Aquaculture Asia Jan 08

8/11/2019 Aquaculture Asia Jan 08

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3January-March 2008

Sustainable aquaculture

Developing guidelines for sustainable freshwateraquaculture planning in Vietnam

Christoph Mathiesen1, Don Griffiths2, Dr Nguyen Cong Dan2, Le Thi Chau Dung2, Jacob Fjalland2,Ho Cong Huong3,Do Duc Tung3, Nguyen Thanh Hai3, Nguyen Huu Hung2

1. Institute for Fisheries Management and Coastal Community Development, IFM; 2. Support to Freshwater Aquaculture,Ministry of Fisheries in Vietnam SUFA; 3. Vietnam Institute of Fisheries Economics and Planning VIFEP.

To promote sustainable aquaculturedevelopment, the Government ofVietnam and the Danish InternationalDevelopment Agency (DANIDA)are supporting the development offreshwater, brackishwater and marineaquaculture in Vietnam through theFisheries Sector Programme Support(FSPS). A key objective of FSPS isto strengthen the capacity of localauthorities to carry out multidisciplinaryplanning and to implement longenduring and adjustable plans.Supporting this, the FSPS component,Support to Freshwater Aquaculture(SUFA) funded a consultancy in the fallof 2004 to pilot freshwater aquacultureplanning in Can Loc district.

Can Loc district of Ha Tinh province,330 km south of Hanoi, has anabundance of water resources includingreservoirs and rivers. The total fresh-

water production in the district increasedfrom 162 to 446 tonnes between 2000and 2003. Pond and rice-fish grow-outare the most common aquaculturesystems. The major culture speciesinclude mud carp (Cirrhinus molitorella),common carp (Cyprinus carpio), silvercarp (Hypophthalmichthys molitrix) andgrass carp (Ctenopharyngodon idellus).Higher value species, including mono-sex tilapia (Oreochromis niloticus),freshwater pomfret (Colossomaspp.),improved common carp, frog (Ranaspp.) and soft shelled turtles (Trionyx

sinensis) are also cultured on a limitedscale.

The output from the consultancy in CanLoc is summarised here, to give readersan understanding of the challenges ofsustainable aquaculture planning inVietnam.

The requirement for external supportfor planning comes from the needto implement policies in a rapidlydeveloping, but minimally controlledfreshwater aquaculture sector. In the

southern provinces, which provide mostaquaculture production, poorly plannedfreshwater aquaculture development

has created extensive environmentalproblems, uncontrolled productionand difficulties in meeting quality andfood safety standards (MRC Technicalpaper 7, 2002; FAO, 2004). Increasingfish prices and the expectation of rapidprofits are attracting various groupsof people with reasonable or insuf-ficient aquaculture production skills.Unplanned and unskilled production isimposing socio-economic vulnerabilityupon the sector, which is at risk fromrapid market fluctuations, resourcescarcity and pollution problems (FAO,2004).

Such unsustainable development canbe prevented if development is carefullyplanned and monitored. However, topursue the overall objective of sustain-able development, it is necessary thatdecision makers agree on specificand measurable strategies. To define

adequate and realistic actions for theimplementation of a plan, a thoroughunderstanding is required of: 1)multidisciplinary causalities behind keyconstraints and opportunities within theexisting local freshwater aquaculturesector and 2) a clear definition of thedecision makers objectives and theirtentative plans for meeting set targets.

Development of

planning guidelines

An external consultant was used tofacilitate the planning process in CanLoc because specific and targeteddirections for implementation ofplanning objectives is a new experiencefor many provincial and district levelgovernment staff in Vietnam. Some ofthe challenges typically encounteredby freshwater aquaculture plannersworking in Vietnamese provinces anddistricts include:

There is little tradition of cooperation

across government institutions(ministries and departments).

Participation of the local communityand farmers in aquaculture planningis limited.

Existing aquaculture sector dataneeds updating and correlation, toprovide both statistical and qualita-tive information.

Multidisciplinary teams need tobe trained for and involved in theplanning process.

Key staff lack awareness and trainingin Environmental Impact Assess-ments (EIAs).

Planning is frequently reactive,i.e. the need for planning is onlyrecognized after the developmentof environmental or socio-economicproblems.

Sustainable and feasible aquacultureplanning is constrained by a lack offunding.

There is little experience of coor-dinating aquaculture planning withdevelopment in other sectors.

There is a need for specializedtraining of personnel in localgovernmental institutions to meetthe demands of multi-disciplinary,participatory and scenario basedplanning.

The development of the planningguidelines in Can Loc district wasconducted in close corporation with thelocal authorities and local stakeholders.Information needed to formulate theplanning guidelines was collectedthrough a series of participatoryworkshops, interviews, meetings, ques-tionnaire surveys (140 households),scenario assessments, and statisticaldata collection at commune, districtand province level. The following keyprinciples were used throughout when

conducting the planning process:


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4 Aquaculture Asia Magazine

ustainable aquaculture

2. Cross sector involvement ofstakeholders

A multi-disciplinary approach callsfor cross sectoral involvement ofstakeholders. Planning at district and/orprovincial level should include decisionmakers in government management

institutions (agriculture and fisheries,planning and environmental manage-ment), local decision making authorities(Peoples Committees), aquaculturespecialists, farmers, irrigation compa-nies, hatcheries, private aquacultureenterprises, mass organization likethe Farmers Association, the financialsector (e.g. banks), fish traders etc.Different stakeholders have varyingdegrees of influence, but all contributeto the planners understanding of localconstraints and the possibilities foraquaculture development as well as tothe implementation of the plan.

3. The use of external facilitator

Planning for sustainable freshwateraquaculture using a multidisciplinaryapproach is a relatively new experienceto Vietnamese decision makers atprovincial or district level. The limitednumber of technical staff at the locallevels can not be expected to possessthe capacities and skills needed for thistype of planning, as this capacity is only

needed at certain times. Furthermore,governmental institutions have littletradition of cooperating horizontally andinvolving private enterprises in decisionmaking. Being neutral, the externalfacilitator has the legitimacy to promotesuch cooperation and encourageextensive use of local institutional andeconomic potentials.

4. Establishing an AquaculturePlanning Steering Committee

(APSC)

The APSC, which is responsible forcoordinating the planning processand facilitating the data collection, isa cornerstone in the chosen planningapproach and a valuable institution forbuilding bridge between the externalfacilitator and the local stakeholdersaffected by the planning. Without the

APSC, the planners have little chanceof monitoring the process, implementingnew ideas and ensuring institutionalmemory once the external facilitatorleaves the process. There is a needto ensure that the stakeholders and

decision makers share a commonunderstanding of planning and areaware of their tasks, responsibilities and

mutual commitments. The membersof the committee should represent keystakeholders (including farmers) butmust also be approved by the localgovernment authorities to ensurepolitical and financial support.

5. Integration of economic, social,

environmental and production/technical factors

The multi-disciplinary approach requiresthat planners correlate economic, socialand environmental factors and pointout the importance of each of these inmeeting the development objectives.The planners must balance the needfor information with the human andeconomic capacity of responsibleinstitutions at the local level. Collectionof data should relate closely with thework of analysing and incorporating newinformation in decision making. Thismay also be a new experience to localmanagers.

6. Correlation of objectives at alllevels of decision making

The point of origin in freshwater aqua-culture planning is to investigate andidentify the objectives of key decisionmakers at all levels of society: national,provincial, district, commune andindividual levels. This includes formal

documents and qualitative informationgathered through workshops, question-naire, interviews, etc.

7. Detailed action plan forimplementation

There is a need for a detailed actionstrategy for how and when to imple-ment a plan. This strategy shouldbe approved by all stakeholders andcontain details on activities to be carriedout, stakeholder involvement, respon-sibility and resource/budget allocation

for specific activities. This principleseems straight forward. However, lackof a realistic and feasible implementa-tion strategy is a common reason fornon-successful aquaculture planning.

8. Continuous monitoring andadaptation of the plan

The aquaculture environment isdynamic and connected with othersectors (agriculture, forestry, industry,tourism, and infrastructure). Even theplanning process itself influences and

changes the circumstances. This callsfor close monitoring and evaluation ofthe plan to ensure that objectives are

1. Peoples participation.

2. Cross sectoral involvement of keystakeholders.

3. The use of an external facilitatorthroughout the planning process.

4. Establish Aquaculture PlanningSteering Committee.

5. Integration of economic, social,environmental and production/tech-nical factors.

6. Correlation of objectives at alllevels of decision making (national,provincial, district, commune andfarmers).

7. Detailed action plan for implementa-tion

8. A process of continuous monitoringand adaptation of the plan.

9. Use of scenarios as a pointer forplanning rather than for prediction ofdevelopment (i.e. precautionary use).

10. Simple realizable district/provinceplanning guidelines, needing onlylimited outside input.

1. Peoples participation

The primary goal of the planningprocess was to ensure peoplesparticipation. The planning of freshwateraquaculture includes great uncertaintyas the natural systems and socio-economic structures are extremelycomplex and the interactions betweenthem are seldom fully understood. Andeven if they are understood locally theycannot be generalized across differentregions. In addition, the social andformal interaction between resourceusers and stakeholders, including

government authorities, marketagents, seed producers, extensionworkers, external advisers etc. maydiffer considerably from one district toanother. The deficiencies of simplifiedand generalised solutions in complexsocial and environmental contextsnecessitate the use of planning toolsthat provide dynamic and detailedsolutions which can be adapted to localcomplexities.


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to understand how to link farmers to theproduction chain, how to produce highquality and safe products, and how tohave on-farm management practicesthat are highly efficient, taking accountof the surrounding environment andsocial issues related to production.

