Small-scale fish hatcheries for Lao PDRSmall-Scale Fish Hatcheries for Lao PDR Based on the work of...

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Small-scale fish hatcheries for Lao PDR Asia Pacific Fishery Commission AD HOC PUBLICATION

Transcript of Small-scale fish hatcheries for Lao PDRSmall-Scale Fish Hatcheries for Lao PDR Based on the work of...

Small-scale fish hatcheriesfor Lao PDR

Asia Pacific Fishery CommissionAD HOC PUBLICATION

THE FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONSBangkok, September 1998

FI:DP/LAO/97/007STS - Field Document no. 3

PROVINCIAL AQUACULTURE DEVELOPMENT PROJECT

LAO PDR

SUPPORT FOR TECHNICAL SERVICES

Small-Scale Fish Hatcheries for Lao PDR

Based on the work of

Samruay Meenakarn, FAO Mini-hatchery Consultant&

Simon Funge-Smith, Aquaculture Development Advisor (LAO/97/007)

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The Food and Agriculture Organization is greatly indebted to the organizations andindividuals who assisted in the implementation of the project by providing information,advice and facilities.

The Provincial Aquaculture Development Project (LAO/97/007) is a nationallyexecuted, UNDP funded project working in five provinces in Lao PDR. Through itsactivities LAO/97/007 aims to :

1. Improve fish fry production from government hatcheries throughstructural improvements and training

2. Support fish fry production by farmers and entrepreneurs through theextension of simple appropriate technology.

3. Develop the capacity of Department of Livestock and Fisheries staff toplan and conduct extension of fish culture techniques to farmers.

4. Form farmers groups and extend improved fish culture techniques aspart of the Department of Livestock and Fisheries extension process.

5. Assist farmers and small-scale hatchery entrepreneurs to undertakeaquaculture activities through provision of fish fry, broodstock andfacilitate access to credit.

LAO/97/007 is working with the Provincial Livestock and Fisheries Section andfarmers groups in: Oudomxay, Sayaboury, Xieng Khouang, Savannakhet andSekong Provinces. Additional technical assistance and training is also provided toLivestock and Fisheries staff and farmers in other provinces.

This publication has been produced by FAO as part of a Support for TechnicalServices agreement for the LAO/97/007 project.

“Small-scale Fish Hatcheries for Lao PDR” is also available in Lao.

SMALL-SCALE FISH HATCHERIESfor

Lao PDR

By

Samruay Meenakarn and Simon Funge-Smith

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TABLE OF CONTENTS

Introduction 1

IMPORTANCE OF SMALL-SCALE HATCHERIES 2

Chapter 1 Small-scale Hatchery Requirements 3

1.1 WATER AND WATER QUALITY 31.2 EARTHEN PONDS 61.3 HATCHERY BUILDING AND EQUIPMENT 6

Chapter 2 Broodstock 12

2.1 SOURCE OF BROODSTOCK 122.2 BROODSTOCK CULTURE 142.3 BROODSTOCK SELECTION FOR SPAWNING 152.4 SPAWNING SEASON FOR WILD FISH 16

Chapter 3 Fish Reproduction 18

3.1 NATURAL REPRODUCTION 183.2 SEMI-NATURAL REPRODUCTION 183.3 ARTIFICIAL FERTILISATION 193.4 ADVANTAGES OF ARTIFICIAL FERTILISATION 19

Chapter 4 Semi-Natural Reproduction Using the Common Carp 20

4.1 BREEDING CHARACTERISTICS 204.2 DIFFERENCE BETWEEN THE SEXES 214.3 PREPARATION OF THE SPAWNING TANK/POND AND SPAWNING SUBSTRATE 224.4 SELECTION OF THE BROODSTOCK FOR SPAWNING 234.5 STOCKING OF MALE AND FEMALE CARP FOR SPAWNING 234.6 NURSING OF COMMON CARP 24

Chapter 5 Artificial Fertilisation of the Silver Barb 25

5.1 BROODSTOCK SELECTION 265.2 HORMONES USED FOR THE INDUCTION OF SPAWNING 265.3 METHOD FOR USING LHRHa 275.4 EQUIPMENT FOR THE INDUCTION OF FISH SPAWNING 295.5 METHOD FOR HORMONE INJECTION 30

Chapter 6 Egg Incubation 36

6.1 FLOATING EGGS 366.2 HALF FLOATING - HALF SINKING EGGS 376.3 STICKY EGGS 386.4 EGG HATCHING 38

Chapter 7 Fry Nursing After Hatching 42

7.1 EARTH POND NURSERY 427.2 ‘ORLON’ CAGES 437.3 BLUE NET CAGES 447.4 CEMENT TANKS 447.5 STOCKING RATES FOR FRY IN NURSERY SYSTEMS 457.6 FEEDING OF FRY IN NURSERY PONDS AND TANKS 467.7 NURSERY REQUIREMENTS FOR CARNIVOROUS FISH SPECIES 48

Chapter 8 Economics of Small-Scale Hatchery operation 498.1 MARKETING 508.2 MINIMAL INPUT SMALL-SCALE HATCHERIES 508.3 SMALL-SCALE HATCHERIES WITH INCREASED INVESTMENT 54

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LIST OF TABLES

TABLE 1. STOCKING RATES AND FEEDING RATES FOR BROODSTOCK 13

TABLE 2. AGE, WEIGHT AND FECUNDITY OF MATURE BROODSTOCK FISH 15

TABLE 3. SPAWNING SEASONS AND OPTIMAL EGG MATURITY FOR COMMONAQUACULTURED FISH SPECIES 17

TABLE 4. DOSAGE RATES, TIME TO SPAWNING AND TIME TO HATCHING FOR A RANGE OFAQUACULTURE FISH SPECIES 22

TABLE 5. DOSAGE VOLUME AND NEEDLE SIZE FOR FEMALE BROODSTOCK ACCORDINGTO WEIGHT 25

TABLE 6. STOCKING DENSITIES FOR DIFFERENT FISH SPECIES IN THREE TYPES OFNURSERY SYSTEM 39

TABLE 7. NURSERY REQUIREMENTS FOR HERBIVOROUS FISH USING DIFFERENTCULTURE SYSTEM 41

TABLE 8. FIXED COSTS FOR HATCHERY CONSTRUCTION AND EQUIPMENT 51

TABLE 9. POND REQUIREMENT AND CONSTRUCTION COST 52

TABLE 10. OPERATIONAL COSTS FOR MINIMAL INPUT HATCHERIES (PER CROP) 52

TABLE 11. THE EFFECT OF FRY SELLING PRICE ON BREAKEVEN PRODUCTION OF FRY 53

TABLE 12. POTENTIAL PRODUCTION PER CROP 53

TABLE 13. FIXED COSTS FOR INCREASED INVESTMENT SMALL-SCALE HATCHERIES. 54

TABLE 14. POND REQUIREMENT AND CONSTRUCTION COST OF INCREASED INVESTMENTHATCHERIES 55

TABLE 15. OPERATIONAL COSTS PER CROP FOR INCREASED INVESTMENT SMALL-SCALEHATCHERIES. 55

TABLE 16. BREAKEVEN PRODUCTION OF FRY PER CROP AT DIFFERENT FRY PRICES 56

TABLE 17. POTENTIAL PRODUCTION PER CROP BASED ON INVESTMENT LEVEL 57

LIST OF DIAGRAMS

DIAGRAM 1 WATER INLET HIGHER THAN THE HATCHERY 5

DIAGRAM 2 WATER SUPPLY IS LOWER OR AT THE SAME LEVEL AS THE HATCHERY. 5

DIAGRAM 3 WATER SUPPLY TO HATCHERY TANKS FROM A RESERVOIR TANK HIGHER THANTHE HATCHERY TANKS 7

DIAGRAM 4. WATER IS SUPPLIED TO HATCHING CONTAINERS BY A SUBMERSIBLE PUMPINSIDE THE CEMENT TANK 7

DIAGRAM 5 ‘ORLON’ UPWELLING HATCHING CONE 9

DIAGRAM 6 ‘ORLON’ CLOTH HATCHING CAGE 9

DIAGRAM 7 IF NO AERATION OR WATER FLOW IS AVAILABLE – MANUAL STIRRING OF THEWATER FOR AERATION CAN BE PERFORMED 10

DIAGRAM 8 SMALL-SCALE HATCHERY BUILDING WITH CEMENT TANKS 11

DIAGRAM 9 SUITABLE LOCATIONS FOR HORMONE INJECTION 32

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LIST OF FIGURES

FIGURE 1 WATER SUPPLIES FROM PADDY FIELDS CAN BE MUDDY DUE TO PADDY PLOUGHING DURING MONSOONSEASON

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FIGURE 2 EXCELLENT WATER SOURCE FROM CLEAR-WATER STREAM (DRY SEASON FLOW) 4

FIGURE 3 COMPARISON OF EXTERNAL APPEARANCE OF MATURE MALE AND FEMALE PUNTIUS GONIONOTUSBROODSTOCK.

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FIGURE 4 THE COMMON CARP (CYPRINUS CARPIO) 20

FIGURE 5 DIFFERENCE BETWEEN MALE AND FEMALE COMMON CARP. 21

FIGURE 6 SPAWNING SUBSTRATES ATTACHED TO A FRAME FOR CARP SPAWNING IN CONCRETE TANKS 22

FIGURE 7 FRAMES PLACED IN A CEMENT TANK FOR COMMON CARP SPAWNING 23

FIGURE 8 PUNTIUS GONIONOTUS - A GOOD CANDIDATE FOR MINI-HATCHERY PRODUCTION 25

FIGURE 9 BROODSTOCK PUNTIUS GONIONOTUS. 26

FIGURE 10 EQUIPMENT REQUIRED FOR INDUCTION OF FISH SPAWNING. 29

FIGURE 11 INJECTION OF FEMALE PUNTIUS GONIONOTUS INTO MUSCLE BELOW DORSAL FIN 33

FIGURE 12 STRIPPING EGGS FROM A FEMALE PUNTIUS GONIONOTUS USING THE DRY METHOD 34

FIGURE 13 STRIPPING MILT FROM A MALE PUNTIUS GONIONOTUS FOR DRY FERTILISATION METHOD 35

FIGURE 14 MIXING THE EGGS AND MILT WITH A CHICKEN FEATHER USING THE DRY METHOD. 35

FIGURE 15 ‘ORLON’ HATCHING CAGE WITH FRAME. 36

FIGURE 16 ‘ORLON’ HATCHING CONE. 37

FIGURE 17 TRANSFER OF PUNTIUS EGGS TO UPWELLING ‘ORLON’ HATCHING CONES 38

FIGURE 18 SPRAYING WATER INTO ‘ORLON’ CAGE TO INCREASE OXYGENATION 39

FIGURE 19 CHECKING EGG HATCHING BY OBSERVATION IN A GLASS – DO THIS REGULARLY TO CHECK THEDEVELOPMENT OF EGGS AND FRY.

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FIGURE 20 EARTHEN POND WITH CLEAN BANKS AND WELL FERTILIZED WATER 43

FIGURE 21 BLUE NET CAGE 4 X 5 METRES (1 METRE DEEP) 44

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INTRODUCTION

Lao PDR is a land locked country located within Southeast Asia and has a wide range ofclimatic environments. The country is composed of mountainous upland regions andlowland plains with a total area of approximately 236,800 km2. Upland areas constituteapproximately 75% of the total area of the country, with the lowlands occupyingapproximately 60,000 km2. The country has 57 major rivers mainly running from thenorth to the south of the country. The lowland areas of Lao PDR are suitable foraquaculture, although aquaculture is practised in some of the upland areas.

Lao PDR has a monsoon season that lasts between May to October allowing ricecultivation in rainfed or irrigated paddies. Upland hill rice cultivation is also widelypractised. During the monsoon season the Lao people obtain a significant amount oftheir nutrition from aquatic animals and fish. These are hunted in paddy fields and waterbodies created by the monsoon rains. After the monsoon, the topography of the countryis such that waters recede rapidly into the main river bodies and there is an extended dryseason where many water bodies dry up completely. During this period there is ashortage of fish and aquatic products, although the Lao tradition of preserving fish intimes of abundance compensates for this to some extent. Fish preservation techniquesinclude: fermenting, drying, smoking and salting. Since fish is popular to the Lao people,it often commands a high market price, which makes the capture and culture of fisheconomically attractive.

Fish fry demand in the Lao PDR is high for stocking into both ponds and rice-fishsystems, however fry/fingerling production is low. Most fry produced in Lao PDRoriginate from the Provincial government hatcheries, which have an overall productionlevel of less than 15 million.

The species currently produced by Lao hatcheries include Common carp, Tilapia,Common silver Barb, Rohu, Mrigal, Bighead carp, Silver carp and Grass carp. There areat least six Puntius species indigenous to Lao PDR that show promise as aquaculturespecies. Besides the barbs, there are also several other possible species that may besuitable for hatchery production; these are: Pristolepis fasciatus (Lao name ‘Pa gah’),Giant gourami (Osphoronemus gouramy) and Snakeskin gourami (Trichogasterpectoralis).

The Lao Department of Livestock and Fisheries estimates that nationwide, demand forfish fingerlings is approximately 52 million. There are significant imports of fry andfingerlings from Thailand, Vietnam and China, but this still does not satisfy demand. Areflection of this demand is the high price that fry in Lao PDR can fetch relative to thesurrounding countries (typically 50 – 300 % higher). The problem with fry and fingerlingshortages is partly due to the lack of hatcheries in the country, but also due to thedifficulties in communications between provinces. In this respect large centralisedhatcheries are not particularly suitable for fry production due to the logistical difficultieswith delivery to the farm locations. Small-scale hatcheries can be effective in producinglow cost fry in the locations where fry/fingerlings are required.

An additional attraction of mini-hatcheries is that they are appropriate for low investmentsituations and thus present income generation opportunities for lower income farmers.

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As a result of this situation, the government of Lao PDR places a high priority onimproving fry production from small-scale hatcheries in Lao PDR.

