32 resultados para cultivation

em Aquatic Commons


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Representatives from the family of Lemnaceae (duckweed) make ideal experimental material for research into a succession of phytophysiological processes with regard to growth rate and vegetative reproduction. They are also easy to maintain in sterile cultures. Lemnaceae belong to the higher flowering plants (flowers are rarely produced), however they are distinguished by a much simplified morphological and anatomical structure. As water plants they possess the advantage, that they can be cultivated in synthetic media under laboratory conditions controlled by the application of both a known light intensity and temperature. This paper describes experimental research of growth of Lemnaceae in different conditions. Some of the variables were mineral media, illumination and aeration.

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The objective of this short project progress report is to investigate the possible water quality implications of modern watercress growing practices. Chalk receiving watercourses are usually of high supply, amenity, game fishing and fish farming value. Any headwater pollution load, therefore, needs characterising and quantifying. Two sites of watercress farming were studied in 1986-87 and nutrient levels examined. Different approaches of watercress farmers in Dorset and Hampshire are summarised.

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The viability of integrating rice farming with fish culture was studied in ten (10) rice plots. The on-farm research was done during one rice-growing season starting May 2003. The rice variety used was IR 2793-80-1 while the fish species was the Nile tilapia, Oreochromis niloticus. The fish culture period lasted 77 days. An average fish production of 132.4 kg/ha was obtained. The mean recovery rate of tilapia was 43 per cent. Total rice yield from the fields stocked with fish was lower than from unstocked fields. The net returns were not significantly different.

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Few marine animals have yet been tamed and harnessed for man's use. Of these the bivalves have the greatest potential, and of the bivalves the pearl oysters are perhaps the most thoroughly exploited. Not only are they eaten and their shell put to use, but their nacre secreting properties are tapped to produce pearls by design, rather than by accident as in nature.

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A brief description is given of experimental rearing of the red alga G. lichenoides using a coir net frame method. Frames of 1x1 m were made and tied to bamboo poles which were planted in water; the frame was fixed at a level about 1 ft below the water level. 2 cm fragments were used as propagating material. Plants were found to grow more luxuriantly and were more greenish than using other methods, and in addition were free from extraneous matter such as sand. The regeneration time of the plant is low, and it reaches marketable size in 3-4 months.

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Aquaculture in Tanzania is still on a subsistence level and most of the ponds are maintained as part time job. The ponds are too small, shallow and over crowded with stunted Tilapia spp. In the present paper the results of experiments conducted in ponds at Nyegezi with T. esculenta and T. zillii are presented. This was part of an overall project of developing techniques of fish cultures with Tilapia under the limited existing conditions at Nyegezi. In a mono - species culture experiement with Tilapia zillii in nine month's time an average size of 172.8 mm/115.0 g was attained. In another experiment with T. zillii and T. esculenta in thirteen month's time, T. zillii attained an average size of 180.2mm/106.6 g and T. esculenta 193.6 mm/118.8 g. In another experiment with intensive feeding schedule an average size of 179.3 mm/126.6 g was attained by T. zillii and 191.0 mm/125.0 g by T. esculenta in four month's time. A locally prepared supplimentary feed with local Brewery Waste and Fish Meal (10:1) was readily accepted by both species of Tilapia. T. zillii voraciously fed on Cabbage leaves, Cauliflower leaves, Chinese cabbage leaves, Cassava leaves and on the common weed Comalina sp. Though all the items mentioned above were readily accepted by T. zillii feeding with Comaltna sp. was the easiest and most convenient because of its availability. In an intensive feeding experiment with vegetable leaves/Comalina sp. and the locally prepared supplimentary feed the fishes attained table size in four months time. Cement cistens of 5 X 3 X 1½ m size could be conveniently used for breeding both species of Tilapia. T. zillii had semi adhesive eggs and they were deposited on the sides of the cement wall. The number of young ones in a brood ranged from 160 to 314 in T. esculenta and 687 to 4,356 in T. zillii.

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Waterhyacinth ( Eichhornia crassipes (Mart.) Solms.) was evaluated at ratios of 25, 50 and 75% with paddy straw ( Oryza sativa L.) for oyster mushroom ( Pleurotus sajor-caju) cultivation. There was an increase in yield with decreasing ratio waterhyacinth.