A further factor is the trend towards

traceability, certification, and improvedfarm management which are drivingcosts and responsibilities down themarket chain to the farmer.

These global trends require changesin management of both large andsmall scale-farms to stay competitive.Whereas some larger farms with largeproduct volumes and access to financeusually have the capacity to adapt,and benefit from such trends, thereare still many uncertainties related tothe influence of such trends on small-scale aquaculture producers and theiradaptation and participation in modernaquaculture production and marketchains.

Certification in

aquaculture

Certification is rapidly being introducedto aquaculture, including mandatoryand voluntary schemes. There are

already a number of voluntary schemesemerging and the number of certificationprograms and labels for aquacultureproducts is expanding. Developmentand implementation of certificationschemes is considered as one tool tohelp towards a more sustainable aqua-culture production and at the same timelink and inform different stakeholders inthe production chain (Anon, 2007).

At the same time, the trends towardscertification risk disadvantagingsmall-scale aquaculture farmers

unless positive actions are takento involve small-scale farmers anddevelop focused strategies to ensuretheir participation. Surprisingly, nocertification scheme as yet targets thesmall-scale sector, but there could besignificant social and economic benefitsif the small-scale sector can be effec-tively serviced to participate in modernmarket chains. Some of the constraintsthe small-scale aquaculture sector facesrelated to certification include:

Small volumes of product from

individual farms and large numbers.

Low or no market incentives as yet tobecome involved in certification.

Complex marketing channels makingtraceability difficult.

Limited access to market, technicaland business knowledge and related

infrastructure.

Limited or inequitable access tofinancial services for investment inchanges that may be required forcertification.

Farms may not be formally registeredand may not be organized intoproducers groups.

Traders-credit relations.

May not be producing an exportproduct, and therefore producing toleast cost to sell within a less wealthydomestic market.

Commercial/government servicingless oriented towards the small-scalefarmer.

Risk management strategies oflarger traders and buyers, requiringlarge volumes of product, workingagainst small-scale farmersproducing small quantities of product.

The above issues need to beaddressed. It is a matter of greatimportance to the industry and to alarge number of people who dependon aquaculture as their main livelihoodto engage small-scale farmers in thedevelopment of certification schemes,to ensure equitable participation. Thereis a need to better understand theprocess, standards, their applicability,and the opportunities and challengesfor small-scale farmers to benefit fromcertification systems.

It is unlikely in the near future thatmany individual small-scale farmscan be easily certified, but one wayforward may be to promote groupcertification or certification of clustersof small-scale farmers, that has beenused successfully in other agriculturesectors (e.g. organic products, IFOAM,undated). The nature of small-scalefarmers is that they only produce smallquantities of their product, making itdifficult and inconvenient for largerbuyers that prefer larger volumes. The

need for solutions to allow small-scale

farmers to participate in market chainsrequiring certified aquaculture productsis therefore evident.

Example from India

As a part of a technical collaboration

between the Marine Products Exportand Development Authority (MPEDA)and NACA, on shrimp disease controland coastal management in India, avillage demonstration program wasconducted from 2002 onwards. Theobjectives of the program were:

To reduce the risk of diseaseoutbreaks and improve shrimp farmproduction

To organize the farmers under SelfHelp Groups / Aquaclubs forsustainable production

To produce better quality shrimps insocially acceptable, environmentallysound and economically viablemanner.

The program was successful inimproving organization of thesmall-scale sector and reduced risks,with nearly 800 shrimp farmers nowparticipating, across all of Indias shrimpaquaculture producing states. Key

elements of success include:

The development of locally-appropriate Better managementpractices (BMPs) formulated withfarmers, based on a science-basedepidemiological study of shrimpdisease risks and the InternationalPrinciples for Responsible ShrimpFarming (MPEDA/NACA, 2003 andFAO/NACA/UNEP/WB/WWF, 2006)

Support to formation of farmerclubs (so-called Aquaclubs) within

villages, and within clusters offarmers. Clusters were defined asa group of inter-dependent shrimpponds, often situated in a specifiedgeographical locality and dependenton the same water source

One of the most significant outcomesof this project is the reduction indisease prevalence and improvedfarm profitability as a result of BMPimplementation in Aquaclub farms.Successful implementation of BMPsreduced disease prevalence and

increased the number of planned(normal) harvests leading to bettercrop outcomes, improved efficiency


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are many opportunities for assistanceand investment. Ideas and partnershipare certainly welcome!

References

Anon (2007) Aquaculture Certification: A

Programme for implementing the recom-

mendation of the Committee on Fisheries

Sub-Committee on Aquaculture. Concept paper

prepared for the FAO/NACA Expert Workshop

The successful development of backyard hatcheries forcrustaceans in Thailand

Hassanai Kongkeo, Michael B. New and Naruepon Sukumasavin

1. Technical Assistant to DG, Network of Aquaculture Centres in Asia-Pacific, 2. Chairman, Aquaculture without Frontiers,

3. Head, Technical Group, Inland Fisheries Research and Development Bureau, Department of Fisheries, Thailand.

One of the important milestones infreshwater prawn farming occurred inthe late 1970s when the United NationsDevelopment Programme decided tofund a three-year FAO-executed project,named Expansion of Freshwater PrawnFarming, in Thailand (New, 2000).This project built on the earlier workof the Thai Department of Fisheries(DOF), led by Somsak Singholka andhis team at the Chacheongsao CoastalFisheries Research and Development

Centre (former Chacheongsao FisheriesStation) in Bangpakong, ChacheongsaoProvince. At first it was assisted by oneof the pioneers of global Macrobrachiumculture, Takuji Fujimura, together withvisiting FAO project manager, Herminio

Rabanal. Michael New was appointedby FAO in 1979 and he and SomsakSingholka co-managed this project until1981, after which the Thai governmentcontinued this initiative. As a result ofthese efforts, farmed freshwater prawnproduction expanded from less than 5t/yr before the project began (1976) toan estimated 400 t by the time it endedin 1981 (Boonyaratpalin & Vorasayan1983). Soon afterwards (1984), the DOFwas reporting to FAO that Thai produc-

tion had exceeded 3,000 t/yr (FAO1989), a very rapid expansion indeed.

This DOF-FAO project not only enabledthe establishment of a significantaquaculture sector in Thailand but also

benefited the development of freshwaterprawn farming globally. One output wasthe publication of a technical manual onthe topic (New & Singholka, 1985; New,2002) that was translated into manylanguages. In addition, the Thai Depart-ment of Fisheries hosted Giant Prawn1980, the first international aquacultureconference ever held in Thailand (New1982), which was attended by 159international participants from 33 coun-tries and 200 local farmers. Many Thai

experts later advised Macrobrachiumprojects and ventures elsewhere in Asia.By 2005, the aquaculture production ofMacrobrachium rosenbergiiin Thailandhad risen to 30,000 t/yr (valued at US$79 million) and to more than 205,000t/yr globally (FAO, 2007). In addition,a similar quantity of a related species,M. nipponense, was produced in Chinain 2007. In total, the global farm-gatevalue of freshwater prawn farming hadreached almost US$ 1.84 billion/yr by2007.

Though there was no seawateravaiable, the Bangkok Marine Labora-tory which has now been allocatedby DOF to the Bangkok Fish Market,successfully cultured to post-larvaestage Penaeus merguiensis, P. semi-sulcatus, P. latissulcatus, Metapenaeusmonocerosand M. intermediusin1972 (Cook 1973). Seawater had to bebrought from offshore by boat. All gravidfemale shrimp were captured in theGulf of Thailand. Experiments on pondculture of artificially bred seed werecarried out at private shrimp farms in

Samutsakorn Province and Bangpoo,Samutprakarn Province but the resultswere not satisfactory.

on Development of Guidelines for Aquaculture

Certification-27-31 March 2007. FAO and

NACA, Bangkok, Thailand. www.enaca.

org/certification.

FAO/NACA/UNEP/WB/WWF.2006. International

Principles for Responsible Shrimp Farming.

Network of Aquaculture Centres in Asia-Pacific

(NACA). Bangkok, Thailand, 20pp.

IFOAM. Undated. Smallholder Group Certification

Producers. Internal Control Systems for

Group Certification Training Kit for Producers.

International Federation of Organic Agriculture

Movement.

MPEDA/NACA. 2003. Shrimp health management:

Extension manual. Marine Products Export

Development Authority (MPEDA), Cochin,

India and Network of Aquaculture Centres in

Asia-Pacific (NACA). Bangkok, Thailand.

Concrete tanks for nursing PL.


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9January-March 2008

Sustainable aquaculture

In 1973, the Phuket Coastal FisheriesResearch and Development Centre(former Phuket Marine FisheriesStation) sucessfully bred P. monodonby induced spawning from broodstockcaught from Andaman Sea. Postlarvaeof the early batches were stocked insemi-intensive ponds in Bangkrachai,

Chantaburi Province, Klongdaan,Samutprakarn Province and Klong-sahakorn, Samutsakorn Province.This brought shrimp farming the muchneeded technique that enabled thefarmers to have better control of theircrop and sustainable production,instead of reliance only on wild seed forstocking as an extensive culture system.This important research later led to thehighest peak of P. monodonproductionof 304,988 mt in 2000 (Kongkeo, 2006)before substitution by P. vannamei.

