Farming freshwater prawns

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FIGURE55There are many different ways of controlling the water entering yourponds: these are some exampleswater flowtwo-way waterdivision boxwater flowing intopond through largepipewater stopped from flowingfurther by filling space betweenboards with earthmechanical valvetwo-way waterdivision boxextend pipe over watersurface to prevent damage tobank and to increase aerationhorizontal inlet pipewater flowing into pondthrough large pipeswinging arm ‘water control(similar to ‘turn-down drain)water inlet withinbamboo pipesmetal plate to openand close pipeoblique cut to pipescrew plugwater flowpipe blocked at endusing the swinging armwater controlSOURCE: EMANUELA D’ANTONI, AFTER FAO (1992b)FRESHWATER PRAWNS94
Figure 56The outletstructure,sometimes knownas a ‘monk’, canbe used to controlthe level of thewater as well as toscreen the waterto prevent the lossof freshwaterprawns (Brazil)financial limitations) have water inlets below the pond water level and receive water froman inlet channel (or a low-lying area such as paddy fields) with the same water level as thepond. In some cases ponds are directly interconnected. These farms produce freshwaterprawns, often profitably. However, the use ofsuch water supplies increases risk substantially;a proper water distribution system is essentialfor reliable high production.Methods of minimizing water losses throughseepage, by sealing ponds with organic matter,puddling, compaction, laying out a ‘soil blanket’,bentonite, or lining them with polyethylene,PVC, or butyl rubber sheeting are described inanother FAO publication (FAO 1996).DISCHARGING WATER FROM THEPONDSIt is preferable to be able to drain ponds by gravitythan to have to pump the water out and,where this is possible, you should construct a‘monk’ or sluice gate outlet structure. TheseSOURCE: JULIO VICENTE LOMBARDI, REPRODUCED structures (Figure 56) will allow you easily toFROM NEW AND VALENTI (2000) WITH PERMISSIONFROM BLACKWELL SCIENCEcontrol water depth and drainage speed and canbe screened to prevent the loss of stock. In flowthroughwater management, water is continually flowing through this structure. The monkallows you to totally drain your pond and, more importantly, enables you to control thewater level during seine harvesting operations, flushing and water circulation.Static (non-flow-through) ponds can have a simple screened and plugged outlet pipeor a turn-down drain, as previously shown in Figure 40. Outlet structures, whether theyare pipes or monks, must be carefully sized so that the pond does not drain too slowly (toprevent poor water quality during harvesting operations), and they should be sited so thatthe pond can be totally drained (Figures 57 and 58). Table 13 gives the appropriate pipesizes for ponds with monk outlets, for example, while Table 14 gives the time to drain apond under various circumstances. Figure 59 is an illustration of a sluice gate structure.The top of the sluice gate should also be constructed at least 50 cm above the highest pondwater level as a safety measure. Detailed information on these topics can be found in otherFAO manuals (FAO 1992b, 1995).Where the pond outlet is apipe below water level, thereshould also be an overflow pipeinserted about 20-30 cm belowPOND SIZE (m 2 )5 000INSIDE DIAMETER OF PIPE (cm)not less than 1010-1515-2020-2525-3040 or morethe top of the pond bank butabove the normal water level inthe pond. This overflow pipeshould be screened in the sameway as the normal pond outlet, toprevent loss of stock. If the waterlevel in the area to which thepond drains also rises, however,the overflow pipe will be ineffective.Sizes of outlet pipes forTABLE13 ponds with monksSOURCE: DERIVED FROM FAO (1992b)CHAPTER 695
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Farming freshwater prawnsA manual f
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The designations employed and the p
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abstractTHE ORIGINAL MANUAL on fres
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table of contentsABSTRACTPREFACEINT
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Feed type 114Measuring feed efficie
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17. Measuring soil pH 10618. Reason
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87. Keeping market-sized prawns ali
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major subject of cultivation becaus
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has little relevance, especially be
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(zoeae) are just under 2 mm long (f
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TABLE1Body segments (somites) in Ma
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Figure 5The major malemorphotypes o
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tions, where a breeding stock of bo
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most hatcheries operated on flow-th
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BOX 1Removal of iron and manganeseW
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TABLE 3Artificial brackishwater (12
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TABLE 4Diluting seawater and brine
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mentally cultured at up to 10 ppt;
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cal quality and its lack of predato
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CHOOSING YOUR SITE: SOIL CHARACTERI
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such as fertilizers and equipment.
