ponds, juveniles of 3 cm in length have been grown to a size of 75 to 100 g in only five to six months.
Due to its large size, it brings a high price to the farmer. monoceros, M. Shrimp with a size of 10 to 12 pieces/kg are common, and sizes of 5 to 7 pieces/kg have been grown in ponds.
It is the fastest growing of all shrimp tested for culture. 450 per kg in India.
It can tolerate a wide range of salinity, 0.2 to 70 ppt. It has also been seen that both these species are suitable for farming in Kerala's environment. monodon
It attains a large size. Mortalities occur at temperatures below 12°C only.
It grows rapidly when fed either with animal or vegetable protein.
Food conversion ratios are favourable. Another potential candidate species that is flooding international market is the White leg shrimp, Penaeus vannamei. brevicornis, Penaeus semisulcatus and P. Apart from these candidate species other commercially important species such as Metapenaeus ensis, M. indicus are generally considered for farming. Salinity within the range of 10 to 25 ppt has no appreciable effect on growth when food is sufficient. Growth is reported to be slower at very low salinities.
It can tolerate temperatures up to at least 37.5°C. Values as low as 1.8:1 have been reported from Taiwan.
It is hardy and not greatly disturbed by handling.
. Due to its large size and high price, Penaeus monodon and P. At peak seasons it demands over Rs. Although the Government of India has not yet given sanctions to culture it in the country, many Asian countries have already started to culture this species.
Advantages of P. Many factors must be considered when a farmer is deciding which species of shrimp he should culture. merguiensis are also potential species that can be grown
This shrimp grows to a fairly large size and brings a good price.
It is fairly fast growing, especially when young. In polyculture with milkfish in earthen ponds, females grew to about 28 g and males to about 12 g in 160 days.
Survival is high during the first three months of growth or up to a size of about 10 cm.
Wild seeds are usually abundant in estuaries near areas where the adults are present.
Gravid females are relatively easy to obtain from the wild in numbers sufficient to operate a hatchery.
Females can be matured in captivity with relative ease.
This shrimp moves out of a pond with water discharge, making harvesting easy.
Good growth has been obtained in intensive culture with a feed having 40 percent protein, which is lower than that required for some other species.
The exoskeleton is relatively thin, giving greater portion of edible meat to total weight.
They are amenable to culture at very high stocking densities of up to 150/m2 in pond culture, and even as high as 400/m2 in controlled recirculated tank culture.
Tolerates a wide range of salinities, from 0.5-45 ppt, is comfortable at 7-34 ppt, but grows particularly well at low salinities of around 10-15 ppt.
P. vannamei is very tolerant to low temperatures (down to 15°C) enabling them to be cultured in the cold season.
P. vannamei require lower protein feed (20-35%) than P. Advantage of P. vannamei
Specific Pathogen Free (SPF) brood stocks are available for this species to produce disease free larvae.
The sites should have minimum vegetative cover, be near the sea or other natural waterways such as rivers and streams, have easy access to roads, a sparse population and be nearly square or rectangular in shape.
In terms of climatic conditions, areas having short and not as pronounced a dry season with moderate rainfall distributed throughout the year are the best suited for shrimp farming. Water quality parameters required for maximum feed efficiency and maximum growth of Penaeus monodon . Site evaluation is not only undertaken to determine if a site is suitable for shrimp farming. In areas where electricity supply exists, it is practical and beneficial to utilize electric power to run the farm, especially for the intensive culture system. A pronounced long dry season may cause an increase in water temperature and salinity, which will promote excessive growth of algae and result in oxygen depletion at night.
Infrastructure :
Accessibility
The farm must have good accessibility either by road or water, and communication systems throughout the year in order to facilitate supervision and transport of materials and products. Top
Site Selection
Selection for a suitable site is a critical activity and must be carefully determined before establishing of a shrimp farm. It is also valuable in determining what modifications are needed concerning layout, engineering, and management practices to make shrimp farming possible at a given site. It is important that the farm be within 3-6 hrs traveling time from the hatchery to avoid excessively long transportation time of the larvae and should be within 10 hrs from the processing plant to avoid deterioration of the product.