Importance of Small-scale Hatcheries

Small-scale hatcheries are an attractive development activity since they presentrelatively low risk to farmers and can return their investment quickly for the followingreasons:

1. Small size results in low construction cost2. Small size is easy to manage at family scale3. They do not always require sophisticated equipment (pumps, aerators, electricity

etc.)4. The range of species that can be produced are not restricted by hatchery size5. They can be located almost anywhere that has a suitable supply of water6. They can be located close to the farmers that will purchase the fry

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CHAPTER 1 - SMALL-SCALE HATCHERY REQUIREMENTS

1.1 Water and water quality

Water is essential for all aspects of fish production – from production of suitablebroodstock to egg production, fry and nursery production. Small-scale hatcheries musthave a supply of good quality water for successful production and ideally must have asupply of water all year round. Suitable inlet water quality parameters for hatcheryproduction are:

• pH between 6.5 – 8.5 (pH below 7.0 will require storage in a reservoir and theaddition of some lime)

• Pond water transparency of 30 – 60 cm (inlet water to hatchery can beclearer)

• Temperature between 23 – 32oC (higher temperatures are acceptable but notdesirable)

• Oxygen concentration not less than 3 ppm (this can be difficult to achieve ifwater temperatures are high)

• Alkalinity between 100 – 200 mg.l-1.

In the consideration of appropriate water sources it is desirable to use water from lakesor rivers that have some degree of water exchange. The presence of healthy populationsof wild fish is a good indicator that the water is of reasonable quality.

Water supplies that may be contaminated by urban or industrial effluents are not suitablefor fish hatcheries since this water is often polluted with organic matter or toxicchemicals. Water that originates as run-off from agricultural land may be unsuitable if theagricultural method involves the use of chemicals and pesticides. Apart from potentialcontamination of wastewater from housing and towns, these situations are not commonin Lao PDR at the moment.

Figure 1. Water supplies from paddy fields can be muddy due to paddy ploughingduring monsoon season

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River water in Lao PDR undergoes wide changes in quality between the dry and themonsoon seasons. In the monsoon season many water sources become heavily loadedwith suspended solids and this water can be unsuitable for egg hatching and fish fryproduction (Figure 1).

The water source should ideally be higher than the nursery tanks so that water can besupplied under some pressure to assist aeration and ensure adequate water flow.Typically the height of the water source or reservoir pond should be more than 2 metresabove the top of the nursery tanks (Figure 2).

Figure 2. Excellent water source from clear-water stream (dry season flow)

Water inlets for hatcheries can be divided into two basic types:• Water inlet higher than the hatchery reservoir and tanks (recommended for Lao

PDR). This type of inlet is typical of irrigation canals, hillside streams and terracedpaddy fields (Diagram 1, Figure 2).

• Water inlet lower than reservoir requiring pumping to obtain water. This type of inletis common in lowland areas where water levels in lakes, rivers and streams are oftenmuch lower than the surrounding land. In this case water must be pumped upwardsand stored in a reservoir (Diagram 2).

The type of water supply presented in Diagram 1. can use a buried pipe to transmitwater to the reservoir and the water will be pressurised. If a siphon system is used watercan be moved uphill if necessary provided the outlet of the pipe is lower than the inlet.For siphon pipe type water transfer strong-walled flexible pipe should be used (softwalled pipe will collapse under the suction).

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Diagram 1. Water inlet higher than the hatchery

Water supplied through a siphon

Water supplied by buried pipe

Inlet water supply – from irrigationcanal, stream or pond

Where water must be pumped upwards to a water storage pond/tank as represented inDiagram 2., the cost of water supply must be considered. This includes the price of thepump and the fuel/electricity required for operation. For some types of pump a foot valveon the pipe inlet is desirable to prevent the water draining out of the pipe when the pumpis stopped.

Diagram 2. Water supply is lower or at the same level as the hatchery.

A water pump lifts water from the supply

IInlet water level

Water level in reservoir

Net bag over outlet toprevent entry of unwanted

predators

1.2 Earthen ponds

Culture in earthen ponds is the best method for maintenance of good quality, healthybroodstock. Earthen ponds are also very suitable for nursing of fry until they reach a sizeof 2 –3 cm (or approximately 1 month old). This is because earthen ponds contain agreat deal of natural feed that can supplement applied feeds to the pond.

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ReservoirThis is used to store inlet water before use in the hatchery and nursery. Inlet watersometimes has a high level of suspended solids, which it is desirable to settle out. Insituations where water supply is not continuous, a reservoir will allow hatchery operationto continue without interruption. A small-scale hatchery should ideally have a reservoir of40 x 40 m (1600 m2) with a depth of about 1.5 m. the reservoir can be used as abroodstock pond in small operations.

Broodstock culture pondsThese ponds can be the same size of the reservoir (1600 m2) and should beapproximately 1.5 – 2.0 m deep. If they are too shallow, the broodstock growth will bepoor and the ponds will tend to dry up completely in the dry season. Ideally the hatcheryshould have two ponds, but if broodstock can be obtained from outside the farm,maintenance of broodstock may not always be necessary.

Nursery pondsThese ponds should be no larger than 40 x 40 m and should be 1 – 1.5 m deep. Smallerponds can be used if only small quantities of fry are produced (i.e. from natural or semi-natural spawning techniques). Two or more nursery ponds are desirable.

1.3 Hatchery building and equipment

Hatchery buildingThis should have an area sufficient to cover all of the hatchery tanks and can beconstructed with available materials. Wood, bamboo, thatch or corrugated iron can beused for the construction. Thatch is both cheaper and cooler than corrugated iron andthe roof should be at least 2 metres above the tanks. The use of the building is to shadethe spawning and hatching tanks. High investment in this structure is not desirable untilthe hatchery has started to yield reliable profits.

Water supply and storage tankWater needs to be supplied to the spawning and hatching tanks under pressure. Thiscan be achieved in several ways.

• Water in a reservoir pond, or water supply to hatchery, is higher than thehatchery spawning and hatching tanks and supplied directly by gravity. Acoarse screen should be used to prevent entry of undesirable particles andpotential predatory organisms.

• The water for the tanks is stored in a tank higher than the spawning andhatching tanks (ideally more than 2m difference in height). This may require apump to lift the water if the reservoir pond is not higher than the spawningand hatching tanks. The volume of this tank should be approximately 1,000 –2,000 litres (Diagram 3).

• Water is supplied under pressure from a reservoir tank by using a waterpump (this requires electricity). This tank can be large (2,000 – 6,000 litres)and should be located under the roof to prevent the water from being heatedby direct sunlight (Diagram 4).

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Diagram 3. Water supply to hatchery tanks from a reservoir tank higher than thehatchery tanks

Water is supplied to tank by gravity or by a small pump(a roof above the tank will prevent the water from overheating)

Diagram 4. Water is supplied to hatching containers by a submersible pumpinside the cement tank (this requires electricity)

Submersible pump (‘DIVO’)

Pipework to send water to hatching cone/cage

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Egg hatching and nursery tanks

Tanks are typically constructed from bricks faced with cement. It is important not to letthe tanks dry out completely for long periods since this will cause the cement to crack,affecting water retention and strength of the tank walls. Other construction materialsinclude wooden walls with a plastic liner to retain the water. Fibreglass water storagetanks are available, but are often too expensive for these purposes.

These tanks can be constructed from the same materials as above. They are used forhatching eggs and also for the first nursing period of the hatched fry. The size and shapeof the tanks depends upon the hatching method. Typical sizes are 2 x 3m with a depth ofapproximately 1 m. slightly deeper tanks are desirable if the hatching cone method is tobe used (see later text). Two or more tanks of this type are desirable.

PVC pipes and fittingsPVC pipework is cheap and widely available in Lao PDR. It is used for supply of waterbetween ponds and reservoirs and also supply to hatchery and nursery tanks. If PVCpipe is not available, flexible plastic hose can be used or even bamboo piping.

Water supplied to a hatchery via channels is not recommended since there is nopressure to spray water and enhance oxygenation. Open channels often cannot supplywater for upwelling hatching cones also.

‘Orlon’ hatching conesThese hatching cones allow water to upwell and circulate eggs during incubation. Thissupplies oxygenated water continuously and also cleans the eggs and preventsclumping and suffocation. The hatching cone is approximately 50 – 70 cm high andapproximately 40 cm wide. ‘Orlon’ cloth is available from Vientiane and widely availablein Thailand. Other types of cloth are suitable but may become clogged if the watersupply has high suspended solids. Between 2 – 6 hatching cones would be required bya small-scale hatchery (Diagram 5).

‘Orlon’ Hatching cagesThese cages can be used for nursing newly hatched fish fry. They can also be used forincubation and hatching of fish eggs. For species which have sticky eggs these cagescan also be effective for hatching. Typically a cage is 2 x 1 m and approximately 50 –60cm high. These cages can be placed inside the concrete nursery tanks and suppliedwater by spraying to increase oxygenation. A PVC pipe frame placed in the bottom ofthe cage can be used to supply water to ensure that eggs and fry are upwelled gently.As with the hatching cones, 2 – 6 cages are required by a small-scale hatchery (Diagram6).

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Diagram 5. ‘Orlon’ upwelling hatching cone

Diagram 6. ‘Orlon’ cloth hatching cage (Note: water flow through holes in PVC pipe frame)

Electricity supplyMany potential hatchery locations in LAO PDR do not have an electricity supply. In thesecircumstances water must be supplied by gravity from a water source above the level ofthe hatchery. This is usually a stream or irrigation channel. Upland areas with terracedrice fields have a good potential since water flows downwards so the hatchery can bepositioned below the rice paddy. Pipework can be used to supply water from a stream tothe hatchery.

Where electricity is available, hatcheries can benefit form the use of low cost electricalwater pumps and also aeration equipment. Aeration and water pumping can significantlyimprove the production and survival of fish fry from a hatchery and are very desirable ifavailable.

The installation of electrical equipment can increase the hatchery production costsignificantly. Where electricity is not available, small 220V AC generators powered byflowing water can be used (e.g. Xieng Khouang and Oudomxay). Since the water supplythat runs these generators is also suitable for small-scale hatcheries, this has goodpotential for upland areas.

The use of 12V car batteries for small aerators has also been successful for shortperiods if a mains battery charger is available locally.

Water flow in

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PumpsWater pumps are required for some small-scale hatcheries for moving water as follows:

• Pumping water from water supply to storage tank/reservoir• Pumping water from reservoir to hatchery/nursery tanks• Pumping water into and out of nursery ponds

If the hatchery is constructed on sloping land and the water supply is higher than thehatchery, pumps may not be necessary (see Diagram 1).

AerationAeration of water for fish culture is essential for good production. Water splashing andwater movement can increase aeration sufficient for fish production. If the water supplyto the hatchery is correctly constructed then aeration is often not a problem, providedthat water supply is continuous. In hatcheries with limited water supply or water flow,aeration can be enhanced by using electrical aerators. There are several types ofaerator that can be used in small-scale hatcheries according to the amount ofinvestment available and electricity supply.

• Compressor type – this is often used in Lao PDR for motorcycle and tyre repairs.The compressor type of aerator supplies a low volume of air at high pressure and isnot generally recommended. It is however, widely available in Lao PDR andtherefore can be used if mains (220V) electricity is available.

• Aquarium type aerator – these are used for small aquariums and can be used forsmall applications. These types of aerators are usually 220V mains electricity,although 12V versions are also produced. This type of aerator can only be used forone tank so if several tanks contain eggs or fry more than one is required. This canincrease costs of hatchery construction.

• Air blower type – this is the best form of aerator since a high volume of air isdelivered allowing aeration of the entire hatchery. The cost of purchase of this type ofaerator, and the requirement for 220V electricity deters their use.

Diagram 7. If no aeration or water flow is available – manual stirring of the waterfor aeration can be performed

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Diagram 8. Small scale hatchery building with cement tanks

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CHAPTER 2 - BROODSTOCK

2.1 Source of Broodstock

Good quality mature broodstock are essential for successful production of fish fry andthey can be obtained from the following locations:

From broodstock culture pondsIdeally, hatcheries should have their own broodstock culture ponds so that theyhave a ready supply of broodfish for spawning. Broodstock ponds also allow thehatchery to ensure that the nutrition of the fish is adequate and the fish are ofgood quality. Maintenance of broodstock ponds involves expenditure throughoutthe year, which may be undesirable for small operations (in these cases thebroodstock ponds are usually fish culture ponds). In Lao PDR the extended dryseason can be a constraint to the all-year culture of broodstock if water is notavailable. In cases such as this, the broodstock must be obtained from outside ofthe farm.

From fish culture pondsDuring the spawning season fish can be taken from culture ponds if they arelarge enough and have reached maturity. The size at which fish reach maturityvaries between species and ideal broodstock sizes are presented in Table 2.Care must be taken to ensure that broodstock females are mature (usuallyindicated by a swollen abdomen) and not just too fat (this is not a commonfeature of Lao fish since they are unlikely to be overfed).

From the wildMature fish can be caught in the natural spawning grounds during the spawningseason. This requires some local knowledge of the species and its habitats. Wildfish can be caught in rivers, lakes and streams. Care must be taken not todamage the fish during catching and transport to the hatchery since this willreduce their quality for spawning. Fish should be transported in bags filled withoxygen, or in water filled tanks together with some form of oxygenation. The fishshould be transported during the coolest part of the day to avoid overheating.

From live fish marketsSome fish species (particularly catfish, snakeskin gouramy, common carp,Tilapia) and transported live to markets for sale. The fish should be in goodcondition and not bruised or damaged. If possible the fish should be checked formaturity although this is difficult in the case of catfish due to their shape andhard abdomen. The fully mature fish should be purchased during the spawningseason for that species.

