editorial panel - mekonginfo · 2011. 11. 14. · 4 catch and culture volume 13, no. 1 april 2007...

Catch and Culture is published three times a year by the Mekong River Commission Secretariat in Vientaine, Lao PDRand distributed to over 650 subscribers around the world. Free email subscriptions to Catch and Culture are availablethrough the MRC website, www.mrcmekong.org For information on the cost of hard-copy subscriptions, contact theMRC's Documentation Centre by email to [email protected]

Contributions to Catch and Culture may be sent to [email protected]

© Mekong River Commission 2007

Editorial panel

Dr Chris Barlow, Fisheries Programme Manager

Dr Suchart Ingthamjitr, Fisheries Programme Officer

Kaviphone Phouthavongs, Fisheries Programme Officer

Virginia Addison, MRC Secretariat Communications Officer

Editor: Peter Starr

Design and cover illustration: Phannavanh Anoulack

All stories by Peter Starr unless otherwise noted.

2 Catch and Culture Volume 13, No. 1 April 2007

3

Edi tor ia l

E d i t o r i a l

When it comes to giant river prawns, it seems farmers want an all male world in their ponds, as they havediscovered that the chaps grow big and strong if there are no females to put them off their stride. So inViet Nam researchers have been busy under the microscope performing sex-change surgery on males toturn them into females. These neo-females are producing only male offspring which, in turn, are growingfaster than those in mixed company. There is still a long way to go with the research but the prospects arebright.

There is also good news from Cambodia where landings from the dai fishery reached the second highestlevel recorded since records have been kept. This means more fish for the prahok makers and a welcomeinjection of money into the local economy.

Fishing folk everywhere enjoy nothing more than exchanging a tale or two, so it was with great delightthat the members of the Technical Advisory Body accepted the kind invitation of the Myanmar governmentto visit that country's fishery. Myanmar has reportedly one of the most productive inland fisheries inSoutheast Asia, so there was much to learn and the trip was a great success.

Netting versus conservation is one of the perennial problems posed in any form of fishery and in theSongkhram River local fishers are up in arms about their rights to use barrage nets. To solve this potentialconflict they have been participating in a study to see how this practice can be made less detrimental,with some promising results.

Siphandone is one of the loveliest areas of the Lao PDR. With its crashing falls, deep pools and wetlands,it is a land of plenty, but if the community doesn't watch out this may change. So this traditional fisheryhas turned to co-management to ensure the sustainability of its fishery. This issue also features a colourinsert which illustrates the richness of this area and the work being undertaken in fish research andbreeding.

Work is also underway by the Mekong giant catfish working group to protect one of the river's iconicspecies. The group has spent two years developing a conservation strategy for the Mekong giant catfish.A joint effort between participating countries' fisheries departments, universities, NGOs, UNDP and theMRC Fisheries Programme, the strategy is an important milestone in the conservation of the basin'slargest migratory fish.

But there is much more in this Catch and Culture, one of our biggest ever issues, so we hope you enjoyyour reading.

The Editors

Catch and Culture Volume 13, No. 1 April 2007


Sex-reversal technique to massproduce all-male giantfreshwater prawns

An obscure town in the Mekong Delta isemerging as the new sex-change capital of

the region, at least for crustaceans.

In some crustacean species, females grow faster thanmales. In others, like giant freshwater prawns(Macrobrachium rosenbergii), maturing males growfaster and are much larger than females. But inmixed sex populations of M. rosenbergii, only a smallpercentage of males grow to a large size, and thesemature, dominant males suppress the growth rate ofother male prawns in the population. Consequentlythe male prawns show a very skewed sizedistribution, with few large ones and numerousmedium and small prawns. Females grow moreuniformly and will all mature, but once they are

breeding size they put their energy into reproductionrather than growth. Consequently, freshwater shrimpfarmers have long wanted to farm all-malepopulations, to take advantage of the superior growthrate of the males, and to have the prawns putting theirenergy into growth rather than reproduction.

Unfortunately, there's a snag – without a microscope,it's hard to determine the sex of a giant river prawn atthe early stages of development, which is when pondsare usually stocked. Farmers have tried manuallysexing the juvenile prawns, but on a commercial scalethis is never 100% effective. Even a few females in apopulation is enough to cause the male sizehierarchies to develop. Farmers face the grim realitythat as many as four out of every five mature adultswill be females at harvest time, and much of the

G e n e t i c s

5

population will be undersized male prawns.

Vietnamese researchers think they've solved thisdilemma with the crustacean equivalent of "gender-reassignment surgery", the politically-correct termused these days to describe a good old-fashioned sexchange. Working with Israeli scientists, the ResearchInstitute for Aquaculture No. 2 (RIA2) in Ho Chi MinhCity is using a novel technique to turn male prawnsinto "neo females" that can mate with regular malesand produce all-male offspring. Under the first phaseof the research programme between 2002 and 2004,the Thu Duc Experimental Research Station forAquaculture developed surgical procedures for sexreversal with researchers from the Department of LifeSciences and the National Institute for Biotechnologyat Ben Gurion University of the Negev.

Under the second phase which started last year, theBreeding Center for Southern Freshwater Aquaculturein Cai Be used 6,591 neo-female prawns for the massproduction of hundreds of thousands of males. As ofOctober last year, the centre had succeeded inproducing more than 350,000 juveniles, distributing200,000 to grow-out farms in An Giang province. Asmass production moves into full swing, Nguyen Nhutof RIA2's Experimental Biology Department says thebreeding center is now focussing on improvingmanagement as well as the quality of the neo-femalesand larvae-rearing techniques. According to Nhut,farmers harvesting prawns after six months can get asmuch as 170,000 dong ($10.60) a kilogram for malesweighing up to 100 grams each. That compares toonly 100,000 dong ($6.30) for a mixed bag of six-month-old males and females weighing as little as 25grams each.

Until now, efforts to increase yields of giant riverprawns have been limited to improving environmentalor nutritional conditions and manipulating thepopulation structure through selective stocking.Although sex-reversal techniques have long beenused on fish species such as tilapia to boost yields,the Vietnamese and Israeli researchers say this is thefirst time in crustaceans that a large-scale protocolhas been developed to create broodstocks producingall-male populations.

The research also marks the first time that the growthof all-male offspring has been monitored. According toa paper by the research team published inAquaculture last year, all-male groups of juvenileprawns grow "significantly faster" than male juvenilesfrom mixed populations. At a stocking density of 15prawns per square meter in fiberglass tanks, theresearchers found that production from all-malepopulations was 37 percent higher than productionfrom mixed ones. That compares favourably with an

earlier Israeli study published in 1988 that resulted ina yield increase of less than 8 percent at an evenlower density of nine prawns per square metre inearthen ponds.

Why all-male culture is more productive than mixedculture is not clear. The Vietnamese and Israeliresearchers suggest the growth of mixed-group malesmay be impeded by the presence of females. Thatcould cause them to divert energy towards competingfor mates. Another explanation is the biologicaladvantage of small males in reproduction.

Manipulating the endocrine system

The microsurgery that turns male prawns into femalesinvolves manipulating the endocrine system, whichregulates an animal's growth and development.Scientists have known for more than 50 years thatsexual differentiation in crustaceans is determined bytheir androgenic gland. Over the past two decades,various studies have shown that it is possible to injector implant extracts of this hormone-producing gland tomake female crayfishes and mud crabs either moremasculine or less feminine. In 1997, Professor AmirSagi of Ben Gurion University made a breakthroughwith giant river prawns. He showed that it waspossible to remove the gland surgically from maleprawns which would then mature as “neo-females”.These neo-females subsequentially mate with normalmales and produce all-male offspring.

Under the research programme that started five yearslater, a novel two-step procedure was developed.Professor Sagi and his Vietnamese colleagues


G e n e t i c s

Performing micro-surgery on small prawns requires skill, patienceand a steady hand.

G e n e t i c s


performed andrectomies on 1,940 male juvenilesaged between 25 and 60 days after metamorphosis.Of the two thirds that survived after 30 days, about200 were suspected of being neo-female prawns. Ofthe 38 which laid eggs, 26 produced all-maleoffspring.

Given the low success rate of 1.3 percent, theresearchers used more than 4,000 of the all-maleoffspring to perform additional andrectomies atyounger ages of between 20 and 30 days aftermetamorphosis. Although survival rates were virtuallyidentical after 30 days, more than 700 suspected neo-female prawns emerged. Moreover, every single oneproduced all-male offspring, an overall success rate ofalmost 18 percent.

In their recent paper, the Vietnamese and Israeliresearchers said the long duration of the process andthe potential loss of genetic variability raised "some

concerns" about the two-step procedure. Theyhighlighted the need for proper management toprevent inbreeding and measures to preserve a largeportion of the genetic variation in the originalpopulations. "Future research is needed to evaluatethe genetic implications of the suggested scheme andto shorten its duration," they said. The researchersalso underlined the importance of understanding theandrogenic gland and sexual differentiation processesin crustaceans. "Elucidation of these processes couldresult in new ways to achieve monosex culture inadditional species," they concluded.

Further reading:E.D. Aflalo, T.T.T. Hoang, V.H. Nguyen, Q. Lam, D.M.Nguyen, Q.S. Trinh, S. Raviv and A. Sagi. 2006. Anovel two-step procedure for mass production of all-male populations of the giant freshwater prawnMacrobrachium rosenbergii. Aquaculture 256: 468-478.

What goes on inside the operating theatre

Nguyen Thu Thuy is an unlikely micro-surgeon. The23-year-old Vietnamese scientist works in alaboratory at the Breeding Centre for SouthernFreshwater Aquaculture in Cai Be, doing sex-change operations on giant freshwater prawns(Macrobrachium rosenbergii).

Using tweezers, she delicately picks up a malejuvenile and places it under a microscope on aplasticine mould that serves as an operating table.Peering though the lense, she locates five pairs ofwalking legs, also known as periopods. At the baseof the pair of fifth legs lies the androgenic gland, ahormone-producing gland that controls thedevelopment of the testes and other male sexualcharacteristics of crustaceans. Grabbing the legwith the tweezers, Thuy delicately removes it fromthe prawn’s thorax before amputating the matchingleg.

After the initial trauma, further surgery is performedby amputating one of the animal’s second pair ofswimmerets, known as pleopods. When maleprawns mature, these swimmerets are modified bya spinous projection known as an appendixmasculina, which is used in copulation and spermtransfer. If this doesn’t grow back on theregenerated pleopod, the prawn will be a “neo-female” capable of mating and producing all-male

offspring. If it does grow back on the regeneratedpleopod, it indicates that removal of the androgenicgland was not successful – such prawns arediscarded from the experiment.

Working half-day shifts, Thuy and her fourcolleagues (Lam Quyen, Tran Nguyen, Ai Hang andHo Thi Lanh) can perform up to 400 sex changeson a typical day. The procedure mainly targets 30 to40-day-old males and had produced more than6,000 neo-female prawns as of October 2006. Atthat time, about 200,000 all-male offspring hadalready been transferred to grow-out ponds onfarms.

In a presentation to the Eighth TechnicalSymposium on Mekong Fisheries in Ho Chi MinhCity in November 2006, Nguyen Nhut of RIA2’sExperimental Biology Department said that between55 percent and 60 percent of the 30-day-old prawnssurvived the microsurgery and reached maturityafter three or four months. With up to 80 percent ofthe neo-female prawns reproducing successfully,mass production of all-male seed in this species isnow considered commercially promising. Researchfindings are expected to be published in theproceedings of the technical symposium later thisyear. In the meantime, human transexuals who wantto have their own kids can only look on in envy.

