Aquaculture is an activity producing fish or shellfish mainly for human consumption. It is carried out in ponds, enclosures or in open water bodies and thus involves continuous interaction with the environment. Aquaculture can be a sustainable activity, if it is carried out in socially and environmentally responsible manner, by adopting good aquaculture practices. Sustainable aquaculture means an aquaculture production system that operates in harmony with the environment and living systems, utilizing renewable resources as far as possible, providing living conditions to the animals as close to that of their natural habitats as well as in tune with the human and social environment of the locality. Sustainability can be achieved by adopting Better Management Practices (BMPs). BMPs involve legal compliance, social responsibility, good site selection and farm construction, good practices in farm management right from pond preparations to harvest and post harvest management activities. Adoption of BMPs would result in better production, productivity and returns on the one hand and environmental and social responsibilities on the other.
For L vannamei (LV) and P monodon(BT)
Crop planning in advance of the cropping season in consultation with all farmers involves stocking density based on pond carrying capacity, crop insurance and bank finance and bulk input purchase like good quality seed through contract hatchery system, lime, feed etc., screen seed, feed and other commonly used chemicals for presence of banned antibiotics, for entering in to marketing contract with processors, setting up of basic water quality lab in society with easy to test water quality
Crop calendar : Preparation of Crop calendar- two months before stocking fix dates for pond preparation, biosecurity, water pumping, contract hatchery, seed stocking and harvest. for analysis of farm inputs like seed, feed and any common ingredient used and shrimp for presence of banned antibiotic residues cluster certification, renewals, inspections/audit before the crop
Adoption of Better Management Practices
Pond preparation practices : To provide the shrimp with a clean pond bottom and good, stable water quality. a. Increase the water holding capacity of the ponds.
to reduce disease risks & to reduce the excessive reliance on water exchange, pond water holding capacity has to be increased maintaining water depth at minimum water level of 1.2 meter at the middle of the pond.
b. Completely drain out the water from the pond
Complete draining of water helps in removing the disease carrying fish and crustaceans from previous crops in the pond. If it is not possible to drain the water follow wet preparation method.
c. Remove the organic waste from pond bottom
Organic matter releases toxic gases like ammonia and hydrogen sulfide in the pond leading to stress or death of shrimps. Organic waste is in the form of layer on the soil with black color found in feeding area, corners, trenches and in the centre in ponds with aerators and should be checked for the presence of black layer when it is in wet condition. Make sure that the displaced organic waste does not enter the pond again through rain water. If it is difficult to completely remove the black soil, plough when it is wet and let it dry.
Dry and plough the pond bottom
Sun drying kills fish/crustacean and their eggs in the pond soil. Drying helps in oxidizing the organic matter thus reducing the sludge. The pond should dry in hot sun for 20 to 30 days till the soil cracks . Plough the pond 2 to 3 times with the gap of 2 to 3 days which will help in oxidizing the organic matter and also help in reducing gastropods. After ploughing compact the pond bottom to reduce the turbidity and seepage
When the ponds cannot be dried farmers can follow wet pond preparation as given below.
- Apply tea seed cake or chlorine (20 ppm) before ploughing, take out all dead animals
- Use the tractor with gauge wheels to plough the pond with 15 to 20 cm water
- After the ploughing drain out the water from the pond.
f. Fertilization and liming of the pond bottom
This will help in improving mineral content of the pond bottom especially in ponds with low soil fertility and ponds which are in culture for more than 10 years.
- Apply dry vermicompost 250-1000kg/ha or compost manure
- Spread the vermin compost/compost manure all along the pond bottom.
- Do not use poultry manure or raw cow dung for fertilization
1. Use a soil pH meter to test the soil pH. Soil should be wet while using the equipment. The levels of lime application during pond preparation depends on the pH of the soil. Follow dosages given in the table below.
Dosage of lime to the soil:
|Soil pH||Quantity of Burnt lime- CaO (Kg/Hectare)||Quantity of Agri. Lime – CaCO3 (Kg/Hectare)|
Spread the lime all along the pond bottom and along the slopes of the pond bund. A large proportion of the lime needs to be applied along the feeding areas and on the wet portions of the pond. When applying lime farmers/workers should wear face mask.If the soil pH is more than 7, there is no need of Lime application.
g. Water screening
Water screening is very important in keeping the disease carriers away. If good water screening is followed, no need for further disinfectants. Use double layer of fine mesh filter net (60#) at water inlet point. Tie filter nets to the delivery pipe and it should be supported properly. Provide additional two layers of 80 mesh hapa below the inlet. Use of reservoir is recommended in the 3:1 ratio (pond area: reservoir area). Pond should be filled with water within 4 days. Foot valve should be placed in bamboo basket or metal cage and it should be covered with 20# mesh to prevent large animals getting in to inlet mesh.Do not use pesticides to disinfect or kill fish, shrimp and crabs in the pond. If necessary use Tea seed cake @ 10 PPM (50 kg/ha at 0.5 m water depth) to kill unwanted fish in the pond.
