Prawn Farming

Uploaded on : September 2019

Introduction

 

Prawn farming is a risky business for new entrepreneurs and for those that do not have experience in the aqua farming sector. However, it is recommended to start a small-scale business that can fetch a lot of knowledge and information about rearing prawns. Prawns are also known as prawns in some countries, rearing them can fetch huge profits, even in the small-scale startup business. The environmental conditions at the farm location play a crucial role in the success or failure of the prawn farming business. Weather, soil, and water conditions play an important role in the prawn farming industry. With advanced technology and modern farming methods, many prawn farmers are making huge revenues in this particular aqua farming business. Modern techniques include intensification of prawn culture operation, increase in prawn density, proper aeration methods, providing formulated feed, and water quality management, etc.. There are two types of prawn farming, freshwater prawn farming, and saltwater prawn farming. Commercial freshwater prawn farming can be done in tropical and sub-tropical climatic regions having reservoirs, lakes, irrigation ditches, rivers, ponds, and other natural water resources. Saltwater prawn farming also is known as marine prawn farming can be done in regions that are nearby to sea waters or coastal regions.

 

The demand for both freshwater and saltwater prawn is high in local and world market. The consumer demand in the world market is always growing consistently. Countries having large coastal regions are taking advantage of this consumer demand and are thriving in this business. The availability of suitable sites and good water quality maintenance are important for success. Entrepreneurs can be successful with decent profits by having a proper prawn rearing business plan and proper marketing strategies. There are many types of prawns available around the world. Cultured prawns are mostly edible while some of the saltwater varieties are not edible. Freshwater prawns are big in size compared to the marine and brackish water grew species.Some of the prawn varieties that are found worldwide are northern brown prawn (P, aztecus), redspottedprawn (P. brasiliensis), crystal prawn (P. brevirostris), oriental prawn (P. chinensis), brown tiger prawn (P. esculentus), carpasprawn (P. paulensis), blue prawn (P. stylirostris), pink prawn (P. notialis), and more.

 

Prawn Varieties for Farming

 

Many prawn varieties do not fetch good market value. Some of the larger size ones are raised in farms. A farmer should consider various factors before choosing which species of prawn he should culture. Some of the in-demand market species are:

 

•  Pacific white prawn (Penaeusvannamei) is also known as whiteleg prawn. This species is mainly cultivated in western countries. Whitelegprawn grows up to 21 to 24 cm in length. Most of the prawn farming is carried on the coasts from Mexico to Peru leading to more than 90% production of this species alone. Taura disease is a major drawback for this species as it easily gets succumbs, but easy to breed in captivity.

 

•  Kuruma prawn (P. japonicas) has great market value in Japan, especially the alive ones reaching $ 200 to $230 per kilogram. The species are farmed mainly in the coastal regions of Japan, Taiwan, and in some regions in Australia.

 

•  Indian White prawn (P. indicus) this species are farmed in the coastal regions of India, Iran, Middleast, and eastern coastal regions of Africa. They grow to a length of 20 to 22 cm long. The species thrive well in sandy mud soils with a depth of 2 to 90 m deep. The lifespan of this species is 18 months and 120 to 145 days culture period. Its edible meat weight is comparatively high to its total weight as the exoskeleton is slightly thin. The yield can be about 10 to 20 tons/ha/yr.

 

•  Giant Freshwater prawn (Macrobrachiumrosenbergi) is also known as giant river prawn found in coastal tropical and subtropical areas of Indo-pacific regions. It grows up to 30 to 32 cm long and is one of the largest freshwater prawns in the world. The females lay eggs five times a year about 10,000 to 50,000 eggs each time.

 

•  Giant Tiger Prawn (P. monodon) is also known as black tiger prawn. This species is commonly found wild in the Indian and Pacific oceans, most of the tiger prawn farming is carried out in the eastern countries coastal regions. This is the largest species growing up to 30 to 35 cm in length. White spot disease is the major drawback for this species as it easily gets succumbs and difficult to breed in captivity.

 

Prawn Farming Business

 

Prawns can be reared in aquaculture, fish farms, backyard waters, ponds, tanks, and in all natural water available resource places. Prawn farming comes to harvest in six months, and prawn farming is a profitable business idea giving a huge profit margin. Prawn consumption demand is always high; successful prawn farming can fill a part of the market demand to make you financially successful. Consumption of prawn provides protein, key nutrients, minerals, and low in calories.