Nip and tuck

7

F i s h e r i e s


Landings from Tonle Sap daifishery in 2006-07 above the12-year average

The dai fishery landings in 2006-07 may be downby more than a third from the record high in 2005-

06, but they are also the second-highest onrecord.

The stationary trawl or dai fishery of the Tonle SapRiver in Kandal Province and Phnom PenhMunicipality has been monitored by the CambodianDepartment of Fisheries since 1980 and more formallywith support from the MRC since 1995 using amethodology described by Ngor and van Zalinge(2001).

The fishery primarily targets small cyprinids of theHenicorhynchus genus, collectively known as trey riel

in Khmer, as they migrate from the Tonle Sap Lake tothe Mekong with receding floodwaters betweenOctober and March each year. Other species makingan important contribution to landings are pelagic rivercarp (Paralaubuca typus), Nilem carp (Osteochilushasseltii) and various species of Labiobarbuscyprinids and Botia loaches.

The fishery provides important seasonal employmentopportunities for more than 2,000 rural people. It alsosupplies the essential ingredient for prahok, afermented paste which is an important protein sourcefor many, particularly towards the end of the dryseason when fish is scarce.

By Ashley S. Halls, Lieng Sopha and Ngor Pengby

MRC data collectors preparing to sample landings from a dai. PHOTO: ASHLEY HALLS

F i s h e r i e s


Last season (2005-06), the fishery recorded itshighest ever landings of 28,300 tonnes, contributingan estimated 9 percent of the total inland catch inCambodia (Department of Fisheries 2006) andgenerating an estimated 720 million riel ($176,000) inrevenues from license fees. The estimated value ofthe landings was 25.3 billion riel (US$6.2 million).

Combined landings for the 64 dai nets this season(2006-7) are estimated at 18,200 tonnes, the second-highest estimate since formal monitoring began (seeFigure 1). This is well above average and representsnearly 4 percent of estimated total inland fisherieslandings for this season (Fisheries Administration2007). The estimated value is 12.9 billion riel (US$3.2million). Approximately 42 percent of the landingscomprised trey riel. Sixteen percent were pelagic rivercarp and 11 percent were a cyprinid species knownas trey khnawng veng in Khmer (Labiobarbuslineatus).

While the number of dais allowed to fish is strictlycontrolled by licensing, MRC data collectors reportedan increase in the use of diesel engines to haul thenets this year. These might allow operators to set andhaul nets more often each day, effectively increasingtheir fishing power (see photo on page 10).

Landings from the dai fishery are regarded as animportant indicator of the health of fishery resourcesof the Great Lake-Tonle Sap (Mattson et al. 2006).Since 1995, estimated annual landings have exhibitedconsiderable fluctuation around the estimated meanof approximately 15,000 tonnes a year with acoefficient of variation (CoV) of 37 percent but with nodiscernable upward or downward trend. Variationshave been particularly marked in recent years.

Hydrological conditions within the system describedusing a simple flood index – the mean water levelover a 31-day period recorded 15 days each side of(and including) the maximum recorded water level atPhnom Penh Port – have been employed to explainthese large inter-annual variations in landings. Otherexplanatory variables have included changes in illegalgear use as well as training and awareness–raisingactivities (Mattson et al. 2006).

Estimates of annual dai landings and a range ofalternative flood indices have also been used toconstruct empirical (linear regression-based) models topredict the effect of forecasted changes in basinhydrology on future dai and other fishery landings (e.g.Ngor and Hom 2000; Baran et al. 2001).

Figure 1. Annual variation in estimated annual dai landings (solid line) and the selected flood index (broken line).

0

2

4

6

8

10

12

95-96 96-97 97-98 98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08

Year

Floo

d in

dex

(m)

0

5

10

15

20

25

30

Dai

land

ings

(000

tonn

es)

9

F i s h e r i e s


For the seven-year period between 1998-9 and 2004-5, empirical models employing the flood indexdescribed above have explained between 44 and 97 % of the variation in the estimated annual dailandings. However, the addition of the two highestlandings estimates on record during the last two yearscorresponding to unremarkable hydrologicalconditions indicates that the catch in the Tonle Sapdai fishery is determined by more than just a simplerelationship with flood height and duration.

The models assume that most of the observedvariation in dai landings reflects the response ofexploitable fish biomass (B) to changes in riverhydrology. Besides biomass, however, landings orcatches will also depend upon fishing effort (e) andthe ability of the fishing gear to catch fish, known as“catchability” (q):

C=BeqTherefore, unless it can be assumed that both fishingeffort and gear catchability remain more or lessconstant through time, dai landings are unlikely to bea reliable indicator of exploitable biomass in thefishery.

Like estimated landings, estimated total annual fishingeffort – measured in terms of dai fishing days or “soakhours”

1– has exhibited variation (CoV=13%) since

formal monitoring began (see Figure 2), contradictingthe premise that dai fishing effort is constant (Mattsonet al. 2006). There is even evidence to suggest thatfishing effort has fallen since the 1998-99 season,possibly reflecting a decline in the number of daislicensed to fish.

Such variation in fishing effort is traditionally dealt withby expressing catch as a proportion of effort, givingestimates of catch per unit of effort (CPUE). Whiledetailed records of effort for the dai fishery exist,estimates should also attempt to include the effort ofother types of gears operating throughout the fullmigratory range of the target species.

Dealing with variation in dai catchability may be equallynecessary. The catchability of dai nets is likely to varyin response to the velocity of the current since this willdetermine how much water and hence fish that passthrough the dai net each hour for a given size of net.The velocity of the current will also affect the ability offish to avoid or escape the net. This ability is likely to

Figure 2. Annual estimates of total fishing days (solid line) and soak hours (broken line) for the dai fishery. (Estimates are currentlynot available for 1995-6 to 1997-1998.) The discrepancies between fishing days and soak hours reflect differences in the meanfrequency at which the dais are hauled each day.

0

2000

4000

6000

8000

10000

12000

98-99 99-00 00-01 01-02 02-03 03-04 04-05 05-06 06-07

Year

0

50000

100000

150000

200000

250000

300000

Dai

fish

ing

days

Hou

rs

1Soak hours refer to how long the nets are in the water catching fish. They exclude the time spent setting and hauling the nets, estimated to be approximately 10 minutes.


F i s h e r i e s

decline as the current speed reaches and exceeds themaximum sustainable swimming speeds of targetspecies. Therefore, at least initially, dai nets are likelyto catch more fish per unit of effort as current velocityincreases. Indeed, this dai catchability response wasrecognised as early as the mid 1960’s by Fily andd’Aubenton (1965), as cited by Lieng et al (1995), andwas also reported this year by the MRC’s dai fisherymonitoring supervisor.

The selected flood index (used to explainenvironmental effects on rates of fish growth, mortalityand reproduction) may also need to be revised sinceit takes no account of hydrological conditions outsidethe 31-day window upon which it’s based, includingthose during the dry season. For instance,hydrological conditions during the dry season are alsoimportant in determining exploitable biomass in flood-pulse rivers (Halls et al. 2001; Halls and Welcomme2004).

During the next two years, the Fisheries Ecology,Valuation and Mitigation Component of the MRC’sFisheries Programme will seek to improve theunderstanding of the response of fish biomass tochanges in river hydrology and fishing effort byemploying indicators of biomass that attempt to

account for changes in fishing effort and gearefficiency, as well as a range of alternativequantitative descriptors of hydrological conditions.

The component is currently preparing a collaborativeresearch proposal with Murdoch University in Australiato undertake this research with financial support fromthe Australian Centre for International AgriculturalResearch (ACIAR).

Expected to begin later this year, the research willalso seek to determine if any significant changes infish diversity and rates of exploitation have occurredin the fishery since formal monitoring began. Theexisting survey and statistical methodologies used toestimate the dai fishery catch and effort will bereviewed to determine if any improvements can bemade to address problems such as overestimation ofcatch, as reported by Ngor and Hom (2002). Moremeaningful measures of fishing effort such as soakhours will also be considered for use in futuremonitoring and model-development activities. Athorough investigation of the dai monitoring databasewill also be undertaken to check for any errors in thedataset and to ensure that the catch and effortestimation methodologies are correct. This isparticularly necessary as the software used to store

Diesel engines are increasingly being used to haul dai nets. PHOTO: ASHLEY HALLS

11Catch and Culture Volume 13, No. 1 April 2007

F i s h e r i e s

References

Baran, E., van Zalinge, N.P. and Ngor, P. (2001). Analysis of the Cambodian Bagnet (“Dai”) Fishery Data. ICLARM,Penang, Malaysia, Mekong River Commission Secretariat, Phnom Penh, 50p.

Department of Fisheries (2006). The Five Year Achievement Report of the Department of Fisheries (2001-2005)including the Action Plan for 2006.

Fisheries Administration (2007). Annual Report on the status of the fisheries year 2006 and the action plan for2007. Fisheries Administration Cambodia.

Fily, M and d’Aubenton, F. (1965). Cambodia. Report on Fisheries Technology in the Great Lake and the TonleSap, 1962-1963. National Museum of Natural History, Paris, 509p.

Halls, A.S., Kirkwood, G.P. & Payne, A.I. (2001). A dynamic pool model for floodplain-river fisheries. Ecohydrologyand Hydrobiology 1 : 323-339.

Halls, A.S. & Welcomme, R.L. (2004). Dynamics of river fish populations in response to hydrological conditions: Asimulation study. River Research and Applications 20: 985-1000.

Lieng, S., Yim, C. and van Zalinge, N.P. (1995). Freshwater Fisheries of Cambodia, I: The bagnet fishery in theTonle Sap River. Asian Fisheries Science 8: 255-262.

Mattson, N.S., Ngor, P., Sam Ath, L., Sopha, L., Cans, G., Ngor, P., Hortle, K.G. (2006). Tonle Sap dai fisheryalmost doubles to reach new record. Catch and Culture 12: 9-12.

Ngor, P. and van Zalinge, N.P. (2001). Dai Bagnet Fishery: 1994/95 – 2001. Catch Assessment Methodology andResults. Mekong River Commission, April 2001, 47p.

Ngor, P. and Hom, C. (2000). Analysis of the dai catches in Phnom Penh/Kandal. In (Ed. Matics, K.I.) Proceedingsof the 3rd Technical Symposium on Mekong Fisheries, 8-9 December 2000, Phnom Penh, Cambodia, pp 105-113.

and process the data has been changed three timessince formal monitoring began in 1995. While thesechanges have allowed the MRC database toaccommodate more species names and providedgreater flexibility in processing the data, errors mayhave resulted.

* Dr Halls is the Coordinator of the Fisheries Ecology,Valuation and Mitigation component of the MRCFisheries Programme. Mr Sopha is NationalComponent Director for Cambodia and also theDeputy Director of Inland Fisheries Research andDevelopment Institute in Phnom Penh. Mr Pengby isthe component’s Database Manager.

12

M y a n m a r f i s h e r i e s

The TAB travels to Myanmar to see thatcountry's impressive inland fisheries and to

promote dialogue with fisheries officialswithin the Greater Mekong Sub-Region

The TAB seeks to strengthen management capacity,create knowledge creation through research andassistance into information flow on regional issues infisheries management. Among the activities aiming atthe latter are study visits for senior government lineagency staff and members of National MekongCommittees to develop a better understanding of theGreater Mekong Sub-region (GMS) and theopportunities for and constraints to the region'sdevelopment, and to engage in dialogue with theircounterparts in the respective countries.