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Table 1. Stocking rates and feeding rates for broodstock

FEEDING

SPECIES STOCKING RATETYPE OF FEED

FEEDING RATE(% OF BODY

WEIGHT)

Common silver barb Separate sexes1,000 pieces/1600 m2

Catfish starter feed,Sprouted corn,Rice bran,Broken rice

1-2 %

Common carp Separate sexes800 pieces/1600 m2

Herbivorous fishpelletSprouted cornRice bran,Broken rice

1-2 %

RohuMrigal

200 pieces/1600 m2

(female to male=1:1)Herbivorous fishpellet,Sprouted corn,Rice bran,Broken rice

2 - 3 %

Silver carpBig head carp

Sexes can be mixed160-200 pieces/1600 m2

Herbivorous fishpellet, Sproutedcorn, rice bran,broken rice

1 - 2 %

Grass carp Sexes can be mixed160-200 pieces/1600 m2

GrassSprouted corn

1 - 2 %

Striped catfish Sexes can be mixed400 pieces/1600 m2

Catfish growout feed 3 %

Walking catfish Sexes can be mixed16,000 pieces/1600 m2

Catfish growout feed 2-3%

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2.2 Broodstock culture

Culture of fish for broodstock has a different objective from culture for consumption.Fish cultured for consumption are often fat due to the nature of the feeding. This is notcommon in Lao PDR where feeds are applied sparingly to ponds (if at all). Culture offish for use as broodstock requires the following features:

Culture pondThe broodstock culture pond should be of an appropriate size and depth for thespecies cultured. This means that fish that mature at a large size (e.g. Chinesecarp and Indian carp) require a relatively large pond area for growth andmaturation. This is often difficult to achieve in Lao PDR and results in slowgrowth rates for these species and the quality of broodstock is poor as a result.

Stocking rateBroodstock are cultured at lower densities than those used for fish forconsumption. Stocking rates vary and are presented in Table 2.

FeedFeed for broodstock should be of good nutritional value and should be providedin sufficient quantity for good growth. Poor quality feed will affect the maturationof broodstock and will result in poor spawning success. Herbivorous fish requirea protein level in their diet of approximately 20% and should be fed at a level of 1- 2 % of body weight per day (see Table 1). Typical feeds include rice bran, freshplants, sprouted cereals (corn, wheat). Grass carp can be fed grasses and othervegetation. Application of manure to maintain a good water colour is alsorecommended since this enhances the natural production of the pond. Sincebroodstock ponds are stocked at low density natural feeds play an important rolein the condition and quality of the broodstock.

Culture environmentThe broodstock pond must not be a stressful environment for the fish. The waterin the pond must not become deteriorated with wastes (e.g. from overfeeding).The ponds should be reasonably deep so that sufficient water is maintained allyear round and does not become excessively hot (1 - 2 metres). Some watersupply to the pond (either pumped from a water supply, or inflow from a stream,river or irrigation canal) is desirable in this respect. If the pond soil tends to beacidic, this can be neutralised by addition of lime.

Management of fishSince some species are able to reproduce in a culture pond under the rightconditions (e.g. silver barb, common carp), separation of the sexes is necessaryat the start of the spawning season. If the sexes are not separated the femalesmay spawn in the pond and thus become unfit for use in the hatchery.

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2.3 Broodstock selection for spawning

Good quality broodstock should be used in fish hatcheries to ensure good spawning andfry survival. Damaged or diseased fish should not be used. The scales and fins of thefish should be intact and the fish should not be deformed (evidence of genetic ornutritional disorder). It is important that the fish are old enough to be mature to ensuregood egg production. Some hatcheries use fish that are too young and are not fullymature or barely mature, the result is poor spawning and fertilisation success. Thecriteria for mature broodstock suitable for spawning are presented in Table 2.

Table 2. Age, weight and fecundity of mature broodstock fish

Species Maturation age Maturation weightFecundity

(eggs/kilo weight)

Common silver barb 6 months - 1 year 0.4 - 0.8 Kg 320,000 eggs / kilo 1,500 eggs /gram

Common carp 6 months -1 year 0.3 - 1.0 Kg 80,000 eggs / kilo

Mrigal 2 - 5 years 1 - 2 Kg 110,000 eggs / kilo900 eggs / gram

Rohu Over 2 years 1 - 2 Kg 200,000 eggs / kilo

Silver carpBig head carpGrass carp

2 years 1.5 - 2 Kg 200,000 eggs / kilo700 - 750 eggs / gram

Striped catfish Over 2 years Over 2 Kg 200,000 eggs / kilo

Walking catfish Over 1 year Over 0.2 Kg 40,000 eggs / kilo465 - 656 eggs / gram

All broodstock fish do not mature and ripen simultaneously and therefore it is importantto know how to select mature fish for breeding. Using immature fish, or fish with unripeovaries will result in poor spawning success and low egg and fry production. This iswasteful of broodstock and will affect the profitability of the hatchery. Broodstocksuitable for spawning can be selected as follows:

Female characteristicsRipe mature female fish will appear to have a swollen belly. If the belly of the fish isgently squeezed it will feel soft and yielding (this is because the muscles of the belly arethin and distended). Gentle squeezing will also cause the genital/anal vent to protrude.

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In some species the genital/anal vent will appear darker than usual (often a red or pinkcolour).

Male characteristicsSuitable male broodstock should be mature and not overly fat or thin. If they have scalesnear the pectoral fin, these will have a rough feeling when rubbed with the hand (e.g.silver barb, common carp). In many species, mature males can be quickly checked bysqueezing the belly to cause secretion of milky white milt. If the milt flow readily thenthe male fish is suitable for use (e.g. silver barb, Chinese carp, Indian carp).

Fish species that have hard testis (e.g. catfish and striped catfish) will not release miltwhen squeezed. In this case the fish are selected by age and weight and the testis mustbe removed by cutting open the fish and removing the testis. Sperm activity can bechecked by observation under a microscope if available.

Figure 3. Comparison of external appearance of mature male and femalePuntius gonionotus broodstock.

2.4 Spawning season for wild fish

Most freshwater tropical fish species lay their eggs during the monsoon season. This isbecause rainfall increases the available habitats and nutrients for the hatching fish fry.The water quality of many water bodies usually improves, with increased oxygen, coolertemperatures. Hardness and pH of the water also change with the inputs of rainwaterrunoff. These changes in environmental factors trigger the maturation of the females sothat they can lay their eggs during this favourable season. When attempting to managereproduction of fish for aquaculture, this seasonality of reproduction must be taken intoconsideration. It is difficult to obtain successful spawning of fish before their natural

Male

Female

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breeding season since the condition of the broodstock fish is not sufficiently developedto produce viable eggs or sperm. Similarly, if the season has passed fish that have notspawned will tend to reabsorb their eggs to preserve nutrients. They cannot then beused until the following year.

Table3. Spawning seasons and optimal egg maturity for common aquaculturedfish species.

Fish species Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.

Common silverbarb

Breeding possible

Eggs optimal

Common carp Breeding possible

Eggs optimal

RohuMrigal

Breeding possible

Eggs optimal

Grass carp Breeding possible

Eggs optimal

Silver carpBighead carp

Breeding possible

Eggs optimal

Striped catfish Breeding possible

Eggs optimal

Walking catfish Breeding possible

Eggs optimal

Table 3 above presents the approximate spawning periods for some commonaquacultured fish species. The broken line indicates the season and the unbroken lineindicates the period for optimal egg maturity.

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CHAPTER 3 - FISH REPRODUCTION

In most tropical countries, spawning of fish takes place during the monsoon season, dueto the abundance of water and natural food during this period. This provides the bestavailable environment for the survival of fish fry. Some fish species are able to spawnalmost all year round (e.g. Common carp). Many fish species are unable to spawnnaturally in culture ponds since the pond environment is different to the conditions inrivers or water bodies where these fish spawn naturally (e.g. Chinese carp, Indian carp).Where pond conditions reflect natural conditions closely, fish reproduction can occurnaturally (e.g. Common carp and Silver barb and other related Puntius species).

In situations where fish species grow well in ponds, but cannot reproduce naturally,some intervention is required. The simplest for of this intervention may be the provisionof flowing water, splashing of water to mimic rain or provision of spawning substrates.More complex interventions include additional actions such as the injection of hormonesto induce the maturation of the eggs in the fish ovary and stimulation of spawningactivity. It is therefore essential to understand the particular requirements of each fishspecies so that efficient spawning and fry production is achieved.

There are three principal methods for seed production.

3.1 Natural reproduction

This is the easiest method and involves placing the male and female fish in a culturepond where they can spawn naturally. After spawning the male and female fish areremoved and the pond is then used as a nursery for the fry produced. Alternatively thefry produced are removed and placed in a nursery pond for on-growing. The species thatcan be produced in this way are Tilapia (Tilapia spp.), snakeskin gouramy (Trichogasterpectoralis) and guppies (ornamental fish)

3.2 Semi-natural reproduction

This method involves placing the male and female fish in a pond or tank, where theenvironment can be controlled. Control of the environment includes spraying water ontothe pond/tank surface to increase oxygenation and to mimic rainfall. Improved waterquality conditions and temperature change can induce the fish to start breedingbehaviour.

The selection of ripe male and female broodfish is important for the success ofreproduction since unripe or immature fish will not be induced to spawn in this way.

Some fish have sticky eggs that must be attached to spawning substrates for successfulfertilisation and hatching, therefore physical materials must be placed in the pond. Suchsubstrates include bunches of string, tree roots, grasses used to mimic growing grass.Other species required a surface for attachment such as cement tiles or plastic pipes.

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The species that can be successfully spawned using this method are common carp(Cyprinus carpio), goldfish (Carassius auratus), crucian carp (Carassius carassius),walking catfish (Clarias batrachus) and the sand goby (Oxyelotris marmoratus)

3.3 Artificial fertilisation

This has become a common practice worldwide with the development of hormonalinduction techniques for species that can mature, but cannot be bred naturally in fishponds. Typically species that require hormonal induction of spawning are those fishspecies whose natural spawning habitat is in rivers or moving water. Parental attentionof these species is usually non-existent and eggs tend to be small and planktonic. Acommon feature of these species is high fecundity and hatching fry require carefulattention for the first week after hatching to ensure good survival.

The principle of hormonal induction is to induce the eggs in the ovary of mature femalefish to ripen. When the eggs are ripe the fish will spawn and fertilise if held communallyunder appropriate conditions, or the eggs and milt (sperm) can be stripped from the fishfor external fertilisation. The fertilised eggs produced in this manner are incubated andhatched in controlled conditions and there is careful attention to the fish fry afterhatching. Typically, the fry are fed supplementary feed and held in tanks for a weekbefore release into prepared nursery ponds.

Some of the principle cultured species that require hormonal induction are: Commonsilver barb (Puntius gonionotus) and other indigenous Puntius species common to LaoPDR, Silver carp (Hypophthalmichthys molitrix), Bighead carp (Aristichthys nobilis),Grass carp (Ctenopharyngodon idellus), Rohu (Labeo rohita), Mrigal (Cirrhinus mrigala),Striped catfish (Pangassius sutchi) other catfish species (Clarias spp.).

Of these three methods of fish fry production, artificial fertilisation requires the mostmanagement attention and range of equipment. The cost of equipment and requirementfor hormones may limit the potential of this method in Lao PDR in the short term,although these materials are inexpensive and all readily available in Vietnam andThailand.

3.4 Advantages of Artificial Fertilisation

• Allows the mass production of fish eggs and fry under controlled conditions,because the selection of broodstock and spawning process can be controlled.

• Allows the production of species that will not spawn naturally in ponds or ricefields

• This control is important in the effective management and economics of hatcheryoperations.

• Allows efficient use of a small number of broodstock• Allows the production of even sized fish• Diseases and parasites can be better controlled• Management of broodstock can avoid inbreeding and allows selection of

desirable traits• Hybrids can be produced (e.g. catfish hybrids)

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CHAPTER 4 - SEMI-NATURAL REPRODUCTION USING THECOMMON CARP.

The culture of common carp (Cyprinus carpio) is widespread in Lao PDR because of itstolerance to adverse environmental conditions and the ease with which it can spawn in arange of habitats. The traditional rice-fish culture systems of Xieng Khouang provinceand other northern areas show that this species has been present for an very long time.The farmers have developed indigenous methods for production of fry in their rice fieldsso that they can have fish all year round. The production of fish fry in this system is lowand could be significantly improved by the use of some basic techniques for enhancingfry production and survival

Figure 4. The common carp (Cyprinus carpio)

.

4.1 Breeding characteristics

In Lao PDR common carp usually start to breed when temperatures start to rise at theend of the cold season during February - March. They will continue to breed throughoutthe monsoon season until October or later. The optimum season for carp breeding isbetween March and September.

Common carp mature at a relatively small size - this is another of their advantages foruse in Lao PDR. Typically a female carp will start to spawn at an age of approximately 6months and a weight of 300 grams. As a result of this, it is important that the male andfemale fish are separated early in the year (February) so that they do not start to spawnnaturally in the ponds before they can be used in the hatchery.

Since the spawning season for common carp is longer than that of other species it ispossible for a well-fed female to spawn up to three times in one year. Common carp arerelatively fecund with egg production approximately 80,000 eggs / kilogram of female.

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4.2 Difference between the sexes

The immature male and female common carp appear extremely similar and thus it maybe difficult to distinguish between the sexes. As the fish mature at the start of thebreeding season, the differences between the sexes becomes more apparent,particularly the genital-anal vent of the fish (Figure 5).

Females• The vent will appear swollen and pink in colour• The body will appear rounded and swollen• The abdomen wall will feel soft and yielding when gently squeezed• In some cases eggs will be released from the vent when the abdomen is

squeezed

Males• The body will appear longer and thinner• The abdomen feels firm and hard when squeezed• When the abdomen is squeezed towards the vent milky white milt will be

released• The scales near the operculum and pectoral fin appear rough when rubbed

with the hand

Figure 5. Difference between male and female common carp.

Female

Male

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4.3 Preparation of spawning tank/spawning pond and spawning substrate

Common carp can be spawned in either earthen ponds, concrete tanks or net cagesheld in ponds (hapas). Concrete tanks are the most suitable, but may be limited to wellestablished hatcheries. The concrete tank should be 6 - 12 m2 and approximately 1metre deep.

For small farmers, net hapas suspended in ponds are the cheapest and most suitablealternative. The size of the hapas should be approximately the same as for concretetanks (6- 12 m2, 1 metre deep). Some form of water flow to the pond is desirable sincethis will assist the oxygenation of the water and also stimulates the fish to spawn

Common carp require a substrate to stimulate spawning and also for egg attachment. Inthe wild this is usually grass in flooded areas or waterweeds. In tanks or cages artificialsubstrate is used and this is usually made of clumps of shredded plastic string, fine treeroots, waterweeds or any other material that resembles grass. The clumps of substrateshould be approximately 20 cm long and when spread out occupy a diameter of about10 - 15 cm.

