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Starting prawn farming in Goa
- Thread starter megand
- Start date
hello Megand
Farming systems
Basically there are three different farming techniques used for Macrobrachium rosenbergii :
A) Extensive Freshwater Prawn Culture:Extensive culture means rearing in ponds (but also in other impoundments such as reservoirs, irrigation ponds and rice fields), which produce less than 500 kg/ha/yr of freshwater prawns. They are stocked, often from wild sources, with PL or juveniles at 1-4/m2 . There is no control of water quality; the growth or mortality of the prawns is not normally monitored; supplemental feeding is not normally supplied; and organic fertilisation is rarely applied.
B) Semi-Intensive Freshwater Prawn Culture:Semi-intensive systems involve stocking PL or juvenile freshwater prawns (usually from hatcheries) at 4-20/m2 in ponds, and result in a range of productivity of more than 500 kg/ha/yr and less than that defined as intensive in this box. Fertilisation is used and a balanced feed ration is supplied. Predators and competitors are controlled and water quality, prawn health and growth rate are monitored. This form of culture is the most common in tropical areas.
C) Intensive Freshwater Prawn Culture: Intensive culture refers to freshwater prawn farming in small earth or concrete ponds (up to 0.2 ha) provided with high water exchange and continuous aeration, stocked at more than 20/m2 and achieving an output of more than 5000 kg/ha/yr. Construction and maintenance costs are high and a high degree of management is required, which includes the use of a nutritionally complete feed, the elimination of predators and competitors, and strict control over all aspects of water quality. This form of culture is not recommended in this manual because it requires more research, particularly on size management.
Based of the management practice employed there are four different management systems being adopted for freshwater prawn farming in India.
The most commonly cultured species in India is Macrobrachium rosenbergii. It is a hardy species by virtue of its ability to adapt to various types of fresh and brackish-water conditions. It accepts pelleted feed and has omnivorous feeding habit.
The breeding takes place in low saline waters which is also needed for larval and post larval development after incubation.
Breeding of M. rosenbergii takes place in estuaries.
Site Selection for Hatcheries and Nurseries:The site requirements for hatcheries and nurseries, which are normally associated with each other, are similar.
The quality of intake water, whether it is saline or fresh, is of paramount importance for efficient hatchery operation. Water quality is thus a critical factor in site selection. Hatchery sites should preferably be far from cities, harbours and industrial centres, or other activities, which may pollute the water supply.
Special care is needed in hatcheries that are situated in or near areas where the use of pesticides, herbicides, and fertilizers is intensive. Ideally, freshwater should be obtained from underground sources. The brackishwater for use in M. rosenbergii hatcheries should be 12-16 ppt, should have a pH of 7.0 to 8.5, and contain a minimum dissolved oxygen level of 5 ppm. High levels of heavy metals, such as mercury (Hg), lead (Pb) and zinc (Zn), should also be avoided, since these are most likely to be caused by industrial pollution.
Soil Characteristics: The ideal soil for freshwater prawn culture should be clay-silt mixture or sandy loam comprising of 60% sand and 40% silt with good water retention capacity. There must be enough soil available for pond construction, whether the ponds are to be excavated or pond banks are to be erected above ground. Although supplemental food is given to freshwater prawns reared in earthen ponds, a considerable amount of their food intake is from natural sources. It is therefore preferable to site the farm where the soil is fertile, as this will reduce the need and costs of fertilisation. Freshwater prawn ponds should be constructed on soil, which has good water retention characteristics or where suitable materials can be economically brought onto the site to improve water retention.
Pervious soils, which are very sandy or consist of a mixture of gravel and sand, are unsuitable unless the water table is high and surrounding areas are always waterlogged. Soils, which consist of silt or clay, or a mixture of these with a small proportion of sand, normally have good water retention characteristics. Peaty soils are not suitable. The clay content should not exceed 60%; higher clay content soils swell when moist and crack during the dry season, thus making repairs necessary.
In addition to having sufficient supplies of good quality water u should have:
• A secure power supply, which is not subject to lengthy power failures. An onsite emergency generator is essential.
• Have access to food supplies for larvae;
• Employ a high level of technical and managerial skills;
• Have access to professional biological assistance from government or other sources;
• Have its own indoor/outdoor nursery facilities or be close to other nurseries and
• Be as close as possible to the market for its PL. In the extreme case, it should not take more than 16 hours of total transport time from the furthest farm to the market.