Myanmar has, reportedly, one of the most productiveinland fisheries in Southeast Asia, said to rival that ofthe Lower Mekong Basin. Its floodplains cover about6 million hectares, which approaches that of the entireMekong. There are also great similarities in thefisheries of the Ayeyarwaddy and Mekong and thecountry presents a fascinating opportunity to compareexperiences between these regions.

It was therefore logical that the TAB would plan astudy visit to Myanmar. In this it was helped by theMRC's dialogue partner in Myanmar, the Ministry ofTransport. The visit was very efficiently organised bythe Department of Fisheries (DoF) of Myanmar andthroughout accompanied by senior DoF staff.

Visits to important fish landing centers and production

Learning from Myanmar'sinland fisheriesWolf Hartmann and Suchart Ingthamjitr


Just across from Amarapura’s famous “monkey bridge” is Taungthaman Inland Fisheries where men and women return to theirboats after a morning’s harvest



sites such as Khanwekaba in Pantanaw Township inthe country's Southern Ayeyarwaddy Divison,Taungthaman and Tethe Inland Fisheries nearMandalay, and at Inle Lake in the eastern ShanHighlands, and numerous discussions with fisheriesmanagers led to important insights for TAB members.Apart from its inland fisheries, Myanmar has asignificant marine fleet catching fish in the Bay ofBengal and Andaman Sea. Main species caught areprawns and shrimp, pomfret, cuttle fish, and threadfin,which are exported to China, the Middle East,Southeast Asia, and Australia. Total marine productionis in the area of 1.23 million tonnes per annum.

While marine fisheries arean important foreignexchange earner, inlandfisheries have the crucialrole of guaranteeing thecountry's food security byproviding important animalprotein.

Inland fisheries are divided into 3,500 "lease fisheries"(similar to the fishing lots known from Cambodia) andmany "open fisheries", i.e. gears set outside leaseareas. All fishing gears officially require a licence andproduction estimates are derived from licence holders,who are organised in the Myanmar FisheriesAssociation (MFA), a user organisation present in all

parts of the country. Reporting of catches is doneabout every two weeks through the MFA, which hasgreatly contributed to Myanmar having one of the bestsystems of catch statistics in the entire region.However licenses (and thus catch statistics) tend tobe neglected for smaller gears and the system mainlytargets those that are perceived as fishing for profit.Similarly, rice field fishers are not covered andalthough catches may be low, rice field fishers couldoutnumber those in open waters and lease fisheriescombined. Another significant contributor to inlandfisheries are about 165,000 hectares of small- andindustrial-scale fish culture ponds.

Total recorded fish production in 2005-2006 wasabout 2.6 million tonnes, of which inland fisheriesprovided almost 50%. While per capita consumptionis officially estimated at 36 kg of fish per year, it maybe much higher considering the country's enormouswetland potential.

Myanmar has reported significant increases inproduction from river and floodplain fisheries over thepast 4-5 years. This has been achieved without anysignificant physical inputs (e.g. fish feed) and is basedpurely upon improved aquatic resources management(environmental restoration and rehabilitation,restocking floodplains and improved governance).This case demonstrates the great benefits on offerthrough applying management effort to river fisheries,

The main role ofMyanmar's inlandfisheries is foodsecurity.

thousand tonnes



contrary to the widelyheld view that riverfisheries cannot beimproved and thereforedo not warrantinvestment.

Fisheries enhancementhas been a majorinstrument inMyanmar's fisheriesdevelopment. Started inthe mid-90s, DoF hasencouraged animportant programme of making its inland leasefisheries "more productive". Here a modest 1 percentof the revenue from lease fees is returned to thefishery through a stocking programme. However, animpressive 30 percent is returned in the form of grantsto lease holders for improved management. Thesefunds are used mainly for undertaking environmentalrehabilitation, restoration or enhancement measures.Common activities include the clearing of floodplainchannels to allow improved access of fish tofeeding/breedinggrounds (which alsoenhances catchability),the planting of treesand river bankengineering worksusing local materials.However, leaseholders are alsorequired to improveliving conditions forpeople living withintheir lease areas and to provide such infrastructure ashealth posts and schools.

While indigenous fish species (such as snakeheadChanna striata, air-breathing catfish Clarias sp,climbing perch Anabas testudineus, etc. inKhanwekabo, for example) are still present, stockingwith exotic species can be massive. This could beobserved in Taungthaman and Tethe Inland Fisheries,where large numbers of fingerlings (3,000-9,000/ha)of Indian Major Carps are stocked. To what extent thiswill impact on fish biodiversity remains to be seen.

Based on what they saw, the study tour membersmade several conclusions: The inland fishery inMyanmar is huge, as expected from a country with aflood plain area approaching that of the entire Mekongbasin. The fishery is politically and culturally valuedfor its contribution to food security.Some management approaches in Myanmar and in

the Lower Mekong Region are similar, for instance the"leases" in Myanmar and the "lot" system inCambodia. But there are differences, such asinterventions to improve physical habitat for fishproduction and large-scale stocking of fingerlings intoopen systems, coupled with efforts to improve livingconditions of people in these areas. Theseinterventions have apparently significantly increasedyields, contrary to the widely-held opinion that riverfisheries cannot be improved.

Further reading:

Coates, D. 2002. Inland capture fishery statistics ofSoutheast Asia: Current status and information needs.Asia-Pacific Fishery Commission, Bangkok, Thailand.RAP Publication No. 2002/11, 114 p.

Myanmar hasdemonstrated thatapplying managementefforts to riverfisheries can result inhuge productionincreases. This iscontrary to the widelyheld view that riverfisheries cannot beimproved.

Fisheriesenhancement has animportant role to playin making river andfloodplain fisheries"more productive"and thus to contributeto poverty reduction.

Tethe inland fisheries on the outskirts of Mandalay is massivelystocked with Indian major carps resulting in bumper harvests.

The TAB delegation with members of the Myanmar Department ofFisheries assess the day’s catch at Taungthaman inland fisheries.

I l l e g a l f i s h i n g g e a r


New approach to resolving oldconflict over fishing gear By Wolf Hartmann

Blocking the mouths of seasonal creekswith nets is a highly effective way to

catch fish. Under Thai law, it's also illegal.Local fishermen along the SongkhramRiver say it's a traditional practice and

want the law reviewed. A new studybrings the feuding parties together to find

a compromise.

The Department of Fisheries and local communitieshave taken their first step to solve frequent conflictsover barrage fisheries known as kad thorn on theSongkhram River in northeast Thailand. The use ofkad thorn is deemed illegal by the authorities (seeCatch and Culture, Vol. 10, No. 2 and Vol. 11, No. 3).

Since September, 2006, a joint research programmehas been underway to find out if - and how - kadthorn fisheries can be improved by making them lessdetrimental and possibly acceptable to the authorities.The joint research follows a stakeholder workshop inmid-2005 and the subsequent formulation of anintegrated, multi-component project to establish a co-management system for the Songkhram River Basin. Kad thorn are a type of large-scale fishing gearconsidered traditional by users and are widelyemployed across the Songkram where more than 100are in operation. The barrages comprise fence nets of300 to 900 m that block the mouths of seasonalcreeks (huay) where they meet the river. They arehighly effective, catching all sizes of fish on theirreturn from the creeks to the mainstream when waterlevels start receding in September. The right to

On 29 November 2006, people from villages in Nakhorn Phanom joined fisheries officials to stock 3.5 million fish into the Songkhram River.

I l l e g a l f i s h i n g g e a r


operate a kad thorn is usually auctioned off by localcommunities to the highest bidder. The fee received isused for community purposes such as infrastructuredevelopment. Past efforts by the Department ofFisheries to outlaw the gear have fallen on deaf ears,with fishers and communities alike requesting areview of the legislation and amendments if possible.

The study is being carried out by the FisheriesManagement and Governance Component of theMRC Fisheries Programme, Sub-DistrictOrganisations (Or Bor Tor) and communities at foursites in Sakorn Nakhon and Nakhon Phanomprovinces. Study objectives were widely discussedwith local community committees and Or Bor Tor, andthe research methodology jointly developed. Asuitable way to communicate research results to theDepartment of Fisheries was also identified. At theoutset, the study focused on the structure andcomposition of species caught, water levels and themesh-sizes of the different parts of the kad thorn.

During the study, fish caught in participating kad thornare shared equally between the highest bidders andlocal communities. Dead fish are used by women'sgroups to make fermented fish and live fish arestocked in community-conservation zones andreturned back to the river. On November 29, the KudKa and Ban Oon communities in Nakhon Phanomprovince stocked more than 3.5 million fish into aconservation zone at Srisongkhram. It was a festiveevent shared with members of the provincial anddistrict governments, the Department of Fisheries'Inland Fisheries Research and Development Bureauin Bangkok and the MRC Fisheries Programme.

Possible improvements to kad thorn include changingthe mesh size of different parts and prohibiting theiruse below certain water levels. While more talks haveto be held, the prospects are good that the results willbe taken up as those concerned were also involved inpreparing the study and carrying it out.

16

Fingerling-sized indigenous fish from controversial “kad thorn” gears are stocked into community conservation zones in Srisongkhram.

M a n a g e m e n t

17

The Siphandone area of the Mekong is oneof the richest fishing grounds in Lao PDR.

Prior to the 1980s, catches were abundant,but used only for family subsistence.

Increasing populations, new gears and highprices have increased the fishing effort.

Now communities are turning to co-management to ensure the sustainability of

their fisheries.

In terms of biodiversity and culture, the southern Laoprovince of Champasack is one of the country'srichest. Rice yields are high and fish are abundant,

particularly in Khong district. One of ten districts inChampasack, it is also known as Siphandone (fourthousand islands) and includes the spectacular KhoneFalls. Thanks to its unique geographical andecological conditions, Siphandone is not only home tomore than 72,000 people but also farmland anddiverse aquatic habitats. In the dry season fromNovember to April, most of the islands are used forgrowing rice and vegetables. In the wet season fromMay to October, more than half the islands areflooded, providing feeding and spawning grounds formany fish species.

Fishing is one of Siphandone's most importantactivities. Most households are engaged in fishing,


An historical view of fisheriesmanagement at Siphandone,Lao PDRBy Kaviphone Phouthavongs *

Parents and children join fishing expeditions on the Mekong River in Champasack Province, Lao PDR.


M a n a g e m e n t

both for subsistence and as a means of earningincome. One study in 2000 found that 80 per cent ofthe fish from the Khong district went the local marketin Champasack with the rest going to Vientiane andThailand.

Fishing in the Old Days

Wild capture fisheries in Khong Island are associatedwith traditional cultures and beliefs. Fishers usefishing time not only to catch fish but also toexchange news and culture within their villages orfamily. Boun Ban village celebration days usually takeplace at the end of the year when the rice harvest iscompleted or in the Lao New Year in April. Ruralpeople prohibit fishing during the full moon (van sin),believing it can bring bad luck. Some deep pools aredeclared vang sak sid –- deep pools for the spiritswho protect and watch over villages.