The clumps of artificial substrate are attached to ropes set in a square frame (Figure 6 -spawning frame) that is suspended in the tank/cage.

If the artificial substrate is not used the carp may not be stimulated sufficiently to spawn.

Figure 6. Spawning substrates attached to a frame for carp spawning in concretetanks

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Figure 7. Frames placed in a cement tank for common carp spawning(Note: water sprayed into tank to simulate rainfall)

4.4 Selection of broodstock for spawning

Ripe females that are ready to spawn are selected according to the criteria listed above(i.e. swollen abdomen, soft when squeezed and yellow eggs may be discharged. Thevent is pink and swollen). Matures males should discharge milt when the abdomen issqueezed towards the vent.

4.5 Stocking of male and female common carp for spawning

One female fish should be stocked with 2 - 3 male fish to ensure fertilisation of the eggs.Stocking of the fish into the spawning tank/cage should be performed in the lateafternoon early evening since spawning occurs during the nighttime, when temperaturescool down slightly.

The water depth in the spawning tank should be 40 - 50 cm to ensure that the spawningsubstrate fills half of the available space. This ensures that the fish contact the substrate,which is necessary to stimulate spawning.

For efficient spawning, water should be splashed into the tank/cage to simulate rainfall(Figure 7). This splashing of the water will also increase the oxygen level in the water,which will also encourage successful spawning. Water flow to the tanks can be providedby a small pump or piped water from a water source higher than the spawning

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tank/cage. This method is quite suitable for ponds in terraced rice fields where waterflows downhill and can be piped into ponds for spawning.

The spawning takes places during the night and starts with the male fish rubbing theabdomen of the female with its head (which has the roughened scales). This activitystimulates the female to lay her eggs by swimming through the artificial substrate. Theeggs are sticky and attach to the substrate. The male follows the female and release miltto fertilise the attached eggs.

Early the following morning the broodstock fish should be removed from the spawningtank, or alternatively the artificial substrate and the attached eggs should be moved toanother tank for incubation and hatching. This is because common carp will eat all of theeggs within 1 - 2 days, if left in the same tank.

Eggs left to incubate will hatch after about 48 hours at a temperature of 28 - 31 oC(although this may be faster or slower according to temperature). During the incubationtime it is important to have some form of water flow to maintain oxygen levels so that theeggs do not suffocate. This is often not done in hatcheries in Lao PDR and will lower thesurvival of the eggs and reduce the number of fry produced significantly.

4.6 Nursing common carp

Fry start to hatch after approximately 2 days and will not eat for the first 2 - 3 days afterhatching. This is because they still have an internal yolk sac that provides food. Whenthis is exhausted the fry will start to eat and it is essential that they have feed availableduring this period. In hatcheries where the water for the hatchery is taken from a pondcontaining greenwater, the first feed of the fry will probably be natural zooplankton suchas Moina. Additional artificial feed can be added such as boiled mashed egg yolks (seesection 7.6 for details).

Fish fry should be fed mashed boiled egg yolks 3 - 4 times a day (or every 6 hours) forthe first 6 - 7 days after they start feeding. After seven days the fry can be transferred toa nursery pond that has been cleared of predators (insects and other fish) and that has awater depth of 50 cm or more. The fry can then be fed on feeds such as finely milled ricebran, finely milled soy waste, finely milled pig or chicken starter feed. The ratio of ricebran to starter feed should be approximately 2:1. The feeding rates for fry of differentages are presented in the section 7.6.

Fish fry should be fed twice a day (morning and evening) until the fry are 2 -3 weeks oldand have reached a size of 2 - 3 cm. Fish of this size can be sold for stocking to ponds,or can be nursed for a further month in net cages until the fish are large enough to stockinto rice fields.

It is important to note that water levels in the nursery ponds should be maintained duringthe nursery culture period and if possible some water should be exchanged.

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CHAPTER 5 - ARTIFICIAL FERTILISATION OF SILVER BARB

Species suitable for small-scale hatchery production in Lao PDR include the indigenousBarb species (Puntius spp.) , Common carp and possibly some of the Chinese andIndian carp species. The attraction of the common carp and the barb species is that theymature at a small size (200 - 300 grams) which means that broodstock sized animalscan be produced within one year of culture. In Lao PDR this means that broodstock fishcan be produced every year from the growout culture of that year. This is in contrast tothe Chinese and Indian carp, which mature at sizes over one kilogram and require atleast 1.5 years or more before they can be used as broodstock. This is important inthose cases where water shortages in growout ponds are a constraint to all year cultureof fish.

Figure 8. Puntius gonionotus - a good candidate for mini-hatchery production

The barbs are attractive as aquaculture species since they are indigenous and there areat least six reported species for Lao PDR. These fish grow well in both pond and rice-fish systems. They have not been widely used as an aquaculture species so far becauseof the limitations of technical knowledge in spawning and nursery production.

Currently more attention is being paid to the Barb family as potential aquaculture speciessuitable for extension to small farmer operations and as an alternative to the Commoncarp.

The principles for culture of Puntius gonionotus are the same as those for both Chineseand Indian carp. There are differences between species relating to spawning season,hormone requirements for spawning and the times to spawning and hatching. Wherethere are differences between species, these have been presented in the form of look uptables.

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5.1 Broodstock selection

Selection of mature broodstock of Puntius gonionotus is similar to the method describedfor common carp. Male and female broodstock fish should be separated early in thespawning season to prevent premature spawning in the ponds. This will waste eggs andfry since survival will be extremely low.

The female Puntius will have a swollen abdomen and this will feel soft when squeezedgently, the abdomen wall will feel thin and non-muscled. The vent on the female will alsobe swollen and appear reddened. Eggs are not released when squeezed since althoughthe female is mature the eggs are not fully ripened. This is the difference betweenspecies of fish that spawn naturally in ponds (e.g. common carp) and those which do not(e.g. Puntius spp., Chinese carp and Indian carp).

Figure 9. Broodstock Puntius gonionotus (Note small size).

Male Puntius will have rough scales in the in the region of the pectoral fins and theindication of maturity is the release of milt when the abdomen is squeezed towards thevent.

Once the broodstock fish have been selected they can be held in a net cage in a pondbefore injection with hormone, or they can be placed in a tank in the hatchery. The tankor cage should not be too small since this will stress the fish, especially if water flow islow. Some splashing of water, aeration or water flow is desirable to ensure that the fishdo not suffocate.

5.2 Hormones used for induction of spawning

Male

Female

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The first hormone to be widely and successfully used for induction of fish spawning wascarp pituitary gland extract. This method involved the collection of large numbers ofpituitaries from mature carp, homogenisation and then injection to female fish to inducespawning. Typically two injections are required to induce spawning and an interval oftime is required between the injections. The timings of the injections are important toensure successful spawning as is the use of the correct dosage.

The advantage for the carp pituitary method was that farms were able to produce theirown pituitaries from fish held on the farm. In Lao PDR this method is not suitable due tothe shortage of large broodstock sized fish from which to take the pituitary. This isbecause most farms do not have the large numbers of mature fish that are required toprovide the pituitaries. The drying up of many fishponds during the dry season furtherlimits the availability of large broodstock sized fish. Those fish that are maintainedthroughout the year are required for use as broodstock and cannot be sacrificed for theirpituitaries.

Another potential source of pituitaries are local fish markets. In countries where carppituitary extract is widely used, fish heads are often discarded and the pituitaries can becollected (e.g. from fresh fish markets, fish farms). However, in many Asian countries,fish are purchased with the head on and this limits the availability of pituitaries. In LaoPDR the lack of large sized fish due to the short growing season and drying up of manyculture ponds is a further limitation to this method.

Human Chorionic Gonadotropin (HCG) has also been successfully used to induce fishspawning and this can be obtained as the dry hormone and can be used directly. This ismore convenient and dosages for fish are more accurate.

The induction of spawning of fish using Luteinizing Hormone Releasing Hormoneanalogue (LHRHa) has now become standardised through repeated experimentationand can be used with certainty for the spawning of many fish species. LHRHa has anadditional advantage in that only one dose is required to induce spawning, in contrast tothe two doses previously required with carp pituitary extract. The chemical name ofLHRHa is ‘buserilin acetate’ and this is available either as LHRHa or as the human drug‘Suprefact’. The effectiveness of LHRHa is further enhanced when used together withdomperidone maleate. This is sold as a drug for human use under the trade name‘Motilium’ or ‘Mirax’ .

Since both ‘Suprefact’ and ‘Motilium’ are now widely available and used in Thailand, thismethod is favoured for hatcheries in Lao PDR. Initially, it is expected that theDepartment of Livestock and Fisheries will facilitate the availability of ‘Suprefact’ and‘Motilium’ through the Provincial Livestock offices and Provincial hatcheries.It is important that hormones for use in fish spawning are stored in a cool place toprevent deterioration. Typically, storage temperature should be between 4 - 20 oC.

5.3 Method for using LHRHa

LHRHa is typically supplied as a standard weight of hormone given as micrograms (ug).The dosages of LHRHa used for female fish are also expressed as micrograms ofhormone per kilo of broodstock fish.

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The most common form of LHRHa currently available is the chemical known as‘buserelin acetate’. This is sold as a drug for human usage under the trade name‘Suprefact’. ‘Suprefact’ has been used successfully in the spawning of a wide range offish species in many countries. Suprefact is sold in bottles containing 10 cm3 ofdissolved hormone. This volume of dissolved hormone contains 10,000 ug of ‘buserelinacetate’, therefore 1 cm3 contains 1,000 ug.

Since the dosages of ‘Suprefact’ are very low (typically 0.2 ug per kilo of fish), thehormone must be further diluted so that it is easier to handle. It is usual to dilute‘Suprefact’ to 1/10 of its concentration with distilled water (i.e. 1 cm3 ‘Suprefact’ + 9 cm3

distilled water). Thus 1 cm3 of the diluted ‘Suprefact’ contains 100 ug of ‘buserelinacetate’.

When using ‘Suprefact’ to induce fish spawning it is necessary to mix it withdomperidone maleate. domperidone maleate enhances the effect of the Suprefact andimproves spawning success. It is sold as a drug for human use under the trade names of‘Motilium’ and ‘Mirax’. ‘Motilium’ comes in tablet form, with each tablet containing 10 mgof domperidone maleate.

When using ‘Motilium’, it is necessary to crush the tablet into a powder and dissolve withdistilled water so that it can be mixed with ‘Suprefact’ for injection into the fish. Thedosage rate for the female fish is determined by the weight of the fish and only one dose(one injection) is necessary to induce spawning. This makes the use of ‘Suprefact’ and‘Motilium’ extremely reliable and successful in the spawning of fish. Comparisons withother methods of hormonal spawning induction also show that egg production and frysurvival are consistently higher using this method than using HCG or carp pituitaryextract. Table 4 below gives the required dosages of ‘Suprefact’ and ‘Motilium’ requiredfor induction of fish spawning, together with the timings for injection and egg stripping.

Table 4. Dosage rates, time to spawning and time to hatching for a range ofaquaculture fish species.

SpeciesDosage of hormone‘Suprefact’ (ug/Kg)

and ‘Motilium’ (mg/Kg.)

Time until strippingafter injection

(hours)

Hatchingtime after

fertilization(hours)

Optimaltemperature

range(oC)

Common silver barb (10 - 15) + (5 - 10) 4 - 8 8 - 12 25 - 30

Red cheek barb (5 - 10) + (5 - 10) 5 - 6 18 - 19 28 - 30

Tinfoil barb (10 - 15) + (5 - 10) 6 - 8 18 - 20 28 - 30

Rohu (10 - 30) + (5 - 10) 5.5 - 11 14 - 18 28 - 32

Mrigal (10 - 30) + (5 - 10) 5.5 - 11 14 - 18 28 - 32

Big head carp (10 - 30) + (5 - 10) 7 - 12 14 - 18 28 - 32

Silver carp (10 - 30) + (5 - 10) 7.5 - 12.5 14 - 18 28 - 32

Grass carp (10 - 20) + (5 - 10) 8 - 12 14 - 18 18 - 30

Walking catfish (10 - 30) + (5 - 10) 14.5 - 17.5 22 28 - 33

Giant carp (20 - 25) + (5 - 10) 10 - 12 2 29 - 30

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Golden shark (20) + (5 - 10) 8 - 10 22 27 - 28

Striped catfish (10 - 30) + (10) 12 - 18 24 - 26 28 – 32

5.4 Equipment required for the induction of fish spawning

During the late afternoon the female fish to be injected must be weighed so that thecorrect hormone dosage can be injected.

Equipment used in hormone induction of spawning

Injection of broodstock to induce spawning is relatively simple and requires the followingequipment.

• Syringe (1 -2 cc size depending on dosage/size of fish)• Needle for injection (18 -27 gauge, depending on size of fish)• Pestle and mortar or glass homogeniser (to crush and mix hormones)• Weighing scales (to weigh broodstock to assess appropriate dosage)• ‘Suprefact’ (Luteinizing Hormone Releasing Hormone analogue, LHRHa,

chemical name -buserilin acetate), diluted to 1/10 of original concentration.• ‘Motilium’ (chemical name - domperidone maleate)• Distilled water (obtained in ampoules, boiled water or distilled water for car

batteries have also been used successfully)

Figure 10. Equipment required for induction of fish spawning.

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Equipment used for egg stripping and fertilisation.

• Bowl (2 - 5 litres volume) - used for collecting the eggs stripped from thefemale and the milt stripped from the male fish.

• Bird feather - used for mixing the eggs and milt so that fertilisation is achievedefficiently. The feather does not damage the eggs.

• Clean cloth - used to wipe the fish down to remove excess water and mucusbefore stripping.

• Jug or suitable container - for holding water for washing eggs• Clean water - water is added to the eggs after mixing to trigger fertilisation.

The clean water is also used to wash the eggs after fertilisation.

Egg hatching equipment

• Net cage made of ‘Orlon’ - used for holding eggs during incubation - can beused for sticky eggs - (e.g. common carp, catfish species)

• Upwelling hatching cone made of ‘Orlon’ - used for hatching eggs that are notsticky (e.g. Puntius gonionotus, Chinese carp, Indian carp)

5.5 Method for hormone injection

Successful spawning of fish requires selection of mature broodstock and also the correctadministration of the hormone. This involves the use of the correct dosage (for thespecies and size of fish) and also careful timing of the process so that maximumspawning efficiency is achieved.

