Powerpoint Templates Page 1 Powerpoint Templates Major Cultivated Species of Shrimps and Prawn. - презентация
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Powerpoint Templates Page 1 Powerpoint Templates Major Cultivated Species of Shrimps and Prawn
Powerpoint Templates Page 2 Introduction The popular names shrimps and prawn have been used to denote crustaceans of the family Penaeidae and Paleomonidae. In most recent aquaculture literature the name prawn appears to be used for fresh-water forms of Paleomonids and shrimp for the others, particular marine species.
Powerpoint Templates Page 3 Contd… Shrimps form a group of subsidiary species in most types of fish culture in coastal impoundments and ponds in Asia. Shrimp aquaculture is triggered by the recent increased market demand and the inadequacy of the capture fishery landings to meet the demand. Shrimp and prawns became high-value commodities in many developing countries, due to their export market.
Powerpoint Templates Page 4 Major Cultivated Species At present attention is towards the culture of tropical and sub-tropical species of shrimps, so called giant fresh water prawn (Maccrobrachium rosenbergii). Spawning and larval rearing of Kuruma shrimp in captivity in Japan about four decades ago aroused considerable interest in intensive farming of this species. It was introduced in many countries of Asia, Southern Europe, West Africa, Southern USA, and Central and South America.
Powerpoint Templates Page 5 Contd… In Asia the more important species are the tiger shrimp, P. monodon and the Indian or white shrimp P. indicus. The Banana shrimp P. merguiensis, the green tiger or bear shrimp P. semisulcatus and the oriental shrimp P. orientalis. The red-tailed shrimp P. penicillatus is a species cultured in Taiwan. Metapenaeus monoceros, M. brevicornis and M. ensis in several Asian countries.
Powerpoint Templates Page 6 Contd… Besides the imported P. japonicus, the main interest in Mediterranian countries of Europe has been in the local Mediterranian shrimp (P. kerathurus). Present effort in establishing shrimp farming in Africa is mainly involve the culture of P. indicus on the East Coast and P. notialis on the West Coast. The most important species in Central and South America are the white leg shrimp are camaron langostino P. vannamei and the blue shrimp P. stylirostris.
Powerpoint Templates Page 7 Contd… There are four other species that have reached commercial level culture in the countries bordering the Atlantic Coast of Central and S. America namely, the brown shrimp (P. aztecus), pink shrimp (P. duorarum), white shrimp (P. setiferus). The bulk of the present production comes from the farming of P. monodon, P. indicus, P. merguiensis, P. japonicus and P. vannamei.
Powerpoint Templates Page 8 Research in Shrimp Production Much of the research effort on shrimp culture has been concentrated on the development of hatchery techniques for controlled spawning and larval rearing. The search for species that may be easier to reproduce and have a shorter larval history are the giant fresh water prawn, Macrobrachium rosenbergii. The success achieved in the mass production of the post larvae of this species in the 1970s led to wide spread interest of this specie in massive number of countries in tropical, sub-tropical and in temperate climate in almost every continent.
Powerpoint Templates Page 9 Contd.. Some experimental work has been done on culture of other species of Macrobrachium, such as M. lanchesteri, M. acanthurus, M. carcinus and M. malcolmsonii. There are considerable similarities in the culture technologies for the various species, but number of differences by environmental requirements, breeding and feeding behavior and compatibility with other species.
Powerpoint Templates Page 10 General Culture Requirement In general water salinity (10-40 ppt) Temperature tolerance (18-33C) Growth rate and harvest sizes based on commercial size of g weight also vary considerably. These factors greatly influence the compatibility of different species of Penaeids in polyculture, but can be advantageously used in rotational production of different species in the same facility.
Powerpoint Templates Page 11 Contd… In temperate climates, different species can be used for culture in summer and winter. In tropical monsoon areas subject to marked changes of salinity can be alternated. The freshwater prawn M. rosenbergii is commercially important because of its size as well as its eating quality. The males can attain a size of about 25 cm and the females about 15 cm.
Powerpoint Templates Page 12 Contd… Though adults are found in fresh water and brackish water areas and requires about 12 ppt salinity for larval rearing. The adults are omnivorous and feed on a variety of foods of animal and vegetable origins.
Powerpoint Templates Page 13 Shrimp Culture System Traditional and modern shrimp culture are carried out mainly in ponds. In traditional systems, natural stocking was achieved through intake of tidal water carrying large number of shrimp larvae. Pond designs were simple as trap ponds. Recently nursery ponds have been incorporated for growing larvae to an advanced juvenile stage, before transfer to production ponds.
Powerpoint Templates Page 14 Contd.. With the adoption of techniques of controlled propagation, many shrimp farms now include hatchery units, nursery facilities. There is also greater specialization in the rearing of post-larvae or juveniles for sale to farmers for grow- out. Such nursery farms may maintain brood ponds, hatcheries and nurseries togather with facilities for growing natural food for larvae.
Powerpoint Templates Page 15 Contd.. Traditional shrimp culture was necessarily a polyculture system because of the inability to control the composition of the seed stock. Polyculture of Macrrobrachium with certain species of finfish is believed to be beneficial. M. rosenbergii is cultured together with Chinese carps in Taiwan and Malaysia. There are also reports of successful culture with grey mullets, tilapia and red swamp crayfish.
Powerpoint Templates Page 16 Intensive culture Intensive systems of shrimp and prawn culture are generally practiced in tanks. Water in tanks is frequently exchanged to maintain high oxygen levels and to discharge metabolic products. When water exchange is low heavy aeration is adapted to keep organic particles in suspension. These suspended particles serve as biological filters having dense colonies of nitrifying bacteria.
Powerpoint Templates Page 17 Contd.. Circular tanks with upto 2000 m2 surface area with adequate water circulation and drainage facilities are in use. Raceway systems with a total exchange of water several times a day have proved particularly efficient for certain species like P. stylirostris. In traditional system of shrimp production in rice fields in India; many farmers raise crops of shrimps in rotation with rice. Similar practices have developed in Bangladesh and in the Mekong delta area in Vietnam.
Powerpoint Templates Page 18 Contd… After harvesting shrimp the fields are stocked with carp during the rainy season, when the salinity in the field is low. Open water stocking of shrimps carried out in Japan to enhance natural populations. It is reported that at least 300 million post-larvae are released every year. Open water stocking of M. rosenbergii is also carried out in lakes and reservoirs in Thailand and is reported to have become a source of food and revenue to local fishermen. Small scale stocking of a river and dams has also been attempted in Taiwan.