Fishing in Siphandone was traditionally forsubsistence only. Elderly fishermen in Ban Hat villagesay fish were abundant and easy to catch 30 yearsago. Since everybody caught enough for theirfamilies, fish had low monetary value and were notfound in markets. People who did not have time to gofishing themselves could ask a neighbour for a fish.This was part of Lao traditional custom – sharing notonly fish but also labour for agricultural work. Fishingwas the main activity for adults. Normally, thehusbands or other head of household would fish whilethe wives and children took part in the processing.

Fishermen used traditional fishing gear that did notharm brood stock. In Ban Don Houat in the 1960s, forexample, only two cast nets existed. These weremade from native trees and took almost a year tomake. The mesh size was large (20 to 30 cm) and thenets were used to catch big fish for traditional culturalceremonies. For regular consumption, only hookswere used to catch fish near the riverbank closest tothe village. People could even use their hands tocatch fish in the roots of trees as fish migrated. Theabundance of fish is reflected in the Lao proverb kangmo wai pa ten kuan eng, which means: put the pot onthe fire and the fish will jump in themselves.

In the dry season, dogs would bark at the sound ofhundreds of pa soi (Henicorhynchus sp.) migratingupstream. To catch enough for a small jar offermented fish, a fisherman with a boat did not needany gear – he simply splashed the water with apaddle and the fish jumped into the boat. Big fish ofup to 80 kg were also found 30 to 40 years ago.Fishermen from Ban Hat, Hatxaykhoun and DonHouat reported finding Mekong freshwater stingrays

(Himantura chaophraya, known locally as pa fa lai)including many specimens more than 100 kg, Jullien'sbarbs (Probarbus jullieni, or pa eun) and small-scalecroakers (Boesemania microlepis, or pa kuang).

Changes since the mid-1980s

The declining catches of some species was firstnoticed in the early 1980s. In general, however,catches were still good. Nylon cast nets and gill netsexisted but they were expensive and not everybodycould afford them. Paddleboards were common and afew motorboats existed but were mostly used fortransport. Fishing was still under control and no harmhad come to brood stock or particular species.Management was traditional, based on rules of districtor provincial agricultural offices that mainly dealt withproblems related to trans-boundary fishing rather thanlocal community issues.

Over the past two decades, the development ofupstream water resources for power and irrigation haspartly affected the aquatic resources and people ofKhong district. In addition, a study in 2001 found thatremoving vegetation from riverbanks and islands tocultivate crops had probably accelerated erosion.Bank erosion has affected villages across the district.With water flows fluctuating in the wet season and a30-fold difference between water discharges in thewet and dry seasons, the riverbanks are movingcloser to gardens and houses.

The improvement of roads has made it easier toaccess cities, and electricity has made it possible topreserve fish for longer transportation. According to a2003 study, more than half of the fish caught in KhongIsland were being transported to the Pakse andVientiane markets and possibly Thailand as well.

Children learn to fish at a young age in Lao PDR.


M a n a g e m e n t

19

Fisheries resources are now threatened by overfishingto meet strong demand. As fishermen compete withsophisticated fishing practices and more boats andgear, yield and species composition have declined.Fishing gear is available at affordable prices and thenumber of motorboats used for fishing has increased.On average, each household owns at least two orthree nylon gill nets and one nylon cast net. Fishingnow involves the whole family including women andchildren. The catch is not only for consumption, butalso for trade – meaning that larger and morevaluable species are being targeted.

Fish are no longer given as gifts. Fishing is now fortrade and the exchange of goods, and it now takesmore effort to catch fish for home consumption. Awareof the difficulties, local communities began looking atmitigation measures to protect and conserve theirresources for sustainable development. In the early1990s, government institutions concerned aboutenvironmental degradation started developing adatabase of fish biology and the socio-economic valueof fisheries. This followed the endorsement in 1989 ofthe Prime Minister's Decree 118 on management andconservation of aquatic animals, wild animals, andhunting and fishing.

At the same time, non-governmental organisationswere promoting the conservation of aquatic resourcesand played an important role in establishingcommunity-based management systems. Withfinancial support from the Lao Community andDolphin Protection Project villagers began to protectdolphins in Hangkhone village in 1993. Other villagesin Khong Island learnt from the project village andbegan to realise that only protected brood stock andrestricted fishing gear would help them to sustain theexploitation of fisheries resources. More and morevillages joined the project.

Siphandone now uses a community-basedmanagement approach where local communitiesestablish their own fish-conservation zones based onthe Ministry of Agriculture and Forestry's decree onthe Conservation of Wildlife and Aquatic Animals.Rules forbid certain fishing methods and the catchingof certain aquatic animals like frogs in the spawning

season. Local and national authorities haveacknowledged and supported the village rules and theco-management system whereby fishermen and theministry share responsibility for protecting naturalresources. Today, local communities believe that thereappearance of some fish species is the result oftheir effective management within fish conservationzones. As a result, the basic regulations of fisheriesconservation villages – such as prohibiting electro-fishing, the poisoning and scaring of fish and certaintypes of fishing gear –have become a general rule forfishing in the Siphandone area

* Mr Kaviphone is a Programme Officer with the MRCFisheries Programme in Vientiane. This article isbased on his M.Sc. research thesis “EmployingGeographical Information System in the MekongRiver: a case study of Lao PDR”, undertaken at theUniversity of Sydney.

Further reading:

Bush S. and Phonvisay A. (2000). Baseline Study ofFish Trade from the Siphandone Fishery,Champassak Province. Living Aquatic ResourcesResearch Centre (LARReC), LARReC ResearchReport No.0004, Vientiane, Lao PDR. 72pp

Elliott S. (2001). Deforestation and the potential forforest restoration in the Siphandone wetlends. InDaconto, G. (ed.), Siphandone Wetlands. CESVI. 55-74pp

Phonvisay, A. (2003). Monitoring of Fish Trade Studyof the Siphandone Fishery, Champassak Province.Living Aquatic Resources Research Centre(LARReC). LARReC Research Report No.0008,Vientiane, Lao PDR. 60pp

Baird I. G., and Flaherty M. S. (1999). FishConservation Zones and Indigenous EcologicalKnowledge in Southern Laos: A First Step inMonitoring and Assessing Effectiveness. CESVICentre for Protected Areas and WatershedManagement, Department of Forestry, Vientiane.45pp.

F i s h e r i e s


Ecological and social factors fueldecline in catch of two Probarbusspecies A recent paper documents the decline of

the catch of two Probarbus speciesduring the 1990s in southern Lao. Thereasons for the decline are complex,involving both ecological and social

factors, and the author stresses the needfor both quantitative and qualitative

measures for assessing the Probarbusfishery in southern Lao.

The thick-lip barb (Probarbus labeamajor) becameknown to science only in 1992. That was whenichthyologist Tyson Roberts “discovered” the giantcyprinid along with another new species from a genusthat had contained only one species since 1880. Thiswas another giant fish known as Jullien’s golden carp(Probarbus jullieni), one of several “flagship species”in the Mekong (see Catch and Culture, Vol. 12, No. 3).In 1989, Lao authorities classified the golden carp asa protected species that can only be caught and eatenoutside its spawning season.

Probarbus jullieni is commonly known as the Isokbarb, the seven-striped barb and Jullien’s barb. Itoccurs in the Mekong basin as well as in Thailand’sChao Phraya and Maeklong basins and Malaysia’sPahang and Perak basins. The fish may havedisappeared from the Pahang basin and is listed as“endangered” by the World Conservation Union(IUCN). It is also listed under Appendix 1 of theConvention on International Trade in EndangeredSpecies (CITES). That means it is threatened withextinction and can be traded only under exceptionalcircumstances.

Probarbus labeamajor occurs only in the MekongBasin, and only between Kratie province in Cambodiaand Nakhon Phanom province in Thailand. It is listedas “data deficient” by IUCN and not yet listed underCITES.

In a recent paper*, Ian Baird describes how variousecological and social factors may have adverselyaffected stocks of these two species over a six-year

period. In 1993, he started monitoring a Lao fishery inthe Siphandone area near the Cambodian border thattargeted the two species between October andFebruary when the fish are near spawning condition.At the time, he estimated that up to 30,000 kg of P.jullieni and up to 7,250 kg of P. labeamajor were beingexported to Thailand. Caught in Lao and Cambodianwaters, local prices for spawning female golden carpscarried a 10 percent premium. In Bangkok, the fishcould fetch up to $10 a kg in fancy restaurants. Peak-season exports of both species in 1993 alone wereestimated to be worth between US$70,000 andUS$90,000.

According to Baird, the paper presents the firstquantitative data on P. labeamajor since it becameknown to science 15 years ago. To conduct themonitoring, eight fishermen from Hang Khone villageagreed to supply information about their fishingactivities using gills nets with mesh sizes ranging from18 to 30 cm. Over the six-year period, the two speciesaccounted for 78 percent of the overall catch of 3,297

Probarbus jullieni caught in the Tonle Sap, Cambodia.

F i s h e r i e s

21

kg. The P. jullieni catch alone came to 2,149 kg,amounting to 65 percent of the total. The P.labeamajor catch amounted to 423 kg, or almost 13percent.

The six-year monitoring revealed steep declines incatches of both species. In the 1993-94 season, thefishermen caught 503 kg of P. jullieni and 174 kg of P.labeamajor. By 1998, the catches had plunged to 154kg for the first species and 29 kg for the second. Bairdsays the steep decline partly reflected increasedproduction of filamentous green algae which getstangled in nets, making them less effective. Theincrease in algae may have been linked to nutrientchanges triggered by upstream agricultural, householdand industrial activities. During the early years of thestudy, algae were not a major factor. In later years,however, the algae started to appear earlier and wasmore frequently encountered.

A decline in the number of gill nets seems to beanother factor behind the plunge in catches. In 1993,fish traders distributed hundreds of imported Thai gillnets to local people on credit. The initial difficulty ofcatching enough fish to recoup the investment wascompounded in 1997 when the value of the kipplummeted, dramatically boosting the cost of the nets.So the number of gill nets targeting the two speciesdeclined and those being used were generally olderand in poorer condition. Increasing thefts of gill netshad also reduced the number of nets, resulting inshorter fishing seasons.

A further complication was that juveniles of the twospecies usually feed in shallow areas of the riverrather than the deep pools that are protected by thefish-conservation zones. In the shallow areas, theywere increasingly getting entangled in smaller netsused to target smaller fish like the Henicorhynchusspecies during the dry season. Baird says these nets,with mesh sizes as little as 2.5 cm, were increasinglybeing used and may have been a “significant”management issue for the two species.

He also notes that the main fishing season alwayscoincides with the spawning season and that“populations are likely to be damaged if a high

percentage of potential spawners are caught beforespawning.” While many small cyprinid species startspawning less than a year after hatching, P. jullienidoesn’t reach maturity until it is almost two years old.While it was not possible to locate spawning groundsfor the two species near Hang Khone during thecourse of the study, local fishermen reported that theybelieved they spawned outside the deep pools.

Although there was no evidence that the size of fishbeing caught had been falling as well, Baird notes thatlocal fisheries targeting smaller species were replacingthose for bigger species. This possibly indicated“fishing down” whereby a decline or disappearance oflarge long-lived species is accompanied by increasedabundance of smaller and more rapidly-reproducingspecies.