The preferred stocking density in the nursery pond is 20/m2. Post-larvae (8-10 mg) may be fed with pellet diet (crude protein 35%; lipid 8%) in crumble form @ 100% of the biomass during the first fortnight and further reduced to 50% in subsequent period. In the absence of pellet diet a mixture of groundnut oil cake (powdered) and rice bran may be given as feed. The feed should be broadcasted in the pond twice daily preferably in the morning and in the late evenings. In nursery ponds approximately 10% of the pond surface may be covered with floating weeds with dense root system such as Eichhornia sp. to improve the survival rate of post-larvae. The weeds should be kept inside a PVC or bamboo frame to avoid their spreading in the pond. Aeration is provided for ~8 h/day.
A fortnight after stocking sampling of post-larvae may be done to observe the growth using cast net or fry net. During nursery rearing water temperature may be checked twice daily. pH, dissolved oxygen, transparency and depth may be checked once every week and to be maintained in optimum ranges. Loss of water due to seepage and evaporation should be compensated by water addition at least once every fortnight. Nursery rearing may be done for 45-60 days. At the end of rearing period the juveniles (>1.0 g) are collected by dewatering the pond and transferred to grow-out ponds
Juvenile prawns can be harvested by seining your ponds two or three times with a 5 to 6 mm mesh seine, or by emptying them completely. Polypropylene boxes or tanks filled with water from the nursery pond and kept aerated, can be used to transport the juveniles to the grow-out ponds if they are close by. There are some advantages in grading the juveniles into two or three groups, depending on their average weight, before stocking them into separate grow-out facilities. This decreases competition in grow-out ponds by reducing Heterogeneous Individual Growth (HIG) and increases productivity. Some mortality (10-20%) will occur soon after PL are stocked, even when the conditions are ideal. Total survival from stocking until removal from the nursery ponds should be at least 75%. The weight of the prawns at the end of the outdoor nursery period should be about 0.8-2.0 g, but the time taken to reach those sizes will depend on local conditions.
pls contact
Contact Us
Director of Fisheries
Name Of The Officer : Shri Santosh C. Verenkar
Address :
Directorate of Fisheries, Dayanand Bandokar Marg,
Panaji Goa.
Telephone (Off) :: 0832-2224838
Telephone (Resi) : 0832-2264011
Fax : 0832- 2227780
Email :dir-fish-goa@nic.in
or
Contact : Contact Us
Farming systems
Basically there are three different farming techniques used for Macrobrachium rosenbergii :
A) Extensive Freshwater Prawn Culture:Extensive culture means rearing in ponds (but also in other impoundments such as reservoirs, irrigation ponds and rice fields), which produce less than 500 kg/ha/yr of freshwater prawns. They are stocked, often from wild sources, with PL or juveniles at 1-4/m2 . There is no control of water quality; the growth or mortality of the prawns is not normally monitored; supplemental feeding is not normally supplied; and organic fertilisation is rarely applied.
B) Semi-Intensive Freshwater Prawn Culture:Semi-intensive systems involve stocking PL or juvenile freshwater prawns (usually from hatcheries) at 4-20/m2 in ponds, and result in a range of productivity of more than 500 kg/ha/yr and less than that defined as intensive in this box. Fertilisation is used and a balanced feed ration is supplied. Predators and competitors are controlled and water quality, prawn health and growth rate are monitored. This form of culture is the most common in tropical areas.
C) Intensive Freshwater Prawn Culture: Intensive culture refers to freshwater prawn farming in small earth or concrete ponds (up to 0.2 ha) provided with high water exchange and continuous aeration, stocked at more than 20/m2 and achieving an output of more than 5000 kg/ha/yr. Construction and maintenance costs are high and a high degree of management is required, which includes the use of a nutritionally complete feed, the elimination of predators and competitors, and strict control over all aspects of water quality. This form of culture is not recommended in this manual because it requires more research, particularly on size management.
Based of the management practice employed there are four different management systems being adopted for freshwater prawn farming in India.
The most commonly cultured species in India is Macrobrachium rosenbergii. It is a hardy species by virtue of its ability to adapt to various types of fresh and brackish-water conditions. It accepts pelleted feed and has omnivorous feeding habit.
The breeding takes place in low saline waters which is also needed for larval and post larval development after incubation.
Breeding of M. rosenbergii takes place in estuaries.
Site Selection for Hatcheries and Nurseries:The site requirements for hatcheries and nurseries, which are normally associated with each other, are similar.
The quality of intake water, whether it is saline or fresh, is of paramount importance for efficient hatchery operation. Water quality is thus a critical factor in site selection. Hatchery sites should preferably be far from cities, harbours and industrial centres, or other activities, which may pollute the water supply.
