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o G=(0.95) 1/10G =0.994883803Figure 3. Probabilities of losing an allele (frequencies f = 0.001 – 0.5) for various N e . These probabilities are for asingle event (spawning season or acquisition of brood stock).• Step 2: Calculate the probability (P) of losing allele per generationoProbability of losing = 1 – probability of savingo Probability of losing = 1 – 0.994883803o Probability of losing = 0.005116196882• Step 3: Calculate the N e that is needed to produce a P = 0.005116196882 when q = 0.01 (the frequency of theallele you are trying to save):ooP = (1-q) 2N e0.005116196882 = (1-0.01) 2N eo N e = 262.5• N e is rounded to the next whole number, so a N e = 263 is needed every generation on order to produce a 95%guarantee of saving an allele with frequency of 0.01 when the 10 th generation is produced.Although we do not expect the farmers to calculate the N e in this case it is advisable that extension officers ortechnical workers be aware of this and help farmers in achieving the goal of the hatcheries.BottleneckIn practice it is difficult to maintain minimum constant Ne. Many factors conspire to occasionally reduce populationsize. These sudden drastic decreases in population size are called “bottleneck”. The genetic effects of bottleneckcan be devastating, i.e. leading to changes in allele frequencies and inbreeding and genetic drift.Causes of bottleneck can be any sudden changes in environment such as disease outbreaks, or flooding, orsudden decrease in temperature that take away large number of brood stock. As such in order to avoid bottleneck,care must be taken into account to avoid sudden changes in the environment that may cause severe fish kills.41
Effect of bottleneck can be illustrated in the example below.Example 3: If a farmer is trying to maintain a constant Ne of 344 for 10 generations in order to produce aguarantee of 99% for keeping an allele at frequency of 0.01 and there is a bottleneck of 25 in the 8 th generation,estimate the probability of losing the allele when the 10 th generation is produced.• Step 1 and 2:N e Probability of losing allele (P) Guarantee of keeping allele (1-P)344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344 0.99900685225 (1-0.01) 2*25 0.394993932344 (1-0.01) 2*344 0.999006852344 (1-0.01) 2*344 0.999006852• Step 3:Guarantee of keeping allele after 10 generations = (0.999006852) 9 *0.394993932= 0.3915• Step 4:Guarantee of losing allele after 10 generations = 1 – 0.3935 = 0.6085As such, the bottleneck of 25 at generation 8 increased the probability of losing the allele in the 10 th generationfrom 0.01 (which was the goal) to 0.6085.ConclusionGenetic management in hatchery is although simple but has not been implemented adequately and scientifically ina majority the ASEAN member countries. This is because most hatchery managers are poorly trained in geneticsand as such it is neglected in the hatchery development plan. Also because not many hatcheries keep record ofperformance of the seed they produce, the effect of inbreeding if occurred would not be able to monitor orvisualised. It is essential that the importance of genetic management be recognised and action is taken at thehatchery level to ensure the long-term supply of good quality seed. Needless to say this needs to go hand in handwith good aquaculture husbandry and developments in nutrition or fish health.42
Page 1 and 2: Training of TrainersProgramme3-7 Au
Page 3 and 4: Table of Contents1. Preface 42. Sen
Page 5 and 6: knowledge about the activities carr
Page 7 and 8: iosphere, in that it is essentially
Page 10 and 11: Importance in narrowing the supply
Page 12 and 13: Figure 7: The trend in aquaculture
Page 14: aquaculture has been a success thus
Page 17 and 18: pathogen transfer is generally cons
Page 19 and 20: • It highlights the importance a
Page 21 and 22: particular animal are identified, t
Page 23: Knowledge at the bottom of the pyra
Page 26 and 27: farmer innovation process. In this
Page 28 and 29: • Rapport building• Working str
Page 30 and 31: shrimp farming is undertaken in the
Page 32 and 33: Reintjes, C and Hiemstra, W. 1989 F
Page 34 and 35: • An increase in reliable product
Page 36 and 37: Principles of AACC are to: 1) Facil
Page 38 and 39: Maintaining genetic quality of fish
Page 40 and 41: Where F is the percent increase in
Page 44 and 45: Aquaculture extension and training
Page 46 and 47: ResearchExtensionFarmersFlow of inf
Page 48 and 49: view of outside world than before a
Page 50 and 51: Along with fish sample, the support
Page 52 and 53: Fungal examinationFungal infection
Page 54 and 55: few different pathogen strains. The
Page 56 and 57: Major finfish diseases in Asia and
Page 58 and 59: A great number and diversity of ani
Page 60 and 61: • -oxidase test positive• -resi
Page 62 and 63: ReferencesAustin, B. and D. Austin.
Page 64 and 65: Accessing better markets-improving
Page 66 and 67: Owing to its importance in generati
Page 68 and 69: adopt standards for responsible shr
Page 70: Tokrisna R, Benheam W., 1995. Gain
Page 73 and 74: of the temperature rise that were d
Page 75 and 76: Principles of developing, validatin
Page 77 and 78: such as determinants, exposures and
Page 79 and 80: How to promote adoption of BMPs?Pro
Page 81 and 82: economic sustainability. BMPs need
Page 83 and 84: Once you understand your stakeholde
Page 85 and 86: As conventional approaches such as
Page 87 and 88: Printed publicationsPrinted publica
Page 89 and 90: Set up a blog or website for your w
Page 91 and 92: If you have a website, all you need
Page 93 and 94:
ought about increased profits among
Page 95 and 96:
• It is a farming system the prod
Page 97 and 98:
Annex 1. The area surveyed for obta
Page 99 and 100:
contribute substantially to maintai
Page 101 and 102:
seawater, but in fresh water its le
Page 103 and 104:
type of ingredients used, since som
Page 105 and 106:
This is a new approach used to buil
Page 107 and 108:
New, M.B., A. G. J. Tacon and I. Cs
Page 109 and 110:
later stages it has become a much m
Page 111 and 112:
c. Improved information exchange an
Page 113 and 114:
implemented by both societies. Inte
Page 115 and 116:
With better informed farmers, the s
Page 117 and 118:
According to FAO, it is estimated t
Page 119 and 120:
Farmer organization as models for p
Page 121 and 122:
NaCSA disseminates BMPs mainly thro
Page 123 and 124:
1. Drain the pond water completely
Page 125 and 126:
Seed transportation and Stocking:
Page 127 and 128:
7. Presently 100% of the society po
Page 129 and 130:
would help in sustaining shrimp sec
Page 131 and 132:
Stress brought about by the capture
Page 133 and 134:
Enhance women participation in aqua
Page 135 and 136:
women in aquaculture and identify a
Page 137 and 138:
major percentage of staff, the need
Page 139 and 140:
having more self confidence through
Page 141 and 142:
Overall status of men and women in
Page 143 and 144:
Compliance to international standar
Page 145 and 146:
(ii) to protect human or animal lif
Page 147 and 148:
c) FAO/WHO Codex Alimentarius Commi
Page 149 and 150:
Annex 1: List of participantsCountr
Page 151 and 152:
Annex 2: AgendaDate Time Presentati
Page 153:
Annex 3: List of resource persons1.
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