Plankton bloom is essential to successful shrimp culture. It shades the pond bottom and prevents the growth of benthic algae, provide the darker environment which the shrimp find less stressful. One week after the water is filled, normally bloom develops in vermicompost /compost manure applied ponds. 3. If the color of the pond water is clear,carry out chain dragging once a week which also helps in stabilizing the plankton bloom. Add 200kg of Dolomite per ha during sunny period. Apply 2 days fermented mixture of rice bran, jaggery and quality brewers yeast @ of 25kg+10kg+0.25 kg/ ha in doses for three days during the morning period. Spread the fermented mixture across the pond using floating device When the color of the water is green the pond is ready for stocking. If there are benthic or floating algae in the pond, remove them. The best approach is manual removal.
i. Stabilization of the plankton bloom
Do not heavily fertilize the water to get dark green water. It will reduce the oxygen in water during night time thus suffocating the shrimps. It is one of the reasons for lower survival rate of shrimp seeds. During the first month of culture whenever the water color intensity reduces (Secchi disc reading of more than 50 cm), add fermented mixture of rice bran, jaggery and yeast @ of 25kg+10kg+0.25 kg/ha. Do not carry out chain dragging from day of seed stocking until 45 DOC. After 45 DOC follow chain dragging of entire pond phased over 3 to 4 days at least once a week. Wherever possible run the aerators two hours every day.
ii. Biosecurity practices
Biosecurity in shrimp farming involves stocking disease free seed, pond preparation, water screening, prevention of entry of disease carriers, personal hygiene and sanitation. General biosecurity precautions that need to be established for each pond to help disease prevention and disease control are given below.
Physical barriers to prevent crabs, birds and other animals:
Ensure all farmers in the society implement these biosecurity measures while pond preparation so that it reduces the risk of disease. The objective is to create a fortress like condition at the pond to prevent entry of animals, predators and carriers whichm could pose disease risk.
Farm Sanitation and hygiene
Area surrounding the farm should be kept clean, should have a toilet in good sanitary condition, located 20 to 30 m away from farm area. must avoid contamination of domestic sewage , avoid use of animal manure. Provide the disinfect solutions like bleached water or KMnO4 in one container and plain water in another container at the entrance of each pond. Each pond should have a separate water sampling container. Farmers/workers should avoid getting in to ponds unless it is very necessary.
Shrimp Seed selection
Selection and stocking of good quality and appropriate quantity of shrimp seed (PL) in to the pond is necessary.
Avoid wild seed and seed from poorly managed commercial nurseries. All the farmers in the area should stock the shrimp seed at the same time as per the crop calendar (within a period of one to two weeks) under contract hatchery system. from sources selling certified specific pathogen-free (SPF) stock or High health disease free seed from registered hatcheries.
PCR tested healthy seeds from healthy disease free tested brood stock should be procured from approved hatcheries complying norms. Shrimp seed should pass a salinity stress tests for salinity and formalin. Seeds of the same batch form a hatchery are to be packed with enough oxygen for optimum quantity based on the distance and time required and temperature maintenance.
Seed should be released in to pond after proper acclimatization during cool hours of the day, i.e., after 8 PM or before 8 AM. Make sure the plankton bloom is good and stable (green color water). Avoid stocking if pond has transparent water or dark green water.
Feed Management Practices:
Feed management is one of the most important aspects of successful shrimp production as the feed accounts for 50 to 60% of the operating cost. Feed should be fresh and of good quality and not more than 90 days old form date of manufacture. Ascertain Size and quantity of feed to be applied following the chart of the manufacturer. Reduce feeding during periods of low DO, plankton crash, rain fall, molting, extremes of temperature and during disease outbreaks. Install feed trays after 10 days of stocking and monitor the feeding from 20 days. Do regular sampling of shrimps once a week after 45 days to determine growth rate and to calculate FCR. Slightly under feeding is better than over feeding. Never mix any antibiotics with the feed. It is preferable to switch off the aerators just before feeding until 2 hrs after feeding, based on stocking density.