 

Prawn Farming Practices

 

Soil Quality: Soil quality is an important component in prawn farming. Soils with heavy metal content, acid-sulfate soils, pH levels less than 5 should be avoided. Sandy areas require high investment along with operational costs. Clayey loamy soils are good for prawn farming and also involve less capital investment. Clayey soils with rich organic matter help in the production of benthic blue algae and plankton production that forms the food for prawns. Ideal soils should have a pH valve (7 to 8), organic carbon (1.5 to 2.5%), soil nitrogen (50 to 75 mg per 100 g soil), soil phosphorous content (4 to 6 mg per 100 g soil), Calcium carbonate (> 5%), and soil electrical conductivity (> 4 mmhos / cm).

 

Water Quality: One of the most important prerequisites for prawn farming is good quality water. A farmer while selecting his farming site should consider the source of water availability during different seasons, its quality, and quantity.

 

S.No	Water Parameters	Optimal Level
1.	Temperature	28° – 33° C
2.	Transparency	25 – 45 cm
3.	pH	5 – 7
4.	Oxygen levels	5 – 7 ppm
5.	Salinity	15 – 25 ppt
6.	Alkalinity	200 ppm
7.	Phosphorous	0.1 – 0.2 ppm
8.	Nitrite	<0.01 ppm
9.	Nitrate	<0.03 ppm
10.	Ammonia	<0.01 ppm
11.	Cadmium	<0.01 ppm
12.	Chromium	<0.1 ppm
13.	Copper	<0.025 ppm
14.	Lead	<0.1 ppm
15.	Mercury	<0.0001 ppm
16.	Zinc	<0.1 ppm

 

In prawn farming, two types of food can be given for prawns to eat and grow. One, either by feeding supplemented prawn food or special feeds and second, natural food that consists of phytoplankton, zooplankton, worms, microorganisms, tiny shellfish and decaying organic matter that is available in the water. Natural food increases by itself by fertilizing the pond and the supplementary food is supplied on a timely basis in a regular quantity depending on the stock intensity in the pond to grow. Prawns consume nutrients directly from the water as well as feed on food that is available around it. In commercial prawn farming, feed cost constitutes about 50 to 65% of the actual variable cost. However, feeds will improve prawn production, giving high profits.

 

Feeds for Larval Prawns: Newly hatched larvae do not feed, but live on the egg yolk. Even in the next naupli stage, they do not feed, but commercial growers do chemical fertilization of rearing tanks. This helps in the availability of phytoplankton for consumption by the time they reach zoea stage. Some growers culture phytoplankton in separate tanks. It takes about two to three days for the naupli change to zoea and feeds on phytoplankton with concentrations of 5,001 to 20,000 cells per ml. Prawns in larval stage show superior growth and survival rate on wet diets. But, manufacturing of wet diets and storage have certain problems. Dry feeds may congest the food pipe and hamper mixing of enzymes with dry foods. Larvae formulated feed (less than 100 u) is fed about 1.2 to 1.5 kg for black tiger prawns and about 2 kg for whitelegprawn for 100,000 stock density. Wet diets are less practical and diets that are not water stable may pollute the water on the farm. Whatever the diet is, whether wet or dry, the final arbiter of the dietary characteristics should be the efficiency of their growth.

 

Feeds for Post Larval Prawns: In the postlarval stage or Penaeids are omnivorous scavengers, consuming a wide range of foods. They feed on molluscs, detritus, algae, insects, aquatic plants, and show cannibalistic behavior. At this postlarva stage, the animals feed most actively at night. To feed natural food in prawn farming, natural food production should be raised over 450 to 500 kg per hectare per annum. There is a commercial postlarval supplemental feed in the market. Following the feed dosage as prescribed can sustain the animal diet and its growth

 

Juvenile and Adult Prawns: In this stage, the prawn's diet can be supplemented or natural. But in a commercial farming system, procuring a continuous supply of large quantities is difficult. Most prawn farmers depend on good supplemental feed that has good food conversion ratio (FCR, 1:1.5 to 1.8). For healthy growth of prawns, they need 40 essential nutrients; they are given by the combination of both natural and formulated feeds. The feed is given through feeding trays, automatic dispensers, or manual broadcasting all over the pond.

 

Prawn Live Body Weight (grams)	Feed Rate @ body weight % / day
2 – 3	7.0 – 8.0
3 – 5	5.5 – 7.0
5 – 10	4.5 – 5.5
10 – 15	3.8 – 4.5
15 – 20	3.2 – 3.8
20 – 30	2.5 – 3.2
30 – 40	2.1 – 2.5

 

The most dreaded thing for a prawn farmer is prawn diseases. Prawns are affected by microorganisms like viruses, bacteria, fungi, parasites, and algal toxins. The cause of diseases in prawns could be a nutritional deficiency, poor water conditions, and environmental pollutants.

