Aquanews ~ Summer 1998

Sustainable Aquaculturefor a Secure Future

POND DYNAMICS/AQUACULTURE COLLABORATIVE RESEARCH SUPPORT PROGRAM NEWSLETTER

Volume 13, Number 3/Summer 1998 Oregon State University ISSN 1062-4996

A quaculture is an importantagricultural activity inHonduras. Tilapia farms, while

concentrated in northern Honduras,also are found in the other regions of

the country. Shrimp farming is locatedexclusively along Honduras’ Gulf ofFonseca coastline. The overwhelmingmajority of shrimp farms have beenconstructed on un-vegetated salt flatslocated in the eastern part of the Gulfnear Nicaragua. Because of these twoimportant aquacultural activities inHonduras and their associatedresearch needs, the Honduras CRSPproject has developed researchprograms for tilapia culture and forshrimp culture.

Tilapia culture in Honduras hasentered a phase of rapid development,yet the production systems currentlyin use have been derived empiricallyby farmers. Thus, it is through theHonduras project that a systematic

research program on tilapia culture isbeing implemented. Priority researchareas include the Global Experimentand production system intensification.Planned research on production

systemintensification willbe applicable notonly to tilapiaculture in LatinAmerica, but also inthe US.

Research activitiesare centered atDIGEPESCAs ElCarao National FishCulture ResearchCenter located inComayagua, wherebiologists CarolinaCardona and NelsonClaros, andtechnician Rene

Palacios are involved in the dailyimplementation of pond studies andwater quality analyses. The El Caraostation, constructed in the late 1970s aspart of a USAID/Hondurasaquacultural development program,has been the Honduras project’stilapia researchsite since 1983.Beginning lastyear theHondurasproject initiateda series ofneededrenovations atthe station usingPD/A CRSPfunds: the water

quality laboratory was renovated,project ponds were repaired, a blowersystem is being installed in the wetlab, and electricity and securitylighting were installed at the ponds.

Honduran shrimp culture relies onextensive to semi-intensive productiontechnologies. Farms often are locatedalong riverine estuaries, which servenot only as water sources, but also asdestinations for pond effluents.

Fresh and Brackish Water Aquaculture in Hondurasby Bartholomew W. Green

. . . continued on p. 8

Need Help with the Acronyms?(NHWA!)

Host-country collaborators include the GeneralDirectorate of Fisheries and Aquaculture (DIGEPESCA),the Ministry of Agriculture and Livestock, theHonduran National Association of Aquaculturists(ANDAH), and the Panamerican Agriculture School (EAP).Auburn University, the University of Texas at Austin,and the University of Arkansas at Pine Bluff are theUS institutions currently involved in Honduras projectresearch.

Ponds at El Carao National Fish Culture Research Center

South central Honduras

them critique what I did. It was anhonor.”

While at TuskegeeUniversity, Malkiawas encouraged tolook into graduatework at AuburnUniversity by hermentor, CathyWinkler, to whomMalkia firstexpressed aninterest in sociology.Malkia choseAuburn because ofthe many projectsunderway there thatinvolvedaquaculture andcommunitydevelopment insome way, and she

felt that Auburn’s program fit herneeds quite well.

A lthough her first official

encounter with the CRSP was atthe CRSPs 16th Annual Meeting

in Las Vegas in February, MalkiaLockhart has been affiliated with theCRSP since she began her Master’sprogram in rural sociology at AuburnUniversity last year. As JosephMolnar’s graduate student, Malkia hasbeen working on the CRSPs Kenyaproject ever since. The data she iscollecting on the Kenya project willform the basis of her thesis, which shehopes to finish by August 1999.

Malkia’s interest in aquaculture andcommunity development grew fairlyrecently out of several sociologycourses she completed while anundergraduate at Tuskegee University,Alabama, where she received her BS inbiology in 1997. In 1995, shecompleted her Associate of Artsdegree in biology with a minor in

chemistry in her home country of theBahamas at theCollege of theBahamas, Nassau.