Volume of hormone dosage for injection

Since the size of fish used for spawning varies according to species and age of the fish,the total volume of the dosage required also varies. Ideally the volume of the mixedhormone dosage should be approximately 1 cm3 per kilo of female fish. Since thevolume of ‘Suprefact’ used is quite low, the extra volume of the dose is made up usingdistilled water. Using correct volume for injection insures that the fish absorbs thehormone efficiently and that the hormone has the required effect.

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Table 5. Dosage volume and needle size for female broodstock according toweight

Weight of female fish (Kg) Total volume to be injected(cm3)

Needle size (number)

0.2 - 0.5 0.3 - 0.7 250.5 - 2 0.4 - 1.0 242 - 5 1.0 - 2.5 22

5 or more 2.5 - 10 18

Hormone preparation

After weighing the female fish the correct dose of hormone can be prepared. Whenusing ‘Suprefact’ that has been diluted to 1/10 of its original concentration theconcentration of hormone is 100 µg / cm3

Worked example:

Three female Puntius gonionotus broodstock females need to be injected andthey have a total combined weight of 900 grams (the fish weight 300, 300 and300 grams).

1. The dosage rate is 15 µg per kg (1,000g) of broodstock female, therefore thequantity required is:

900 / 1000 x 15 = 13.5 µg

1 cm3 of diluted ‘Suprefact’ (1/10) contains 100 µg of hormone, therefore the totalvolume of hormone required is:

13.5/100 x 1 = 0.135 cm3

2. The dosage rate of ‘Motilium’ required is 10 mg per kg of broodstock female,therefore the quantity required is :

900 / 1000 x 10 = 9 mg

One tablet of ‘Motilium’ contains 10 mg of active chemical so just less than awhole tablet could be used.

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3. The volume of the total dose should be approximately 0.4 cm3 for each of the300g fish giving a total volume of 1.2 cm3.

Since the volume of ‘Suprefact used is only 0.135 cm3 the rest of the volumeshould be made up with distilled water (approximately 1.1 cm3).

4. The ‘Suprefact’ and ‘Motilium’ are combined and ground into a paste by addingsome of the distilled water. When they two are fully mixed the rest of the distilledwater is added to make the final volume. In this situation, the fish are given equalvolumes of the hormone mixture since they are the same size.

Injection location

The hormone mixture must be injected into the muscle of the fish. Suitable locations forinjection are illustrated in Diagram 9

2.1 Behind the dorsal fin2.2 Into the muscle below the dorsal fin on the side of the fish2.3 Behind the pectoral fin2.4 In front of the tail fin on the side of the fish2.5 Behind the pelvic fin

Diagram 9. Suitable locations for hormone injection

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Figure 11. Injection of female Puntius gonionotus into muscle below dorsal fin

Female fish are isolated in a net and injected. After injection of the female fish, theyshould be held together with male fish, in a tank or an ‘Orlon’ net cage fixed in a pondthat contains well-oxygenated water. The male and the female should be held togetherso that if they spawn before they can be stripped, the males can fertilise the eggs in thenet cage, and the eggs will not be lost. If a large mesh net cage is used the eggs will bereleased into the pond and cannot be transferred into the hatching container.Oxygenation of the ‘Orlon’ cage or tank can be achieved by flowing water into the cageor tank and allowing the water to splash to increase aeration.

Fertilisation of the eggs

From Table 4 , the time after injection of hormone until female Puntius are ready to bestripped is between 4 - 8 hours. This time is variable depending upon temperature andthe dosage of hormone. The female fish should be checked every 30 minutes to onehour to see when the eggs begin to be released into the water. This can be checked bysampling the water using a glass and looking for the first signs of egg release. Wheneggs are first observed, the female fish should be removed quickly for egg stripping.There are two methods for fertilising the eggs using the artificial method

• Wet method - eggs are stripped into a bowl (2 -5 litres) of water from afemale fish that is ready to spawn. The milt from the male is strippedsimultaneously if possible to ensure that the eggs are fertilised. This methodcan result in low fertilisation rates if not done quickly and the eggs and milt

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are not mixed well. The only advantage of this method is in cases where theamount of milt from the males is low such as the Climbing perch (Anabasanabas) and small sized Common Silver barb (Puntius gonionotus).

• Dry method - this is the best method since high fertilisation rates areguaranteed. The milt and eggs are stripped from the male and female into adry bowl and then mixed together using a feather. After mixing, clean water isadded to fill the bowl. The sperm in the milt is only activated once the water isadded and so efficient fertilisation is obtained. It is important that once thewater is added to the eggs that they are not disturbed for about 5 - 15minutes to allow the eggs to swell. If the eggs are disturbed before swellingthey can be easily broken and survival will be low as a result. Once the eggsare swollen they should be washed in clean water 2 -3 times to removemucus that is discharged with the eggs from the female (this will encouragebacterial growth if left with the eggs and may affect hatching). This method issuitable for most species of aquaculture fish (especially, Puntius spp.,Chinese carp, Indian carp, catfish species)

Figure 12. Stripping eggs from a female Puntius gonionotus using the drymethod

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Figure 13. Stripping milt from a male Puntius gonionotus for dry fertilisationmethod

Figure 14. Mixing the eggs and milt with a chicken feather using the dry method.

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CHAPTER 6 – EGG INCUBATION

Fish eggs can be split into three categories according to whether they float or sink andwhether they are sticky or not. Floating and sinking eggs tend to be from species whichrelease eggs into moving water and allow the eggs to be washed away with the waterflow. Species that have sticky eggs deposit the eggs on substrates so that the eggs arenot lost from the spawning site. Since eggs have different characteristics, the methodsfor incubation and hatching vary as follows.

6.1 Floating eggsThe eggs can be hatched in a pond, concrete tank or ‘Orlon’ hatching cage. Since theeggs float they will not clump together and suffocate. Some water movement is desirableso that oxygen concentrations are kept at a healthy level. Typically the incubation andhatching tank/cage should be approximately 2 x 1m and 0.5 m deep. The hatching cageis made of ‘Orlon’ cloth and its shape is maintained by using a wire or plastic frame. Thebest material to use is blue plastic pipe since water can be passed through the pipe toprovide upwelling water from the bottom of the cage (see Diagram 6). If possibleaeration should be provided to maintain oxygen levels and also to strip the oil that isreleased from the eggs from the surface of the water. This oil can foul the water andencourage bacterial colonisation of the eggs. The eggs are incubated until hatching,after which the fry are held for a further 2 -3 days, until the yolk sac is reabsorbed andthe fry start feeding. After this point the fry can be transferred to nursery tanks or stockedto a prepared nursery pond. This method can also be used with half-sinking half-floatingeggs as well.

Figure 15. ‘Orlon’ hatching cage with frame (Note: water flows out of the framethrough holes in the pipe)

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6.2 Half floating - half sinking eggs (e.g. Rohu, silver barb)For species such as Chinese and Indian carp and the Barb species (e.g. Puntius spp.),swelling after fertilisation is completed in about 10 minutes and the eggs can be gentlywashed and transferred to a hatching container. For these species which have floatingor semi-floating eggs, the best hatching container to use is the upwelling hatchingcone (Diagram 5, Figure 16).

Figure 16. ‘Orlon’ hatching cone (Note: water flow enters through the funnel inthe bottom

Once the eggs have been placed in the ‘Orlon’ upwelling hatching cone or the hatchingcage, water flow should be provided. This ensures that the eggs do not clump on thebottom of the container and suffocate. The water movement also helps clean the eggs.The water coming into the hatching container should be clean if possible and should bescreened to exclude anything that might eat the eggs (e.g. insect larvae, tadpoles etc.).‘Orlon’ is a suitable material for this. The water flow should be sufficient to keep the eggsmoving continuously. If the water flow is too strong the eggs will be damaged, if it is toolow then the eggs will not be circulated. The best method for setting the water flow is toobserve the eggs in the hatching container and adjust the flow until the desiredmovement is obtained.

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Figure 17. Transfer of Puntius eggs to upwelling ‘Orlon’ hatching cones

6.3 Sticky eggsCommon carp eggs and the eggs of the catfish species are sticky once they arereleased and fertilised. These eggs cannot be incubated in the upwelling hatching conesince they would clump together and suffocate. For common carp the technique used isto allow the fish to deposit their eggs naturally on a spawning substrate (see previouschapter). If the eggs are stripped (e.g. during artificial fertilisation the eggs must bepoured onto a flat surface so that they will attach. Once attached to the surface the eggsmust have flowing water past over them continuously. The best method for this is to usethe ‘Orlon’ hatching cage method (see above) and take care to pour the eggs over thecage evenly so that they attach in a thin layer. Water is passed over the eggs by the flowout of the plastic pipe that is in the base of the cage.

Techniques exist for washing eggs to remove the stickiness, however this process ismore complicated, and the chemicals required are difficult to obtain in Lao PDR.

6.4 Egg Hatching

From Table 5 , the hatching of Puntius eggs occurs between 8 - 12 hours afterfertilisation. The hatching time and hatching efficiency depends upon a variety of factorsespecially temperature, which if high, will shorten the hatching time. The factors thatneed to be considered for good egg hatching efficiency are listed below

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Maintain good water quality

• Water should not be too hot. Water temperatures over 32 oC are undesirableand will reduce hatching efficiency. Care should be taken not to take waterfrom shallow ponds or stored in metal water tanks. Hatching tanks should beshaded to prevent heating from direct sunlight.

• Water should be clean and not contain high levels of suspended solids• Water should not appear dark green (indicating high phytoplankton

concentration) or have visibly high number of zooplankton (can be observedin a glass held to the light). These will use up oxygen and some zooplanktonspecies can damage eggs

• Predatory water insects should be excluded from the hatching tank sincemany of these species can be predators of eggs and fry (e.g. dragon flylarvae, water boatmen). Blue netting screens around tanks and on the waterinlet can be used to avoid their entry.

Figure 18. Spraying water into ‘Orlon’ cage to increase oxygenation

Maintain high oxygen concentration in the water

• This is very important if water temperatures are high, since the oxygenconcentration in the water will be lower.

• Water can be splashed to increase oxygenation before it is introduced tohatching container

• Water can be sprayed into tanks to increase oxygenation (see Figure 18)• The oxygen level of the water must be high during the time when the eggs

are about to hatch.

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• Low oxygen concentrations can slow hatching times, but if they become toolow egg survival will be low and the number of fry hatched will be reduced.

Minimise waste products

• During the egg swelling period just after fertilisation, mucus is produced thatwill foul the water. If the water flow is not sufficient, this will allow bacterialnumbers to increase and this might infect the eggs. Waste products form theeggs provide food for bacteria and good water exchange is essential for theirremoval.

• Some of the waste products formed in the water may be directly toxic to theeggs (e.g. ammonia).

• Water exchange is very important if the water is cloudy or contains highconcentrations of phytoplankton or zooplankton.

Ensure good water circulation

• The eggs must be continuously circulated and washed by the water flow.• This increases oxygen availability and cleans the eggs• If water circulation is too strong, the eggs will be damaged due to impact with

the container.• If the circulation is too low then the eggs will not be stirred sufficiently and the

eggs will suffocate.• If water flow cannot be used, small air pumps can be used to provide aeration

and water circulation.

Once the eggs have hatched, the fry can be transferred from the upwelling hatchingcone to an ‘Orlon ‘ hatching cage. If the eggs have been hatched in a hatching cage,then the newly hatched fry do not need to be transferred. Fry should be maintained inthese nursery cages until transferred to nursery ponds. This process is described in thenext chapter.

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Figure 19. Checking egg hatching by observation in a glass – do this regularly tocheck the development of eggs and fry.

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CHAPTER 7 - FRY NURSING AFTER HATCHING

After the fry have hatched they are transferred to a nursery area. There are many formsof fry nursery - earth ponds, concrete tanks, fibreglass tanks and ‘Orlon’ cages have allbeen used successfully to rear fish fry. The decision as to which nursery system to usedepends upon the species of fish, materials available and the amount of money that canbe invested. Small-scale hatcheries have small budgets for construction therefore low-cost nursery techniques are a priority.

7.1 Earth pond nurseryEarthen pond nurseries are effective for the production of many species of fish. Thenaturally feed that occurs in a well-prepared nursery pond assists survival andcompensates for poor quality supplemental feed. Growth rates are high in earth ponds,but survival rates can vary greatly. This is due to the problems of controlling earth pondsbecause they are difficult to feed and predators of the fish fry can enter easily. One ofthe principle problems in Lao PDR is the entry of predatory dragon fly larvae nymphs,tadpoles and carnivorous fish. These prey on the larval fish and can reduce the survivalgreatly. Correct preparation of the earth pond is essential for good survival of the fish fry.This is often poorly done due to difficulty in draining ponds, lack of fertilisers or rainfall tofill ponds at the required time. Good pond preparation requires the following steps to beobserved:

• Empty the water out of the pond (drain or use a pump) and dry the pond.

• If water cannot be drained, predators in the pond can be killed by the additionof rotenone (derris powder) at a rate of 1.5 g per m3 of pond water. Derris isdifficult to obtain in Lao PDR and therefore draining and drying the pond isthe most effective method for eliminating predators.

• Add lime to the pond at a rate of 1 kg for every 25 m2 of pond area. Lime canusually be purchased from building supplies shops. Lime assists soil fertilityand reduces the amount of fertiliser required to produce greenwater in thenursery pond.

• Add fertilizer to the pond at the rate of 1.5 kilos per 10 m2. This is equivalentto one full bucket per 20 m2 of pond area. Fertilizers that can be used includebuffalo, cow, chicken and pig manures. After the manure is applied the pondcan be filled to a depth of 5 - 10 cm to allow the breakdown of the manure.After 3 - 5 days, the pond should be filled to a depth of 30 - 50 cm and is thenready for stocking.

• Fry are stocked to the nursery pond at a rate of 125 - 500 individuals/m2 (seeTable 6).

• After stocking the fry to the pond (usually done in the early evening) the waterlevel is maintained for one week. One week after stocking the water level isthen increased to 80 cm.