Electricity
Availability of relatively cheap and reliable power source is a major consideration in site selection. The cost of pumping increases in highly elevated sites. It is advisable to have a back-up electricity generator as a secondary power source.
Security
Areas free from security risks result in favorable working conditions, productivity and less extra costs.
Availability of Labor and Other Factors
The availability of labor, equipment and commercial feed and supplies ensure smooth operations and successful crop.
Water Supply
Site should have good pollution free water supply of both freshwater and brackish water. No site will have all the desirable characteristics, so a number of judgements have to be made for every site.
There are several factors involved during site selection.
Topography and Climatic Condition
Topographically, the best areas for shrimp culture are those with average natural ground elevations of about 1-3 m above mean sea level or at least 1 m above the highest high tide level to allow drainage and harvesting.
Such data will be useful during pond construction and preparation.
Mangrove or acid sulfate soils are not suitable for shrimp pond culture due to their high organic matter contents and acidic nature that require a high water exchange rate and low stocking density. A settling pond or a large reservoir should be used in such areas for sedimentation and treatment. Prior to construction of ponds, samples of soil should be taken randomly from 5-10 spots at the surface and at 1 meter deep and sent to a laboratory for the analysis of soil texture and pH. A pond built on mangrove soil will also encounter the problems of hydrogen sulfide and ammonia accumulation in the pond bottom. Usually, clay or loam-based soil containing more than 90% clay and pH between 6.5-8.5 is preferable. The freshwater should be good enough for use and adequate throughout the year.
Soil Conditions
The type of soil is the most critical in site selection, since the shrimp will spend most of their time on the pond bottom during the culture period. Water from polluted areas containing high concentrations of suspended solids and organic wastes such as effluent water from industry; urban areas, agricultural and other farm locales should be avoided. Sites with sandy or silty soil should be avoided due to their porous nature that may lead to erosion, seepage of water and easy infiltration of waste into the soil. In saline areas, a source of freshwater is useful for adjusting the salinity in the ponds and for domestic use by farm staff. In the acid sulfate soil areas, the soil will develop high acidity when dried and then flooded which will lead to difficulty in stabilizing the pH of the pond water and in inducing the growth of plankton during the culture period.
Feeding
Therefore, feed and feeding practices for semi-intensive or intensive shrimp farming require a basic understanding of nutrition and feed requirements.
Shrimp diets may be supplementary or complete. The availability of nutrients from feeds depends on the type and quality of the raw material used, the formulation, the feed processing, feed storage conditions and the feeding management. Feed and Feeding
Cost of feed constitutes a major part of the production cost and accounts for 50% to 70% of the total variable cost. The feeding could be done by using automatic feed dispensers, or by broadcasting all over the pond. If feeding trays are employed in selected pockets in the pond wastage in feed can be reduced. The use of feeds will improve shrimp production and increase profits. At present most of the aquaculture farms depend on imported feed with a FCR (Food Conversion Ratio) of 1:1.5 - 1.8. Although natural food items have good conversion values but they are difficult to procure in large quantities and maintain a continuous supply. In a extensive system the shrimps need a complete diet.
Nutrient Requirements
Shrimp requires approximately 40 essential nutrients. The recommended levels of nutrients and dietary components for black tiger shrimp are listed in table below. Although the nutrition principles are similar for all animals, the quality and quantity of nutrient requirements vary from species to species. These nutrients are provided in various amounts by natural food and supplemental feeds.
Thus, essential amino acids must be provided in adequate quantities and qualities (well-balanced) in the diet. In addition, the recommended lipid level ranges from 6.0 % to 7.5 % and the level should not exceed 10 %.