Among heraccomplishments atTuskegee was aresearch paper shewrote entitled“Females and theirTolerance of VerbalAbuse,” which shepresented atmeetings of theSouthernSociologicalAssociation inMemphis, Tennessee.

Malkia enjoyed thisopportunity,explaining that “Itwas a wonderfulexperience to be able to converse withso many intellectuals I met and to have

CRSP Graduate Student Profile: Malkia Lockhartby Matt Niles

I n E n g l i s h , F r e n c h , & S p a n i s h

1 9 8 7 - 1 9 9 5

F R O M T H E P D / A C R S P R E S E A R C H R E P O R T S E R I E S

New Publication From PD/A CRSP

THE COLLECTED ABSTRACTS FROM THE PD/A CRSPRESEARCH REPORT SERIES

IN ENGLISH, FRENCH, & SPANISH, 1987-1995

Translations by Félicien Rwangano and Gabriela Montaño.

The Research Report Series of the PD/A CRSP waslaunched in 1987 as a means of disseminating CRSP-sponsored research results. Each report consists of anabstract, of research work that has been published either inthe peer-reviewed literature or by the CRSP. To increaseaccessibility the series of reports through 1995 has now beencompiled in this single publication, together with previouslyunavailable French and Spanish translations.

This is a 187-page collection of 88 abstracts. Each abstract ispresented in English, French, and Spanish. In the case ofreports published in peer-reviewed journals, referenceinformation is provided. Copies of reports published by theCRSP can be obtained from CRSP Publications. Copies of theCollected Abstracts can also be requested from the CRSP:

PublicationsPond Dynamics/Aquaculture CRSPOregon State University400 Snell HallCorvallis, OR 97331-1641

E-mail: crsp.mail@orst.edu or check out our website atwww.orst.edu/Dept/crsp/homepage.html

Malkia Lockhart, graduate student in ruralsociology at Auburn University, Alabama

Aquanews ~ Summer 1998

I n May Gabriel Marquez-Couturier presented a seminar atOregon State University entitled

“A Multidisciplinary Project forSustainable Management of NativeFlora and Fauna of the Wetlands inTabasco, Mexico.” He was in Corvallison a scientific exchange with thePD/A CRSP from the UniversidadJuarez Autonoma de Tabasco, where,in addition to conducting research onthe larval development of fish in therivers of Southern Mexico, he has beeninvolved with several aquacultureprojects.

Gabriel described hisefforts to date towardsdeveloping a project tosustainably manage theextensive wetland areasof Tabasco. This projectis intended to bedeveloped in an areapopulated by the“Chontales,” anindigenous grouplinked with the ancientOlmec civilization. It isan ambitious project,spanning many

disciplines andcurrently involvingnine professors andtheir combinedresources, includinglabs, students, andlibrary materials.

The native people inTabasco andsurrounding regionshave a very strongconnection to theenvironment; in thepast, developmentprojects have

overlooked this. The fundamental goalof Gabriel’s project is to establish amanagement plan for naturalresources and wetlands that will strikea balance between the environmentand the existing political andsocioeconomic dynamics of the region.Earlier management plansimplemented in this area have ignoredthese factors.

The University of Tabasco is alsoworking to complete an assessment ofthe environmental impact ofdevelopment in the area anddetermine possibilities for theenvironmental improvement of theregion. The biodiversity of the nativewetland flora and fauna of the regionhas been particularly affected bydevelopment, and the Universityhopes to reverse this trend byrecovering traditional uses of nativespecies in the region. One way theUniversity hopes to accomplish this isto use native species, such as thetropical gar, in several of itsaquaculture projects.

Tropical gar are among the mostimportant food fish in the region,and gar culture has been triedsuccessfully in the lab at theUniversity of Tabasco. Severalstudies have been performed on garfry, which can be raised in the lab,brought to aquaculture sites, andreleased when they reach about 5 cmin length. Projects such as these canbe easily transferred from theUniversity to the community.