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CHAPTER 8 - ECONOMICS OF SMALL-SCALE HATCHERYOPERATION

The types of hatchery appropriate for extension in Lao PDR differ greatly dependingupon local conditions. Typically, small farmers are unwilling to invest money in a small-scale hatchery unless they have had evidence of the success of such an operation. Thisusually means somebody locally who was in a similar situation and was successful.Even with the evidence that such a hatchery would be profitable, many farmers are stillunwilling to commit finances to invest in cement tank and pond construction.

Farmers can be introduced to small-scale hatchery techniques gradually, starting with alow cost hapa-based method (i.e. ‘Orlon’ and blue net cages suspended in a pond),followed by gradual up-scaling to methods that employ flowing water and possibly evenpumping.

The choice of species produced by the farmers should also reflect the type of operation.Typically, hapa-based methods favour species such as Common carp and Tilapia. Ifspawning hormones are made available, the production of other species is also possibleusing these simple methods (especially Common silver barb)

The ultimate goal of this is to take farmers beyond simply producing fish fingerlings fortheir own purposes to actively selling them as a commercial enterprise. Until thishappens, the shortage of fry for both pond and rice-fish culture will continue to constrainLao aquaculture.

The economic breakdowns that are presented in this chapter demonstrate:

• The investment required for different types of hatcheries• The effect of different survival rates (10 – 50 %) on potential production per

crop.• The effect of fish sale price variation (10 – 50 Kip)• Breakeven fish production for different types of hatcheries

These economic breakdowns can also serve as an approximate guide to the investmentrequired to establish a fish hatchery depending upon the required production. Economicindicators (e.g. Internal Rate of Return, Net Present Value) have not been included sincethese have little meaning to many small-scale hatchery entrepreneurs. In most casessmall hatcheries are constructed on the basis of payback within the first year or two,hence the calculations are presented to reflect this. Most farmers are unwilling to borrowor invest for periods over two years since this presents an unacceptable degree ofuncertainty (i.e. risk).

At the time of writing , these values are based in Kip and the exchange rate is $1equivalent to 3,500 Kip.

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8.1 Marketing

Important note:

The economic projections provided here assume that the fingerlings produced bya hatchery are marketed soon after they are produced.

A potential problem for some locations is that farmers only purchase a small numbers offingerlings and thus the hatchery must hold the fingerlings for periods longer than maybe economically feasible. In this respect the timing and marketing of fish production mustbe well established before investment in a hatchery. Most hatcheries will have problemsmarketing their fry until sufficient numbers of farmers know of their location. This maytake more than one year and in this respect credit provision for hatcheries may requirelonger than one-year payback periods.

Fry price is currently 30 – 50 Kip per piece and this is unlikely to reduce in the nearfuture. As previously mentioned, the constraint of a hatchery producing large numbers offry is the eventual marketing of the production. In this respect hatcheries should also belocated near to an area where demand for fingerlings is high (e.g. for rice fish culture orfish ponds). It may be necessary to lower the price of the fish fingerlings in order to sellsufficient quantities.

In interviews with fish farmers in Lao PDR it is often mentioned that they require fry to bedelivered to their village – in this respect the transportation by the hatchery may becrucial in ensuring sales. Visiting villages which grow fish and taking orders is onemethod for selling larger quantities. In areas with good road access, fingerlings arecarried along the road and are sold in each village along the route.

8.2 Minimal input small-scale hatcheries

This type of hatchery represents the lowest level of inputs for hatchery, ponds andequipment. It is thus the type of small-scale hatchery that would suit a small farmeroperation that was producing fry for sale.

Operations smaller than this are not considered here, since the investment required isbelow that at which credit would be required to construct the hatchery. Typically, smalleroperations would also be unlikely to produce a fry surplus for sale, therefore would notconstitute an income generating activity. This type of hatchery would only require the netcage components and self-constructed ponds.

The table below gives the investment and returns expected from three different types ofminimal input hatchery : The three hatchery types are distinguished by their differentsources of water and electricity. These are:

• Type 1 - The water supply is under gravity and thus represents a site that isfed by a small stream, irrigation canal, or pond/reservoir that is higher thanthe hatchery site.

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• Type 2 - Again, water may be supplied under gravity to the hatchery orflowing water is present nearby. This water is used to power a smallgenerator of the type that is readily available in Lao PDR (Chineseconstruction). The pump is used to pressurise water in the hatchery, orprovide aeration etc . (the cost of these additional components have not beenincluded here).

• Type 3 – This hatchery has an electricity supply that is use to power anelectrical pump for the hatchery. This hatchery also has a 5hp petrol waterpump for filling and emptying ponds.

All three types of hatchery have the same nursery and broodstock pond areas. Thedifference between the types is related to investment cost and potential productionlevels.

From Table 8 the fixed costs of net cages, tanks and equipment for the three types ofhatchery range between 243,000 – 1,333,000 Kip. Labour is not included as it isassumed that there is no hired labour on a hatchery of this scale. Pond constructioncosts are considered separately (Table 9) since in many cases small-scale hatcheriesalready have ponds. The cost of pond construction is often a considerable deterrent tofarmers starting fish fry production, therefore attention for small-scale hatcherydevelopment in Lao PDR is initially directed at farmers with existing ponds.

Where water is supplied by gravity there may be no need for pumping since water canbe pressurised to the hatchery. Often, hatcheries and fish ponds are not located lowerthan the water supply and thus some form of pumping is required. In the case ofhatcheries relying on rainwater, pumping is always necessary. This type of situationusually requires electricity nearby, or a petrol driven water pump. In this case, thereservoir for water for the hatchery needs to be large.

Table 8. Fixed costs for hatchery construction and equipment

Type 1 Type 2 Type 3Unit cost Unit water flow generator electricity

Item Number of itemsOrlon' upwelling hatching cone (80 litres) 10,000 each 1 1 1Orlon' nursery cage (1,000 litres) 40,000 each 1 1 1Blue net nursery hapas (20 m2) 35,000 each 2 2 2Cement tank (3 m2) 250,000 each 0 0 1Pipework to tanks or cages 50,000 total 0.5 0.5 1Fittings (valves) 15,000 total 0 0 1Roofing - thatch plus wood 50,000 section 1 1 2Electric pump (small submersible) 150,000 each 0 1 15 hp Petrol pump (for emptying/filling ponds) 500,000 each 0 0 1Hoses for pump 50,000 set 0 0 1Water powered generator (220V) 120,000 each 0 1 0Aerator (12 v) 50,000 each 0 0 1Broodstock feed (3 kg/ kg of fish/year) 1,000 kg 24 24 24Broodstock females 3,000 kg 4 4 4Broodstock males 3,000 kg 4 4 4

Total fixed costs 243,000 513,000 1,333,000

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Table 9. Pond requirement and construction cost

Pond Type Pond Area(m2 )

Pond Construction(Kip)

Nursery 378 567,000Broodstock 200 300,000

Total 867,000

The operational costs listed in Table 10 concern those costs incurred for the preparationand feeding of nursery cages and ponds. These costs are related to the nursery pondarea and also to the fuel usage for pond draining and filling.

The greater degree of flexibility in management that could be achieved by the use ofpumps will be reflected in higher production rates. This is due to higher survival in thehatchery because of better water quality and aeration and pumping. In many cases theinputs such as rice bran are also derived from rice production activities of the farmer andthis can reduce operational costs. In all three cases the cost of manure for fertilisation isnot included as it is assumed to be available to the farmers at an opportunity cost ofcollection. Chemical fertilisers can be used and must be added to the operational cost.

Table 10. Operational costs for minimal input hatcheries (per crop)

Type 1 Type 2 Type 3Unit cost Unit water flow generator electricity

Item Number of itemsHormones 3,000 dose 4 4 4Rice bran 350 kg 18 18 18Eggs 300 each 3 3 3Pellet feed 3,000 kg 0 0 0Pig/Chicken starter feed 1,500 kg 9 9 9Fuel for pump 800 litre 0 20 20Lime 1,000 kg 16 16 16

Total operational costs (Kip) 48,700 64,700 64,700

The breakeven production of fry required to cover the fixed costs and one crop of fry ispresented in Table 11. This clearly shows that these types of hatcheries can pay backwithin one to three crops, providing fry price remains higher than 20 Kip per piece andthe survival from the nursery pond is greater than 20%. Low survivals in nursery pondsare encountered in Lao PDR as a result of poor pond preparation, poor water quality andinadequate feeding. Using the equipment listed above, survivals higher than 10% shouldbe consistently achieved.

It is important to note that more than one crop is possible within the ideal growingseason. The number of crops depends on a variety of factors such as availability ofwater and seasonal demand for fry, but generally three crops could be produced duringthe optimal season for fry production. Subsequent crops after the first will only incuroperational costs and possible increased broodstock and broodstock feeding costs.

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Table 11. The effect of fry selling price on breakeven production of fry (assumed overone year)

Required Fry Production(not including pond construction)

Required Fry Production(including pond construction)

Selling price(Kip) Type 1 Type 2 Type 3 Type 1 Type 2 Type 3

20 14,585 28,885 69,885 57,935 72,235 113,23530 9,723 19,257 46,590 38,623 48,157 75,49050 5,834 11,554 27,954 23,174 28,894 45,294

Table 12. Potential production per crop (based on area of nursery ponds and hatcheryequipment)

Survival from nurseryponds

(%)All types

10 7,56020 15,12030 22,68050 37,800

The potential production figures listed in Table 12 have been conservatively estimated.Higher production figures are possible if careful attention is paid to pond and hatcherymanagement. These values are however, what might be expected initially fromhatcheries of this type. The values in Table 12 represent the production per crop andcould be multiplied by 3 to give an estimate of annual production.

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8.3 Small-scale hatcheries with increased investment

The hatchery types presented in this section are those types of hatcheries which arecapable of relatively high levels of production of fry, but that require significantlyincreased levels of investment due to increased infrastructure. Principally the increasedfixed costs are for the construction of cement tanks, better roofing structures, pumpingand aeration.

Table 13. Fixed costs for increased investment small-scale hatcheries.

Investment levelMedium High

Item Unit cost Unit Number of itemsOrlon’ upwelling hatching cone (80 litres) 10,000 each 3 5 6 9Orlon’ nursery cage (1,000 litres) 40,000 each 3 4 5 7Blue net nursery hapas (20 sq. metres) 35,000 each 5 7 9 14Cement tank (3 sq. metres) 250,000 each 2 3 4 6Cement tank (12 sq. metres ) 600,000 each 0 1 1 1Pipework to tanks 50,000 total 1 2 4 8Fittings (valves) 15,000 total 2 4 4 8Roofing - thatch plus wood 50,000 total 0 0 0 0Roofing – galvanised ( 8 sheets + wood) 300,000 total 1 2 2.5 3Electric pump (small submersible) 150,000 each 1.5 2 2 35 hp Petrol pump (for emptying/ filling ponds) 500,000 each 1 1 1 1Hoses for pump 50,000 set 1 1 1 1Water powered generator (220V) 120,000 each 0 0 0 0Aerator (compressor type, 220V) 300,000 each 0 1 1 1Aerator (12 v) 50,000 each 1 0 0 0Labour 60,000 w/m 4 12 24 36Broodstock feed (3 kg/ kg of fish/year) 1,000 kg 96 144 192 288Broodstock females 3,000 kg 16 24 32 48Broodstock males 3,000 kg 16 24 32 48

Total fixed costs 2,462,000 4,723,000 6,159,000 8,416,000

Labour and broodstock maintenance have been included as fixed costs (Table 13) sincethey are incurred annually and not on a by-crop basis. For subsequent years these costsshould be considered additional to the operational costs, whereas the equipment costsmay be depreciated over 1 – 3 years.

Cement tanks can be written off over 3 – 5 years depending upon quality of construction.Earthen ponds will require periodic maintenance every two - three years.

The pond construction costs will vary according to construction method. These pondshave been calculated based on an excavation depth of 0.5 metres. The final depth of thepond would be expected to be 1.5 metres or more.

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Table 14. Pond requirement and construction cost of increased investmenthatcheries

Investment levelUnit Medium High

Area of Nursery ponds required m2 1512 2268 3024 4536Area of Broodstock ponds m2 800 1200 1600 2400Nursery pond Kip 2,268,000 3,402,000 4,536,000 6,804,000Broodstock pond Kip 1,200,000 1,800,000 2,400,000 3,600,000

Cost of ponds 3,468,000 5,202,000 6,936,000 10,404,000

Table 15. Operational costs per crop for increased investment small-scalehatcheries.

Investment levelUnit cost Unit Medium High

Hormones 3,000 dose 8 12 16 24Rice bran 350 kg 69 103 137 205Eggs 300 each 11 16 21 31Pellet feed 3,000 kg 36 54 72 108Pig/Chicken started feed 1,500 kg 35 52 69 103Fuel for pump 800 litre 40 60 80 120Lime 1,000 kg 61 91 121 182

Total operational costs 304,950 455,850 606,750 909,550

The operational costs per crop in these systems are very much increased due to thelarger area of nursery ponds and the increased usage of fuel. If fuel is not used forpumping, then a similar electricity cost for pumping could be expected. Feed prices areover-estimated due to the inclusion of pellet feed. The use of pellet feed may not benecessary, however it has been included since fingerling sales may not be immediateand they may be required to be held for some time in blue net cages until sale. Duringthis time they should be fed pellet feed. The increased size of the fish produced in thisway would assure a sale price of over 40 Kip per piece and covers the additional feedcost. Intensive nursing in cages is only successful if water quality does not deteriorate. Inthis situation it is important to have some form of water flow and preferably additionalaeration. It is only suitable for hatcheries with pumps and aeration, or those that aresituated where there is a steady supply of flowing water (e.g. hillside stream).

Table 16. Break-even production of fry per crop at different fry prices

Required Fry Production forInvestment level

Selling price(Kip) Medium High

Inclusive of pond construction cost (3 crops) 20 114,081 188,209 248,588 359,14430 65,889 110,278 145,500 209,11150 39,533 66,167 87,300 125,467

Not inclusive of pond construction cost (3 crops) 20 56,281 101,509 132,988 185,74430 27,356 52,478 68,433 93,51150 16,413 31,487 41,060 56,107

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The cost of pond construction is not included in the hatchery fixed costs table and henceis considered separately since in some cases ponds have been previously constructed.For high investment type hatcheries, the nursery ponds and cement tanks are almostcertainly not previously constructed and therefore the construction cost of the pondsshould be considered in the overall economics of the operation.