Special care is needed in hatcheries that are situated in or near areas where the use of pesticides, herbicides, and fertilizers is intensive. Ideally, freshwater should be obtained from underground sources. The brackishwater for use in M. rosenbergii hatcheries should be 12-16 ppt, should have a pH of 7.0 to 8.5, and contain a minimum dissolved oxygen level of 5 ppm. High levels of heavy metals, such as mercury (Hg), lead (Pb) and zinc (Zn), should also be avoided, since these are most likely to be caused by industrial pollution.
Soil Characteristics: The ideal soil for freshwater prawn culture should be clay-silt mixture or sandy loam comprising of 60% sand and 40% silt with good water retention capacity. There must be enough soil available for pond construction, whether the ponds are to be excavated or pond banks are to be erected above ground. Although supplemental food is given to freshwater prawns reared in earthen ponds, a considerable amount of their food intake is from natural sources. It is therefore preferable to site the farm where the soil is fertile, as this will reduce the need and costs of fertilisation. Freshwater prawn ponds should be constructed on soil, which has good water retention characteristics or where suitable materials can be economically brought onto the site to improve water retention.
Pervious soils, which are very sandy or consist of a mixture of gravel and sand, are unsuitable unless the water table is high and surrounding areas are always waterlogged. Soils, which consist of silt or clay, or a mixture of these with a small proportion of sand, normally have good water retention characteristics. Peaty soils are not suitable. The clay content should not exceed 60%; higher clay content soils swell when moist and crack during the dry season, thus making repairs necessary.
In addition to having sufficient supplies of good quality water u should have:
• A secure power supply, which is not subject to lengthy power failures. An onsite emergency generator is essential.
• Have access to food supplies for larvae;
• Employ a high level of technical and managerial skills;
• Have access to professional biological assistance from government or other sources;
• Have its own indoor/outdoor nursery facilities or be close to other nurseries and
• Be as close as possible to the market for its PL. In the extreme case, it should not take more than 16 hours of total transport time from the furthest farm to the market.
The preferred stocking density in the nursery pond is 20/m2. Post-larvae (8-10 mg) may be fed with pellet diet (crude protein 35%; lipid 8%) in crumble form @ 100% of the biomass during the first fortnight and further reduced to 50% in subsequent period. In the absence of pellet diet a mixture of groundnut oil cake (powdered) and rice bran may be given as feed. The feed should be broadcasted in the pond twice daily preferably in the morning and in the late evenings. In nursery ponds approximately 10% of the pond surface may be covered with floating weeds with dense root system such as Eichhornia sp. to improve the survival rate of post-larvae. The weeds should be kept inside a PVC or bamboo frame to avoid their spreading in the pond. Aeration is provided for ~8 h/day.
A fortnight after stocking sampling of post-larvae may be done to observe the growth using cast net or fry net. During nursery rearing water temperature may be checked twice daily. pH, dissolved oxygen, transparency and depth may be checked once every week and to be maintained in optimum ranges. Loss of water due to seepage and evaporation should be compensated by water addition at least once every fortnight. Nursery rearing may be done for 45-60 days. At the end of rearing period the juveniles (>1.0 g) are collected by dewatering the pond and transferred to grow-out ponds
Juvenile prawns can be harvested by seining your ponds two or three times with a 5 to 6 mm mesh seine, or by emptying them completely. Polypropylene boxes or tanks filled with water from the nursery pond and kept aerated, can be used to transport the juveniles to the grow-out ponds if they are close by. There are some advantages in grading the juveniles into two or three groups, depending on their average weight, before stocking them into separate grow-out facilities. This decreases competition in grow-out ponds by reducing Heterogeneous Individual Growth (HIG) and increases productivity. Some mortality (10-20%) will occur soon after PL are stocked, even when the conditions are ideal. Total survival from stocking until removal from the nursery ponds should be at least 75%. The weight of the prawns at the end of the outdoor nursery period should be about 0.8-2.0 g, but the time taken to reach those sizes will depend on local conditions.
pls contact
Contact Us
Director of Fisheries
Name Of The Officer : Shri Santosh C. Verenkar
Address :
Directorate of Fisheries, Dayanand Bandokar Marg,
Panaji Goa.
Telephone (Off) :: 0832-2224838
Telephone (Resi) : 0832-2264011
Fax : 0832- 2227780
Email :dir-fish-goa@nic.in
or
Contact : Contact Us