Hatchery production of

crustacean postlarvae

The major extension thrust in theDOF-FAO project was the provisionnot only of technical advice but also offree M. rosenbergiipostlarvae (PL) forstocking the initial grow-out operationson each farm. Freshwater prawnswere distributed by road and rail allover Thailand. Large quantities of PL

were produced for this purpose in aseries of huge concrete tanks sited atthe fisheries station in Bangpakong.However, many of its technical staffalso began to produce PL successfullyin other, less conventional and smallercontainers, such as the klong potsused for storing potable water. Beforelong, some of the stilted houses onthe site had small production unitsunderneath their living quarters. Evennon-scientific staff learned the neces-sary techniques quickly. Soon, thefirst commercial backyard hatcheries

began to spring up in nearby areas ofChacheongsao Province. One of thereasons why these backyard hatcherieswere to prove so successful was theability of Thai entrepreneurs to followchanging market requirements. Unlike

the massive species-specific hatcheriesthat were set up in the 1970s and 1980sfor fish and crustacean species else-where, which were almost impossible tomodify, many of these simple backyardhatcheries could easily and cheaplyadapt themselves to produce marineshrimp PL (P. monodon) and seabassfingerlings (Lates calcarifer) accordingto demand.

Backyard hatcheies are generallymanaged with simple but efficienttechnology mainly by farmers with littleeducation. The technology which wasoriginally developed for M. rosenbergii,can easily be switched to P. monodon,P. vannameior nursery of seabass andgrouper fingerling if prices of existingspecies drop or disease problemsoccur. The initial investment for land,construction and equipment, as well asoperation costs, is very low because ofthe simple techniques used. Fortunately,Thai farmers have had a long experi-

ence and tradition of aquaculture andcrop production. They are also enthu-siastic to learn and practise advancedtechnologies which have beensuccessfully done on a research scalein government institutions or by largescale entrepreneurs. They always havenew ideas for development or modifica-tion to suit with local conditions andare eager to experiment on their own.Sometime, they start to experiment onnew culture techniques by themselvesand learn by mistakes from the results.The present success of Thailand in

shrimp and prawn industry is testimonyto the persistence and ingenuity of Thaifarmers in utilising applied science to its

utmost potential. It is a good exampleof blending research work done bygovernment with farmers enthusiasm inadoption of new technology.

Due to the long distance of hatcheriesfrom the sea, hypersaline water fromsalt farms is transported by truck andsubsequently diluted to the desiredsalinity with disinfected freshwater. Thishypersaline water is pathogen-free and

virus carrier-free due to its high salinity.These hatcheries purchase P. monodonor P. vannameinauplii from naupliiproducers who are located near theopen sea areas for better water qualityand circulation needed in the maturationprocess. For Macrobrachium, hatcheryoperators use spawners both fromgrow-out farms and from the wild. Smallhatcheries run by owners and familiesare more efficient than big hatcherieswhich are run by paid workers due tosense of belonging. The decrease inprice of shrimp fry caused by the spread

of these backyard hatcheries alsohelped to stimulate the rapid expansionof grow-out ponds.

When problems occur, productioncan be discontinued, even for a longperiods, without undue expense.This family business is in contrast tolarge scale sophisticated hatcheries,in which the cost of wages, powersupply, supporting facilities and otheroverheads still has to be borne duringthe closure. Periodic discontinuationof operations is, in fact, necessary for

both hatchery and grow-out in order


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Hypselobarbus

pulchellus**

An endangered medium carp ofpeninsular India, commonly calledpeninsular carp. It is distributed inthe peninsular rivers including the

Krishna, Godavari and Tungabhadra.It is a herbivorous fish and changesits feeding habits depending up onthe availability of food. It feeds on softvegetation preferably Vallisneria. Thefish attains sexual maturity at the end offirst year when it grows to about 17-25cm. It is a post-monsoon breeder andthe breeding season is from July toNovember. It is reported that it can growup to 6 kg in nature. Some attemptshave been made to culture this speciesat the Peninsula Aquaculture Division ofCentral Institute of Freshwater Aquacul-ture, Hessarghata, Bangalore.

Thynnichthys sandkhol

It is a medium carp and resemblesas silver carp. It is commonly calledas sandkhol carp. It is distributed inthe Krishna, Godavari, Tungabhdraand Mahanadi River systems in India.It is a column-cum-surface feederand a planktophagus fish. The fishattains sexual maturity in first year at

30 cm in length and 500 g in weight.It is a monsoon breeder and breedsonce per year and does not breed inconfinement. The fecundity of the fishis about 125,000/kg body weight. Theinitial growth rate of the fish is fast and itcan grow to 0.9-1.4 kg in 9-12 months.

Although a potential culture species, noattempt has been made to breed andculture on a commercial scale.

Prospects of culturing

the alternate carpspecies:

Except for Cirrhinus rebaandPuntius sarana, all other speciesdescribed are hardy in nature.

Many of the minor and medium carpsfetch better prices than the Indianmajor carps in different parts of thecountry.

They are high fecund fish.

The initial growth rate of many minorand medium carps is fast, beingadvantageous in short durationculture in seasonal water bodies.

The marketable size of the fish issmall (100-300 g) compared to700-800 g in major carps.

Many have prolonged breedingseasons.

Compatible to Indian major carps forcomposite fish culture.

Suitable for integrated fish culturesystems (rice-fish, poultry-fish,pig-fish, cattle-fish, etc.).

Can be cultured in low water depth,as they are hardy.

Two crops/year can be easilyharvested.

Suitable for high stocking densityculture.

They can be cultured in pens andcages.

Most of them are omnivores/herbiv-ores and can easily digest theplant protein source. Therefore, thedifferent plant based agro-industry

by-products, which are rich in proteinand are abundantly available in ourcountry, can be used for low-costfeed formulation of these species.

Can be easily domesticated to thepond environment.

They are easily adaptable to artificialfeed.

Some of the species likeB. gonionotusmay be cultured ininland-saline areas of the country,

as it can tolerate up to 8 ppt salinewater.

As they are suitable for shortduration culture, farmer can gethis returns in a shorter duration ascompared to Indian major carps.

Problems in culturing the alternatecarp species:

Most of these carps grow slow after4-5 months of culture and are noteconomical for long duration culture.

Most the minor and medium carpslay eggs that are small in sizeand are transparent, posing someproblem for commercial seed produc-tion.

Although the fecundity of the fish ishigh, the survival rate of larvae is low

under natural conditions.

Suggestions for culture expansion ofalternate carp species:

Exploratory survey are required toknow the present status of thesecarp species in different freshwatersystems of the country.

Recording of catch statistics of thesefishes is required as a priority.

Detailed study on the biology andbreeding behaviours of those specieson which such information is lackingshould be taken up.

Seed production technology mustbe standardized to provide sufficientseeds to the farmers desirous ofculturing these species on commer-cial scale.

Standardization of culture techniquesof these valued species is essentialfor encouraging farmers to take up

culture of hitherto new but economi-cally important species.

Research on low-cost feedformulation for these species needsimmediate attention, as no attemptshas been made so far.

Farmers should be encouraged totake up the culture of small andmedium carp in the form of mono-culture or composite fish culture.

Horizontal expansion for the culture

of these species are required,covering both season and perennialwater bodies which are unutilized atpresent.

More research and development isrequired to improve the growth offish through hybridization or geneticimprovement.

** = Puntius pulchellus.


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17January-March 2008

Genetics & biodiversity

Developing biotechnology capabilitiesby government and industry will provideclear triple bottom line benefits whichare;

1. Economic; through the develop-ment of the Murray cod aquacultureindustry and sustaining Murray cod

recreational fisheries;2. Environmental; from using micros-

atellite markers to help understandbiodiversity in Murray cod popula-tions, and;

3. Social; through enhanced geneticmanagement of wild populations forconservation and recreation.

Project progress

Selective breeding

Currently, approximately 4,600 fishfrom 40 genetically diverse families(1st generation stock) of Murraycod, obtained from two governmenthatcheries and three private hatcheriesover two different breeding seasons,have been established in custom builtrecirculating aquaculture systems tocreate the founder population. An addi-tional 20 families will be obtained duringthe current breeding season to boostdiversity of the founder population.These fish, once mature will provide agenepool from which new broodstock

possessing traits of interest will be usedto breed new domesticated strains ofMurray cod selected for high perform-ance (growth etc.) in aquaculture. Somefish are now reaching maturity and willbe ready to spawn for the first time in2008.

An industry survey of fish farmers andfish retailers indicated that importanttraits of interest for the aquacultureof Murray cod included fast growth,hardiness (eg. stress resistance anddisease resistance) and survival during

production, while at market, fish size,skin colour and flesh texture (amongstothers) were important. Retailers preferlarger fish (>2 kg), and lighter colouredfish, typical of those caught from thewild, over darker coloured fish. Thisinformation will be used to guide theselective breeding program for Murraycod.

In order to link the microsatellitemarkers to the aquaculture traits ofinterest, fish from four families of knownparentage were combined at three

weeks of age and communally-reared.At eight months of age these fish wereimplanted with microchips (Trovan Pty

Ltd, Australia) to identify individuals,and a tissue sample was collected fromeach fish for DNA analysis. Subsequentmeasurement of these fish showed thata number of important traits were quitevariable within and between families.Fish from one family in particular(Sp5) grew faster (Figure 2) and moresurvived than in the other three families.

At 14 months of age, weight ranged

from 57g to 886g. Researchers alsoobserved considerable differences infish condition and skin colour (Figure 3).

We have successfully amplified 103microsatellites in Murray cod, of which101 were polymorphic and two weremonomorphic (Rourke et al. 2007b).Excluding the monomorphic loci, thenumber of alleles per locus rangedfrom two to 19 alleles per locus (meanseven alleles per locus). The expectedheterozygosities ranged from 0.066 to0.95 (mean 0.64), and most loci were in

Hardy-Weinberg equilibrium. These newloci have been used for the identificationof quantitative trait loci to improve theproductivity of cultured Murray cod,and to assess wild and hatchery stockstructure of Murray cod for managementpurposes. A genetic map for Murraycod is currently being developed andanalysed for the four communallyreared Murray cod families. So far, 20linkage groups, with between two andseven markers per group, have beenidentified. Cross-amplification of the locideveloped for Murray cod was tested

on 19 other species of fish. Within thePercichthyidae, 79-94% of loci crossed-amplified in three other Maccullochella

species and 18-38% four Macquariaspecies (Rourke et al. 2007). Theseresults make this set of microsatellitemarkers an extremely useful resourcefor future genetic studies of percich-thyids.