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perate (usually originating from st
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3.2 Holding your broodstock in temp
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ing system that consists of a 300 L
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4CHAPTERHatchery phaseALL FRESHWATE
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SOURCE: HASSANAI KONGKEOand dust. T
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FIGURE17This shows the water flow t
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Figure 21The water inthese larvalta
Page 57 and 58: FIGURE24Turn-down drains are the be
Page 59 and 60: FIGURE26Installing a ring main air
Page 61 and 62: Figure 28Power supplies arenot alwa
Page 63 and 64: Water dischargeYou should take care
Page 65 and 66: is recommended. The volume of these
Page 67 and 68: then multiply to cope with the nitr
Page 69 and 70: Regular monitoringof larval waterqu
Page 71 and 72: initial stocking rates shown inBox
Page 73 and 74: Recommendations forgood larval wate
Page 75 and 76: FIGURE35Many of the larvae that go
Page 77 and 78: TABLE 8Hatchery feeding scheduleLAR
Page 79 and 80: ing to avoid BSN leaving the tank.
Page 81 and 82: TABLE10The major diseases known to
Page 83 and 84: Notes on potential disease problems
Page 85 and 86: FIGURE36aA method of evaluating the
Page 87 and 88: occurred). You are therefore recomm
Page 89 and 90: 5CHAPTERPostlarval holdingand nurse
Page 91 and 92: Figure 39Substrates can beused in n
Page 93 and 94: FIGURE41Postlarvae in plastic bags
Page 95 and 96: pH and temperature of the rearing f
Page 97 and 98: It is difficult to recommend exact
Page 99 and 100: 6CHAPTERGrow-out phaseFRESHWATER PR
Page 101 and 102: FIGURE44ponds may become low enough
Page 103 and 104: FIGURE46Pond banks should have the
Page 105 and 106: FIGURE50The dissolved oxygen levels
Page 107: Figure 53Where thetopography of the
Page 111 and 112: Figure 58This freshwaterprawn pondh
Page 113 and 114: FIGURE59 cont.CROSS SECTIONSOURCE:
Page 115 and 116: Figure 64Long-shaftaeratorin action
Page 117 and 118: there is only a single stocking), t
Page 119 and 120: TABLE16Lime requirements for treati
Page 121 and 122: semi-intensive stocking rates vary
Page 123 and 124: Keeping rootedplants out ofyour pon
Page 125 and 126: advantages obtained in temperate cu
Page 127 and 128: Polyculture of freshwater prawnswit
Page 129 and 130: only increases the availability of
Page 131 and 132: Using water-stable feeds provides y
Page 133 and 134: MEASURING FEED EFFICIENCYYou should
Page 135 and 136: Example of feeding ratefor freshwat
Page 137 and 138: allowed to become too low and there
Page 139 and 140: found to be hosts for the bopyrid i
Page 141 and 142: Figure 81A large BCMacrobrachiumros
Page 143 and 144: 7CHAPTERHarvesting andpost-harvest
Page 145 and 146: FIGURE83You can cull-harvest your p
Page 147 and 148: FIGURE85Larger ponds may also be cu
Page 149 and 150: Figure 91HarvestingMacrobrachiumros
Page 151 and 152: (Figure 95). To kill a batch of 50
Page 153 and 154: described earlier in this manual) a
Page 155 and 156: Once the prawns arrive at the point
Page 157 and 158: properly. They should also be displ
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ANNEX 1, Figures 1-12Macrobrachium
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4ANNEXSource, hatching andenrichmen
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The nutritional quality and physica
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decapsulation improves the energy c
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starved versus enriched BSN. Lavens
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1ANNEX 4TABLEDetermining hatching p
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4ANNEX 4TABLE Hydrating and decapsu
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7ANNEX 4TABLE1. Set up the hatching
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grades the particles and washes the
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2. Stock estimation when postlarvae
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animal, particularly within the gil
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ANNEX 7 FIGURE1The size of the mesh
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8ANNEXSize managementAS MENTIONED I
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2. BehaviourThe behavioural charact
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ANNEX 8 FIGURE3Changing the stockin
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ANNEX 8 FIGURE4Orange claw (OC) and
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9ANNEXFarm-made pond feedsTHIS ANNE
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ANNEX 9, Figure 3Farm-made feedsnee
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4ANNEX 9TABLEFarm-made grow-outfeed
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which the requirements are applied.
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Carapace:Caridean:Cephalon:Chela:Ch
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Genital pores:Gill chamber:Greenwat
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Puddling:Rostrum:Salinity:Sequester
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ConversionsTHIS SECTION OF THE ANNE
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Financial considerationsSOME COMMEN
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ReferencesAlston, D.E. & Sampaio, C
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Fujimura, T. & Okamoto, H. 1972. No
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New, M.B., Singholka, S. & Vorasaya
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This new manual, which replaces an
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Farming freshwater prawns

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