The break-even production costs in Table 16 assume that the hatchery can produce andsell fingerlings from three production cycles during the year. Annual production offingerlings can be obtained by multiplying the values in Table 16 by 3.

The level of investment required for hatcheries of this type would normally require alonger term loan (at least two years). It can be seen that provided survivals areconsistently higher than 25 %and selling price remains higher than 30 Kip per piece,these hatcheries would achieve payback within three crops (i.e. one year). The annualproduction from these types of hatchery ranges between 100,000 to 1,400,000.

Since marketing the output from the largest of these hatcheries might be a problem inthe short term, it is always advisable to start the farm as a small-scale operation, whilstallowing the potential for expansion should the market develop. Many hatcheries fail inthe early stage of operation due to over-investment before the market developssufficiently to support a hatchery of that size. The construction of too many ponds is afrequent problem therefore the hatchery layout can be planned, but construction maytake place over several years.

Table 17. Potential production per crop based on investment level

Expected Production for Investment Level

Survival from nursery ponds(%)

Medium High

10 30,240 45,360 60,480 90,72020 60,480 90,720 120,960 181,44030 90,720 136,080 181,440 272,16050 151,200 226,800 302,400 453,600

The potential production figures presented in Table 17 may possibly be underestimatedin cases where the hatchery has a good supply of water and good management. In othercountries, production levels higher than this have been achieved, however theexperience of the hatchery manager is a critical factor and skilled hatchery managersare uncommon in Lao PDR.

For annual potential production of fish fingerlings, multiply the values in Table 17 by 3.

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Earth pond nurseries typically have an area of 100 - 1600 m2, and should have a waterdepth of 1.5 metres. Nursery ponds in Lao PDR are often shallow (70 cm), but they canstill be used to produce fish fry.

Figure 20. Earthen pond with clean banks and well fertilized water

7.2 ‘Orlon’ cages Earth ponds are difficult to keep free of predators, therefore it is sometimes better tokeep the predators out using a cage. Holding the newly hatched fry in a cage made of‘Orlon’ will prevent predators from eating the fry and also prevent the fry from escaping.The cage is usually 1 x 2 m and 60 cm deep.

Fry cultured in ‘Orlon’ cages must be fed since the natural food in the pond will beunavailable. Feeding starts approximately 1 -2 days after the fry hatch. After the fry havegrown they can be transferred to an earth pond or to a larger cage made of blue netting.Some water exchange may be necessary since the oxygen levels in the cage canbecome low. Uneaten food in the cage will breakdown releasing toxic products andthese must be flushed out using water exchange.

If no water pump or flowing water is available, water exchange can be performedmanually before feeding the fry. The water should be screened to prevent the entry ofpredators from the pond water.

Fry cannot be cultured for longer than one week in the cage because they will sufferfrom nutritional deficiency and high mortality because of polluted water and oxygendeficiency; unless water can be pumped into the cage from the pond

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7.3 Blue net cage

Once fry are large enough not to escape through blue netting (about 2 - 3 weeks afterhatching) , they can be cultured in cages made of this material. The advantage of fryculture in cages is that they do not suffer from predation from larger fish, frogs or largewater insects. The fish need to be fed more than if they were cultured in the pond, butthe high survival will compensate for the extra cost of the feed.

Figure 21. Blue net cage 4 x 5 metres (1 metre deep)

If water can be supplied to the cage this will increase aeration and remove wasteproducts. This will allow higher densities of fry to be cultured than is otherwise possiblewithout water flow.

• Blue net cage (4 x 5 m) without water supply - stock 2,000 fry (>2 weeks old)• Blue net cage (4 x 5 m) with water supply - stock 5,000 to 10,000 fry (>2

weeks old)

The fish should be fed pig or chicken starter feed mixed with soft rice bran to ensure thatthey obtain sufficient food and grow well.

7.4 Cement tanks

Cement tanks are easily controlled since they are above ground and can be drained anddried. When cement tanks are filled the water can be screened to exclude unwantedpredators. It is important to shade cement tanks from direct sunlight because they willbecome too hot and this can kill the fish fry.

Cement tanks cost more money to construct but they can be used for many years.Cement tanks also require some form of water delivery system to fill the tanks. If water isheld in a reservoir pond higher than the cement tank, then water can be supplied by

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gravity. If the water supply is at the same level or lower than the cement tank, thismeans that a water pump is needed to fill the tanks and to exchange water.

It is important that newly constructed cement tanks are soaked for 2 weeks before useso that the new cement is weathered completely. If green algae is seen growing in thecement tank, this is a good indication that the weathering is complete and fry can benursed in the tank.

Before stocking the fry, fill the tank with clean water to a depth of about 20 - 30 cm. Thefry will not need to be fed immediately after stocking since they still have a yolk sac.Puntius fry will start feeding after approximately 24 hours and so boiled egg yolk must beprepared beforehand (feeding rates for different species are given in Table 6).

Uneaten feed will decompose in the tank and foul the water quickly, so some form ofwater exchange is necessary to prevent waste accumulation and subsequent problemswith bacteria and ammonia build-up.

The cement tanks also need some form of aeration - either from an aerator, or byspraying water into the tank. Without aeration stocking rates that can be used in cementtanks are usually lower than those that can be used in earth ponds as can be seen forTable 6.

7.5 Stocking rates for fry in nursery systems

The stocking density for fry depends upon the fish species used and the type of nurserysystem. The table below indicates recommended stocking densities for young fry(approximately 1 week old) of the different species commonly cultured in southeast Asia.The values given for the earth pond assume a depth of more than 80 cm for the nurserypond. Values for the cement tank and net cage assume that the water depth in the tankand cage are greater than 50 cm.

Table 6. Stocking densities for different fish species in two types of nurserysystem

Species Earth pond(pieces / m2)

Cement tank / blue netcage (pieces / m2)

Common silver barbCommon carpRohu, MrigalGrass carp Silver carp, Bighead carpTilapiaSnakeskin gouramy, Giant gouramySnakehead, Climbing perchCatfish (all spp.)Sand goby

50019025025019013019031063

25015010010020050300

3,500100

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Fish fry can be held at these densities for up to 1 month or until they reach a size of 2 - 3cm. After this size the densities should be reduced since competition for food and spacewill increase rapidly and the growth rate and survival of the fry will deteriorate. Once thefry reach 2 - 3 cm then intensive nursing in net cages is an option if flowing water andaeration is available.

7.6 Feeding of fry in nursery ponds and tanks

The types of feed used in nursery culture of fish depends upon the feed available. It isimportant that the feed given to the fish fry is of a size that can be ingested. If the particlesize of the feed is too large the fish fry will starve, even though sufficient feed may beapplied.

Boiled egg yolksA common starter feed for fish fry is boiled egg yolk. This is prepared by boiling eggsand removing the hardened yolk. The yolk is mashed with a small amount of water untilit forms a paste. This past is then rubbed through several layers of ‘Orlon’ cloth to obtainthe small particles required for newly feeding fish fry. The resulting suspension will havethe appearance of milk. Some more water is added to the egg yolk so that it is easy tohandle and the suspension is poured around the tank, cage or pond. In larger pondscare must be taken to get the egg suspension further from the pond bank, in thissituation some form of sprayer maybe used.

Rice branSoft rice bran is a suitable early feed for young herbivorous feed after they have beennursed for approximately 7 days on egg yolk. Rice bran is readily available, but caremust be taken to ensure that the bran is soft bran and does not contain a high proportionof husk. Sieving the bran is advisable so that the particle sizes are small enough for thefish to ingest and a single layer of ‘Orlon’ cloth is suitable for this.

Chicken and pig starter feedStarter feed are excellent for fish fry feeding if they are ground to an appropriate size.Usually starter feeds are coarse since they are intended to chicks or piglets and it maybe necessary to pound the feed to reduce the particle size. A single layer of ‘Orlon’ clothcan be used to sieve the particles so they are of the appropriate size. Starter feeds areavailable in Lao PDR, but are quite expensive, however the amount of feed required islow and its’ cost is low when compared to the income from the sale of the fingerlingsproduced.

Catfish PelletThis feed is excellent due to its high protein content. It should be ground and sieved asfor starter feeds and rice bran. The cost and availability of this feed limits its use in LaoPDR. Other fish feeds could be used as a substitute, but tend to have lower proteincontents.

PR

OVIN

CIAL A

QU

ACU

LTUR

E DEVELO

PMEN

T PR

OJEC

T (LAO/97/007) S

MALL-SC

ALE HATC

HER

IES FOR

LAO

PDR47

Table 7. Nursery requirem

ents for herbivorous fish using different culturesystem

s.Comments

Requires a roofto shade fromdirect sunlight

As above

Water depth inpond should be

50 -80 cm

Water depthshould be 1 metre.

Stocking densityin cage

5,000 - 10,000(20 square

metres)

Fish fry can beheld at high

density if waterflow is good andfeed is supplied.

Aeration

Use airpump or

spray water

As above

-

-

Use airpump or

spray water

Water exchange

Flow watercontinuously

orchange

10 - 20 cm/ day

As above

-

Maintain water level inpond

Flowing water intocage will increase

survival (clean net regularly)

Use piped water tospray into cage. Thiswill increase oxygenand keep good water

quality.

Amount

-

1 egg yolk / 200,000fry/day

Feeding3-4 times /day

1 kg/ 400,000 fry/ day.

Fry are fed2-3 times/ day

2 kg / day spreadaround the whole

pond (pond 400 m2).

100 g / day for netcage (1 sardine

can/day)

1 kg./day per 100,000fry of size 2 - 3 cm.

Fish are fed 2 timesper day

Feed

Type

Fry do not feed(still using yolk sac)

Boiled egg yolkMoina, zooplankton

Mixed feed, 2:1 ratio. (soft rice bran :pig/chicken starter feed)Catfish feed is excellent ifavailable.

As above

As above

Tank/cage/pond

Orlon net cage (2 - 3 m2)

Cement tank (2 - 8 m2)

Orlon net cage (2 - 3 m2)

Cement tank (2 - 8 m2)

Earth pond (100 - 400 m2)

Earth pond (100 - 400 m2)

Blue net cage (10-20 m2)

Blue net cage (10-20 m2)

Earth pond (50 - 400 m2)

Age(days)

0 – 2

3 - 6

7 - 14

15 - 25

26 - 50

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7.7 Nursery requirements for carnivorous fish species.

Carnivorous fish are cultured rarely in Lao PDR due to their requirement for high proteindiets. There are some examples of cage culture of carnivorous fish in reservoirs (Giantsnakehead - Channa micropeltes), but the fry for this is currently wild caught. Smallcatfish farms do exist also, but the low price for cultured catfish relative to wild caughtcatfish currently limits its profitability.

• Carnivorous fish fry are fed Moina or Artemia at the rate of 12- 15 kg/ rai / day (7 -10 g/m2) for the first seven days after stocking. Fry can be cultured in earth ponds orconcrete tanks. Supplemental feed can be used and this is usually boiled egg yolksliquidised with water, which are fed at a rate of 10 eggs per rai (1 egg / 160 m2). Theemulsion of egg yolk is sprayed around the edges of the pond.

• Finely mashed fish mixed with water can also be used at a rate of 3 - 5 kg / rai / day(2 - 3 g/m2 /day) for the first 5 - 7 days. Fry are fed twice a day, morning andevening.

• 7 days after stocking fry are fed finely chopped fish at a rate of 5 kg/rai /day (3 g/m2

/day) for a further 3 days.

• 10 days after stocking floating catfish starter feed should be used. The feed shouldbe soaked before feeding to soften the pellets.

• For a 1 rai pond (1600 m2) containing 500,000 fish fry, feed 3 times a day ata rate of 5 kg / time.

• For a 100m2 pond, containing 30,000 fry, feed 3 times daily with 0.3 kg / time• This rate should be maintained for 3 weeks.

(Note: 1 rai is equivalent to 1600 m2, e.g. a pond 40 m x 40 m)

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CHAPTER 8 - ECONOMICS OF SMALL-SCALE HATCHERY OPERATION

The types of hatchery appropriate for extension in Lao PDR differ greatly depending upon local conditions. Typically, small farmers are unwilling to invest money in a small- scale hatchery unless they have had evidence of the success of such an operation. This usually means somebody locally who was in a similar situation and was successful. Even with the evidence that such a hatchery would be profitable, many farmers are still unwilling to commit finances to invest in cement tank and pond construction.

Farmers can be introduced to small-scale hatchery techniques gradually, starting with a low cost hapa-based method (i.e. ‘OrIon’ and blue net cages suspended in a pond), followed by gradual up-scaling to methods that employ flowing water and possibly even pumping.

The choice of species produced by the farmers should also reflect the type of operation. Typically, hapa-based methods favour species such as Common carp and Tilapia. If spawning hormones are made available, the production of other species is also possible using these simple methods (especially Common silver barb)

The ultimate goal of this is to take farmers beyond simply producing fish fingerlings for their own purposes to actively selling them as a commercial enterprise. Until this happens, the shortage of fry for both pond and rice-fish culture will continue to constrain Lao aquaculture.

The economic breakdowns that are presented in this chapter demonstrate:

• The investment required for different types of hatcheries

• The effect of different survival rates (10 — 50 %) on potential production per crop.

• The effect of fish sale price variation (10 — 50 Kip)

• Breakeven fish production for different types of hatcheries

These economic breakdowns can also serve as an approximate guide to the investment required to establish a fish hatchery depending upon the required production. Economic indicators (e.g. Internal Rate of Return, Net Present Value) have not been included since these have little meaning to many small-scale hatchery entrepreneurs. In most cases small hatcheries are constructed on the basis of payback within the first year or two, hence the calculations are presented to reflect this. Most farmers are unwilling to borrow or invest for periods over two years since this presents an unacceptable degree of uncertainty (i.e. risk).

At the time of writing , these values are based in Kip and the exchange rate is $1 equivalent to 3,500 Kip.

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8.1 Marketing

Important note:

The economic projections provided here assume that the fingerlings produced by a hatchery are marketed soon after they are produced.