A subset of microsatellite markershave been successfully linked to anumber of important aquaculture traits,

including growth (weight at measure-ment and specific growth rate), skincolour, fish condition and carcass fatcontent (Figure 1). However, analysesperformed on the surviving fish foundno evidence of any of the DNA markersbeing inherited with the survival trait.Nevertheless, this information can nowbe used to select broodstock with thesetraits to produce new, high performingstrains of fish for the aquacultureindustry.

Reproduction

Research into the controlled reproduc-tion of Murray cod is being conductedon a group of mature broodfish heldin a recirculating aquaculture systemunder an artificial photo-thermal regime.These fish were successfully inducedto spawn outside their normal breedingseason by manipulating the temperatureand light regimes in the recirculatingaquaculture system and hormone-induction of ovulation (Figure 4). In2004, when the first spawning trialswere conducted, 90% of fish injected

with hormone (HCG) ovulated and werestripped, but hatch rates averaged3%, and were substantially lower than

Figure 2. Growth of four families of Murray cod reared communally (lines =mean values), and frequency distribution of weight at four sampling dates(bars).

Sp5Sp6Sp7Sp9

Weight(g)

0

200

400

600

800

1000

Age (Days)

0 50 100 150 200 250 300 350 400 450 500 550


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enetics & biodiversity

hatch rates observed in natural pondspawnings at DPI, Snobs Creek (mean50%). However by the third year of trialshatch rates of up to 67% were obtained.Controlled breeding of this species willincrease the flexibility of the selectivebreeding program and enable greatercontrol over fish mating and seedstock

production.

Triploid fish (fish with three sets ofchromosomes) are desirable in aquacul-ture because they are generally sterile.Since no energy is spent in the develop-ment of gonads, these fish exhibit fastermuscle growth. Triploidy is also usedas a means of genetic containment byreduction of unwanted reproduction.Triploidy was induced in Murray cod byshocking eggs shortly after fertilisation.Eggs in some shock treatments failedto hatch while in other treatments hatchrates ranged from 100% ofcontrol (non-shocked) hatch rates.Heat and cold shocks failed to inducetriploidy, whereas some pressureshocks induced various levels oftriploidy (up to 100% in some replicates)(Figure 5). Further experiments are nowbeing conducted to refine techniques.

Hybrid fish are used in aquaculture toincrease growth (hybrid vigour), transferor combine desirable traits betweenspecies and reduce unwanted repro-

duction through production of sterileoffspring. Hybridisation was successfullyinduced in both direct and reciprocalcrosses between Murray cod and troutcod (Maccullochella macquariensis).Murray cod x trout cod hybrids, thoughrare, occur naturally in the wild whereboth species occur sympatrically. Asmall number of hybrids are currentlybeing reared to evaluate their aqua-culture performance (eg. growth andenvironmental tolerance) and ultimatelyto determine their fertility.

In collaboration with the Monash Insti-tute of Medical Research (Melbourne),we are investigating options for cryop-reserving sperm in liquid nitrogen as ameans of cost-effectively storing geneticmaterial for conservation and selectivebreeding programs (Figure 6). Trialshave identified cryoprotectant composi-tion and freezing methods for Murraycod sperm that provide high levels ofsperm motility post-thawing. In fertilisa-tion trials, we have achieved hatch ratesup of to 65% of the hatch rates for eggsfertilised with fresh sperm.

Figure 3. Variation communally reared Murray cod in size. (A) growthvariation within and between four families. (B) Skin colour. (C) Condition

(fattiness).

A

B

C

Genetic analyses of captive Murraycod broodstock and their offspring haveprovided insights into the previouslyunknown breeding habits of thisspecies. Murray cod are generally

believed to form monogamous pairsand breed once a year. In captivity,broodstock are allowed to spawnnaturally in ponds and during thebreeding season nesting boxes located


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Genetics & biodiversity

Figure 4. Hand-stripping Murray cod eggs.

in the broodstock ponds are regularlychecked for spawnings. However,parentage analysis of captive-spawnedoffspring has revealed that broodstockare occasionally polygynous with upto 17% of spawnings involving threeparents (mostly 1 male and 2 females).Some fish (both male and female)

spawned twice in a single season, andlarger males contributed more to spawn-ings than smaller males. These resultshave substantial implications for geneticmanagement of captive broodstockused in stock enhancement programs.

Early detection of sex is important inevaluating reproduction technologiesthat affect or manipulate sex. However,outside the breeding season Murraycod cannot be accurately sexed withoutapplying invasive techniques whilst

juveniles cannot be sexed at all. Wefound that testing for the presenceof vitellogenin (yolk protein) in bloodplasma, was a reliable method fornon-destructively identifying maturingand mature female Murray cod.

Population genetics

In order to determine the geneticstructure of contemporary wild Murraycod, tissue samples (finclips and fishscales) were obtained from 700 fishfrom 19 river catchments across MDB.

A historical collection of Murray codscales of 361 fish collected from sixsouthern river catchments between1948 and 1953 were compared againstcontemporary samples (post 1995) to

identify temporal changes in the geneticstructure of Murray cod in the southernpart of the MDB, and to identifypotential impacts of stock enhancementprograms, which commenced in theearly 1980s.

Genetic analysis of contemporary fish

samples revealed up six populationsacross the MDB. Fish from two rivercatchments (Lachlan and Macquarie-Bogan) each represent a discretegenetic cluster, while fish from threeothers (Border, Namoi and Gwydir)show a slightly lower degree of differen-tiation and evidence of restricted geneflow. Fish from other MDB catchmentsare apparently one large panmicticpopulation (Figure 7). These resultsindicate that the populations in riversflowing into the Murray River are highlyconnected, while those terminating inswamps and wetlands, (Lachlan andMacquarie-Bogan), are historicallyisolated.

Results of this study suggest thatstock enhancement practices havehad a mixed effect on the Murray codpopulations in the MDB. Temporalcomparisons between the historicaland contemporary samples from fivesouthern catchments showed limitedgenetic differentiation, indicating nochange in either genetic diversity or

structure in these catchments overthe past half century, despite thecommencement of stock enhancementin the 1980s. This is probably due tobroodstock being obtained primarily

Figure 5. Application of hydrostaticpressure to induce triploidy in Murraycod eggs.

within these southern catchments,which represent a single panmicticpopulation and continual replacement ofbroodstock in breeding programs withfresh stock from the wild. On the otherhand, there is evidence that stocked fishhave interbred with local populations intwo catchments (Macquarie-Bogan and

Gwydir), while one distinctive population(Lachlan) has retained its geneticuniqueness despite extensive stockingof fish into large impoundments withinthese catchments. These manmadebarriers may have prevented stockedfish from mixing with native strains inthe rivers downstream.

This is important information for thelong-term management of the geneticdiversity of wild populations of Murraycod. The data has shown that somepopulations are unique and need tobe managed accordingly. We are nowusing these data to develop a model toevaluate the effects of different breedingand stocking practices on the geneticdiversity of wild populations. Thismodel will assist fisheries managersto implement genetically sound stockenhancement programs.

Conclusions and future

work

Murray cod aquaculture is a newand developing industry that exhibitsefficient and profitable use of naturalresources (water and fish). This projecthas established an excellent foundationfor establishing a selective breedingprogram for the species (family linesand tools for selection). While no selec-


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enetics & biodiversity

tive breeding took place in the currentproject, due to the limited timeframe,the results from this work are the firststage of such a program. Now that agenetically diverse founder populationof broodstock has been establishedand microsatellite markers have beenlinked to favourable aquaculture traits,a proof-of-concept project will beundertaken to evaluate the performanceof selectively bred strains of Murray cod.In addition, discussions with potential

industry partners to commercialisethe breeding program have alreadycommenced.

Information from this project will assistfisheries managers in assuring thefuture of wild stocks, ensuring sustain-ability of aquatic resources and mainte-nance of biodiversity. The existence ofunique populations of Murray cod andare now being recognised and beingincorporated into management plans forthe species by some fisheries agencies.The microsatellite markers developed

for Murray cod are now being used byother researchers in population geneticsstudies of percichthyid species forconservation purposes.

Another achievement of this projecthas been the development of newcapabilities in fisheries and aquaculturegenetics and genomics within the DPI.These capabilities will be applied toother aquatic species for aquaculture(eg. selective breeding of bluemussels, Mytilusspp.), sustainablefisheries management (development of

genetically sound stock enhancementpractices for native species) and aquatic

Figure 6. Straws of Murray cod sperm being frozen in liquid nitrogen.

Figure 7. Potentially unique populations (management units) of Murray cod inthe Murray-Darling basin.

species conservation (eg. geneticstructure of stocked populations of theendangered trout cod).

References

FAO (2007). The State of World Fisheries and

Aquaculture 2006. FAO Fisheries and

Aquaculture Department, Food and Agriculture

Organization of the United Nations, Rome.

Foresti, F. (2000). Biotechnology and fish culture.

Hydrobiologia, 420, 45-47.

Hew, C.L. & Fletcher, G.L. (2001). The role

of aquatic biotechnology in aquaculture.

Aquaculture, 197, 191-204.

Ingram, B.A. (2007). Genetic and reproduction

technologies for enhanced production of Murray

cod Our Rural Landscape. Sustainable develop-

ment through innovation. Technical Note 17.