Store feed in clean, cool and ventilated area, well protected from sunlight keeping bags stacked neatly on pallets (no more than 10 bags per stack) 30 cm away from walls to prevent feed from being in direct contact with damp floor. Keep the store and outside premises clean and use traps to prevent rodents. Do not keep any fuel or liquid items in the feed store. It is important to protect feed bags from sunlight and rain, by storing them off the ground in simple, pond side storage sheds. During the rain proper care should be taken to prevent feed bags getting moist. Store the empty feed bags properly and recycle them by selling to traders.
Water quality management practices:
To reduce risk of disease through contamination with the water from outside the farm follow the minimal water exchange system*. If water quality and the pond bottom are good, shrimps are healthy and growing well there is no need to exchange water. Plankton bloom is essential to successful shrimp culture. Avoid use of ground water.
Do not exchange or in-take water frequently. Starting third month, if necessary, water exchange can be done but try to minimize as low as possible. Do not release or in-take more than 10-20 cm (8 to 15%) of water per day. 4. It is recommended to use water for exchange from a reservoir wherever possible. If there is no reservoir, take the water in only when there is no disease contamination in water source. Do not exchange water when there is drainage from nearby disease affected pond. Wait for couple of days. Always follow good water screening as mentioned earlier. In early stages of culture (4 to 6 weeks) if the color of the pond water is clear, add fermented mixture of jaggery, rice bran and yeast @ of 25 kg+10kg+025 kg/ha to get bloom. If the water color is too dark, do not use any chemicals to kill the algae, instead change 10cm of top water, if you can during afternoon and intake during the night preferably at high tide. If you cannot, reduce/stop feeding during this period. To control water pH within the optimum range of 7.5-8.3, and limit diurnal pH fluctuation to less than 0.5, o If the pH is lower than 7.5 apply shell lime to increase the pH. High pH results from over liming and excess plankton bloom. If the pH is higher than 8.3, apply 50 litres of molasses or fermented juice of rice powder, jaggery and yeast to reduce the pH. 10. After every water intake / exchange and after rains, use agricultural lime. Agrilime (100 Kg/Ha) should be mixed with water and applied through out the pond. It acts as a buffering agent for water.
Water quality parameters:
For optimum growth of shrimp maintain water quality parameters in the below given range.
|Dissolved oxygen(DO) concentration||4 to 6 ppm||Instant kit or DO meter||5 to 6 AM|
|Temperature||28 to 320C||Thermometer||6 AM and 3 PM|
|pH||7.5 to 8.3||Liquid Indicator or calibrated pH meter||6 AM and 3 PM|
|Salinity||10 to 25 PPT||Refractometer||Any time|
|Total Alkalinity||100 to 200 PPM||Use alkalinity instant test kit||Any time|
|Total Ammonia||0.5 PPM||Use ammonia instant test kit.||Morning|
|Transparency||30 to 40 cm||Secchi Disc||12 noon|
|Water color||Green or brown||Visual observation||Day time|
Use aerators where stocking density exceeds 30,000/ha. The use of aerators in pond has a strong influence on the maximum yield that can be achieved from the pond.If concentrations fall below 4 ppm during night and early morning, use aerators. If oxygen levels deplete in the pond, shrimp will start swimming near the water surface especially during early morning period. Use one HP aerator for every increase in 400 kg of shrimp biomass in the pond. For biomass less than 500 kg in extensive ponds there is no need for aerators. Fix aerators at least 3 m away from the dyke. Maintain the aerators RPM 80 to 100. Aerator should be positioned correctly and operated efficiently to minimize pond dike erosion and suspension of pond bottom sediments The position and orientation (clockwise direction) of the aerators should encourage the maximum water flow within the pond adequate to concentrate waste in the centre of the pond and provide a clean feeding area. Aeration can be used while application of lime and fermented juice into the water. Stop aeration during feeding and chain dragging If for any reason of mismanagement or equipment failure the pond gets into 3 ppm dissolved oxygen levels, first increase mechanical aeration, and as the last choice perform (bottom) water exchange.
Remove Benthic, filamentous algae and hydrilla
Presence of benthic, filamentous algae and hydrilla results in increased water pH, reduced minerals in water. If not removed, they will decay in the pond bottom and release toxic gases and become stressful shrimp. Do not use fertilizer in the ponds where benthic, floating algae or hydrilla present. Remove them manually without disturbing whole pond. Follow chain dragging during morning and remove benthic algae in the evening when it comes to the corners. If the water is transparent carry out chain dragging followed by application of fermented juice of rice powder, jaggery and yeast. After completion of removal apply dolomite to compensate for the loss of minerals. Maintain water level of 1.2 m throughout the crop period.
