Farming freshwater prawns

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ANNEX 4 FIGURE7BSN can be enriched to improve nutritional quality and (at least infish culture) for the control of some diseases1essential nutrients, pigments, prophylacticsand therapeutics can be incorporated indiets fed to Artemia2Artemia nauplii are enriched byingesting diet3<strong>freshwater</strong> prawn larvae ingestenriched naupliiSOURCE: EMANUELA D’ANTONI, DERIVED FROM MERCHIE (1996)FRESHWATER PRAWNS160
1ANNEX 4TABLEDetermining hatching percentage (H%), hatchingefficiency (HE) and hatching rate (HR).1. In triplicate, incubate 1.6 g of cysts 14 in 800 ml of 33 ppt seawater under continuous illumination (2 000 lux) at 28°Cin cylindrico-conical tubes (preferably) or in graduated cylinders, which are provided with aeration from the bottomsufficient to keep all the cysts in suspension but not so strong that foaming occurs.2. After 24 hours, take six 250 µl sub-samples out of each tube/cylinder. Pipette each into a small vial and fix the BSNby adding a few drops of lugol solution 15 .3. Using a dissection microscope, count the number of hatched BSN in each sub-sample and calculate the mean number(N). Also, count the number of umbrella stage embryos 16 (Annex 4, Figure 1) in each sample and calculate themean number (U).4. Decapsulate the unhatched cysts and dissolve the empty cyst shells by adding one drop of sodium hydroxide solution17 and 5 drops of domestic bleach solution 18 to each vial.5. Using a dissection microscope, count the unhatched (orange) embryos in each sub-sample and calculate the meannumber (E).6. Calculate the hatching percentage (H%) for each sub-sample: H% = (N x 100) ÷ (N + U + E). Calculate the meanfor each tube/cylinder and determine the mean value and standard deviation of the three replicates.7. Calculate the hatching efficiency (HE) for each sub-sample: HE = (N x 4 x 800) ÷ 1.6 (which can be simplified toHE = N x 2 000). Calculate the mean for each tube/cylinder and determine the mean value and standard deviationof the three replicates.8. The hatching rate (HR) can be determined by starting to take sub-samples after 12 hours incubation, followed bynew sub-samples every three hours and calculating HE according to the procedure above. Sub-sampling should becontinued until the HE becomes constant (maximum HE). Mean values at each sampling time can then be calculatedand expressed as a percentage of the maximum HE. This enables you to construct a hatching curve (Annex 4,Figure 2) and make comparisons of the hatching rate of different cyst batches.SOURCE: DERIVED FROM VAN STAPPEN (1996) AND MORETTI, PEDINI FERNANDEZ-CRIADO, CITTOLIN AND GUIDASTRI (1999)2ANNEX 4TABLEDisinfecting 19 1 kg of Artemia cysts1. Prepare 20 L of 200 ppm active chlorine solution (see Annex 4, Table 3).2. Add 1 kg of cysts and keep them in suspension by vigorous aeration for 20 minutes.3. Harvest the cysts on a 125 µm sieve and rinse thoroughly with plenty of tap water.4. Transfer the disinfected cysts into the hatching/incubation tank.SOURCE: DERIVED FROM VAN STAPPEN (1996) AND MORETTI, PEDINI FERNANDEZ-CRIADO, CITTOLIN AND GUIDASTRI (1999)14 it is important to use exact quantities of cysts and water, etc., in order to ensure that valid comparisons are being made.15 lugol solution: Dissolve 50g potassium iodide (KI) and 25g iodine (I 2 ) in 100 ml boiling water (= solution A). Dissolve 25 g sodium acetate(CH 3 COONa) in 250 ml water (= solution B). When solution A cools, mix solutions A and B and store in a cool dark place.16 the umbrella stage is when the embryo hangs beneath the empty shell of the cyst, still within the hatching membrane.17 dissolve 40 g NaOH in 100 ml distilled water.18 5.25% NaOCl.19 some of the chemicals used in disinfection and decapsulation are toxic and/or can cause burns. Wear gloves and protective eyeglasses.ANNEX 4161
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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
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
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: starved versus enriched BSN. Lavens
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
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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