Department of Primary Industries, Melbourne.

4 pp.

Ingram, B.A. & De Silva, S.S. eds. (2004). Develop-

ment of Intensive Commercial Aquaculture

Production Technology for Murray cod. Final

Report to the Fisheries Research and Develop-

ment Corporation (Project No. 1999/328).

Primary Industries Research Victoria, DPI,

Alexandra, Victoria, Australia. 202 pp.

Ingram, B.A., De Silva, S.S. & Gooley, G.J. (2005a).

The Australian Murray cod - A new candidate

for intensive production systems. World

Aquaculture, 36, 37-43 and 69.

Ingram, B.A., Rourke, M.L., Lade, J., Taylor, A.C.

& Boyd, P. (2005b). Application of genetic and

reproduction technologies to Murray cod for

aquaculture and conservation In Management

of Murray cod in the Murray-Darling Basin.

Statement, recommendations and supporting

papers (Workshop held in Canberra, 3-4 June

2004) (Lintermans, M. & Phillips, B. eds.), pp.

107-109. Murray-Darling Basin Commission,

Canberra.

Melamed, P., Gong, Z.Y., Fletcher, G. & Hew,

C.L. (2002). The potential impact of modern

biotechnology on fish aquaculture. Aquaculture,

204, 255-269.

Rourke, M., McPartlan, H. & Ingram, B.A. (2007a).

Genetic technologies for the management

of natural Murray cod populations Our Rural


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esearch & farming techniques

Results showed that generally mostfarm managers are aware of theimportance of environmental issues anddisease prevention. All farms claimedto have stocked with post-larvae thathave tested negative for White SpotSyndrome Virus (WSSV). In terms ofdisease experience, four farms reported

to have been affected by WSSV, onefarm experienced Vibriodisease in theponds and six farms are free of anyshrimp disease (Table 1). The resultsof this case study are synthesized andgrouped into two components.

Disease management

Questions and observations regardingdisease management were focused onhow farm managers treated the wastewater, sludge, and dead shrimp fromponds that have been affected withdisease and post-harvest processes.Regardless of their experience withdisease, all farm managers reportedthat dead shrimp of commercial valuewere sold and smaller shrimps weredisposed off. Direct disposal of dead ordiseased shrimp is not a good practicebecause it can spread disease to othercrustaceans and neighbouring farms.Technical site observations revealedthat such practices were commonamong shrimp farmers. Horizontal

transmission of WSSV through waterand feeding of infected shrimps andmovement of infected live animalshave been known to be a probableroute for the spread of the disease(Mohan et al., 1997; Bondad-Reantasoet al. 2005). Farmers should be madeaware that disposing dead or infectedshrimp without treatment is not environ-ment-friendly and of the environmentalimplications of their practices and theirimpact on shrimp aquaculture itself.

Different procedures were applied for

treatment of waste water and effluent.Some farmers released waste waterwithout treatment, others dischargingit into nearby mangrove and estuary.One farm had tilapias and milkfish inthe settlement pond as biological filterand two farms kept discharge waterin settlement ponds for some timebefore releasing it to the open water.Farm managers related the importanceof water quality, the use of certifieddisease-free post-larvae, seed selectiontechniques, use of vitamins and probi-otics, and good nutritional management

as steps in health management andspecifically in reducing the chances ofdisease outbreak. It was encouraging to Sludge area.

note that even with certified disease freepost larvae, half of the farms observedstill go through post-larvae selectiontechnique.

This case study indicated that farmswith disease experience exhibited somepeculiarities. Since some of the farms

are situated in the same area, it is likelythat untreated water could have beenpumped into culture pond or reservoirponds. Disease outbreaks could verymuch be associated with the lack ofresponsible farm operations, especiallywaste disposal.

Six out of ten of the shrimp farmssurveyed were neighbours and sharedthe water source but results of inter-views indicated that not all managersinformed their neighbours when facedwith disease problems. This practicecould have negative impacts on theecosystem and the water source theyare sharing. WSSV could affect pondrapidly with mass mortalities and readilytransmitted disease from diseasedshrimp to healthy susceptible shrimp viacontaminated water (Rajan et al. 2000).Not informing the authorities and nearbyshrimp farms could give shrimp farmingan irresponsible and generally badreputation, and contribute to self-pollu-tion that escalates disease problems.

It was observed that the use of pet dogsfor security and preventing intruders isvery common in all shrimp farms. Oneshrimp farm employed contract securityguard on contract basis but only at theentrance gate. Pet dogs were observed

wondering freely around the shrimpponds and workers quarters. Thisshould not happen because dogs couldalso be a disease carrier, particularlywhen they wonder from one shrimpfarm to another. Investing resourcesto employ more contract securitypersonnel could add to the operation

cost but will be a worthy investment.Visitors and vehicles that enter thefarms are not subjected to any sanitarymeasures, which showed a lack ofbiosecurity and poor health manage-ment standard.

Managers reported that the use ofprobiotic base products and vitaminsare helpful for health management andto reducing disease risk by fortifyingnatural defences of the stock. Thereis are growing evidence that show theeffectiveness of probiotics in inhibitinga wide range of fish pathogens anddisease problems in shrimp farming(Moriarty, 1999; Rengpipat et al.,2000; Irianto and Austin, 2002). Thisis a good indication that shows somefarm managers are accepting newapproaches to health management.

Certified disease free post-larvae andpond preparation were recognizedas two of the most important stepsin disease prevention. All the farmsindicated that ponds were properly

dried and green water was preparedbefore stocking the post-larvae.Several measures had been applied inhealth management to reduce diseasewhich included post-larvae selection,specific pathogen free brooders,


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Research & farming techniques

Black thick soil formed as sludge. Out flow water canal.

Table 1: Farm Size, Disease Experience and Effluent Treatment

Farm size Disease experience Ef fluent treatment7 acres None Closed system, solid waste recycled into fertilizer.

7 acres None No treatment of waste water, sludge is left to dry at pond bottom.19 acres White spot disease Water is treated and kept in treatment pond before discharge. Sludge is

recycled, used as fertilizer.11 acres None No treatment of waste water, sludge is left to dry at pond bottom.30 acres White spot disease Discharge of water to nearby mangrove, drying of pond sludge.30 acres None No treatment of waste water, sludge is left to dry at pond bottom.40 acres White spot disease

Discharge of water to nearby estuary, sludge is kept in specific area in the farm.

50 acres None No treatment of waste water, sludge is flushed, ploughed and left to dry at pondbottom.

60 acres None Use of settlement pond, treatment of water before discharge, sludge is kept inspecified area, used as fertilizer after two years.

100 acres White spot disease Water is treated, kept in settlement pond with tilapias and milkfish as bio-filters,sludge is kept in specified area.

Site observation.Farm technician explaining feeding schedule.

closed systems, recirculation systems,probiotic application and some form ofbiosecurity (Donovan, 1997; Kongkeo,1997; Moriarty, 1999; Kautsky et al.,2000; Irianto and Austin, 2002; Mustafa,2004).

Training needs in health managementwere assessed to find out their technicalcapabilities in disease and effluent

management. Only four farm managerswere reported to have obtained formaltraining in disease management. Twoof them attended training conducted bythe Department of Fisheries Malaysiaand the other two attended trainingorganized By Charoen Pokphand (CP)group in Thailand. Other farm managersreported that they gained knowledge

through their own experience workingin different farms without attending anyformal training at all. It was reported thatthere is shortage of local experts andqualified personnel to assist them withshrimp disease. Farm managers arevery concerned about disease threatsand voiced their interest in attendingcourses for health management if


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Schering-Plough Global Aquaculture

Vaccination benefits highlighted as Schering-Plough reinforces

commitment to Asian aquaculture

A series of key aquaculture events andpresentations have confirmed Schering-Ploughs ever growing presence andsupport in S.E. Asia. Aquaculture iscontinuing to develop at a pace in theregion where the demand for Tilapiais especially strong. As producers lookto establish long-term and sustainableoperations, the focus on health manage-ment becomes crucial. Whilst thereturns are attractive, endemic diseaseis a factor in Asia as much as anywhereelse. Schering-Ploughs strategy is towork across all the major stakeholdergroups with education and technicalawareness programmes.

The company has a longstandingrelationship with The World AquacultureSociety (WAS) which hosted thisautumns key event, the WAS Asia

Pacific conference in Hanoi, Vietnam.The programme was very well attendedand attracted a wide group of localand visiting delegates. Amongst thekey speakers was Schering-Ploughs

leading immunology andfish vaccineexpert, Professor Patrick Smith who

presented a highly informative paperwhich summarised the global successesof fish vaccine programmes.

Professor Smith highlighted howvaccine programmes are now impactingfive key areas of world aquaculture.Sighting firstly pathology, he explainedhow the introduction of vaccineprogrammes had greatly reduceddisease threat and burden across awide spectrum of species. Welfare,

an issue of increasing global focuscorrespondingly benefits from improvedtools for disease prevention. Moving tothe environment he confirmed the clearadvantages of introducing vaccines toreplace the number of chemicals andantimicrobials that have historicallybeen required in disease control.The link between vaccination andnutrition, another key area in modernaquaculture, was highlighted withProfessor Smith explaining that throughimproved health and well formulateddiets farmed fish now have the ability

to grow and convert to a level nearertheir genetic potential. The fifth of thesecritical factors was that the benefits from

the other key areas provided a range ofsignificant commercial benefits rangingfrom improved cost of productionthrough to the capability to build andsustain fish farming operations withcontrol and confidence.