“Since the Probarbus fishery targets some of thelargest fish in the Hang Khone area, it would not besurprising if it were one of the first casualties ofdeclines in large species,” Baird says. “The Probarbusfishery may be an important indicator of changes infish community structure, but the interaction betweenthe fishery and various ecological and social factorsmakes the situation quite complex.” Baird also warnsthat the construction of large dams poses a “seriousthreat” to the species. In the Perak basin in Malaysia,he says, the construction of big dams has destroyedseveral of spawning sites of P. jullieni. Since bothspecies are generally intolerant of habitat alterations,“populations of both species are expected todisappear as more impoundments are constructed inthe Mekong basin,” he says.

Further reading:* Baird, Ian G. 2006. Probarbus jullieni and Probarbuslabeamajor: the management and conservation of twoof the largest fish species in the Mekong River insouthern Laos. Aquatic Conservation: Marine andFreshwater Ecosystems 16(5): 517-532.

Roberts, T.R. 1992. Revision of the Southeast Asiancypranid fish genus Probarbus, with two new speciesthreatened by the proposed construction of dams onthe Mekong River. Ichthyl. Expl. Freshw. 3: 37-48.



C o n s e r v a t i o n o f f l a g s h i p s p e c i e s

22

A conservation strategy for theMekong giant catfish

The Mekong giant catfish Pangasianodon gigas isone of the world's largest freshwater fish and acharismatic animal revered throughout the lowerMekong. Its capture in fisheries is very rare, andinvariably attracts great attention in the local andregional media. For this reason and the fact that itslife history (long-lived, late-maturing and long-distancemigrant) makes the species vulnerable to humandisturbances from fishing to dam building, it is widelyseen as a 'flagship species' for conservation of thelower Mekong ecosystem its fisheries.

The Mekong giant catfish has long been consideredrare and endangered. As early as in the 1940s,French investigators in Cambodia recommended thatthe species be afforded special protection. Since2003 it is listed as 'critically endangered' on the IUCNRed List. The species is protected by national law in

most countries of the lower basin, and subject to avariety of conservation initiatives. Harvesting of thegiant catfish is controlled throughout much of its rangeby a combination of laws and voluntary agreements.The Thai Department of Fisheries runs a captivebreeding programme, and several organisationsconduct work to identify and protect the species'habitat. Until recently the various conservationinitiatives were at best loosely coordinated, and theireffectiveness was often unknown. Some measures,such as the capture of wild spawners to establish acaptive population, were highly controversial.

Mekong Giant Catfish Working GroupIt was against this background that in 2005, theMekong Giant Catfish Working Group (MGCWG) wasset up to coordinate and evaluate conservationinitiatives and develop an overarching conservation

By Kai Lorenzen and Naruepon Sukumasavin

0

1020

30

40

5060

70

8090

100

1970 1980 1990 2000 2010

Year

Cat

ch (n

umbe

r)

Reconstructed

Directly reported

Figure 1. Reported and reconstructed catches of Mekong giant catfish since 1970.


23

strategy. The MGCWG brings together the majorrelevant organisations including the MRC FisheriesProgramme, Mekong Wetlands BiodiversityProgramme, Cambodian Fisheries Administration, LaoDepartment of Livestock and Fisheries, ThaiDepartment of Fisheries, Network of AquacultureCenters in Asia-Pacific, Kasetsart University, WWF,IUCN, and Imperial College London. The conservationstrategy was developed through a series ofworkshops, combined with focused research to assessthe status of the wild and captive populations and thelikely effectiveness of management options. Theconservation strategy process and the populationassessment research informing it were supported by atwo-year project from the UK Darwin Initiative.

Historical catchesTo assess the status of the wild population, data onthe history of catfish fishing (fishing practices, effortand catches) and environmental change in theMekong basin were collated from multiple sources.The data indicate that the giant catfish is unlikely everto have been caught in large numbers. For much ofthe 20th century the basin-wide catch averaged about20-30 fish per year. Annual catches increaseddramatically from the early 1980s to a maximum of 90in 1990, but declined thereafter and are now well

below the pre-1980 average (Figure 1).

The changes in catches over the past 25 years reflectan intensification, and subsequent decline of thetraditional fishery near the species' main spawninggrounds at Chiang Khong/Houasai in NorthernThailand and Lao. The intensification of this fisherywas linked to the initiation of the captive breedingprogramme, which directly increased demand formature wild fish but also attracted great mediaattention and established the catfish fishing season atChiang Khong as a national tourist attraction. Thefishery eventually declined as the population becamedepleted and returns to fishing effort diminished.Environmental change in the Mekong basin has beengradual and of moderate magnitude until the veryrecent past, and is unlikely to have been a significantfactor in past population change.

Population modellingA mathematical model was used to reconstruct thedynamics of the population since 1970, and to predictits future development under different scenarios(Figure 2). Reconstructed spawner abundance showsa relatively stable population of about 240 animalsprior to 1983. Intensification of the Chiang Khong /Houasai fishery then depleted the population by 80%


0

50

100

150

200

250

300

350

400

450

1970 1990 2010 2030 2050 2070

Year

Spaw

ner P

opul

atio

nNo fishing

Moderate 'historical' fishing

Reproductive failure since 1990

Figure 2. Spawner population numbers of Mekong giant catfish from 1970 to 2050. Numbers from1970 to 2006 were estimated from fisheries data using a population model. Predictions to 2050 wereobtained from the same model, for different assumptions regarding future fishing and reproductivesuccess. Predictions are shown for different assumptions about the unknown degree of recruitmentcompensation at low population size.



24

to just 50 in 1995. The model predicts that thepopulation has since recovered significantly, largelydue to maturation of fish that were spawned prior to1990. The current spawner abundance is estimated at155-185 animals, depending on the (unknown) degreeof compensation in the species' stock-recruitmentrelationship. Spawner abundance in the absence offishing has been estimated at 400-730 animals, andthis is broadly consistent with an independentassessment of genetically effective population sizebased on molecular genetic techniques.

The population is predicted to return to its pre-1980abundance if moderate 'historical' levels of fishing aremaintained, but is unlikely to do so until well after2050. If fishing ceased completely, the populationwould increase faster and exceed its pre-1980abundance by 2030. Given the species' longevity andlate maturation, reproductive failure due toenvironmental factors or depletion of the spawningstock would become evident in the spawnerpopulation only after about 20 years (Figure 2).

ThreatsWhile the threat of fishing is now largely controlled,new and potentially severe threats to the wildpopulation are emerging. The most important is theaccelerating and increasingly significantenvironmental change in the Mekong basin.

Navigational improvements including 'rapid blasting',the commissioning of hydropower dams, and land usechange in seasonally flooded areas are among thefactors likely to affect much of the species' habitatover the next decade. Multiple initiatives are underway to control these developments, but the new threatis undoubtedly serious and much less quantifiablethan the impact of fishing. In this situation of greatuncertainty for the wild population, the captivebreeding programme provides a vital safeguard forthe species' existence.

A second new threat may arise from escapes of giantcatfish from commercial aquaculture, and theecological and genetic interactions of partiallydomesticated animals with wild fish. At present, giantcatfish farming is not a major industry and the threatof escapees is low, but this situation should bemonitored.

Conservation strategyBased on population assessment and extensiveconsultations, the MGCWG has developed aconservation strategy with the following key elements: (1) Very restricted harvesting of giant catfish (lessthan 10 animals per year basin-wide at the current,depleted state of the population, and no more than 20per year in the long term). At present this target isbeing met, and institutional arrangements to manage

The Mekong giant catfish, an iconic species from the Mekong River system, is one of the world’s largest freshwater fishes.PHOTO: ZEB HOGAN


25

fishing pressure are largely in place.

(2) Conservation of essential habitat. Given thathabitat use and migration patterns of the species arepoorly known, the spawning grounds north of ChiangKhong / Houasai is the only area that can be clearlyidentified and demarcated as essential habitat.However, maintaining the wider Mekong ecosystem(flows, physical habitats and connectivity) clearly isimportant in ensuring the long-term survival of thespecies in the wild.

(3) Maintenance of a viable and geneticallyrepresentative captive population for eventualsupplementation or re-introduction, should the wildpopulation decline further. Genetic analysis showsthat the population maintained by the ThaiDepartment of Fisheries will meet this aim, providedthat it is carefully managed. A management strategyto this end has been developed. However, noreleases of captive-bred fish into the Mekong basinare recommended while the wild population has thecapacity to recover naturally.

(4) The development of commercial aquaculture ofgiant catfish should be monitored, and measurestaken to minimise escapes into the Mekong basinshould the industry expand significantly.

(5) Regular monitoring of threats and the populationwill be undertaken under the auspices of theMGCWG, and conservation measures adapted asrequired. The strategy will be implemented by multipleinstitutions, hopefully with the MRC Technical Advisory

Body for Fisheries Management (TAB) assuming acoordinating function and conducting annual reviewsof monitoring information.

The Mekong giant catfish conservation strategy is animportant milestone in the conservation of the basin'slarge migratory fish. It provides an example of asystematic, science-based and consultativeconservation planning process for a large freshwaterfish that is likely to be applicable to other species inthe region and elsewhere in the tropics. It also showshow long-term monitoring data, such as that beingcollected under the MRC Fisheries Programme, canbe utilized to support rigorous assessment and betterdecision making in resource management. Last butnot least, it sets an example of constructiveengagement between multiple organisations, fromgovernment departments to NGOs, for the purpose offreshwater conservation.

Further reading:Documents relating to Mekong giant catfish populationmodelling and the conservation strategy can be foundon:http://www.aquaticresources.org/mekongcatfish.html .

Dr Kai Lorenzen is a Senior Lecturer in AquaticResource Ecology at Imperial College London, andleader of the Darwin Initiative project. Dr NarueponSukumasavin is Head of the Inland FisheriesResearch and Development Division at the ThaiDepartment of Fisheries, and chair of the MekongGiant Catfish Working Group.


April 2007 Catch and Culture Volume 13, No. 1

W e t l a n d s

26

Awareness has improved. But to addressthe root causes of wetland degradation,

there's still a long way to go

The Mekong Wetlands Biodiversity Conservation andSustainable Use Program has come to an end threeyears ahead of schedule following a change in thefunding priorities of the Global Environment Fund(GEF) of the United Nations. The United NationsDevelopment Programme (UNDP) and the WorldConservation Union (IUCN) had been jointly managingthe program with the MRC.

Since the launch of its first phase in mid-2004, theprogramme had been working at four wetlandsdemonstration sites including Stung Treng inCambodia, which was recognised as internationallysignificant under the Ramsar Convention in 1999.Other sites were located in wetlands in Attapeu in LaoPDR, the Songkhram River Basin in Thailand and thePlain of Reeds in Viet Nam.

Also known as the Mekong Wetlands BiodiversityProgramme (MWBP), the regional initiative hadselected four species including the Mekong giantcatfish (Pangasianodon gigas) to promoteconservation efforts. The other three species were the

Mekong Wetlands BiodiversityProgramme - an early end maybe,but attitudes have changed

Tram Chim National Park in the Mekong Delta in Viet Nam. This wetland is home to the Sarus crane. PHOTO CHARLOTTE MACALISTER

W e t l a n d s

27

Irrawaddy dolphin (Orcaellabrevirostris), the Siamese crocodile(Crocodylus siamensis) and theEastern sarus crane (Grus antigonesharpei).

Managed from Vientiane, the programhad been expected to last five years.But with the GEF changing its policiesto focus on national rather thanregional programs, funding for thesecond phase from 2007 to 2009 wasnot secured. As a result, theprogram's nine offices in the fourcountries closed at the end of 2006.