A potential problem for some locations is that farmers only purchase a small numbers of fingerlings and thus the hatchery must hold the fingerlings for periods longer than may be economically feasible. In this respect the timing and marketing of fish production must be well established before investment in a hatchery. Most hatcheries will have problems marketing their fry until sufficient numbers of farmers know of their location. This may take more than one year and in this respect credit provision for hatcheries may require longer than one-year payback periods.

Fry price is currently 30 — 50 Kip per piece and this is unlikely to reduce in the near future. As previously mentioned, the constraint of a hatchery producing large numbers of fry is the eventual marketing of the production. In this respect hatcheries should also be located near to an area where demand for fingerlings is high (e.g. for rice fish culture or fish ponds). It may be necessary to lower the price of the fish fingerlings in order to sell sufficient quantities.

In interviews with fish farmers in Lao PDR it is often mentioned that they require fry to be delivered to their village — in this respect the transportation by the hatchery may be crucial in ensuring sales. Visiting villages which grow fish and taking orders is one method for selling larger quantities. In areas with good road access, fingerlings are carried along the road and are sold in each village along the route.

8.2 Minimal input small-scale hatcheries

This type of hatchery represents the lowest level of inputs for hatchery, ponds and equipment. It is thus the type of small-scale hatchery that would suit a small farmer operation that was producing fry for sale.

Operations smaller than this are not considered here, since the investment required is below that at which credit would be required to construct the hatchery. Typically, smaller operations would also be unlikely to produce a fry surplus for sale, therefore would not constitute an income generating activity. This type of hatchery would only require the net cage components and self-constructed ponds.

The table below gives the investment and returns expected from three different types of minimal input hatchery : The three hatchery types are distinguished by their different sources of water and electricity. These are:

• Type 1 - The water supply is under gravity and thus represents a site that is fed by a small stream, irrigation canal, or pond/reservoir that is higher than the hatchery site.

• Type 2 - Again, water may be supplied under gravity to the hatchery or flowing water is present nearby. This water is used to power a small generator of the type that is readily available in Lao PDR (Chinese construction). The pump is used to pressurize water in the hatchery, or provide aeration etc. (the cost of these additional components have not been included here).

• Type 3 — This hatchery has an electricity supply that is use to power an electrical pump for the hatchery. This hatchery also has a 5hp petrol water pump for filling and emptying ponds.

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All three types of hatchery have the same nursery and broodstock pond areas. The difference between the types is related to investment cost and potential production levels.

From Table 8 the fixed costs of net cages, tanks and equipment for the three types of hatchery range between 243,000 — 1,333,000 Kip. Labour is not included as it is assumed that there is no hired labour on a hatchery of this scale. Pond construction costs are considered separately (Table 9) since in many cases small-scale hatcheries already have ponds. The cost of pond construction is often a considerable deterrent to farmers starting fish fry production, therefore attention for small-scale hatchery development in Lao PDR is initially directed at farmers with existing ponds.

Where water is supplied by gravity there may be no need for pumping since water can be pressurised to the hatchery. Often, hatcheries and fish ponds are not located lower than the water supply and thus some form of pumping is required. In the case of hatcheries relying on rainwater, pumping is always necessary. This type of situation usually requires electricity nearby, or a petrol driven water pump. In this case, the reservoir for water for the hatchery needs to be large.

Table 8. Fixed costs for hatchery construction and equipment

Type 1

water flow

Type 2

generator

Type 3

electricity

Item

Unit cost Unit

Number of items

Orion upwelling hatching cone (80 litres) 10,000 each 1 1 1

Orion’ nursery cage (1,000 litres) 40,000 each 1 1 1

Blue net nursery hapas (20 m 35,000 each 2 2 2

Cement tank (3 m 250,000 each 0 0 1

Pipework to tanks or cages 50,000 total 0.5 0.5 1

Fittings (valves) 15,000 total 0 0 1

Roofing - thatch plus wood 50,000 section 1 1 2

Electric pump (small submersible) 150,000 each 0 1 1

5 hp Petrol pump (for emptying/filling ponds) 500,000 each 0 0 1

Hoses for pump 50,000 set 0 0 1

Water powered generator (220V) 120,000 each 0 1 0

Aerator (12 v) 50,000 each 0 0 1

Broodstock feed (3 kg/ kg of fish/year) 1,000 kg 24 24 24

Broodstock females 3,000 kg 4 4 4

Broodstock males 3,000 kg 4 4 4

Total fixed costs 243,000 513,000 1,333,000

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Table 9. Pond requirement and construction cost

Pond Type Pond Area

(m2)

Pond Construction

(Kip)

Nursery 378 567,000

Broodstock 200 300,000

Total 867,000

The operational costs listed in Table 10 concern those costs incurred for the preparation and feeding of nursery cages and ponds. These costs are related to the nursery pond area and also to the fuel usage for pond draining and filling.

The greater degree of flexibility in management that could be achieved by the use of pumps will be reflected in higher production rates. This is due to higher survival in the hatchery because of better water quality and aeration and pumping. In many cases the inputs such as rice bran are also derived from rice production activities of the farmer and this can reduce operational costs. In all three cases the cost of manure for fertilisation is not included as it is assumed to be available to the farmers at an opportunity cost of collection. Chemical fertilisers can be used and must be added to the operational cost.

Table 10. Operational costs for minimal input hatcheries (per crop)

Type 1

water flow

Type 2

generator

Type 3

electricity

Unit cost Unit

Number of items

Hormones 3,000 dose 4 4 4

Rice bran 350 kg 18 18 18

Eggs 300 each 3 3 3

Pellet feed 3,000 kg 0 0 0

Pig/Chicken starter feed 1,500 kg 9 9 9

Fuel for pump 800 litre 0 20 20

Lime 1,000 kg 16 16 16

Total operational costs (Kip) 48,700 64,700 64,700

The breakeven production of fry required to cover the fixed costs and one crop of fry is presented in Table 11. This clearly shows that these types of hatcheries can pay back within one to three crops, providing fry price remains higher than 20 Kip per piece and the survival from the nursery pond is greater than 20%. Low survivals in nursery ponds are encountered in Lao PDR as a result of poor pond preparation, poor water quality and inadequate feeding. Using the equipment listed above, survivals higher than 10% should be consistently achieved.

It is important to note that more than one crop is possible within the ideal growing season. The number of crops depends on a variety of factors such as availability of water and seasonal demand for fry, but generally three crops could be produced during the optimal season for fry production. Subsequent crops after the first will only incur operational costs and possible increased broodstock and broodstock feeding costs.

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Table 11. The effect of fry selling price on breakeven production of fry (assumed over one year)

Required Fry Production Required Fry Production

(not including pond construction) (including pond construction)

Selling price (Kip) Type 1 Type 2 Type 3 Type 1 Type 2 Type 3

20 14,585 28,885 69,885 57,935 72,235 113,235

30 9,723 19,257 46,590 38,623 48,157 75,490

50 5,834 11,554 27,954 23,174 28,894 45,294

Table 12. Potential production per crop (based on area of nursery ponds and hatchery equipment)

Survival from nursery ponds

(%)

All types

10 7,560

20 22,680

30 15,120

50 37,800

The potential production figures listed in Table 12 have been conservatively estimated. Higher production figures are possible if careful attention is paid to pond and hatchery management. These values are however, what might be expected initially from hatcheries of this type. The values in Table 12 represent the production per crop and could be multiplied by 3 to give an estimate of annual production.

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8.3 Small-scale hatcheries with increased investment

The hatchery types presented in this section are those types of hatcheries which are capable of relatively high levels of production of fry, but that require significantly increased levels of investment due to increased infrastructure. Principally the increased fixed costs are for the construction of cement tanks, better roofing structures, pumping and aeration.

Table 13. Fixed costs for increased investment small-scale hatcheries.

Investment level

Medium High

Item

Unit cost Unit

Number of items

Orion’ upwelling hatching cone (80 litres) 10,000 each 3 5 6 9

Orion’ nursery cage (1,000 litres) 40,000 each 3 4 5 7

Blue net nursery hapas (20 sq. metres) 35,000 each 5 7 9 14

Cement tank (3 sq. metres) 250,000 each 2 3 4 6

Cement tank (12 sq. metres) 600,000 each 0 1 1 1

Pipework to tanks 50,000 total 1 2 4 8

Fittings (valves) 15,000 total 2 4 4 8

Roofing - thatch plus wood 50,000 total 0 0 0 0

Roofing — galvanised (8 sheets + wood) 300,000 total 1 2 2.5 3

Electric pump (small submersible) 150,000 each 1.5 2 2 3

5 hp Petrol pump (for emptying! filling ponds) 500,000 each 1 1 1 1

Hoses for pump 50,000 set 1 1 1 1

Water powered generator (220V) 120,000 each 0 0 0 0

Aerator (compressor type, 220V) 300,000 each 0 1 1 1

Aerator (12 v) 50,000 each 1 0 0 0

Labour 60,000 wlm 4 12 24 36

Broodstock feed (3 kg! kg c fish/year) 1,000 kg 96 144 192 288

Broodstock females 3,000 kg 16 24 32 48

Broodstock males 3,000 kg 16 24 32 48

Total fixed costs 2,462,000 4,723,000 6,159,000 8,416,000

Labour and broodstock maintenance have been included as fixed costs (Table 13) since they are incurred annually and not on a by-crop basis. For subsequent years these costs should be considered additional to the operational costs, whereas the equipment costs may be depreciated over 1 — 3 years.

Cement tanks can be written off over 3 — 5 years depending upon quality of construction. Earthen ponds will require periodic maintenance every two - three years.

The pond construction costs will vary according to construction method. These ponds have been calculated based on an excavation depth of 0.5 metres. The final depth of the pond would be expected to be 1.5 metres or more.

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Table 14. Pond requirement and construction cost of increased in vestment hatcheries Investment level

Medium High

Area of Nursery ponds required m2 1512 2268 3024 4536

Area of Broodstock ponds m2 800 1200 1600 2400

Nursery pond Kip 2268,000 3,402,000 4,536,000 6,804,000

Broodstock pond Kip 1,200,000 1,800,000 2,400,000 3,600,000

Cost of ponds 3,468,000 5,202,000 6,936,000 10,404,000

Table 15. Operational costs per crop for increased investment small-scale hatcheries.

Investment level Investment level

Medium High

Hormones 3,000 dose 8 12 16 24

Rice bran 350 kg 69 103 137 205

Eggs 300 each 11 16 21 31

Pellet feed 3,000 kg 36 54 72 108

Pig/Chicken started feed 1,500 kg 35 52 69 103

Fuel for pump 800 litre 40 60 80 120

Lime 1,000 kg 61 91 121 182

Total operational costs 304,950 455,850 606,750 909,550

The operational costs per crop in these systems are very much increased due to the larger area of nursery ponds and the increased usage of fuel. If fuel is not used for pumping, then a similar electricity cost for pumping could be expected. Feed prices are over-estimated due to the inclusion of pellet feed. The use of pellet feed may not be necessary, however it has been included since fingerling sales may not be immediate and they may be required to be held for some time in blue net cages until sale. During this time they should be fed pellet feed. The increased size of the fish produced in this way would assure a sale price of over 40 Kip per piece and covers the additional feed cost. Intensive nursing in cages is only successful if water quality does not deteriorate. In this situation it is important to have some form of water flow and preferably additional aeration. It is only suitable for hatcheries with pumps and aeration, or those that are situated where there is a steady supply of flowing water (e.g. hillside stream).

PROVINCIAL AQUACULTURE DEVELOPMENT PROJECT (LAO/97/007) SMALL-SCALE HATCHERIES FOR LAO PDR

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Table 16. Break-even production of fry per crop at different fry prices

Inclusive of pond construction cost (3 crops)

Required Fry Production for Investment level

Selling price (Kip)

Medium High

20 114,081 188,209 248,588 359,144

30 65,889 110,278 145,500 209,111

50 39,533 66,167 87,300 125,467

Not Inclusive of pond construction cost (3 crops)

Required Fry Production for Investment level

Selling price (Kip)

Medium High

20 56,281 101,509 132,988 185,744

30 27,356 52,478 68,433 93,511

50 16,413 31,487 41,060 56,107

The cost of pond construction is not included in the hatchery fixed costs table and hence is considered separately since in some cases ponds have been previously constructed. For high investment type hatcheries, the nursery ponds and cement tanks are almost certainly not previously constructed and therefore the construction cost of the ponds should be considered in the overall economics of the operation.

The break-even production costs in Table 16 assume that the hatchery can produce and sell fingerlings from three production cycles during the year. Annual production of fingerlings can be obtained by multiplying the values in Table 16 by 3.

The level of investment required for hatcheries of this type would normally require a longer term loan (at least two years). It can be seen that provided survivals are consistently higher than 25 %and selling price remains higher than 30 Kip per piece, these hatcheries would achieve payback within three crops (i.e. one year). The annual production from these types of hatchery ranges between 100,000 to 1,400,000.

Since marketing the output from the largest of these hatcheries might be a problem in the short term, it is always advisable to start the farm as a small-scale operation, whilst allowing the potential for expansion should the market develop. Many hatcheries fail in the early stage of operation due to over-investment before the market develops sufficiently to support a hatchery of that size. The construction of too many ponds is a frequent problem therefore the hatchery layout can be planned, but construction may take place over several years.

PROVINCIAL AQUACULTURE DEVELOPMENT PROJECT (LAO/97/007) SMALL-SCALE HATCHERIES FOR LAO PDR

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Table 17. Potential production per crop based on investment level

Expected Production for Investment Level

Survival from nursery ponds

(%) Medium High

10 30,240 45,360 60,480 90,720

20 60,480 90,720 120,960 181,440

30 90,720 136,080 181,440 272,160

50 151,200 226,800 302,400 453,600

The potential production figures presented in Table 17 may possibly be underestimated in cases where the hatchery has a good supply of water and good management. In other countries, production levels higher than this have been achieved, however the experience of the hatchery manager is a critical factor and skilled hatchery managers are uncommon in Lao PDR.

For annual potential production of fish fingerlings, multiply the values in Table 17 by 3.

ASIA-PACIFIC FISHERY COMMISSIONFAO Regional Office for Asia and the Pacific

39 Pra Athit Road, Bangkok, Thailandwww.apfic.org