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Waterhyacinth ( Eichhornia crassipes (Mart.) Solms.) was evaluated at ratios of 25, 50 and 75% with paddy straw ( Oryza sativa L.) for oyster mushroom ( Pleurotus sajor-caju) cultivation. There was an increase in yield with decreasing ratio waterhyacinth.

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Editorial An increasingly secure future for wastewater-fed aquaculture in Kolkata, India? by Peter Edwards. First culture-based fisheries growth cycle in Lao PDR is overwhelmingly encouraging, by Sena De Silva. Revival of abandoned shrimp farms in Krishna District of Andhra Pradesh, by National Centre for Sustainable Aquaculture (NaCSA). Growth of forward and backward industries linked with aquaculture in Kolleru Lake area, Andhra Pradesh, India, by A. K. Roy, G. S. Saha, P. Kumaraiah and N. Sarangi Effective marketing strategies for economic viability of prawn farming in Kuttanad, India, by Ranjeet K. and B. Madhusoodana Kurup. Applications of nutritional biotechnology in aquaculture, by S.D. Singh, S.K. Nayak, M. Sekar and B.K. Behera. Some technical and management aspects of catfish hatcheries in Hong Ngu district, Dong Thap province, Vietnam, by H. P. Hung, N. T. T. An, N. V. Trieu, D. T. Yen, U. Na-Nakorn, Thuy T. T. Nguyen. Nodavirus: An emerging threat to freshwater prawn farming, by Biju Sam Kamalam, J., Saravanan, S. and Ajith Stalin, J.L. Asia-Pacific Marine Finfish Aquaculture Network Magazine: Asian seabass farming: Brainstorming workshop and training in India. Comparative study for broodstock management of grey mullet (Mugil cephalus L.) in cages and earthen ponds with hormone treatment, by Nani Gopal Das, Md. Shahadat Hossain, Sushanta Bhattacharjee and Prabal Barua. Cultivation of gilthead sea bream (Sparus auratus L.) in low saline inland water of the southern part of Israel desert, by Samuel Appelbaum and A. Jesu Arockia Raj. Mariculture development opportunities in SE Sulawesi, Indonesia, by La Ode M. Aslan, Hotman Hutauruk, Armen Zulham,Irwan Effendy, Mhummaed Atid, Michael Phillips, Lars Olsen, Brendan Larkin, Sena S De Silva, Geoff Gooley. Improved hatchery and grow-out technology for marine finfish. NACA Newsletter

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Rice cultivation at any level in the Sacramento–San Joaquin Delta (existing or expanded) compels the need to quantify surface and subsurface loads of dissolved organic carbon (DOC), disinfection byproduct precursors (DBPPs) and nitrogen. This information can be used to develop Best Management Practices (BMPs) to reduce export of these constituents in order to improve drinking water quality. Although rice cultivation in the Delta is relatively limited, several factors outside of this research could contribute to increased rice acreage in the Delta: • Recently developed rice varieties seem more suitable for the Delta climate than earlier varieties which required warmer conditions; • Previous economic analyses (Appendix A.10) suggest rice is more profitable than corn, a dominant land use in the Delta; • Recent studies on wetlands at Twitchell Island suggest rice production can help mitigate oxidative subsidence (Miller et al. 2000); • The different oxidative states that result from flooding in rice as compared to those found in crops that require drained soils may help control crop specific weeds and nematodes when rice is incorporated into a crop rotation; and • Providing flooded conditions during a greater part of the year than other crops may benefit water birds. ... (PDF contains 249 pages)

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A review is made of some of the methods that can be used for mass cultivation of natural fish food and the types of organisms that are cultured, which include various algae and zooplankton. Some examples are given of successful case histories in the mass cultivation of natural fish food in order to stimulate the interest of Nigerian scientists on research activities of live fish food for use by fish farmers in the country

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The paper introduces the tilapias as important culture fish; their classification, breeding habits and general ecology are discussed. The versatility and plasticity of their reproduction and growth are major advantages as well as draw backs in their use as culture species. The culture of tilapias in ponds, cages, pens and raceways are described and a comparison of extensive and intensive cultivation is made. The major factors in commercial cultivation of tilapias such as feeds, hatchery/fry production and disease control are discussed. Recommendation is made for the consideration of tilapia as the equivalent of the common carp in tropical African fish culture in either monoculture or in polyculture with other fish species