Finding a Natural Niche for Aquaculture in Southern Mexicoby Matt Niles

Malkia feels that the CRSP Kenyaproject can be a “win-win” situationfor everyone involved. “The USgovernment and organiz-ations,Kenyan organizations, and theKenyans themselves all gain becausethey can all benefit from the datacollected in the study,” Malkiaexplains, adding, “There is so muchthat is not known about practices inAfrica, so I see how beneficial theCRSP work is.”

“How can other countries assistAfrica in moving toward self-sufficiency if they know nothing aboutthe socio-economics and culturalviews of the country?” Malkia asks.

Additionally, she explains, “Othercountries are at an advantage becausethey have these studies to compareand maybe perhaps implement asimilar plan or perhaps to use thetheories in the adoption of another

innovation. For example, maybe nottilapia but shrimp instead.”

Although the work at Auburn isMalkia’s first exposure to aquaculture-related research, Malkia hopes to assistwith at least two publications before shecompletes her degree, and at 21 yearsold, Malkia has already compiled animpressive list of accomplishments. Sheis a member of Zeta Phi Beta SororityInc., which is a social and communityservice organization. Her chapter holdsblood drives, visits with delinquentyoung men to encourage and mentorthem, and conducts health awarenessprograms on AIDS, breast cancer, andother diseases.

“I really enjoy giving back to thecommunity because I think of all thepeople who have given me a chance toimprove myself, and I would like topass along this kindness and joy toothers.” . . . continued on p. 8

Aquaculture research pond at the University of Tabasco

The wetlands of Tabasco support a wide variety of native species thatare threatened by development

T he CRSP is delighted to reportthat one of its long-termassociates, Félicien Rwangano,

successfully defended his doctoralthesis “Growth and reproduction ofOreochromis niloticus (L.) in tropicalaquatic microcosms at fluctuatingtemperature regimes” at Oregon StateUniversity on 15 April 1998.

Félicien Rwangano joined the CRSPin Rwanda as a host country ResearchAssociate in 1985. He held aBaccalaureate degree in Mathematicsand Natural Science with a minor inScience Teaching Methods, and anIngénieur Agronome (AgriculturalEngineering) degree with emphasis onanimal production and its economics.He also held a research post as afaculty member of the College ofAgronomy at the National Universityof Rwanda. He worked with the CRSPat the Rwasave station on Cycle I to IIIexperiments, encompassing work onsite characterization during wet anddry seasons and organic inputsincluding composted grass, rice brans,and chicken manure.

From 1988 to 1990 Rwanganoworked towards his masters degree inFisheries Science at Oregon StateUniversity. He conducted growthtrials at Rwasave where he tested theeffects of various organic inputs on theproductivity of ponds stocked withNile tilapia. His investigationdemonstrated the efficacy of mixedgreen grass for the fertilization oftilapia ponds. Rwangano completedhis Masters in 1990 and returned tovisit the National University ofRwanda and the Rwanda NationalFish Culture Project to investigatetilapia farming at high elevations.

Much of Rwanda is a mountainousregion, presenting a particularchallenge to aquaculture. Withconsideration of the low watertemperatures recorded above 1500 mand during the dry season in theseregions, the PD/A CRSP research inRwanda focused on revising theknowledge of high-altitude constraintsto aquaculture. Aquacultural efforts inRwanda demonstrated that tilapia

could be grown atelevations up to 2300m (the CRSP prime siteat Rwasave was at analtitude of 1700 m).Integrated systemsusing poultryproduced 250- to 400-gtilapia, andexperiments withchicken manure(optimum applicationof 500 kg dry weighthectare-1 week-1) andadditional nitrogen orphosphate, if thesewere limiting, provided yields of up to2,000 kg ha-1 yr-1.

