![]() In tropical areas tanks in flow-through hatcheries can be situated in the open but you should provide, at the minimum, simple shading (palm fronds or a bamboo framework, for example) where there is a possibility of the water temperature rising too high. When artificial sea salts are used, only freshwater is needed on the site. Site location for hatcheries operating recirculation systems is less dependent on the proximity of supplies of seawater or brine, because they minimize the quantities required. Your water supplies - freshwater, seawater, brine, or made from artificial sea-salts - must have excellent quality, as described earlier in this manual. This is preferable but it is technically possible to transport PL for long distances, so it is not essential for technical reasons. You might think that your hatchery needs to be close to the nursery or grow-out pond locations where your product (postlarvae, referred to as PL) will be stocked. Power failure can quickly result in total stock mortality. You may wish to generate all your own power but a back-up facility is still essential. Even where public power supplies are reliable, you need a back-up generator. Hatcheries need a reliable power supply, because continuous operation of the aeration system is essential. The size of specific items of equipment depends on the number of postlarvae (PL) to be produced by each hatchery. Broodstock facilities and management have already been discussed. This is because you need to start the larval rearing cycle early, so that grow-out facilities can be stocked as soon as the climatic conditions are favourable. However, they are necessary in areas of seasonal grow-out, where over-wintering of broodstock is essential. In tropical freshwater prawn hatcheries, special facilities for holding broodstock do not normally exist. SOURCE: HASSANAI KONGKEO 4.1 Buildings and equipment facilities Interior of a simply-constructed inland hatchery for freshwater prawns (Thailand) Small hatcheries can be very simply constructed (Peru) Where there are special requirements for recirculation systems, these are described under each sub-heading of the section. The general details (facilities and management) for flow-through and recirculation systems are similar. However, the risk has to be balanced against the capital and maintenance costs of multiple filtration systems. The latter is naturally more risky because a failure in the system may affect a large number of larvae. This system can have individual biofilters for each larval tank or a common biofilter serving several larval tanks. ![]() This is based on continuous circulation of the larval water through physical and biological filters to remove solid and nitrogenous wastes. ![]() In the rest of this section of the manual this will be referred to simply as the recirculation system. The second type of hatchery described in this section uses a specific form of water recirculation and is known as the dynamic closed system 6. They range from simple systems utilizable by small hatcheries to sophisticated systems used for research work and commercial hatcheries. Recirculation systems involving the use of biological filtration have been developed to conserve water and energy usage, reduce the demand for seawater or brine, and facilitate the establishment of inland hatcheries. high-density culture, ‘greenwater’ versus ‘clearwater’ management, coastal versus inland hatcheries) are discussed later in this section. The variants of the flow-through system that exist (e.g. The first type is known as the flow-through system, which is effectively used in many parts of the world and evolved from the original facilities developed by Takuji Fujimura and his team at the Anuenue Fisheries Research Centre in Hawaii in the 1960s and 1970s. Two basic types of hatchery are described. This section of the manual is derived not only from the original manual but also draws heavily on recent reviews (Correia, Suwannatous and New 2000 Valenti and Daniels 2000). This manual therefore does not attempt to provide a complete design but it does describe the various features and techniques used in them. No precise prototype hatchery would suit every local situation. A manual for the culture of the giant river prawn (Macrobrachium rosenbergii)ĪLL FRESHWATER PRAWN HATCHERIES are unique.
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