Farming freshwater prawns

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Figure 96Freshwaterprawns needsorting whilebeingprocessed(Brazil)SOURCE: MICHAEL NEWNewly frozen prawns shouldbe put in the back of the storagefacilities and the prawnsat the front used first. Thistechnique for ensuring freshnessis sometimes referred toas ‘FIFO’ (first in, first out).You must always avoid thealternatives, which could becalled ‘FILO’ (first in, last out)or ‘FISH’ (first in, still here).If your farm is large and youintend to freeze your ownprawns the best solution is touse special processing andfreezing equipment and packaging (Figures 96 and 97). This topic is beyond the scope ofthis manual but an introduction can be found in Madrid and Phillips (2000) and moredetails in another FAO publication (Johnston, Nicholson, Roger and Stroud 1994).If your market prefers it, you can pre-cook your prawns before freezing (Madrid andPhillips 2000). The appearance of cooked versus uncooked prawns is shown in Figure 98.HANDLING FOR LIVE SALESSometimes you will want to sell your prawns alive, either at your farm gate or after transportto markets and (especially) restaurants. These prawns also require careful, but differenthandling; the techniques are similar to those used to sell other live aquatic products.You will need to change your holding and transport water regularly to eliminate ammoniabuild-up. Keep the dissolved oxygen level above 5 ppm with aeration. Prawns to be transportedlive should be washed in non-chlorinated clean water and then brought to the sametemperature that can be maintained during transport to prevent thermal shock throughsudden transfer into water of a totally different temperature. It is recommended that youkeep the transport temperature at about 20-22°C. Use small amounts of ice, if necessary,to keep this temperature constant. Transport techniques similar to those used to transportprawn postlarvae from hatcheries to distant grow-out facilities by road transport (asFigure 97Packageyour prawnsattractively(Mauritius)Figure 98Freshlyharvested (blue)Macrobrachiumrosenbergii canbe cooked (pink)at the pond-sideto provide atasty barbeque(Brazil)SOURCE: YANN VON ARNIMSOURCE: MICHAEL NEWFRESHWATER PRAWNS138
described earlier in this manual) are suitable. In general, restaurants and shops or marketstalls selling live prawns will have aquariums to display them. You are recommended,for best quality, not to keep live animals in these aquaria for more than five days beforesale and consumption.7.3 Code of practice for harvesting, processingand handling prawnsDetailed technical guidelines and essential requirements for the harvesting, processingand handling of prawns, which apply both to those that are caught from open waters orobtained through farming, is contained in the relevant international code of practice, whichis continuously updated (FAO/WHO 2001).CHAPTER 7139
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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
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FIGURE24Turn-down drains are the be
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FIGURE26Installing a ring main air
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Figure 28Power supplies arenot alwa
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Water dischargeYou should take care
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is recommended. The volume of these
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then multiply to cope with the nitr
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Regular monitoringof larval waterqu
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initial stocking rates shown inBox
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Recommendations forgood larval wate
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FIGURE35Many of the larvae that go
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TABLE 8Hatchery feeding scheduleLAR
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ing to avoid BSN leaving the tank.
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TABLE10The major diseases known to
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Notes on potential disease problems
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FIGURE36aA method of evaluating the
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occurred). You are therefore recomm
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5CHAPTERPostlarval holdingand nurse
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Figure 39Substrates can beused in n
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FIGURE41Postlarvae in plastic bags
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pH and temperature of the rearing f
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It is difficult to recommend exact
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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 and 108: Figure 53Where thetopography of the
Page 109 and 110: Figure 56The outletstructure,someti
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: (Figure 95). To kill a batch of 50
Page 155 and 156: Once the prawns arrive at the point
Page 157 and 158: properly. They should also be displ
Page 159 and 160: ANNEX 1, Figures 1-12Macrobrachium
Page 161 and 162: 4ANNEXSource, hatching andenrichmen
Page 163 and 164: The nutritional quality and physica
Page 165 and 166: decapsulation improves the energy c
Page 167 and 168: starved versus enriched BSN. Lavens
Page 169 and 170: 1ANNEX 4TABLEDetermining hatching p
Page 171 and 172: 4ANNEX 4TABLE Hydrating and decapsu
Page 173 and 174: 7ANNEX 4TABLE1. Set up the hatching
Page 175 and 176: grades the particles and washes the
Page 177 and 178: 2. Stock estimation when postlarvae
Page 179 and 180: animal, particularly within the gil
Page 181 and 182: ANNEX 7 FIGURE1The size of the mesh
Page 183 and 184: 8ANNEXSize managementAS MENTIONED I
Page 185 and 186: 2. BehaviourThe behavioural charact
Page 187 and 188: ANNEX 8 FIGURE3Changing the stockin
Page 189 and 190: ANNEX 8 FIGURE4Orange claw (OC) and
Page 191 and 192: 9ANNEXFarm-made pond feedsTHIS ANNE
Page 193 and 194: ANNEX 9, Figure 3Farm-made feedsnee
Page 195 and 196: 4ANNEX 9TABLEFarm-made grow-outfeed
Page 197 and 198: which the requirements are applied.
Page 199 and 200: Carapace:Caridean:Cephalon:Chela:Ch
Page 201 and 202: 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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