rare. More incentives should be provided for technical staff recruitment.

Larval rearing tank

Penaeus monodon maturation tank

Penaeus monodon female brood stock selection

Penaeus monodon spawning tank

Penaeus monodon brood stock rearing tanks

Site selection• The location of a shrimp hatchery should satisfy following requirements,• Sea water supply• The seawater used in hatchery should be clean, clear and relatively free

from slit.• The water generally should be good with minimum fluctuations in salinity all

year round. • Suitable site are usually found near sandy or rocky shores.• Sites, which are not suitable for hatchery, include areas, which are heavily

influenced by rain or turbulence. • River mouth should be avoided as abrupt salinity changes occurs after a

heavy rainfall.• An added advantage of having a site on rocky shores is that good quality

sea water is relatively near the shore line. • This reduces the cost piping installation and pumping.• The hatchery site should also be free from any inland water discharges

containing agricultural and industrial wastes.• The seawater with temp 28 to 32 C salinity 28-34 ppt, pH 7.7-8.2 and

suspended solid below 20ppm, is required.

Accessibility

• Ideally, a hatchery site should be selected in areas where there are active shrimp farming operation so that the seed produced can be easily transported and distributed to the grow-out ponds.

• The site chosen for a hatchery must have an easy access to communication and transportations channels.

Topography

• The ideal site should be spacious, situated on flat to gently sloping grounds, well drained and not susceptible of floods, strong wave and tidal actions.

• It should be on compact soil and accessible by paved road.

Availability of power sources

• A shrimp hatchery cannot be operated without electricity.

• Electricity is essential to provide the necessary power to run equipment and other life support system of the hatchery.

• Hence, the site must have a reliable source of power.

• Installation of a standby generator is absolutely necessary especially in areas where there are frequent and /or lengthy power failures and fluctuation or without power supply.

Other requirements

• The stable quality of fresh water is essential. • There must be a source of broodstock of the

farm for brood stock development nearer to the hatchery.

• Availability of technical hands and skilled labours are also needed.

• It is also advisable to pay attention to land values early in the site selection phase to ensure that the site is available for purchase or lease and at a price consistent with the project budget.

Classification of Hatcheries• The hatcheries are classified into four

categories:• Backyard Hatcheries: these hatcheries can

produce 1-2 million seeds per year.• Small Scale Hatcheries: these hatcheries can

produce upto 10 million seeds per year.• Medium-scale Hatcheries: these produce 10-40

million seeds per year.• Large Scale Hatcheries: the hatcheries, which

produce more the 40 million seed per year called large-scale hatchery.

Sea Water Intake and Filtration Unit

• Generally pure seawater is drawn from the sea by a pumping unit through filter.

• The filter is made up of different layer of sand, pebbles and granite throughout which the water is drawn into a pvc pipes having slit opening.

• This is called slow sand filter. The rapid sand filters are also available in the market now a days.

• The water is pumped up into chlorination unit and then dechlorination unit. These tanks are of RCC from there, water is pumped into the over head tank and located at an elevated level adequate enough to flow the water to the hatchery by gravity.

Aeration Unit

• Oil free air compressor is required in the hatchery to ensure oxygen supply for maturation rearing and related system.

• A pair of positive displacement blowers are required for a 10 million seed hatchery.

• The air supply grid with pvc pipes is connected for all the facilities.

Power Supply Unit

• The power requirement varies depending upon the capacity and type of hatchery.

• A 10 million/annum capacity hatchery needs around 80kw power supply.

• A stand by generator to combat power failure with the alternative power supply is required.

Brood stock development and maintenance unit

• The maturation tank used in hatchery is generally of 10-16 tones capacity, round or rectangular with oval shape inside.

• A 50 mm diameter pvc stand pike regulated the water flow during cent percent water exchange.

• The maturation unit should be sound proof. • A photo-period of 12 h light; 12 h dark is maintained in

maturation unit.• Diffused illumination for 12 h a day is provided by

fluorescent light of 40 watt each suspended at 1 m above the tank.

• The total lighting stimulated like a deep sea environment for breeding.

Spawning and Hatching Unit

• Spawning and hatching unit can be combined with the maturation shed, free from dirt.

• FRP tanks or 250 liter capacity are generally used to spawn the mature female.

• These tanks should be aerated well and water quality should be maintented very well.

Larval rearing unit• The larval rearing section is one of the main area

of activity. • The tanks used are either parabolic shape and

cement construction of cylindro-conical or round flat bottom and made of FRP material.

• RCC tanks may also be used and capacity of tanks differs from 2 tons to 10 tons water.

• Each tank has one out let with maximum slope drawn to wards the out let which enables to drain out even the last drop of bottom water.

• Aeration from air grid is provided in each tank and throughout water supply unit treated sea water is filled in larval rearing tank.

• The inner surface of the tank is painted with green apoxy paint.

Post Larval Rearing Unit• The hatcheries having indoor post larval rearing

facility use cemented tanks either of rectangular flat bottom or parabolic ‘U’ shape of which the latter is most efficient.

• The capacity varies from 20 to 30 tones of water holding capacity.

• The inner surface of the tank is coated with good apoxy resign painted of fiber coating for maintaining better hygienic condition.

• The post larval unit (PL) is also well connected with water and aeration system.

Algal culture Unit

• Algal section has got two wings that is indoor algal section and outdoor algal section.

