Farming freshwater prawns

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decrease the frequency of fighting (which reduces growth suppression). This resultsin fewer SM, more OC and BC males, and higher average harvest weights.the potential advantages of monosex culture, not only because of the differentialgrowth rates of males and females but also because there is less HIG in females thanin males, may eventually become exploitable.Further reading on the experimental results of following these management optionsis provided in the review by Karplus, Malecha and Sagi (2000).FRESHWATER PRAWNS184
9ANNEXFarm-made pond feedsTHIS ANNEX PROVIDES a very brief introduction to farm-made grow-out feeds and theiruse for freshwater prawns. Further reading on this topic is provided in New (1987) andNew, Tacon and Csavas (1995).1. Feed preparationThe following general instructions are for the preparation of diets, which may be fed moistor dried.1. Mix all your dry ingredients (except vitamin mix, if used) thoroughly, preferablyin a mechanical mixer.2. Add your vitamin mix, if your formula contains one, and remix as in No. 1 above.3. Add any liquid ingredient (such as fish oil) or any wet materials (such as choppedtrash fish). [Note of caution: commercially processed shrimp by-products, such asshrimp meal and shrimp head meal, are very valuable from a nutritional point ofview in feeds for freshwater prawns. There is no danger that such ingredients willcause disease problems (Flegel, 2001). However, the use of raw (unprocessed) shrimpor prawn wastes, such as prawn heads, may introduce viruses (e.g. WSSV) into yourfarmed animals. Although this may not cause any visible symptoms it may makethem carriers of the disease for other crustaceans.]4. Remix all your ingredients thoroughly.5. You will now need to add up to 30-35% of water. The exact quantity depends onthe moisture of the ingredients. You will need to add enough water to produce a verythick paste. Add water a little at a time and test the mixture. It is easy to add morewater (but not possible to remove it if you add too much at first!). You can test theconsistency (stickiness) of the diet by squeezing it within your clenched hand. If the‘sausage’ of mixed diet (consistency of bread dough) which emerges from your fistbetween your first finger and your thumb is too crumbly, you need to add more water.If it runs out like a liquid, you have already added too much water!6. Continue mixing. You can help to mix your ingredients thoroughly by passing themixture through the coarse die of a meat mincer (see No. 7 below). This works welland also helps to bind the diet together.7. You can now shape the mixed diet into small balls or discs by hand. However, it isbest if you extrude the mixed diet through a meat mincer, this time usingANNEX 9185
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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
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FIGURE44ponds may become low enough
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FIGURE46Pond banks should have the
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FIGURE50The dissolved oxygen levels
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Figure 53Where thetopography of the
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Figure 56The outletstructure,someti
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Figure 58This freshwaterprawn pondh
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FIGURE59 cont.CROSS SECTIONSOURCE:
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Figure 64Long-shaftaeratorin action
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there is only a single stocking), t
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TABLE16Lime requirements for treati
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semi-intensive stocking rates vary
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Keeping rootedplants out ofyour pon
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advantages obtained in temperate cu
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Polyculture of freshwater prawnswit
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only increases the availability of
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Using water-stable feeds provides y
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MEASURING FEED EFFICIENCYYou should
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Example of feeding ratefor freshwat
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allowed to become too low and there
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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
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: ANNEX 8 FIGURE4Orange claw (OC) and
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
Page 203 and 204: Puddling:Rostrum:Salinity:Sequester
Page 205 and 206: ConversionsTHIS SECTION OF THE ANNE
Page 207 and 208: Financial considerationsSOME COMMEN
Page 209 and 210: ReferencesAlston, D.E. & Sampaio, C
Page 211 and 212: Fujimura, T. & Okamoto, H. 1972. No
Page 213 and 214: New, M.B., Singholka, S. & Vorasaya
Page 215: This new manual, which replaces an
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Farming freshwater prawns

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