FRESH WATER PRAWN CULTURE
Indian aquaculture has been evolving from the level of subsistence activity to that of an industry. This transformation has been made possible with the development and standardization of many new production and associated techniques of input and output subsystems. In recent years aquaculture has created great enthusiasm and interest among entrepreneurs especially for shrimp farming in coastal areas. Shrimp farming is capital intensive activity and uncontrolled mushrooming growth of it has led to outbreak of diseases and attributed environmental issues calling for closure of shrimp farms. Although India has vast freshwater resources they are not fully exploited except for carp culture in limited scale. Fresh water fish culture employing composite fish culture technology has become popular for use in large number of tanks and ponds in the country. To meet the raw material required by the processing units for export demand there is urgent need to expand our production base. In addition it is always stressed that there is a need to utilize our natural resources productively to ensure the much needed food security. 2. Scope for Fresh Water Prawn Culture
Considering the high export potential, the giant fresh water prawn, Macrobrachium rosenbergii, the scampi, enjoys immense potential for culture in India. About 4 million ha. of impounded freshwater bodies in the various states of India, offer great potential for fresh water prawn culture. Scampi can be cultivated for export through monoculture in existing as well as new ponds or with compatible freshwater fishes in existing ponds. It is exported to EEC countries and USA. Since the world market for scampi is expanding with attractive prices, there is great scope for scampi production and export. 3. Technical Parameters
The giant freshwater prawn is suitable for cultivation in tropical and subtropical climates. 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. In the natural enviroment, lower reaches of rivers, tidal inlets, where water is directly or indirectly connected with sea are their preferred habitat specially during spawning. 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. Though seed may be available in natural sources to a limited extent, for large scale culture there is a need to ensure regular supply of seed. For ensuring availability of quality seed in predictable quantity freshwater prawn hatcheries should be encouraged, technology for which is already developed. Freshwater prawn hatcheries are coming up in many states. 3.1. Site selection
The site selection plays an important role as the entire management aspect of the farm ultimately depends on specific conditions of the site..
3.2 Soil quality
The ideal soil for Macrobrachium culture should be clay silt mixture or sandy loam comprising of 60% sand and 40% silt with good water retention capacity. 3.3. Water quality
There should be availability of abundant and good quality water. The water should be free from any kind of pollution. The pH should be maintained at 7 to 8.5. The temperature should range from 18 0 to 340C with an optimum range of 270 C to 310 C. Dissolved oxygen content should be higher than 75% saturation. 3.4 Pond construction
Rectangular ponds are suitable mainly from the harvesting point of view. A convenient width is 30-50 m, whereas length of the pond depends on site, topography and farm layout. Normally a size of 0.5 to 1.5 ha is found suitable. The average depth of the ponds should be 0.9m with a minimum of 0.75m and a maximum of 1.2m. Dike and pond slope may be kept at 2:1. Bund must have a freeboard of at least 60 cm above the highest water level in the pond. Designing and layout of the farms...
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