Pond contains lot of major and minor minerls naturally. In general they will be available in water source and also through various inputs. In shrimp farming especially in vananmei farming calcium and magnesium plays major role. Minerals in water can be verified through test kits or chemically at laboratories. What ever the farming system, an ratio of 1:3 of Ca:Mg to be maintained for vannamei farming.
Pond bottom management practices
Condition of the pond bottom has major effect on the shrimp where shrimp spend most of the time. Maintaining a healthy pond bottom is essential in all types of culture system. Check the bottom soil weekly for the presence of black soil or bad smell. If the soil is black or smells it means pond bottom has deteriorated. Avoid feeding in areas where the soil is black. Check the feeding rate, reduce the feeding rate for couple of days. Change 5-10 cm of bottom water while exercising precautions. Do regular Chain dragging at feeding areas to get organic matter oxidized. Chain dragging can also help to dislodge the benthic algae but this practice should not be applied to more than ¼ of the pond bottom in any one day. Fermented mixture should be applied immediately after the chain dragging. Take out accumulated benthic algae/black soil at the pond corners regularly. During routine application of Agri. lime to the pond, spread more lime in areas where the pond bottom is bad. Clean feeding area can be maintained with adequate number of properly positioned of aerators.
Health and Disease Management practices
Check the health of shrimp in feed check trays on daily basis. If there is poor feed consumption for consecutive three to four days it indicates health problem of shrimp. Check the general health and growth of shrimp collected by cast net on weekly basis. Carry out sampling during early morning or late evening at different places. The shrimp should be clean with normal color, have a full gut and without any infection of legs or antennae. Gut content of >80% of the shrimp sampled from a healthy, recently fed pond should be full of food. If not it could be an indication of onset of disease. If there is antennae cut with out black tip, check under feeding. If the antennae tip is black it could be bacterial infection due to poor pond bottom. If the gills of shrimp are black it means that the pond bottom is not clean. Improve the pond bottom by adopting better pond bottom management practices. Check shrimp for external fouling-which is growth of organisms and accumulation of debris on the surface of the shrimp. This indicates poor pond condition. Improve water quality to encourage shrimp to moult regularly. Check if the shrimp have black spot- The causes include -Localized bacterial infections- eg. Vibrio sp. -Fungal infections, eg. Fusarium sp. -High nitrite levels -acidic water Solution- keep the feeding area clean. Vibriosis- Infection caused by bacteria of the genus Vibrio. -Shrimp at the side or surface of the pond –lethargy -lack of appetite -discoloration either red or blue Solution-Improve pond water quality. If sick/dark shrimp are found on the surface water then check if they have dirty or black gills. If so, reduce feeding and exchange cm of water exercising precaution. Check the pond daily during early morning hours for sick or dead shrimp or other signs (oxygen problems or any other unusual observations) and follow the disease management practices and inform all the society farmers.
Disease management practices:
Make sure total biosecurity including good water screening is maintained through out the crop period. Any problem during the crop like shrimp coming to the side, mortality should be immediately reported to all society farmers, farmers should be called to address the issue immediately. If there is antenna cut, fouling or gill problem–corrective measures to improve general pond condition should be carried out. If shrimp have white spots do not let water out and inform immediately all the farmers of society. Do not panic in emergency situation, co-ordinate with other farmers. All society farmers should implement agreed emergency action plan in case of white spot disease outbreak. If any serious infectious disease is detected which has the potential to spread widely the pond should be isolated, a. If the size of the shrimp is small, do not abandon/ drain the pond disinfect the affected pond with 20 ppm chlorine. Keep the water for one week with out discharge. If the size of the shrimp is harvestable, harvest all the shrimp with out draining the water. Disinfect the affected pond with 20 ppm chlorine. Keep the water for one week with out discharge. When the disinfected water is discharged after a week inform all society farmers and ensure water is not pumped in at least for two days. Put up bird net to prevent birds picking up dead shrimp and carrying it to other ponds. Care should be taken to collect all the shrimp in the pond to prevent contamination. Dead and affected shrimp would be buried under soil away from the pond area. Necessary precautions should be taken to avoid transfer of shrimp or equipments or anything used in the disease-affected pond to other ponds. Cooperation and communication with neighboring shrimp farmers and farm workers with regular meetings regarding disease problem should be practiced to minimize the spread of disease. Do not stop feeding the normal ponds during disease outbreak. With out feeding shrimp gets weak and susceptible for disease During disease situation, stay at farm and ensure there is no contamination from other workers and animals. Do not move any equipments from affected pond to other ponds. Wherever possible let farmers put up KMnO4 solution for washing hands, dipping legs, washing equipments etc.