In addition to its exhibition stand whichwas continually busy, Schering-Ploughhosted a number of private customerconsultation sessions which enabledproducers to discuss their productionand health programmes one-to-onewith the companys technical and salesexperts. We have had very goodfeedback on these sessions at previousevents, explains Robin Wardle, Directorof marketing and technical serviceswith the company. The opportunity tounderstand the issues that are currentlyfacing operations in the area allowsus to develop a dialogue on suitablevaccination strategies. WAS Hanoi wasparticularly successful in this respectand we have made firm commitments tofollow up with specific visits to assist in

establishing the most effective vaccina-tion programmes to suit individualoperations, he confirmed.

Vaccination for Streptococcosis inTilapia is one specific area wherepreventive programmes are deliveringsignificant protection around the world.Schering-Plough Regional TechnicalManager, Aries Madethen presented atechnical paper reporting on recent trialsconducted in Latin America and Asiausing the companys AquaVac Garvetil*and AquaVac Garvetil* Oral vaccines as

part of the companys Total ProtectionStrategy, a tailored programme toprevent disease through appropriatevaccination.

The trials demonstrate that AquaVacGarvetil, and AquaVac GarvetilOral vaccines are safe and highlyeffective for use in Tilapia. They alsodemonstrated significant improvementsin survival when the fish are exposed toa natural challenge. Added benefits inincreased feed efficiency and the qualityof production were also identified.

This theme continued at Tilapia 2007 inKuala Lumpur, Malaysia later in Augustwhere producers again registeredan increasing interest in developingvaccination programmes. Robin Wardlesees Schering-Ploughs involvementincreasing, Our commitment is tocontinue to develop relationshipswith producers in the region and inaddition to supplying vaccines we lookto build and support long-term healthprogrammes to help take their busi-nesses forward.

Producers or vets looking to establishAquaVac vaccine programmes orseeking further information on Schering-Plough Aquaculture products shouldcontact Schering-Plough Aquacultureoffices on +44 1799 528 167, log on tohttp://www.spaquaculture.com/ or [email protected].

Schering-Plough is a global science-

based health care company with leading

prescription, consumer and animalhealth products. Through internal

research and collaborations with

partners, Schering-Plough discovers,

develops, manufactures and markets

advanced drug therapies to meetimportant medical needs. Schering-

Ploughs vision is to earn the trust of

the physicians, patients and customers

served by its approximately 33,500

people around the world. The company

is based in Kenilworth, N.J., and its Website is www.schering-plough.com.

* AquaVac and Garvetil are worldwidetrademarks of Schering-Plough Ltd. or

any affiliated company.

Article Copyright 2007 Schering-

Plough Animal Health Corporation. All

rights reserved.


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is best and the number of eggs andfertilization rate declines thereafter(Table 3).

Fertilization and incubation:Thestripped eggs are fertilized using milttaken from the male immediately by drymethod. The fertilized eggs washed in

1% salt solution for disinfection and thenwashed 3-4 times with fresh water. Thefertilized swollen eggs, after hardening,

ARE poured on screen-trays (33 cm 33 cm size) for incubation and loadedtrays are tied tightly in a stack andplaced in a glass-fiber Atkin's incubationapparatus for incubation, supplyingspring water regularly at the rate of1.5-2 l/minute. The water temperatureand dissolved oxygen recorded were20-22C and 4-5 mg/l, respectively andhatch within 90-125 hours (Table 4). Thehatching time is dependent on the watertemperature (Shrestha et al. 1990;FRC 1998/99; Baidhya et al. 2000;FRC 2001). It takes about 48-72 hoursto hatch at 26.5-31.0C (FRC 1994;1995). F2 generation sahar broodsare successfully bred from March toNovember at water temperature rangingfrom 19.0-30.0C (Gurung et al. 2001).However, frequent brood fish checkingis necessary preferably biweekly toavoid over-ripening.

Nursing and rearing:The yolk sac is

absorbed within 3-4 days after hatchingand then the larvae need natural foodor special artificial feed. Rotifer is anexcellent natural food for many marineand fresh water fish larvae (Fontain andRevera 1980).

Importance and prospect of saharculture industry:Sahar is veryimportant native riverine sport fish. Thedevelopment of its breeding technologyleads a very positive development withthe mass production of fingerlings,which can be stocked in the naturalwater bodies to maintain or increase

its population as well as to supportaquaculture industry. Sahar is verypopular and has a very high demandand sells for a higher price than othercultured carp species. The study hasshown that sahar culture is suitable inwarmer areas particularly in southernpart of Nepal, though the mid-hill regionis suitable a breeding area and for eggdevelopment with its cool temperatures.

Trans-Himalayan cold water fishhatchery:Among the trans-Himalayanfish, sahar (Torspp.), Katle (Neolis-socheilus hexagonolepis) and asla(Schizothoraxspp. and Schizotho-raichthysspp.) are very important andeconomically high value fish, whichare under study at FRCs, Trishuli andPokhara. These economically highvalue fish species have high demand inthe whole South Asia region. Successfulspawning of these species in captivecondition has been achieved althoughit needs further more detail studies tostandardize the technique. There areother economically high value indig-

enousfish species, which also deservestudy and to develop technology for

culture practices. In order to carryout studies and develop technology,facilities and human resources and therequired infrastructure developmentare essential. The basic facilities fortrans-Himalayan fish spawning have

Breeding was carried out continuouslybut achieved success partially atFRC Trisuli (FRC 1996; 1998/99).However since 2000, F2 sahar havebeen spawning naturally without use of

hormonal injections and without post-spawning mortality. Male sahar matureafter 2 years and release milt yearround but females reach maturity after3-5 years cultured in earthen pondsfeeding with 30-40% protein contentdiet. Based on few years data compila-tion on breeding activities of T. putitora,it can spawn up to nine months peryear from March to November withoutusing hormonal injection at preferablewater temperature between 19.5-33.0C (Gurung et al. 2001), whereasChaturavedi (1976) has reported that awater temperature between 21.5-23.5Cis preferable with more than 9.5 mg/l ofdissolved oxygen for sahar spawning.McDonald (1948) reported that mahseerspawn three times in a season, Desai(1994) noted mahseer breed from Julyto March and Pathani (1983) reportedsahar spawn at least four times basedon four types developmental stages ofeggs. Mahseer is a partial spawningand release low number of eggs duringsingle spawning event explained bymany authors (Joshi 1994; Shrestha

1997; Shrestha et al. 1990), however itneeds to examined more frequently toavoid over maturation of eggs. Shresthaet al. (1990) also stripped sahar threetimes but the third time obtained veryfew eggs and a very low fertilizationrate, suggesting that the first spawning

Brood fish Pituitary gland injection timeMale (kg) Female (kg) Feed fed for brood fish 1600 hrs 2200 hrs 1000 hrs

Ingredients Composition (%)

0.8 1.8 Rice bran 400.6 2.0 Wheat flour 20Corn flour 20Oil cake 20

Female(kg)1.8 1.08 mg (10%) 8.64 mg (80%) 1.08 mg (10%)2.0 1.20 mg (10%) 9.60 mg (80%) 1.20 mg (10%)Male(kg)0.8 4.80 mg (100%)0.60 3.40 mg (100%)

Date Time Stripping Released eggs (no.) Fertilized (no.) Survival (%)2/8/1988 17:00 1st 4,500 4,479 99.53/8/1988 10:30 2nd 2,000 1,945 97.3

3/8/1988 16:00 3rd 100 30 30Source: Shrestha et al. 1990

Table 3. Sahar (Tor putitora) fed with artificial feed and spawned using pituitary gland.

Status of sahar domesticationContinued from page 27.


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been well developed at the Pokhara andTrishuli Fisheries Research Centres andthe fish hatchery at Kaligandaki, whichserve the lakes/reservoirs in Pokharaand for rivers in Trisuli and Kaligadaki,respectively.

Among the trans-Himalayan fishspecies, sahar, katle and asla havebeen domesticated and are maintainedwith parental stock up to the F2generation, which are very convenientfor breeding. Therefore FRC Pokhara

has the potential to be developed asa Trans-Himalayan Cold Water FishHatchery Centre in for the South-Asianregion. The center will aim to study oftrans-Himalayan cold water fish specieson a regional basis with the coordinationand exchange and maximum involve-ment of different specialists in differentsubjects of the region and to developa complete technology package toenhance the culture industry in suitableplaces, particularly in mid-hill region,and to provide job opportunities as wellas to increase the economic status in

that region. The program will supportand conserve the diminishing stocks ofeconomically high value trans-Hima-layan fish species.

Conclusion

Sahar is a very important sport andhigh value riverine native fish species,which is highly preferred in the market.To increase its yield and conservethe declining population in naturalenvironment, breeding techniques

should be standardized for mass seedproduction as well as should developproper artificial feed for different stages.

Breeding studies have been carriedout regularly for a decade but there isstill need to standardize the techniquefor mass seed production due to itscomplex or partial spawning pattern.

References

Azadi, M.A., M. Shafi, M.A., Islam 1991. Studies on

the age and growth of mahseer Tor tor(Ham.)

from the Kaptal Lake Bangladesh. Journal of

Zoology 19:47-54.

Baidhya, A.P. and G.P. Lamsal 1996. Breeding ofmahseer Tor putitorain natural and artificial

condition. Annual Technical Report. NARC,

FRC, Pokhara, Nepal. 13-116.

Baidya, A. K., T.K. Gurung and B. Shrestha 2000.

Study on the propagation of sahar (Tor putitora)

in relation to hormones and nutrition manage-

ment. Annual Technical Report (1999-2000).

NARC, FRC, Pokhara, Kaski, Nepal. 44-49.

Baidya, A. P. and B. K. Shrestha 1997. On the

propagation and mass production of mahseer,

Tor putitora. Annual Technical Report. NARC,

FRC, Pokhara, Nepal. 56-58.