At a final seminar in Vientiane inMarch, the UNDP program teamleader Peter-John Meynell said one ofthe programme's key activities was totake a big delegation to Ninth Meetingof the Conference of the Parties to theRamsar Convention in Uganda in2005. "For me, that study tour wasactually one of the turning points on thisproject," he said. "It was very instrumental in changingattitudes and approaches in this region." Meynellnoted that the programme had also drawn up aregional Ramsar initiative for the Lower Mekong Basinwhich was "now sitting on the shelf" for anystakeholders who were interested.

Among other major achievements, Meynell said, wereestablishing a wetlands working group in Cambodia'sMinistry of Agriculture, Forestry and Fisheries, andpreparing Lao PDR to the accede to the RamsarConvention with Siphandone as its first Ramsar site.The program also worked on the possible designationof Thailand's Songkhram River Basin as a newRamsar site and through scientific work at the TramChim National Park, influenced Viet Nam to change itspolicy in Special Use Forests to recognise theimportance of hydrological balance in wetlandprotected areas.

During the seminar, the MRC MWBP ProgrammeManager, Dr. Charlotte MacAlister briefed participantson the mapping of the four wetland sites and wetlandsbasinwide. The Wetlands Map Service, available onthe MRC Information System Portal(http://portal.mrcmekong.org/), provides access toinformation on the wetlands via an interactive map. Itintegrates GIS and earth observation layers with fieldsurvey data including photographs and providesaccess to additional information by linking to othermap layers, relevant websites and documentation. Dr.

MacAlister also outlined the long term wetlandactivities of the Environment Programme andconfirmed MRC's commitment to promoting WetlandWise Use throughout the Lower Mekong Basin. MRChas been instrumental in supporting the accession ofLao PDR to the Ramsar convention and developingtransboundary wetland cooperation throughout thebasin.

Meynell said the wetlands programme realised at theoutset that it could not address conservation ofbiodiversity without addressing livelihood and povertyissues. The British biologist said he knew that theprogramme could only make a start on addressing theroot causes of wetland degradation such asinappropriate land use, poor water management andunsustainable resource use. But he was confident thework would raise regional awareness of wetlands.

"It's so unfortunate that we had to shut it down just aswe were starting to get things off the ground," Meynelltold the final seminar, noting that there was still a "lotof work to be done" in the area. As for tackling theroot cause of the degradation of wetlands in theLower Mekong Basin, "I don't think we have started toscratch the surface," he said. "There's an enormousdistance to go."


The Wetland Map Service of the MRC Information Portal helps users with no GIS experiencecreate and print their own maps.

As the Cambodian Prime Minister issuesa wake-up call, the clearing of flooded

forest for rice farming is seen as biggestthreat to the lake.

Prime Minister Hun Sen has warned that populationpressures, severe poverty and unequal access to thebenefits of economic growth are exerting an"enormous risk" on the ecological system of the TonleSap Lake. "The lake is facing a serious threat of over-exploitation and its ecosystem has turned quite fragile.Honestly, if this problem is not addressed decisivelyand soon enough, Cambodia could face a seriousenvironmental disaster," he told a national forum onthe Tonle Sap sponsored by the Asian DevelopmentBank (ADB) in March.

Samdech Hun Sen said the biggest threat came fromthe clearing of flooded forest for large-scale ricefarming. "I would like to appeal to the provincial andlocal communities to take immediate action againstthis disastrous practice and report directly to me sothat we can move effectively to save the Tonle SapLake," he said. The Prime Minister said agriculturalencroachment and the collection of firewood from theflooded forest had "severely impacted" the productivityof Tonle Sap fisheries which account for almost twothirds of Cambodia's freshwater fish output. "At thesame time, the rapid degradation of natural resourcesin the Tonle Sap basin has resulted in high povertyincidence in the region and reinforced the pressure onthe lake's resources," he said. "Moreover, theincreasing use of fertilisers and pesticides in the basincould create serious environmental problems in theTonle Sap Lake.

"Harnessing waters of the upper catchments wouldpose a threat to the natural habitats of several speciesand introduce potentially conflicting uses of water forhydropower, domestic consumption, and irrigation.Furthermore, the encroachment of the forest areas -whether for water, timber and firewood, or clearing theforest for agriculture purposes - would destroy theecosystem's sustainability and cause erosion, loss ofsoil fertility, silting, flooding, and polluting thedownstream's water sources."

The Prime Minister called for an "integrated basin-wide approach" for Tonle Sap development. "Theeffort to save the Tonle Sap and to preserve it as anational and global asset should extend beyondCambodia's borders. Outside Cambodia, the mainthreat to Tonle Sap is the cumulative impact ofinfrastructure construction of the hydrology in theMekong basin," he said.

Samdech Hun Sen said recent fisheries reformconverting 56 percent of commercial fishing lots tolocal households had achieved "considerableprogress" in getting local communities involved innatural-resource management and environmentalprotection. "However, this reform is not the magicbullet to solve the entire regional conflict," he said"There are many more issues and problems that needto be addressed in order to help the communities getout of poverty, and manage the natural resources forsustainable development. A key issue is to provide thelocal communities with the power to governthemselves."

The Prime Minister also called on the forum toconsider a supreme council for the Tonle Sap as an"effective, proactive, responsible and accountableorganisation that can mobilise and galvanise supportfrom all ministries and from wide-ranging developmentpartners."

Serious environmental disaster ifTonle Sap problems ignored

T o n l e S a p


Prime Minister Samdech Hun Sen discussing environmentalmanagement of the Cambodian Great Lake.


M e k o n g R i v e r

Using satellite imagery and fieldwork,Chinese researchers pinpoint the source

of the Mekong as being 4,909 km from theriver’s mouth.

Scientists have long known that the Mekong Riveroriginates from the snow and ice that melts everysummer in remote mountains on the Tibetan Plateau.But where exactly is the start of the river? A team ofresearchers led by Dr Liu Shaochuang of the ChineseAcademy of Sciences reckons it’s a stream at the footof Mount Jifu, located on the borders of Zaduo andand Zhiduo counties of Qinghai province. Accordingto their study published in the March issue of Geo-spatial Information Science, the elevation of the

source is 5,200 m and the location is latitude33°45’48”N and longtitude 94°40’52’’E.

Dr Liu says this stream, the Guyong-Pudigao Creek,is 1.7 km longer than another stream previouslybelieved to be the main source. This second stream,the Gaoshanguxi Creek, originates not from MountJifu but a nearby peak, Mount Guozongmucha (alsoknown Lasaigongma) with an elevation of 5,160 m.The Guyong-Pudigao Creek also has greater waterflow than other source tributaries.

The two creeks merge a bit more than 20 kmdownstream at Yeyongsongduo. Here, they form theGuyong River which later becomes the Zhaa Riverand eventually merges with the Zhana River at

Chinese scientists find sourceof the Mekong

The Zhaa River in Tibet, approximately 100 km from the source of the Mekong. PHOTO: LIU SHAOCHUANG



Ganasonduo, almost 80 km downstream fromYeyongsongduo. From here, the renamed Zha Riverflows more than 500 km southeast to the city ofChangdu where it becomes Lancang River, flowinganother 1,585 km before leaving Chinese territory.

Dr Liu bases his conclusions on satellite imagery andfield visits to the Tibetan Plateau in 1999 and 2002. DrLiu calculates the distance from source to mouth at4,909 km. That compares with estimates of 4,000 kmto 4,880 km that have appeared in variouspublications over the past 15 years. Compared withnew measured lengths of other major rivers, heconcludes that the Mekong is the tenth-longest river inthe world. The longer rivers, in order, are: the Nile,Amazon, Yangtze, Mississippi, Yenisey, Yellow, Ob,Amur, and Zaire-Congo.

Further reading:Liu Shaochuang, Lu Pingli, Liu Donghui, Jin Peidong.(2007). Pinpointing Source of Mekong and MeasuringIts Length through Analysis of Satellite Imagery andField Investigations. Geo-spatial Information Science10(1): 51-56.

Name Stretch Length (km)

Guyong-Pudigao Creek Mount Jifu to Yeyongsongduo 22.7

Zhaa River Yeyongsongduo to Ganasongduo 76.7

Zha River Ganasongduo to Changdu 513.8

Lancang River Changdu to China-Lao border 1,584.8

Mekong River (SongTien) China-Lao border to South China Sea 2,711.0

Total: 4,909.0

Table: Length of consecutive stretches of the Mekong River.

Ground view of Mt Jifu, source of the Mekong River.PHOTO: LIU SHAOCHUANG


E d u c a t i o n

Lao scientists return fromstudies abroad

Over the past few years, Lao capacity inthe field for fisheries research and

development has been considerablystrengthened by the return of variouspeople awarded scholarships to study

abroad. The scholarships were from theDanida-funded National Aquatic Research

Institute (NARI) project 1999-2006.

Among the returning scholarsis Dr Sinthavong Viravong,the new Lao NationalComponent Director for theFisheries Ecology, Valuationand Mitigation (FEVM)Component of the MRCFisheries Programme. He hasjust completed a doctoralthesis at Britain’s University ofHull on the life-history

strategies of four Mekong species. These are theorange-fin loach (Botia modesta), the Siamese mudcarp (Henicorhynchus siamensis), Jullien’s barb(Probarbus jullieni) and a catfish species known insome parts of the Mekong as a rat or rat-face fish(Helicophagus waandersii).

Sinthavong also has a master’s degree in fisheriesscience from Kasetsart University in Bangkok andanother master’s degree in zoological engineeringfrom the University of Livestock and VeterinarySciences in Stara Zagora, Bulgaria.

Over the past six years, Sinthavong has beeninvolved in using hydro-acoustic techniques toestimate fish biomass in deep pools in various Laoprovinces. He has conducted fishery surveys aroundthe Nonglom Swamp in Attapeu province, in ahydropower project area in Champasack province andthe Nakai Reservoir in Khammouane province. Healso conducted a survey of species diversity in theNam Theun II hydropower project area.

Mr KaviphonePhouthavongs,the newProgrammeOfficer at the MRCSecretariat inVientiane (seepage 34),graduated with anM.Sc. from theUniversity of

Sydney in Australia. His thesis was on integratinglocal knowledge with Geographical InformationSystems (GIS) to manage fisheries in the Siphandonearea (see page 17). The idea is to use the integratedknowledge as a communications tool for monitoringand planning. He says he wants to use theexperiences gained from his research to improvemanagement in the Siphandone area, especially indeep pools where GIS can be used for visualisingand analysing hydro-acoustic data.

Delegates to theEighth TechnicalSymposium onMekong Fisheriesin Ho Chi MinhCity in Novemberwill recall MrAlounPhounvisay fromhis presentationon using market

data for fisheries resources management anddevelopment. Aloun returned to Vientiane in 2005after completing a master’s degree in applied scienceat the University of Sydney where he analysedeconomic and market-related research in relation toLao fisheries. He graduated from the same universityin 2003 with a B.Sc. in resource economics whichincluded research on the economic management ofNam Ngum Reservoir fisheries. Since returning toVientiane, he has worked as an assistant to theActing National Director of the Fisheries, Ecology andMitigation component on the MRC FisheriesProgramme and as a technical officer at LARReC’s



data and information unit. In January, he wasappointed to the permanent secretary’s office at theLao Ministry of Agriculture and Forestry.