Better harvest and post harvest practices:
To improve the freshness and quality of shrimp for the export markets following BMPs are suggested for harvesting and post-harvest handling of shrimps. Coordinate the harvest with the contract processor. Exchange 20% of the water one week before the planned harvest date. Immediately after water exchange apply agricultural lime (100-200 kg/ha) to the pond and pond bottom where it is more black especially in corners. Avoid harvest during the molting period (full moon or new moon). 2 days before harvest check if there are any newly molted shrimp, if newly molted shrimp are>10%, delay the harvest by a day or two. Do not exchange water or reduce water level 2 to 3 days before harvest. Do not feed the shrimp 6 hours prior to harvesting to keep the gut empty and improve the shelf life. Complete the harvesting process (draining and harvesting) within 6-8 hrs. between 6 PM to 6 AM. Avoid harvesting and packing shrimp during hot time of the day. Use the Drag net to harvest. Avoid using cast nets. If normal draining of the pond water is difficult, use artificial gates (made up of bamboo sticks or fish nets) in a corner at deeper side of pond for fixing the bag net. Use more pumps if necessary to complete the harvesting in time and to catch most of the shrimp with the bag net. Thoroughly wash the handpicked shrimps in clean water and pack them separately from bag net harvested shrimp. Do not use any chemicals while washing the shrimp or chill killing with out processors knowledge Make sure good quality ice is used (preferably from the processor) during harvesting and packing. Workers with wounds, open sores or skin infections should not handle harvested shrimps. Do not smoke or spit in packing area. Pack the shrimps in transport tubs (insulated boxes) with crushed ice:shrimp @2:1 ratio for better preservation. Load the packed crates quickly to the truck and send to the processing plant immediately without any delay. Ensure the insulated truck temperature is <50C.
Record keeping is a key component of managing shrimp farm efficiently. Records are necessary for identifying water quality problems, monitoring day-to-day activities, identifying and learning from past mistakes and for minimizing production costs. Society farmers should make use of NaCSA supplied pond record books to keep full records of following general management, key activities/events and parameters.
- Pond ID (with CAA registration number)
- Pond area (ha)
- Name of the hatchery
- Stocking density (Seed qty stocked)
- Management details on daily basis
- Days of culture
- Feeding details-qty, feed company, feed batch no., Feed monitoring
- Water exchange details
- Water quality parameter readings
- Details of fertilizers, probiotics and chemicals used
- Hrs of Aeration
- Management details on Weekly basis
- Pond bottom condition
- Shrimp Health, growth monitoring
- Harvest details
- Date of harvest
- Production (MT)
- Survival (%)
- Economics- Cost of production, revenue, profit
VI. General Farm management
Involvement of farmer: In shrimp farming complete involvement of farmer in day today operations is very important as the shrimp farming needs more attention compared to other husbandry practices. Farmers must spend time in the farms at night and early morning hours.
Adequate Investment: Farmers must invest sufficiently in implementing BMPs and other crop activities to get successful crop. Part of the profit must be invested back in improving farming facilities.
Farm workers management: Employ local workers. Workers must be paid fair wages as per the national labor laws and essential facilities like proper accommodation, toilets, safe drinking water must be provided. Farm workers must be adequately trained in all practical aspects of BMP implementation. No child labor should be employed.
Personnel safety Workers must be trained in safe operation of pumps, motors, aerators and other electrical equipments. Care must be taken during water exchange. Farmers and farm workers should be aware of nearest hospital with anti venom in case of any snake bite. First aid facilities must be provided on site.
Harmony with neighbors: Good relationship with neighbors should be maintained. Traditional access route to public resources has to be maintained.
Farm Security: Adequate security must be provided to prevent theft during night hours.
Equipments Maintenance: All the farm equipments must be serviced and maintained regularly for smooth operation. In the off season all equipments must be serviced, painted wherever necessary and must be kept safely. Farmers should have backup generator in case of electricity failure.
Resource management: Rain water can be judiciously harvested and used in the farm. Solar lights can be made use of in the farm.
Waste Management: Farm premises must be kept clean, waste generated must be segregated and reused as much as possible and unused items must be disposed off properly. Fuels and lubricants should not be stored near feed, in employee housing or kitchen areas, or near harvest equipments.
Precautions during natural calamities: Adequate precautions must be taken prior to any natural calamity when there is advanced information available. Have emergency plan in place to face any natural calamity successfully.