 

Diseases in Hatcheries

 

Necrosis of Appendages: Bacteria attacks when there is a physical damage to the appendages. Exoskeleton and tips of appendages in affected larvae start browning making them appear eroded and opaque. Regular pathogenic bacteria through standard microbiological methods will identify the disease. Isolation, optimal stock densities, and improving water quality will help in control and prevention.

 

Luminescent Bacterial Disease: As the name suggests, infected larvae glow in darkness and is one of the terrible diseases leading to heavy mortality. Based on their morphological and biochemical characteristics this disease can be identified. UV sterilized water and chlorination (Ca(ClO)2 200ppm for 60 mins) will control the disease.

 

Filamentous Bacterial Disease: Infected prawn larvae show fouling of gills, appendages, and its body surface. The larva may die due to hypoxia. Based on signs and symptoms, copper sulphate bath treatment (0.25 – 1 ppm for 4 to 6 hrs) should be given.

 

Larval Mycosis: This is a fungal disease highly susceptible to Zoea and Mysis larva. Infected larva appears opaque and within a day or two, the whole stock larva may die. The infected larva is given Treflan (0.1 to 0.2 ppm) bath for one day will control the disease.

 

Diseases in Juveniles and Adult Prawns

 

Monodon Baculovirus (MBV) Disease: This is a viral disease affecting both postlarvae and adults prawns. Infected prawns are lethargic with the surface and fouling of gills. This disease has high death rates. There is no medicine for treatment but can be controlled by using MBV-free stock. Affected prawns are burnt or buried after mixing with lime away from the farm.

 

Bacterial septicemia: This is also known as Vibrio disease caused by bacteria. This disease can be found when the prawns are lethargic with abnormal swimming behavior. In severe cases, the gill covers appear flared up sometimes extensively melanized black blisters on the abdomen region. Infected prawns are fed with antibiotic fortified feeds (1.5g Oxytetracycline per kg feed at 2 – 10% of body weight) for two weeks.

 

White Spot Disease (WSD): This is caused by virus SEMBV. The infected prawns swim to the water surface and gather near the pond dikes are the symptoms. Physical signs include white patches or spots on the shell and abdomen regions. There is no treatment for this disease.

 

Market Potential

 

According to Indian statistics, the brackish water area that is highly suitable for prawn farming in India is estimated to be 11.90 lac ha. Having such vast brackish water resources and only 14% is used for prawn farming. Yet, India stands second largest producer of prawns after China. Therefore, there is a huge opportunity in this segment of aquaculture expansion. Aquaculture is growing at an annual growth rate of 6.5%, giving a scope to become a major area of business exploration. India has a large coastline with large inland water bodies along with favorable climatic conditions. Aquaculture production is more cost-effective compared with agriculture/animal husbandry production. More efficient in feed to end-product conversion both in natural and controlled farming.

 

Pond Management

 

There is no particular design for prawn ponds. The pond design is made on the basis of physical and economic conditions along with optimum and carrying of smooth functional works. Water depth in the pond is maintained at 50 to 100 cm height level, while water levels about 90 cm is recommended in prawn farming. 20 to 30% of water is exchanged every 7 to 10 days and in the first 30 days of the culture period, avoid water exchange. Depending on the stocking density and the water, deteriorating rate, water exchange should be taken up. Oxygen in water levels has to be maintained maximum. Aeration of water levels is maintained by using paddlewheel aerators. About two paddle wheels are required for a hectare and aeration work has to be conducted four to six hours in a day. A couple of laborers are kept for regular culture operations such as monitoring the quality of water, soil, animal health, and feed intake.

 

Additional unskilled laborers are required at the time of pond preparation, harvest, and post-harvest operations on a daily basis. Most countries practice three types of prawn culture.

 

Traditional or Extensive Farming

 

In this type, the pond may not be in regular size and shape, mostly more than 1.5 hectares in size. The bottom of the pond need not be leveled, but free from tree stumps and any other plants. Ponds are constructed in a way that they are filled with gravity flow. In extensive prawn farms, the stocking density is maintained at one to five pieces per square meter and is partially harvested.

 

Semi-Intensive Farming :

 

In this type, the ponds are about one to one and a half hectares in size. The ponds are constructed with earth walls (or dikes) to hold water about 100 to 150 cm deep. Stocking of animals is done at 10 to 15 prawns per square meter with fresh diets or with supplementary feeds or in some cases both. Harvesting is usually carried out after 100 to 120 days after stocking.