The Asian Institute ofTechnology (AIT) in Bangkok inThailand has been a popularuniversity for Lao students. MrVannaxay Soukhaseumcompleted an M.Sc. at AIT’sSchool of Environment,Resources and Development in2004. His thesis was on thestatus of fish seed supply inVientiane Municipality, Lao PDR.

Vannaxay is now responsible for fisheriesmanagement and catch per unit effort studies andalso deals with hydro-acoustics with the FisheriesProgramme’s FEVM Component.

Ms Souvanny Phommakonecompleted her M.Sc. in 2004with her thesis on the toxiceffects of two pesticides(Dimethoate and Profenofos) onNile tilapia fry and water fleas(Moina macrocopa). Theobjective of the study was toassess the consequences fromtwo frequently used pesticideson aquaculture production.

Souvvanny has since moved to the Living AquaticResources Research Centre Aquaculture Unit whereher main area of expertise is aquatic nutrition. Shealso works with the Fisheries Programme’sManagement and Governance Component as anatural resource planner.

Mr Oulaytham Lasasimmawrote his M.Sc. thesis in 2005on the potential for thedevelopment of integratedaquaculture systems in LuangPrabang. Since his return hehas been an active staff memberof the Aquaculture Unit and isstill keen on research into riverprawns in Lao PDR’s uplands.He also is a member of a newJapan/Lao cooperation project

“Development of Sustainable Freshwater AquacultureTechnology Suitable for Southeast Asia (JIRCAS)”.

Mr Boungsong Vongchivitgraduated from the InternationalAquaculture Master DegreeStudy Programme at KasetsartUniversity in Bangkok in 2006.His thesis was on frog culture(feed formulas). He is now theleading staff member in this fieldat LARReC.

Mr Thavone Phommavongreturned to LARReC in 2004with a diploma degree inaquaculture he earned at AIT.Prior to studying in Bangkok,Thavone worked for the CaptureFisheries Unit, LARReC, wherehe assisted the FisheriesProgramme with field surveys offish migration studies in theMekong River. He is now

responsible for database management andinformation dissemination of LARReC's technical andresearch publications, under the Data and InformationUnit.

We congratulate and acknowledge these staff, andwish them every success in their future work in thedevelopment of the aquatic resources in Lao PDR.


Cambodian governmentpresents award to FisheriesProgramme

Minister awards program with medal

The Cambodian government has presented an awardto the MRC Fisheries Programme in recognition of itscontribution to collaborative research in the fisheriessector over the past 12 years.

Agriculture, Forestry and Fisheries Minister Dr ChanSarun bestowed the programme with a Sahametreymedal which was received by programme manager DrChris Barlow in a ceremony in Phnom Penh in

January. The medal is one of the highest bestowed inCambodia.

The ceremony at the Inland Fisheries Research andDevelopment Institute took place during the annualmeeting of the Fisheries Administration, the first sinceit changed its name from the Department of Fisheriesunder a new fisheries law passed last year.

E v e n t s

MRC Fisheries Programme Manager Dr Chris Barlow receives the Sahametrey medal on behalf of the FisheriesProgramme from H.E. Dr Chan Sarun, Minister for Agriculture, Forestry and Fisheres, at a ceremony held at theFisheries Administraion, Cambodia.


S t a f f

Staff movements

Incoming

Ashley HALLS

Dr Ashley Halls has been appointed component coordinator for Fisheries Ecology,Valuation and Mitigation for the MRC Fisheries Programme. He has been based at theInland Fisheries Research and Development Institute (IFReDI) in Phnom Penh sinceJanuary 15.

Ashley joins the programme from Bath, England, where he had been director of his ownfisheries consultancy firm Aquae Sulis Ltd since 2005, mainly working for the London-based Marine Resources Assessment Group (MRAG). Before that, he was a seniorfisheries scientist and project manager at MRAG where he first started working in 1993after completing a master’s degree in applied marine science at the University ofPlymouth. He completed his Ph.D. on applied population biology at Imperial College,

University of London, in 1998. The research included studies on river fish ecology and migrations.

Over the past 15 years, Ashley has worked extensively in Asia, Africa, the Caribbean and Europe, mostly for theBritish agency DFID but also other agencies, notably the WorldFish Center and FAO. His work has largelyfocused on assessing the impacts of engineering structures and other hydrological modifications on fisheries. Inthe Mekong Basin, he has worked on several projects related to Cambodian fisheries including a DFID-fundeddata-collection project in collaboration with the MRC and other partners in 2003. He also made a presentationon modelling river fisheries to the Second Large Rivers Symposium in Phnom Penh in 2003.

Kaviphone PHOUTHAVONGS

Mr Kaviphone Phouthavongs has been appointed as a Programme Officer for the MRCFisheries Programme. He has been based at the MRC Secretariat headquarters inVientiane since December 2006.

Kavi rejoined the programme last year after completing a MSc. in fisheries management atthe University of Sydney under a DANIDA-funded scholarship awarded by the NationalAquatic Research Institute in Vientiane.

He originally joined the programme in 1998 as an officer with the Assessment of MekongCapture Fisheries Component, later becoming a senior socio-economic and databaseresearcher and acting component director. During this period, he also worked for the

Living Aquatic Resources Research Center (LARReC) as chief of the data and information unit. Kavi alsoattended a three-month GIS training course at the Vitus Bering Center for Higher Education in 2000.

Before joining the Fisheries Programme, Kavi worked on socio-economic aspects of livestock and fisheries forthe Lao Department of Livestock and Veterinary Services. He completed his first Master’s degree — in animalhusbandry — at the Kharkov Livestock and Veterinary Institute in the Soviet Union in 1991.


S t a f f

Outgoing

Khamtanh VATTHANATHAM

Mr. Khamtanh Vatthanatham has returned to the Department of Livestock and Fisheries of theLao Ministry of Agriculture and Forestry after almost seven years with the MRC FisheriesProgramme. Khamtanh joined the MRC in Phnom Penh in early 2000 and originally worked asa Programme Officer with the Management of River and Reservoir Fisheries component, nowknown as the Fisheries Management and Governance component. Between 2004 and the endof 2006, he was Programme Officer with the Assessment of Mekong Capture Fisheriescomponent which is now the Fisheries Ecology, Valuation and Mitigation component.

As one of the three members of the technical support group for the Technical Advisory Body forFisheries Management (TAB), Khamtanh became widely known among senior fisheries officialsin the Lower Mekong Basin. In late 2006, he accompanied TAB members on their first visit to

Myanmar, one of the MRC’s two dialogue partners (see page 12). During his time with the programme, Khamtanhalso played a leading role in organising seven annual meetings and six technical symposia on Mekong fisheries.

SENG Moheth

Mr Seng Moheth has returned to Cambodia after two and half years as an AssistantProgramme Officer with the Fisheries Programme at the MRC headquarters in Vientiane.Moheth joined the programme in 2004. Before that, he was an assistant research officer at theCambodian Department of Fisheries and an assistant technical officer with WetlandsInternational in Phnom Penh. He completed his Bachelor of Science degree in fisheries at theUniversity of Agriculture, Economy and Forestry in Viet Nam in 1997.


I n f o r m a t i o n

MRC Technical Paper No. 14 Fish migration triggers in the Lower Mekong Basinand other tropical freshwater systems.

Most of the commercially importantspecies of Mekong fish undergomigrations at some stage of their life-cycle and many of the Basin’sfisheries have developed specificallyaround the migratory behaviours ofthese fish. However, despite theimportance of migration to the fishand the fisheries we know little about

the biological and environmental factors that trigger, orcue, these migrations.

This report presents the conclusions of acomprehensive review of the published information onthis subject that the Technical Advisory Body forFisheries Management (TAB) commissioned in 2005.The first part of the review identifies a number ofenvironmental phenomena that seem to influence fishmigrations. The second part provides a quantitativeevaluation of information about the migration ofindividual species held in the Mekong Fish Databaseand FishBase databases. The report concludes withan assessment of the impact that manmademodifications to the natural flow of the Mekong and itstributaries will have on fish migration and as aconsequence to the wild fish stocks and to fisheries.

Proceedings of 7th Mekong Fisheries TechnicalSymposium

This volume contains twenty-nine ofthe papers and posters presented atthe 7th Technical Symposium onMekong Fisheries that was held inUbon Ratchathani, Thailand, duringNovember 2005. The papers areorganised around three themes: theassessment of Mekong fisheries, themanagement of river and reservoir

fisheries, and the aquaculture of indigenous Mekongfish species. The papers represent the work of overone hundred fisheries expects from the four membercountries of the Mekong River Commission as well asguest speakers from as far afield as Australia andSweden. The topics covered include subjects as

diverse as prawn fisheries in southeast Cambodia andfisheries co-management in the Central Highland ofViet Nam.

Fishing gears of the Mekong delta (in Vietnamese)

This book provides a catalogue ofthe great variety of the gearsemployed by the fishers of theMekong Delta of Viet Nam. It givesdetails of the construction of thegears, how and when they are used,and the fish and other aquaticanimals they are designed to catch.Fine-line hand drawn illustrationsand colour photographs support the

description of each gear. An English version of thetext is in preparation and will be published by theMRC in 2008.

The Mekong Delta: Fish, Farms and Families(available in Vietnamese and English)

Fishing is an integral part of the wayof life of many the rural families wholive on the Mekong Delta. Fishing,farming and families all interweavein a complex socio-economicstructure that is rooted in thebountiful aquatic resources that theMekong River and its distributariesprovide.

This documentary film, which was produced by theResearch Institute for Aquaculture No. 2 (RIA2) in HoChi Minh City, takes a close look at the fisheryresources of the Delta. Using exquisite footage shotover the varying seasons, the film explores theseresources at all levels from solitary fishers to large-scale commercial aquaculture enterprises. It alsodescribes the aquaculture and breeding programmesundertaken by the Vietnamese Department ofFisheries.

The film is one of four documentaries about onMekong’s fisheries. A documentary on the Cambodianfishery, Where There Is Water There Is Fish, wasreleased in 2003 and similar films on the Mekongfisheries of Lao PDR and Thailand are in the finalstages of production.

New InformationProducts


F i s h e r i e s i n d e x

Mekong FisheriesIndexMinistry to build aquatic breeding centreNhan Dan, 6 December 2006

The Ministry of Fisheries has approved a project tobuild a national aquatic breeding centre at the cost ofVND 49.9 billion (US$ 3.11 million). The project will bein Khan Hoa Province on the central coast and willinclude a breeding production research centre in VanHung Village, Van Ninh District and an experimentalquarter in Phuoc Dong Village for breeding specialaquatic species native to central Viet Nam.

Catfish are jumpin’ and exports are highViet Nam News, 27 December 2006

The Viet Nam tra and basa catfish industry sawrecord export earnings of US$661 million in 2006,twice as much as last year’s figure (US$328 million)according to the Ministry of Fisheries. Processed traand basa reached 250,000 tonnes from the 800,000tones harvested and the fish were exported to 65countries – an increase from 50 in 2005. TheEuropean Union became the major consumer of thefish and European exports represented 64 per cent ofthe total international shipments. Exports to Russiaalso soared and now accounted for 11.2 per cent ofall exports.

Precious Mekong Delta fish saved from extinctionThanNien News, 10 January 2007

A fish species on the brink of extinction has beenbred successfully at a research centre in southernViet Nam. Pham Van Khanh, head of the NationalCentre of Southern Freshwater Aquaculture in TienGiang province, said in the last two years ca ho, also

known as “the king of fish”, a giant carp weighing upto 160kg (Catlocarpio siamensis), had been bred atthe institute. The programme to breed endangeredfishes is part of a project in the Mekong Riversponsored by the Mekong River Commission and theDanish International Development Agency. Khanhsaid the species was in danger of disappearingbecause of over-fishing. The centre is now trying tobreed other rare fishes like ca vo co (Giantpangasius) and ca tra soc (Probarbus jullieni).

