construction and maintenance of prawn farms

Construction and Maintenance of Prawn Farms

By

Balwant Singh

Dheeraj Shukla

balwantsingh1642@gmail.com

Requirements and Characteristics of Prawn Farm

• A good hatchery site should also have thefollowing characteristics:

1) A secure power supply which is not subject tolengthy power outages. An on-site emergencygenerator is essential for any hatchery where thescale of investment warrants it.

2) Good all-weather road access for incomingmaterials and outgoing post-larvae and prawns.

3) Access to professional biological assistance fromgovernment or other sources.

Cont……4) Land, of an area appropriate to the scale of the

hatchery, with good access to seawater andfreshwater supplies. The cost of pumping watersupplies to a site elevated high above sea level isan important factor in the economics of theproject.

5) A climate which will maintain water in theoptimum range of 28o -30o C without costlyenvironmental manipulation.

6) Access to food supplies for larvae, adults andbrooders.

7) A high level of technical and managerial skills.

FARM FACILITIES • A freshwater prawn farm is very similar to a

freshwater fish farm.

• Freshwater prawns are stocked into concrete andearthen reservoirs, ponds, irrigation ditches,cages, pens and into natural waters.

• Cage and pen culture is experimental, while theproduction from irrigation ditches is low; stockinginto natural waters and reservoirs is not strictlyprawn farming.

Cont…..• Hatchery design will depend on the scale of

production desired, the characteristics of the site

(such as topography, climate, etc.), the type of

building materials obtainable locally and the

finance available.

• A complete hatchery design for freshwater prawns

is simple to construct and operate in sequence.

Fresh Water Prawn Farming Concepts

• Fresh Water Prawn Culture are grown in earthenponds located in coastal areas of countries withtropical and subtropical climates.

• Ponds are filled with freshwater, Prawn isreproduced and raised in captivity are stockedinto the ponds and are ready for harvest in 90 to120 days.

Prawn hatchery

• The hatchery building is usually associated withthe nursery tanks and grow-out ponds in termsof water supply and other requirements.

• A freshwater prawn hatchery produces PL forgrowing out in ponds and for sale to other prawngrow-out enterprises.

Farming of Fresh Water Prawn• Fresh Water Culture are depend upon following

things:

1) Location of farm

2) Farm Permits

3) Farming Strategies

4) Pond Construction

5) Crop Species & Feeding

6) Stocking

7) Management

8) Harvesting

Farm Location1) A study of the potential market for the product

and careful selection of suitable sites for prawnculture, whether it be for the larval (hatchery)or grow-out phases, is an essential prerequisitefor successful farming.

2) Farm constructed near of fresh water body.

3) Road access, power supply, communicationfacilities and emergency generator are allessential components to run the equipment andoperating systems in the hatchery.

Farm Permits• Construction permits from Corps of

Engineers

• Aquaculture Permits from state

• Local permits

Farming Strategies• Extensive

– Large ponds– Low stocking densities– Little management or investment

• Semi-Intensive– Falls in between the two extreme of intensive and

extensive

• Intensive– Smaller ponds– Aeration– High stocking densities– Feeding

Water quality• Freshwater from a river, stream or lake,

rainwater, or groundwater can be used.

• Hardness (as CaCO3) should be in the range 50–100 ppm.

• Seawater is needed to mix with the freshwaterto produce brackish water for the larvae.

• The seawater is disinfected with 10 ppm ofcalcium hypochlorite and stored for at least aweek before use.

Water Quality for Grow out

Ponds

• Temperature: > 68F

• Salinity: 0.5 - 35 ppt

• Dissolved Oxygen: > 5 ppm

• pH: 7.0 – 8.3

• Unionized Ammonia: < 0.01 ppm

• Nitrite: < 1.0 ppm

• Nitrate: < 60 ppm

Pond Construction• Ponds range in size from 1-10 acres

• 4-7 feet deep

• Gentle bottom slope

• Well maintained level

Pond Design

• 1 to 25 acre in size

• Silt soil

• Good water source

• Rectangular in shape

Pond Preparation

Hatchery components

• Some of the basic hatchery components and equipment are:

1) Building to house the larval rearing space

2) Hatch tanks 1000 L

3) Larval rearing tanks (LRTs)

4) Holding tanks 1000 L for PL, also used for brood stock holding

5) Nursery tank 5000 L for PL (optional)

………

Cont……

6) Freshwater storage tank

7) Saltwater storage tank

8) Mixed water storage tank

9) Water pump management

10) Plastic buckets, basins, containers

11) Equipment for packing and transport of PL

12) Feed and chemicals

13) Ponds (200–400 m2) for rearing andmaintaining adult prawns for breeding

Management• Fertilize ponds prior to stocking

• Feed good quality prawn feed

–35% protein

–3-5% bwt per day

• Provide aeration when necessary

Harvesting• Harvest in October month

• Drain and seine pond net

• Direct market or sell to processor

• Store after dry

Prawn Harvesting in River & Pond

Push nets

Commonly Cultured Marine Shrimp

• Penaeus merguiensis – Banana prawn

• Penaeus indicus – Indian prawn

• Penaeus japonicus - Kuruma prawn

• Penaeus duorarum – Atlantic pink shrimp

• Penaeus aztecus – Atlantic brown shrimp

• Penaeus setiferous – Atlantic white shrimp

• Litopenaeus vannamei – Pacific white shrimp

• Penaeus monodon – Black tiger prawn

Brood stock• The adult male and female prawns chosen for

breeding are called brood stock.

• On average, 500–1000 prawns (male and female)need to be kept as brood stock.

• Berried females 10–12 cm long usually carryabout 10,000–30,000 eggs each and 40 g females,35 g males.

• Brood stock are usually reared in ponds, startingwith an initial stocking density of 4–5 PL/m2. ofpond area and reducing to 2/m2 at adult size.

Growth to maturity• The PL grow to maturity within 4–7 months

in freshwater ponds.

• The PL grow to maturity is depending ontemperature, food and environmentalconditions.

• The maturity stages of females and malecan be determined by external examinationof the ovary, and testis.

Feeding brood stock• An example of a pellet feed formulated for brood

stock feeding should roughly consist of:

1)Protein - 40%

2)Fat - 10%

3)Carbohydrate - 33%

4)Ash - 09%

5)Fiber - 08%

6)Gross energy - 04.3 kcal/g (18 kJ/g)

Hatch tank management• Berried females ready for spawning should not be

disturbed and should be kept secluded in thehatch tanks.

• Start with 500 L freshwater in a 1000 L hatch tank,and stock a maximum of 3–4 berried females.

• Keep the temperature at 25°–30°C and pH 7.0–7.3until the eggs hatch.

• Tank water should be kept clean and free of dirtand debris through regular water changes andbottom-siphoning

FACTORS ENCOURAGING PRAWN FARMING EXPANSION

• Compatible with agriculture

• Small farmers can practice in their own land

• No interference with mangrove or environment

• Can be normally grown in salinity up to 8 ppt

• Large suitable areas all over the country

PRAWN FARMING REDUCING POVERTYMore than 80% of the farms less an acre

and handled by small farmers.

Large numbers of mono-crop low-yieldingpaddies now converted into farmsproducing high priced prawn and fish inrotation with paddy .

Pond embankments grow vegetables andfruits fetching extra income and providingbetter nutrition.

SOME CURRENT PROBLEMS• Culture mostly dependent on rain water; no

assured perennial water supply or drainagenetwork.

• Available commercial feeds are either ofinadequate quality or are too expensive.

• Poor nursery practices.

• Declining wild brood-stock population due toover-fishing.