Carbohydrates
The utilization and metabolism of carbohydrates by shrimp are limited. The requirement for cholesterol ranges from 0.25 % to 0.4 %. About 20 major amino acids make up most of the proteins and 10 are essential including methionine, arginine, threonine, tryptophan, histidine, isoleucine, leucine, lysine, valine and phenylalanine. Calcium should not exceed 2.3% in the diet. There are four fatty acids, which are considered essential for shrimp, namely linoleic (18:2n6), linolenic (18:3n3), eicosapentaenoic (20:5n3) and decosahexaenoic (22:6n3). Starch as the carbohydrate source is utilized better than dextrin or glucose for Penaeus monodon.
Vitamins
Little is known about vitamin requirements in shrimp. The minimum requirement for vitamin C, which is easily lost, is about 50-150 ppm for Penaeus monodon.
Minerals
Shrimp can absorb or excrete minerals directly from the aquatic environment via gills and body surfaces. However, its level in feed needs to be monitored because it is important to maintain calcium to phosphorus ratio of 1:1 to 1:1.5. Commercial shrimp feeds are usually over-fortified with vitamins to overcome shortfalls due to processing loss and feed storage. It is believed that post-larval shrimp require a higher protein level than larger shrimp.
Lipid
The lipid requirement of shrimp depends on their essential fatty acids and phospholipid content. In general, plant oils are high in 18.2n6 and 18.3n3, while the marine animal oils are high in 20:5n3 and 22:6n3. Protein
Shrimp consume dietary protein to obtain a continuous supply of amino acids for normal growth. The dietary requirement for minerals is largely dependent on the mineral concentration of the environment in which the shrimp are being cultured. On the other hand, the recommended dietary protein levels for shrimp vary from 30 % to 55 % depending on the shrimp size and species. In intensive farming, vitamins must be supplied in the diet for normal growth. Calcium is not considered to be a dietary essential. The phospholipid requirement is 2 %; however if lecithin is used this level can be reduced to 1 %. Among the other minerals, phosphorus is the most important, and is recommended at 0.9% as available phosphorus in the diet. Their type and level in the diet have been shown to affect shrimp growth.
Only the superior quality of feed can achieve an FCR of 1.2. According to recent data, an FCR as low as 1.2 has been achieved, but many farmers are still obtaining FCRs of higher than 2.2. Feed should not be stored in direct sunlight and should not be kept longer than 3 months from the time of processing. The spoiled or old feed should not be used.
Feeding Management
A high FCR or high amount of feed required to produce unit weight gain indicates overfeeding, and consequently, a poor FCR is usually associated with poor growth rate, low weight gain, stressed shrimp, mediocre water quality and adverse pond bottom conditions. Therefore, besides the feeding management, the FCR is also closely related to the quality of feed.
Attractability
The model quality shrimp feed must be highly palatable.
Good Water Stability
Since shrimp are a slow feeder animal, the water stability of suitable feed should be over 2 hours for Penaeus monodon.
Packaging and Optimal Conditions Storage
Feed quality will rapidly deteriorate if feed is not packed well and properly stored. Since many factors are involved in shrimp feed consumption, careful and frequent observation of shrimp is the most reliable approach for determining the optimal feeding amount. Use of good quality feed with better feeding management by low feed conversion ratios and improved farm management are the important goals to farmers, not only for gaining greater profit, but also for minimizing the pollution of shrimp farming area. There are many major key factors for successful intensive shrimp culture. Therefore, the proper amount of feed is the most critical factor of feeding management. The practical indicators of good quality feed are:
Feed Conversion Ratio (FCR)
An ideal FCR always results in model growth rate, healthy shrimp and clean pond bottom conditions. Feed should be stored in a dry, cool and well-ventilated place to maintain consistent moisture and temperature. The guidelines for feeding adjustment to be made according to the mean body weight of the shrimp are shown in table below. Feed Quality
The use of good quality feed will improve shrimp production and profits, and minimize the environmental pollution from shrimp farming.
Water quality management
monodon pond. Generally, shrimp farmers use dissolved oxygen (DO), pH, ammonia, water color and water odor as indicators to judge the water quality of the pond.