Bista, J. D. and O. Yamada 1996. Feed develop-

ment for rearing mahseer. Annual Technical

Report. NARC, FRC , Pokhara, Kaski, Nepal.

28-32.

Bista, J. D. and R. K. Shrestha 2000. Quantification

of Dietary protein requirement of sahar (Tor

putitora). NARC, FRC , Pokhara, Kaski, Nepal.

50-53.

Chaturvedi, S.K. 1976. Spawning histology of tor

mahaseer Tor tor(Ham.). J. Bombay Nat. Hist.

Soc. 73(1):63-73.

Das, P. and K. D. Joshi 1994. Mahaseer conserva-

tion present and future, P. Nautiyal (com. &

ed.) Mahaseer the Game Fish, D3-D9.

Day, F. 1958. The fishes of India: Being a natural

history of the fishes known to inhabit the seas

and fresh waters of India, Burma and Ceylon.

Vol (text), London. William Dawson and Sons

Ltd. London. 564 pp.

Desai, V.R. 1993. Studies on fishery and bilogy

of Tor tor(Ham.) from River Narmada. Proc.

Indian Nat. Soc. Acad 39:228-248.

Desai, V.R. 1994. Ecostatus of mahseer in river

Narmada (Madhya Pradesh). In Mahseer

the game fish Natural History, Status and

conservation practices in India and Nepal, ed

(P. Nautiyal), Rachna, Garhwal UP, India.

Dubey, G. P. 1985. Conservation of dying King

mahaseer the mighty game fish and its future

role in reservoir fisheries. Punjab Fisheries

Bulletin. Vol. IX No. 182.

Fontaine, C.T. and D.B. Revera. 1980. The mass

culture of rotifer, Brachionus plicatitisfor use as

food stuff in aquaculture. World Maricult. Soc.11:211-218.

FRC, 1993. Breeding techniques of sahar, katle and

asla. Annual Technical Report (July 16 1992 to

July 15 1993). NARC, FRC, Trisuli, Nuwakot,

Nepal. 29-33.

FRC, 1993. Feeding trials on sahar, katle and asla.

Annual Technical Report (July 16 1992 to July

15 1993). NARC, FRC, Trisuli, Nuwakot, Nepal.

34-46.

FRC, 1993. Study of local fish katle and mahaseer

in Raceway system. Annual Technical Report.

NARC, FRC, Pokhara, Nepal. 26-28.

Description 2000 200121 April 22 April 12 March 3 April

Water temp. (C) 22.0 22.0 20 21No. of Female 3 2 1 1

Average female weight (kg) 7.5 6.6 3.4 2.2Average. total length (cm) 80.0 75.0 74 69

No. of male 3 1 2 2Average male weight (kg) 7.5 6.0 4.0 5.5Time of stripping 10:00 16:00 10:30 10:45Total weight of eggs (g) 950 550 62 82Total no. of eggs 88350 50600 3348 13202Egg size (mm) 2.7 2.4 2.9 2.0Dissolved oxygen (mg/L) 4 -5 4 -5 4-5 4-5Fertility (%) 93-96 90-95 85 80Incubation period (hours) 90-115 90-110 120-125 120-125Total no. of hatchlings 57143 36836 2,500 8,800Mean hatchibility (%) >90 >80 73.9 66.6Size of hatchlings (mm) 7.0 -8.0 7.0 -8.0 7-8 7-8

Table 4. Breeding record of Sahar (Tor putitora).


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FRC, 1994. Breeding of mahseer and study of

the possibility for mass production. Annual

Technical Report. NARC, FRC, Pokhara, Nepal.

37-40.

FRC, 1995. Breeding of mahseer in natural and

artificial condition. Annual Technical Report.

NARC, FRC, Pokhara, Nepal. 16-19.

FRC, 1996. Growth and survival of golden mahseer.

Annual Technical Report (1995/96). NARC,

FRC, Trisuli, Nuwakot, Nepal. 6-11.

FRC, 1997. Growth and survival of golden mahseer.

Annual Technical Report (1995/96). NARC,

FRC, Trisuli, Nuwakot, Nepal. 6-11.

FRC, 1998/99. Spawning bahavior of sahar Tor

putitora. Annual Technical Report. NARC, FRC,

Trisuli, Nuwakot, Nepal. 16-20.

FRC, 2000. Domestication and spawning behavior

of sahar Tor putitora. Annual Technical Report.

NARC, FRC, Trisuli, Nuwakot, Nepal. 16-20.

FRC, 2001. Domestication and spawning behabior

of sahar Tor putitora. Annual Technical Report

(2000/01). NARC, FRC, Trisuli, Nuwakot,

Nepal. 21-26.

Gurung, T. B. and G.B.N. Pradhan 1994. Genetical

resources of sahar (Tor putitora, Ham.) in

Nepal. Fisheries Dev. Division, Dept. of

Agriculture, MOA, Nepal.

Gurung, T.B., A.K. Rai, P.L. Joshi, A. Nepal, A.Baidhya, J. Bista and S.R. Basnet. 2001.

Breeding of pond reared golden mahseer (Tor

putitora) in Pokhara, Nepal. Coldwater Fish

Species in the Trans-Himalayan Region, (10-14

July, 2001), Kathmandu, Nepal.

Joshi, C.B. 1994. Conservation of Tor putitora.

Hatchery Practices D15-D25. In Mahseer

the game fish Natural History, Status and

conservation practices in India and Nepal ed (P.

Nautiyal) Rachna, Garhwal UP, India.

Juyal, C.P. 19994. Food conservation efficiency of

Himalayan mahaseer, P. Nantiyal. Mahaseer-The game fish. Rachna, Srinagr, India:

D91-D97.

Kaushal, D.K., M.D. Pirolker and Y.R. Rao 1980.

Observation on the food habits of T. putitora

(Ham.) from Gobindasagar reservoir, Himanchal

Pradesh. J. Inland Fish. soc. India. 12(1).

Kulkarni, C.V. 1970 Spawning habits, eggs and

early development of Deccan Mahaseer Tor

khudree(Sykes). J. Bombay Nat. Hist. Soc. 67

(3): 510-521.

Kulkarni, C.V. 1980. Eggs and early development

of Tor tormahseer. J. Bam. Nat. Hist. Soc.

77:70-75.

Malhotra, A. 1982: Bionomics of hill stream

cyprinids. Food parasites and length weight

relationship of Garhwal Mahseer Tor tor(Ham.).

Proc. Indian Aced. Sci. (Anim. Sci) 92(6):493-

499.

Masuda, K. and K.R. Bastola 1984. Breeding of

sahar Tor putitorausing naturally matured

broods in Tadi river central Nepal. A report

submitted to the Fisheries Development

Division, HMG/ Nepal.

McDonald A. St. J. 1948. Circumventing the

mahseer and other sporting fish in India and

Burma. The Bombay Nat. Hist. Soc. 114(6):306.

Morimoto, N., Sakai. K. and Basnyet S. R. 1995.

Basic Research Study of Mahaseer (Tor

putitora) in Pokhara Fisheries Center, Nepal.

Negi, S. S. 1994. Himalayan fishes and fisheries,

carps or cyprinoids, 106.

Pathani, S.S. 1981. Fecundity of mahseer Tor

putitora. Proceeding of India, Academy of

Sciences 90:253-260.

Pathani, S.S. 1983. On the age and growth of

Mahaseer Tor tor(Ham.) by opercular bone.

Ind. J. Zool. 2(1):13- 19.

Rai, A.K., R.M. Mulmi, M.K. Shrestha, K. Bajra-

charya, N.K. Roy, S. Rai and R.P. Shrestha

2001. Growth study of sahar (Tor putitora)

and Freshwater Prawn (Macrobrachium

rosenbergii). Annual Technical Report, FisheriesResearch Division, Godawari, Nepal. 62-67 pp.

Samoon, M.H. 1994. Cultural feasibility of Deccan

mahaseer, Tor khudree (SYKES), P. Nautiyal.

Mahaseer-The game fish, Rachna, Srinagar,

India:D79-D84.

Shrestha, T.K. 1981. Fishing with open Wale Catch

Boat in Narayani River System. J.Nat.Hist.Mus.

5(1-4):99-104.

Shrestha, B. C., A. K. Rai, T. B. Gurung and K. Mori

1990. Successful artificial induced spawning

of Himalayan Mahaseer (Tor putitora, Ham.) inPokhara Valley, Nepal. The second Asian fish.

Forum. Asian Fish. Soc. 573-575.

Shrestha, B.C. and T.B. Gurung 1990. Declining

fishing of sahar (Torspp.) from lake Begnas,

Pokhara Nepal. Paper presented in National

Conference on Science and Technology 25-29

April, b1988, Kathmandu, Nepal. 1-8.

Shrestha, T.K. 1990. Behavior of mahseer Tor

putitorain nature and captivity. J. Freshwater

Biology 2(3):209-219.

Shrestha, J. 1991. Cold water Fish and Fisheries

of Nepal. Fish and Fisheries at higher altitudes,

Asia. FAO. Fisheries Technical Report 385.

Shrestha, T. K. 1994. Development of Mahaseer

culture towards ranching, P. Nautiyal (com. &

ed.) Mahaseer the Game Fish, D26-D41.

Shrestha, J. 1995: Enumeration of the Fishes

of Nepal. HMG/Govt. of the Netherlands,

Biodiversity Profiles Project, Technical Publica-

tion No 10, 64 pp.

Shrestha, T. K. 1997. Prospects of propagating the

Mahaseer in Phewa Lake of the Pokhara Valley,

The Mahaseer, 70-71.