The outbreak of violence in Rwandain October 1990, which climaxed in1994, led to the loss of life of severalmembers of CRSP personnel,including Dr. Valens Ndoreyaho, thenCRSP PI and Rwangano’s supervisor.The crisis prevented Rwangano fromconducting his doctoral research inRwanda. However, Rwanganocontinued his interest in the growthand reproduction of tilapia undervarious temperature regimes. Hedesigned and successfully conducted

laboratory experiments simulatingtropical conditions at Oregon StateUniversity’s Department of Fisheriesand Wildlife. Now that his doctoralprogram is completed, he wants tocontinue research on tilapiaaquaculture, especially integratedsystems, which he values for theirparticularly efficient use of resources.He is also interested in developingtemperature-related models incombination with other factors such asfeeding and stocking rates.

The 1994 crisis in Rwandainterrupted CRSP work at the

GROWTH AND REPRODUCTION OF OREOCHROMIS NILOTICUS (L.) IN TROPICAL

For his doctoral research Rwangano investigated the growth andreproduction of tilapia under various temperature regimes, with particularemphasis on the generally overlooked aspect of temperature fluctuation.He carried out two experiments using 0.7-m3 (1.4-m2) experimental tanks,mimicking the conditions of aquaculture ponds found at differing altitudesin Central Africa. In the first experiment, he grew tilapia at 19 and 25°C,with daily temperature fluctuations of ± 1, 3, or 6°C. Tilapia grew morerapidly at 25°C (yields ranging from 26 to 33 kg are-1 yr-1) than at 19°C (yieldranging from 20 to 30 kg are-1 yr-1). However, at both temperatures, thehighest yields were obtained under the greatest temperature fluctuations.

The second experiment investigated the effects of temperature and temper-ature fluctuation on both growth and reproduction. In this experiment tilapiawere reared at 22 and 28°C, again with daily temperature fluctuations of ± 1,3 or 6°C. The results confirmed those of the first experiment, that growth wasmore rapid at the higher temperature and at greater temperature fluctuations:in addition, they showed that reproductive output was also greater underthese conditions.

These results have practical management and economic implications.Under cool temperature conditions tilapia can be grown with little

Interview with an Alumnus—Félicien Rwanganoby John Baker

Rwangano at his office in Nash Hall, Oregon State University

Aquanews ~ Summer 1998

ikelihood of the occurrence of reproduction although the production cycle isonger due to slow growth, and the fish production in these regions is lowerhan that from warmer areas. Tilapia culture projects undertaken in coolemperature areas need to investigate sources of fingerling supply, since it

will not be possible to produce these locally. Methods for controlling tilapiareproduction must be considered in warmer regions. The linear relationshipbetween cumulative degree-days and growth and production in theseexperiments is of predictive value to researchers, extension agents, andprospective farmers. Expected fish yields in a particular climatic zone can becalculated, allowing farmers to assess whether expenditure on plannedaquacultural ventures will pay off financially.

Rwangano recommends the adoption of pond management/constructionstrategies to maximize both pond temperatures and the capacity of thepond water as a heat sink. Ponds should be located in warm locations andnot incorporate water flow-through, which can reduce pond temperatures,as the inlet water is several degrees cooler (average 5°C difference inRwanda) than the pond water. Shallow ponds (minimum and maximumdepths of 0.4-0.5 and 1.0 m, respectively) with 1-2% slopes arerecommended since they tend to maintain warmer temperatures.

Rwasave station and its researchactivities at different elevations.However, prior to this time, CRSPresearchers at Rwasave were involvedin aquacultural research and extensionwork in liaison with the National FishCulture Project, funded by a USAIDgrant to Auburn University, Alabama.One of the impacts of the CRSP inRwanda was the spread of fish culturetechnology further afield, as Rwasavebecame the regional center of focus fortilapia culture in Central and EasternAfrica. Rwangano points out thatresults from CRSP research carried outin Rwanda are applicable to otherlocations and believes thatcollaborators from Zaire, Burundi,Tanzania, and Kenya who visitedRwasave will have benefited from thework carried out there.