 

Intensive Farming

 

In this type, the ponds are lesser in size about half to one hectare with pond water depth of about 150 to 200 cm deep. In these types, water aeration plays an important role and oxygen levels have to be maintained with strong aeration. Feeding is carried four to six times on a daily basis; this is because of the high stock density of about 30 to 60 prawns per square meter

 

Cost

 

In prawn farming, feeding, digging, and equipment are the main sources of investment. The capital investment amount also depends on the amount of seed you are going to farm. On an average, the investment can be anywhere from 7 to 12 lakhs that include seed, feed, equipment, and medicines. The farmer should have equipment such as water aerator sets, pumps, and generator that is mandatory in this culture. To reduce the capital investment, some farmers get this equipment for lease/rent. It takes about 4 to 5 lakhs to dig and prepare a hectare pond. An already built prawn pond may help you in capital investment. The main risk factor in prawn farming is a virus and WSD, proper pond maintenance and medicine availability is very important. On a successful crop, at the time of harvest, a farmer can make profits twice or thrice on the investment. The sale price of the harvest is based on the number of prawns per kilogram, the lesser the count, more is the selling price. Depending on the current market rate, on an average with a count of 40 per kg, a farmer can make about 13 to 15 lakh per crop.

 

Central Government Subsidies and Schemes

 

To strengthen the food security and to utilize the vast natural resources such as reservoirs, lakes, tanks, canals, ponds, and other water bodies having immense scope for development and production of aquaculture to generate employment opportunities and earn foreign exchange. The central government undertook the objective of improving the socio-economic status aqua-farmers by launching a centrally sponsored scheme on “Development of Inland Fisheries and Aquaculture” under macro-management during the 10th plan. Development of Freshwater and Brackishwater Aquaculture are the components approved. Assistance can be provided for construction of new ponds, renovation of ponds and tanks, aerators, pumps, the establishment of freshwater prawn seed hatchery, purchase of vehicles, and more. More information can be obtained from the department of fisheries and aquaculture at the local offices for the rate of assistance and other benefits.

 

Harvesting and Post-Harvesting

 

There are two types of harvesting: Culling and Drain harvesting.

 

Harvesting is carried out on market size requirement and animal growth-rate. In cull harvesting, a seine is pulled into the pond to harvest prawns that are marketable in size. Nets are made of monofilament nylon having floaters and sinkers. The size of the seine is 2.5 m high and length 1.6 times the pond size. It takes about five to six experienced laborers for harvesting 30 m wide ponds and eight to ten laborers for a 50 m wide pond. In Drain harvesting, water is drained through sluice gate or harvesting sump. Care must be taken at the time of harvesting without stressing the animals. Oxygen deficiencies, overcrowding, and high temperatures are some of the stress factors. Water is pumped out the night before harvesting, and harvesting is carried out in the cool time of the day preferably early morning. Prawn growth is optimum during summer crop. It takes about 120 to 150 days to harvest and the farmer can expect a harvest of 1-2 tonne per hectare per crop. While in winter the harvest can be around One-tonne per hectare. After harvesting the prawns are segregated and graded on their size.

 

Cost and Profits in Prawn Farming

Fixed Capital

 

S. No	Particulars	Cost. Rs
1.	Broodstock Pond 2. Nos	1,08,000
2.	Larva Rearing Tank 12. Nos	1,15,000
3.	Hatchery Shed 10×6 m	2,35,000
4.	Water Storage Tank	46,000
5.	PVC Drainage Piping	21,000
6.	Aerator Set 5hp, 2. Nos	1.50,000
7.	Water Pump sets 2 hp, 2. Nos	30,000
8.	Generator 5 kva	65,000
9.	Electrical Installation	25,000
10.	Borewell	45,000
Total Fixed Capital Investment		8,40,000

 

Operational Cost

 

S. No	Particulars	Cost. Rs
1.	Chemical and Organic Fertilizer	7,500
2.	Broodstock Development	50,000
3.	Pumping and Aeration Charges	15,000
4.	Pelleted Feed and Artemia @ Rs.4000/kg	2,20,000
5.	Seawater Transportation	27,500
6.	Fuel and Electricity	35,000
7.	Refrigerator	25,000
8.	Salaries and Wages	1,90,000
9.	Miscellaneous	30,000
Total Operational Investment		6,00,000

 

Total Cost

 

S. No	Particulars	Cost.Rs
1.	Operational Cost	6,00,000
2.	Depreciation on Fixed Cost @ 10% / year	84,000
3.	Interest on Fixed Investment @ 15% / year	1,26,000
Total Cost		8,10,000

 

Source

 

Ministry of Micro, Small & Medium Enterprises
Government of India
Nirman Bhavan, New Delhi - 110011

 

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