Rare Mekong dolphin making a comebackReuters, Cambodia, January 2007

Cambodia’s rare Mekong dolphin is making atentative comeback from the edge of extinction afternet fishing was banned in its main habitat, Cambodianand World Wildlife Fund officials said on Wednesday.There are now about 160 dolphins, up from only 90before net fishing was banned last year in the upperMekong River in the eastern provinces of Kratie andStung Treng borders, they said. The absence ofgillnets strung in the river, allowing dolphins fromother reaches of the river to move in, was the mainreason for the sudden jump in numbers.Touch Seang Tana, chairman of Commission forMekong Dolphins Conservation, said there should beabout 20 new babies born every year if this trendcontinued. Fishing was banned in the area last yearand local people were encouraged to grow crops, orwork in the growing tourism industry instead offishing. “The awareness, conservation and provisionof alternative livelihoods to fishermen, have helpedreduced adult mortalities,” the WWF said in astatement.


F i s h e r i e s I n d e x

Fisheries college trains farm staffViet Nam News, 8 February 2007

The Ministry of Fisheries is planning to improvevocational training for fishers and staff to meet thedemands of higher growth in aquaculture farms.Currently the Fisheries College No 4 is cooperatingwith other localities to open short term courses inmodern fish breeding methods for fishers. Shrimpfarmers have achieved higher productivity afterattending these classes and demand for the traininghas increased. Many farmers were initially notinterested in going to the classes but once they foundout they were effective in improving knowledge andproductivity they became keen to attend. The collegeis also experimenting in new breeding methods tomeet local demands.

Viet Nam catfish prices reach record highThanh News.com, 21 February 2007

Catfish prices have continued to rise in the MekongDelta. Some businesses said the low output of tra andbasa catfish on farms this year had forced their pricesup. The higher prices have encouraged more farmersin the delta to invest in expanding their fish farms,also forcing up breeding stock prices considerably.The country hoped to earn $1 billion from catfishexports this year, said Ngo Phuoc Hau, chairman ofthe Vietnam Association of Seafood Exporters andProcessors (VASEP)’s Mekong Fresh FishCommittee. Tra and basa from Viet Nam together withtuna and tilapia had changed Americans’ andEuropeans’ eating habits, the Vietnamese fisheriesministry quoted the Fisheries Information System, acommercial fishing industry web site, as saying.

Two new Oreoglanis namedPractical Fishkeeping, March 2007

Scientists from China have described two newspecies of sisorid catfish from the Yunnan Province.Kong De Ping, Chen Xiao Yong and Yang Jun Xingnamed the two new species as Oreoglanisjingdongensis and O. immaculatus in a paper in the

latest edition of the journal Environmental Biology ofFishes. The catfishes were discovered in the Mekongand Salween River basins in Yunnan Province, China,and reach a size of around 10-11cm. Oreoglanisjingdongensis is known only from the upper MengpianRiver, a tributary of the Mekong River, in JingdongCounty, Yunnan. It is a rheophilic species with a longslender body, and broad flattened head, which allow itto hug the bottom in fast-moving water. The authorssaid that the species is a member of the siamensisgroup: “[It] can be separated from all other Oreoglanisspecies by lower lip with distinct median notch andcaudal fin lunate with lower lobe longer than upperlobe. Males have a lunate caudal fin with extendedprinciple caudal fin rays. Oreoglanis immaculatus wasdiscovered during the examination of specimens offrom the upper Salween in Yunnan. The species isalso a member of the siamensis group and can bedistinguished from its congeners by the followingfeatures: lower lip with a strait median notch, posterioredge with indentations; caudal fin emarginate andlower lobe about the same length as upper lobe,having no yellow patches on sides of body belowadipose fin.” The Oreoglanis genus is part of thefamily Sisoridae, and contains around 10 species.

Irrawaddy Calf Mortality Rate Worrying, Says WWFCambodia Daily, 13 March 2007

More than five Mekong Irrawaddy dolphins have diedin Cambodia this high-fishing season since December– fewer than last year’s 14 deaths during the sameperiod, but worrisome because this year’s dead weremostly calves, according to WorldWide Fund forNature official Richard Zanre. “High calf mortality is ahuge problem for small population recovery. A total of19 dolphins died last year, also mostly claves,” Zanresaid. Usually born in December, calves are vulnerablewhile learning to swim and are easily caught infishermen’s nets, said Seang Tana, chairman ofCambodia’s dolphin conservation commission. TheMekong River’s 200 km stretch between Lao PDRand Kratie in Cambodia is the last Irrawaddy habitat inCambodia and home to about 100 dolphins.

38

39

F i s h e r i e s I n d e x


MRC launches first 24-hour navigational aidsystem in CambodiaMRC press release, 5 April 2007

The Mekong River Commission today laid theinaugural navigational buoy in Chaktomuk area in theaccess channel to Phnom Penh Port as the start ofwhat will be the first 24-hour navigational aid systemon the Mekong in Cambodia. The buoy was releasedin an onboard ceremony by H.E. Mr. Sun Chanthol,Minister of Public Works and Transport, H.E. Mr. TramIv Tek, Secretary of State of the Ministry of PublicWorks and Transport, Vice Chairman of the CambodiaNational Mekong Committee and, H.E. Mr JanMatthysen, Ambassador of Belgium to Thailand andDr Olivier Cogels, Chief Executive Officer of theMekong River Commission Secretariat. Over the nextsix months, the Aids to Navigation on the MekongRiver Project, will install 56 buoys of three types and12 leading markers over a 100km stretch of theMekong River, the busiest stretch of the Mekong inCambodia. These buoys will mark a safe channelfrom Phnom Penh Port to the Cambodia-Viet Namborder. The installation of this internationallyrecognised system of aids to navigation such asbuoys, beacons and shore marks, aims to improvesafety and efficiency of navigation so that sea-goingvessels and inland barges can safely navigate for 24hours a day in safety. The navigational aids project ispart of the MRC’s Navigation Programme which isfunded by the Government of Belgium.

Giant catfish to be hunted againBangkok Post, 19 April 2007

Chiang Rai: Fishermen are getting poorer waiting fora promised job creation scheme that convinced themto stop catching Mekong River giant catfish. So theyhave decided to resume the hunt. Many fishermenfrom Hat Khrai village in Chiang Rai's Chiang Khongdistrict say their income has plummeted since theypledged to stop catching the giant catfish, or pla buek,said Poom Boonnak, chairman of the Pla Buek Club

in the village. Some of the affected fishermenyesterday sought district authorities' permission tocatch the rare species again, he added. On April 18last year, local fishermen agreed to stop catching thegiant catfish after local and international conservationgroups led by former Chiang Rai senator TuenjaiDeethes, now a member of the National LegislativeAssembly (NLA), promised to come up with economicmeasures to help them. The fishermen had alsoagreed to sell 68 seine nets, worth about 20,000 bahteach, to symbolise the end of the hunt. Last year, theconservation groups sought donations worth around1,360,000 baht to buy the seine nets from thefishermen. They also promised to set up a fund tohelp the fishermen start new careers. Mr Poom saidhis group recently received 1,260,000 baht for 63seine nets. The payment for the five remaining nets,worth 100,000 baht, has not been made, he said.Since the agreement was made, there have been nomeasures to help the affected fishermen. The jobcreation scheme has not yet taken off. Ms Tuenjaiearlier promised to seek cooperation from theLivestock Development Department to provide cattlefor fishermen wanting to raise cows to earn a living.So far not a single cow has been distributed to them,said Mr Poom. A close aide of Ms Tuenjai said theNLA member has tried to find ways to help theaffected fishermen. She has sought help from otherNLA members to donate money to buy cows for thefishermen. A source said hunting the giant catfish hasbeen a crucial source of income for Hat Khraifishermen for decades. Before they agreed to stopcatching it, they normally caught the fish during Apriland May in the Mekong river. Around 60 to 70 plabuek were caught a year, each weighing around 100to 250kg and fetching around 100 to 250 baht a kilo.

Published by the Mekong River Commission Secretariat

P.O. Box 6101, 184 Fa Ngoum Road, Unit 18, Ban Sithane Neua,Sikhottabong District, Vientiane 01000 Lao PDR

Phone: 856-21-263 263 Fax: 856-21-263 264Website: www.mrcmekong.org

Mekong River CommissionP.O.Box 6101, 184 Fa Ngoum Road, Unit 18, Ban Sithane Neua,

Sikhottabong District, Vientiane Lao PDRTelephone: (856) 21 263 263 Facsimile: (856) 21 263 264

E-mail: [email protected]: www.mrcmekong.org

Sex change shrimps breed more males

Dai fishery records another good year

Fisher community joins study on netting impacts

Focus on the fishery of Siphandone

Conservation strategy for Mekong giant catfish

Volume 13, No. 1 ISSN 0859-290X April 2007

Fisheries Research and Development in the Mekong Region

INSIDE

Research


The Vientiane-based Living Aquatic Resources Research Centre (LARReC) conducts research inthe area in collaboration with the MRC Fisheries Programme and the French Agricultural

Research Centre for International Development (CIRAD). Research has covered areas from fishbiology to the sustainable use of fisheries resources and co-management. To assess

migrations, studies of catch per unit of fishing effort (CPUE) have been carried out since 1991.An aquaculture station at Ban Hat village is used to domesticate indigenous species for

aquaculture. So far, seven species have been bred successfully. To conserve and sustain theuse of fisheries resources, fisheries co-management has been introduced.

Photos: LARReC and Philippe Cacot

In Lao, Siphandone means "four thousandislands" and refers to the area around the Khong

district of Champasack province borderingCambodia. A popular tourist spot, it featuresmany rocks and rapids that create a unique

environment in terms of fish diversity, traditionand culture. The area is also home to the

Mekong dolphin. The falls form a natural barrierto navigation between the lower stretches of theMekong River in Cambodia and Viet Nam and the

upper reaches in Lao PDR and Thailand.

Photos: Joe Garrison

Bird's eye view

S i p h a n d o n e F i s h e r i e s

Spec ia l inser tSpec ia l inser t

Catch and Culture Volume 13, No.1 April 2007

Wild capture fisheries


Wild capture fisheries play a very important role in local livelihoods. More than 90 percent ofSiphandone families are engaged in fishing or related activities. The two main fishing seasonsare during the Lunar New Year during the dry season (usually in February) and between May

and July during the wet season. Most of the fishes caught during these two periods aremigratory species. Overall, more than 200 species have been documented in the area.

Photos: Joe Garrison, Philippe Cacot and LARReC

Fishing gear

Catch and Culture Volume 13, No.1 April 2007

Wing traps, known as li in Lao, areunique to the area. Gill nets and castnets as well as hooks and lines are

also common. The selection of fishinggear depends on the season and

water conditions. For instance, gillnets and cast nets are used in the dryseason when water levels and flowsare low. Traps, along with hooks and

lines, are used in the wet seasonwhen water levels are high and

currents strong. Li traps are used inchannels near waterfalls to captureschools of fish migrating upstream

from Cambodia.

Photos: Joe Garrison, Philippe Cacot and LARReC.