• Indoor section is completely air conditioned for culture of algea.

• As the space is indoor air condition algal unit is limited, 20 liters to 200 liters carbouoys are shifted to out door algal culture section.

• For mass culture 1 to 6 ton cemented tank or 200 liters FRP tanks may also used.

Artemia Hatching Unit

• For hatching of Artemia cyst 200-500 liter capacity FRP cylindro-conical shaped tank having bottom drain facility with a side glass window is needed.

• Continuous aeration and 40w light fixed at 20 cm above the tank are provided.

Counting and Packing Unit

• For counting, packing and transportation of seeds a separate section is engaged. Now a days is just an open shed.

• All these together around 130 sq. meter ground area per million seed.

• A totally indoor rearing facility of the hatchery will need 50-70 sq. meter area per million built up space, in a hatchery shed protected by walls and roofed with asbestos sheet inter-spred with translucent FRP sheet for lighting.

Nursery rearing • The larval rearing is one of the most sensitive activity. Larval

rearing in each tanks is separately monitored. • The nauplii from the spawning tank collected in the harvesting

bucket is estimated for population using sampling method before stocking.

• Mean values of atleast three samples of 50ml from the bucket is considered for the estimation.

• The nauplii are stocked in larval rearing tanks normally 60 to 100 number per liter.

• The larvae are reared upto PL4/PL5 for about 15 days clean healthy environment is needed for the rearing which is maintained through water exchange daily for zoea stage.

• The feed are provided Arrtemia nauplii and micro algae. The survival rate upto PL state is bout 50 percent.

• When the attack of any disease occur, antibiotics and other medicines of aquatic grade are used.

• Post larval rearing is done upto PL20 stage which takes about 20days PL20 is then harvested for selling.

• Post larvae of good quality, active and healthy are stocked in the indoor PL rearing tanks 25-50 PL/Liter and 8-10 in outdoor PL rearing tanks.

• Algal feeding is continued at 50,000/ml concentration.

• Artemia nauplii is added 2 nauplii PL. in addition egg is given up to PL5. from PL6 and above pleted feed is give at 2-3 percent per day.

• If any disease problem is seen, the post larvae are feed with antibiotic with egg lusted or aquatic grade antibiotic or medicines are directly applied.

Transportation of Prawn seed • Packing of seeds:• Polythene bags of 15-20 liters capacity are used for packing of

prawn see. • The corners of the plastic bags are rounded off with the help of

rubber bands so as to prevent the prawn seed from getting trapped during packing.

• For filling the plastic bags, the water from the post larval tank is used.

• The use of new water is avoided for packing. If new water is used, most of the post larvae will moult during transportation with consequent losses through canniblism.

• In order to provide shelter to post-larvae, a few 10 mm plastic thread should be placed in the bags.

• The avoid cannibalism of post larvae during long distance transportations post larvae are fed with like feed such as Artemia properly, the post larvae in appropriate densities (75 PL/125 L) depending on the distance of transportations.

• After placing post-larvae the air present in the bag is removed by folding it and remaining 2/3 of the bag is filled with oxygen by inserting the oxygen supply pipe in the water from oxygen cylinder.

• This helps in saturation of dissolved oxygen in the water.

• The bag is then sealed tightly with a rubber band.

• For very long distance, the ploythene bags are placed in a insulated containers.

• Hatchery production of seed in prawns

• 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.

• 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.

• Breeding Management1. Selection• For breeding select the males who are

above 60 gm size or 18-20 cm long. Mature females are bigger than the males.

• Hence, for selection of females a specific weight is not mentioned. Obviously the females selected will be bigger than the males. The selected males and females are placed into the maturation tank. Select only the good ones: without any abnomlalities, infection or injuries, having proper shape and size.

• Induced maturation

• Under the natural conditions the female attains full ovarian development in the sea while the male can become mature even in brackish water.

• Some species may not mature or may be shy to mature sexually and spawn under the artificial rearing conditions. Therefore in the commercial rearing of shrimps! prawns certain methods of induced maturation is employed.

• The most common and easy method of inducing maturity in the shrimps and prawns is to remove one of the eyes (eye stalk ablation) either with a sharp blade or with an electrocautery unit:

• This method is preferred, because there is no bleeding. However the shrimp/prawn experiences some stress due to eye ablation and 5-10 % mortality occurs due to this. Usually only the females are subjected to eye ablation but if the males are held captive more than two weeks they are also subjected to eye ablation.

• Soon after the eye ablation maturation takes place. The gap between eye ablation and maturity in P monodon is about 10-15 days and in P indicus about 2-3 days.

• The fully mature females will have a diamond shape of ovarian lobe in the first abdominal segment. In the case of P indicus the shells are translucent and hence the ovary can be seen clearly but in the case of P monodon we need an underwater torch to examine the ovarian condition. An experienced person can observe the ovary and assess the stage of the maturity of the ovary.

• The spermatozoa produced by the male is non motile and are packed inside spermatophores and they are transferred by the male through the petasma to the thelycum of the female during mating.

• At the time of spawning the female releases the eggs as well as the spermatozoa and the fertilization takes place outside the body of the female in the water.

• Every day the water level in the tank is reduced by about 80% m the evening and the shrimps are examined to see whether the females are mated or not which can be ascertained by the presence of the spermatospore in the thelycum. The females that have been mated are netted out and placed in the spawning tank.

? Shrimp eyestalk ablation.mp4