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No Thumbnail AvailableProjectSoil quality considerations in the selection of sites for aquaculture
Establishment of African Regional Aquaculture Centre
1987Also available in:
No results found.Soil quality is an important factor in fish pond productivity as it controls pond bottom stability, pH and salinity of overlying water and concentrations of plant nutrients required for the growth of phytoplankton, which is the base of food chain of the fish. A satisfactory site for constructing fish ponds is that where the soil is very deep, with low salinity levels and neutral pH, water infiltration is very low, mineralization of organic matter takes place rapidly, nutrients are adsorbed and r eleased slowly over a long period. Moderately heavy textured soils because of their high surface area and surface charge density posses the above characteristics. Too heavier textured soils such as pure clay may not be satisfactory as they have very high adsorptive property and thereby act as a sink for nutrients like phosphorus which may not be easily released to the overlying water. These soils may also give problems of developments of deep cracks when dry (on draining the ponds) thereby allow ing seepage losses of water. In order to have a clear understanding of the various physicochemical and biological processes which are controlled by the soil in the ponds and to make decisions on the suitability of sites for aquaculture as well as effective managements of the soils for increased productivity of the ponds, one needs to have a good background knowledge of the nature and properties of the soil. This chapter presents basic information on soils, their characteristics and their appli cations to aquaculture. The physicochemical characteristics of water as they affect aquaculture. are discussed separately elsewhere. The science of aquaculture has many similarities with that of agriculture though it is of recent development compared to the latter. Many of the ideas in aquaculture are derived from the experiences in agriculture. -
No Thumbnail AvailableProjectSite selection for aquaculture: Climatic factors
Establishment of African Regional Aquaculture Centre
1987Also available in:
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No Thumbnail AvailableProjectSite selection for aquaculture: chemical features of water
Establishment of African Regional Aquaculture Centre
1987Also available in:
No results found.As indicated already chemical features of water like the other characteristics of water are most important in deciding on the suitability of a site for aquaculture. Site selection from the major habitat point of view is obviously chemically related. The types of waters are classified for culture according to the salt content (salinity) of the medium - the common distinctions are the freshwater, brackish water and marine and then hard and soft water at the lower scale. The suitability of the me dium would be decided on the specific organisms to be cultured and the specific culture systems to be used. Thus the physical aspects of water have already been referred to. Now we shall look at the chemical aspects of water, including dissolved gases, such as oxygen carbon dioxide and ammonia, and concentrations of various ions, and their summated effects (eg. pH, dissolved solids, conductivity etc). As for some of the other major factors the chemical factor alone could rule out a site, i.e. in case proper reclamation, in view of economics) is not possible. The importance of chemical factors, is owing to their lethal and sublethal effects on culturable organisms, and also owing to their effect on biological productivity, i.e. productivity of the organism in the food chain. This aspect is discussed separately under ‘Biological Productivity’. A review through the various chemical factors as done hereunder should enable one to establish criteria to select or reject a site for aquacul ture. As this needs considerable information on the background, we have accepted to provide such information as needed. One should refer to more elaborate references as indicated at appropriate places herein if further information is required.
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