Shrestha, T.K. 1997. The mahseer in the rivers

of Nepal distributed by dams and ranching

strategies. RK Printers, Teku, Kathmandu,

Nepal. 259 pp.

Swar D.B. and T.B. Gurung 1988. Introduction and

cage culture of exotic carps and their impact

on fish harvested in lake Begnas, Nepal.

Hydrobiologia 166:277-287.

Tripathi, Y.R. 1978. Artificial breeding of Tor putitora

(Ham.) J. Inland Fish. Soc. India 9:161.

Wagle, S.K. and J.D. Bista 1999. Catch efforts

and capture fishery in lakes of Pokhara valley.

Status and management perspective. Paper

presented in the 3rd National workshop on

livestock and fisheries held at Lumle on 21-23

June, 1999.

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Comparative advantage analysis of shrimpproduction in Asia

Yuan XinhuaFreshwater Fisheries Research Center, CAFS, No. 9 West Shanshui Road, Wuxi, Jiangsu, China. E-mail: [email protected].

Shrimp is a fisheries commodity of greatimportance in the international aquaticproduct trade, particularly to Asia andsome South American nations. Shrimpproducts are a universally popular foodcommodity consumed through out theglobe and rarely restricted by gender,age and religion etc. The USA anti-dumping case against Asian countrieshas brought about much public andgovernmental attention on the shrimpproduction sector and its internationaltrade.

In order to analyze the status of Asianshrimp production, and to promotesustainability of its trade, comparativeadvantage and competitivenessanalysis was undertaken. It is hopedthat such an analysis will be useful inunderstanding the current situation ofthe shrimp industry and its develop-ment, and will be helpful in making theshrimp production more efficient andviable.

General information

Asia has favorable natural resourcesfor shrimp production, with the coasts ofthe Pacific and Indian oceans providingadequate coastal resources. Theclimate of Asian countries is tropical orsubtropical. These favorable naturalconditions are suitable for shrimpproduction and development. Shrimpproduction includes production fromcapture and aquaculture and Asiancountries take advantage of both. Asia

is the most important shrimp producingregion of the world, particularly South-East Asia. In 2003, the cultured shrimpfrom Asia accounted for 85% of the totalworld cultured shrimp production.

Total shrimp production in the lastdecades has increased dramatically;the production has increased from 2.63million tonnes in 1990 to 5.329 milliontonnes in 2003. The top five shrimpproducing countries of the world areall Asian, ie. China, India, Indonesia,Thailand and Viet Nam (Table 1). China

had the highest share (36.5%) of worldshrimp production in 2003.

This article emanates from Yuan Xianhuas PhD thesis submitted to NanjingUniversity, PR China, and deals with trading aspects of the shrimp sectorwith special reference to Asia. Shrimp has proved to be the largest tradecommodity of aquatic products. In 2003, the total trade value of frozenshrimp and PUD shrimp was US$ 9.15 billion, and was about 14.8% of totalaquatic products trade. The export market price of shrimp from China wasthe lowest and that from Thailand the highest. Based on the available datamarket occupation ratio (MOR), the revealed comparative advantage (RCA)and normalized trade balance (NTB) for shrimp in the Asian countries werecalculated. Thailand had the largest MOR (21.9%) of the world shrimp market,followed by Indonesia, India, and China of 8.8%, 7.5% and 4.9%, respectively.

Among the Asian major shrimp producers, Bangladesh, China, India,Indonesia, Philippines, Thailand and Viet Nam have higher NTB (above 0.70).The RCA for Thailand, China, Indonesia and Philippines have significantlydecreased, whilst India and Viet Nam has retained the same level and forBangladesh the RCA increased since 1998.

Country Total production Composition of total productionCapture Aquaculture

Tonnes (x103) % Tonnes (x103) % Tonnes (x103) %China 1945 36.5 1452 74.7 493 25.3

India 517 9.7 404 78.1 113 21.9

Indonesia 457 8.6 266 58.2 191 41.8

Thailand 381 7.2 83 21.8 298 78.2

Viet Nam 310 5.8 78 25.2 232 74.8

USA 147 2.8 142 96.9 5 3.1

Greenland 142 2.7 142 100 0 0.0

Canada 121 2.3 121 100 0 0.0

Brazil 117 2.2 26 22.9 90 77.1

Mexico 100 1.9 54 54.1 46 45.9

Other 1092 20.3 755 69.14 337 30.86

Total 5329 100 3524 - 1805 -

Source: FAO, FishStat Plus (http://www.fao.org/figis)

Table 1. The worlds top 10 countries, in order, in shrimp production in 2003.

Country Aquaculture production(1,000 tonnes)

% of total worldaquaculture production

China 493 27.3Thailand 298 16.5Viet Nam 232 12.8Indonesia 191 10.6India 113 6.3Brazil 90 5.0Ecuador 57 3.2Bangladesh 57 3.1Mexico 46 2.5Philippines 37 2.1

Other 191 10.6Total 1805 100.0Source: FAO, FishStat Plus (http://www.fao.org/figis)

Table 2. Top 10 country of shrimp aquaculture production of the world

in 2003.


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Since 1990, the capture shrimp produc-tion has decreased year by year, whilstthat from aquaculture is increasing at anaccelerated rate, and cultured shrimpproduction now leads in world shrimpsupply. In 2003, the top five countriesfor cultured shrimp were Asian, i.e.China, Thailand, Viet Nam, Indonesia

and India. The production from the topfive countries took a share of 73.5% ofthe world cultured shrimp production(Table 2).

Shrimp trade of

the world

Among all fisheries products traded,shrimp was the most importantcommodity. In the last 20 years, theshrimp trade accounted for over 20%of the total fisheries product trade. In2003, the total shrimp imports of theworld were 1.955 million MT, valued atUS$12 billion. Shrimp has proved to bethe largest trade commodity of aquaticproducts. In 2003, the total trade valueof frozen shrimp and PUD shrimp wasUS$ 9.15 billion, and was about 14.8%of total aquatic products trade. Thetrade value of prepared and chilledshrimp was US$ 2.396 billion, and US$0.457 billion for other shrimp products.

In recent years, the trade of shrimpproducts has developed very rapidly.Developed countries, such as USA,Japan and European countries are themajor importers of shrimp products.Developing countries, especially Asiancountries, act as the main shrimpsupplier of the world. In 2003, theimportation of shrimp to USA reached500 000 tonnes, approximately 27.8% of

the worlds imports, and were followedby Japan, Spain, Demark and France.

Approximately 61.6% of the importedshrimp was consumed by people livingin the developed countries, such as US,Japan and Europe (Table 3).

With continued increasing demand on

shrimp products, the shrimp trade hasalso become highly competitive, andmore countries are being engagedin shrimp production. Since 1990,

Asian countries have become themajor supplier of shrimp exports tothe developed countries. Thailandand China were the major exportingcountries, followed by India, Viet Namand Indonesia. (Table 4).

Market occupation ratio

(MOR)

The market occupation ratio can berepresented by the percentage ofshrimp exports from one country to thatof the world. Table 5 shows the shrimpmarket occupation ratio of Asian majorshrimp producers from 1990-2003.Comparing the average market occupa-tion ratio in 1990-2003; the result showthat Thailand had the largest marketoccupation ratio (21.9%) of the worldshrimp market, followed by Indonesia,

India, and China of 8.8%, 7.5% and4.9%, respectively. Since 1990,Thailand has lead shrimp exportation tothe world.

Market price

The market price of exportation wascalculated by dividing the total exporta-tion value with the total exportationamount of each country. In 1990-2003,China has the lowest average price(US$ 4.95) for shrimp exports, while

Thailand has the highest (US$ 9.54).The export price fluctuated during thelast 14 years. In 1994 to 2000, the pricewas higher, and after 2000, the marketprice was decreased for all countries.

Revealed comparative

advantage (RCA)

Revealed comparative advantage(RCA) is based on observed tradepatterns. An increase in the value ofRCA means an increase in a countryscompetitiveness in a commodity. It canbe computed by the formula below:

RCAik=(X

ik/X

i) / (W

k/W)

Where RCAik represents k commodityin country i has the revealedcomparative advantage, X

ikis exports of

commodity j by country i. Xiis the total

exports by country i, Wkis the world

total exports of commodity k, W is theworld total exports of all commodities.

If RCAik>1, it shows that the exportsby the country is focused on fewcommodities, and it has a comparativeadvantage on that commodity; RCA

ik


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In table 7, the RCA of shrimp in majorAsia shrimp production was calculated.Thailand, China, Indonesia and Philip-pines have significantly decreasingRCAs, whilst India, Viet Nam hasretained the same level of RCA.For Bangladesh the RCA increasedsince 1998. Malaysia has the lowestRCA among Asian countries, withan average of 1.14. The decreasingRCA in Thailand and China showeda significant losing of comparativeadvantage for shrimp products, andcould be related to a major shift in the

species cultured.

Normalized trade

balance (NTB)

Normalized trade balance also knownas net exportation ratio, shows thedifference between exports and imports,

Year Bangladesh China India Indonesia Malaysia Philippines Thailand Viet Nam1990 2.2 10.0 4.9 9.4 1.7 3.2 14.4 1.61991 1.9 6.9 6.3 9.9 1.9 3.7 17.9 2.31992 1.8 7.7 5.9 9.3 1.7 2.8 20.5 2.81993 2.2 4.9 7.3 10.0 1.5 2.8 23.2 3.31994 2.8 3.9 8.3 9.5 1.5 2.6 25.7 3.4

1995 2.8 3.4 6.8 8.9 1.5 2.1 26.6 2.91996 2.9 2.2 7.5 8.8 1.4 1.6 25.5 2.71997 2.4 2.7 7.9 8.6 1.6 1.3 24.7 3.

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