These parameters are observed regularly by using either scientific equipment or the farmer's experience in order to control them within the optimum range.
Optimum water quality for P. Water Quality Management
Water conditions in the rearing pond deteriorate through the production cycle due to uneaten food, animal's excretion, etc.
Secondly, by controlling plankton density to an optimum level and thirdly, by minimizing excess organic substances, such as uneaten food.
pH Adjustment
Shrimp farmers control water pH within the optimum range of 7.5-8.5, and limit diurnal pH fluctuation to less than 0.5 by applying lime. This is not only causes proper water circulation, but also adds oxygen to the pond water. Too many nutrients in some cases may lead to excessive plankton bloom, followed by plankton crash. However, in the rearing pond, dissolved oxygen is mainly consumed by pond sediment (50-70%) and plankton (20-45%). Plankton density and species are two management aspects that require attention of shrimp farmers.
In the first 2 months of shrimp culture, an additional fertilizer either organic (10-30 kg/ha) or inorganic (1-3 kg/ha) is added to the pond in order to ensure that there are enough nutrients for plankton bloom. The application of lime is as follows:
At the beginning of a crop cycle, when water pH ranges between 7.5-7.8 about 4.8-8.0 kg/ha of dolomite should be used every 2-3 days.
When pH is in the range of 7.5-7.8 and there is less than 0.5 unit difference between the pH in the morning and the pH in the afternoon, 4.8-8.0 kg/ha of dolomite should be used every 2-3 days.
If the pH in the morning is less than 7.5, 4.8 kg/ha dolomite should be used every day until the morning pH is increased to above 7.5.
If the pH in the morning is higher than 8.0 and the pH in the afternoon is higher than 9.0, 4.8-8.0 kg/ha of dolomite should be used every day until the day's pH difference is less than 0.5.
In the second half of a crop cycle, 8.0 kg/ha of dolomite should be used every day or at least every 2 days, depending on water color.
Every time before exchanging water, 4.8-8.0 kg/ha of dolomite should be used.
Water Color Control and Adjustment
The color of pond water mainly results from suspended particles of phytoplankton. Dissolved Oxygen
The amount of oxygen dissolved in the pond water is vital to the shrimp's health. Only a small portion of dissolved oxygen is consumed by the shrimp (5%).
The level of dissolved oxygen can be controlled in 3 ways. But in a closed system, where exchanging water is not needed, shrimp farmers use algaecides such as calcium hypochloride or benzalkonium chloride (BKC) 0.1-1 ppm to reduce plankton density.
In cases where undesirable water color appears like the ‘red tide' caused by certain types of plankton such as dinoflagellates, the plankton can be controlled by switching-off the aerators for a period of time and applying BKC (0.1-1 ppm).
Water Exchange
Mass shrimp mortality in a pond associated with deteriorating environmental conditions has occurred frequently during the last 5 years. After this period, nutrients derived from uneaten food normally are at adequate levels. In an open shrimp culture system the farmers exchange pond water with natural clean seawater to reduce excess plankton density. Firstly, by increasing the water surface area by means of placing paddle wheels in the right position. Shrimp farmers have tried to solve this problem by changing the culture system to a low water exchange system, including.
Quality control
Unhealthy shrimps, which are easily recognized through their appearance, will not be acceptable to consumers and market value could be reduced. Therefore, samples of shrimp should be sent to a reliable laboratory to conduct necessary test to certify the hygienic quality of the products, before exporting or sending them to market. Quality Control
Before harvesting and/or exporting, shrimp should be examined for their health, hygienic quality and safety for consumers. The harvested shrimp should also be checked for antibiotics and heavy metal residues before export. Unhealthy shrimp should be treated before harvesting or removed during harvesting and processing if the proportion of unhealthy shrimp in the stock is low.
Human pathogenic organisms could contaminate the shrimp during harvesting, storage and processing. If the shrimp have been treated for unhealthy conditions with antibiotics, the recommended withdrawal period should be followed.
Banned Antibiotics, Pesticides and Pharmacologically Active Substances.
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