Rwangano believes that of the manyachievements of the CRSP in Rwanda,particularly valuable outcomes werethe establishment of baselineaquacultural data, furthering theunderstanding of pond dynamics forhigh-elevation sites where resourcesare limited, and the demonstrationthat at such sites aquaculture provedto be not only a source of protein forhuman nutrition, but also yieldedgreater financial income than anysubsistence crop.

T he work of the PD/A CRSPwas presented to Oregon StateUniversity staff and students

and to the Corvallis communityduring OSUscelebration ofEarth Week (April20-24). DuringEarth Week,OSUs StudentAffairsCommitteeorganized a seriesof environmentalevents. The CRSPstaffed a booth atthe InformationFair showcasingaquaculture andthe work of CRSPin aquaculturaldevelopment. Ata time when thegeneral public is questioning theenvironmental impacts of aquacultureand the media are tending to focus onits environmentally damaging aspects,it is important that the sustainabledevelopment of warmwateraquaculture and its potential benefitsare presented as widely as possible.

Earth Week’s Information Fairprovided the opportunity to presentwarmwater aquaculture in the contextof environmentally benign

developments. The booth generatedinterest and questions from EarthWeek participants and was received ina positive manner.

In keeping with the informalatmosphere of the Fair, the CRSPorganized an aquaculture poetrycompetition. The winning entry“Untitled # 5,” below, was written byKris McElwee and Sayea Jenabzadeh,who were awarded a CRSP T-shirtand mug. The following two poemsgo some way towards capturing thedepth of talent of this newlydiscovered literary duo:

CRSP Booth at OSUs Earth Weekby John Baker

Untitled # 5

From Kenya to far-off PeruYou want boys? Here’s what you do;MDHT in a pailYour fish come out all male.Ten months later just see how they grew.

Untitled # 6

Goats poop in my pond.Look how quickly my fish grow.

Yum, tilapia.

Kris McElwee (left) and Sayea Jenabzadeh model T-shirts and a tilapia hat atCRSPs Earth Week booth at Oregon State University

AQUATIC MICROCOSMS AT FLUCTUATING TEMPERATURE REGIMES

Fishellaneous Items

Farmed Shrimp Production IncreasesColombia—June 9, 1998

Production of farmed shrimp on Colombia’s Atlanticcoast increased from 5,500 to 6,217 tonnes in 1997,

despite the reduction in the farming surface, whichdecreased from 2,251 to 1,919 hectares. Export revenues alsorose, from US$26.64 million to US$35.35 million.

According to a study, Colombia has a big potential for shrimpfarming, since there are 24,000 hectares suitable for aquacultureactivities.

Source: Fish Info Service, www.sea-world.com. Reprinted withpermission.

British Investment in Costa Rican Tilapia

T he Commonwealth Development Corporation (CDC) hasstrengthened its position in the aquaculture sector by

taking a controlling (85 per cent) interest in AquaCorporacionInternational SA (ACI) and ownership of the brand RainForestTM from the US owners who were responsible for thesuccessful development of the company.

Based in Costa Rica, ACI was founded in 1986. Its principalactivities are the growing, processing and exporting of freshtilapia fillets to the North American markets under the RainForestTM brand name. Under CDC ownership ACI is expectedto expand from 4,000 to 8,000 tonnes per annum.

US sales are controlled through a Maine based sales andmarketing subsidiary of ACI, Rain Forest Aquaculture whichsells and distributes most of the fish produced by ACI.

Cosmetics Based on FishChile—May 23, 1998

S almon, among with other animal and vegetableproducts, can be used in the cosmetics industy,

according to an article published in the Chileannewspaper El Mercurio.

The article said that an extract obtained from thesalmon’s flakes could be used in creams, cosmetics andeven in nail enamel. From 100kg of flakes, about 2kg ofextract could be produced, which was enough to prepare8kg of final product.

This industry might be very important for Chile, as thecountry is the world’s second biggest salmon exporter.

Source: Fish Info Service, www.sea-world.com. Reprintedwith permission.

T he Thai government is takingnew steps to discourage farmers in

rice-producing areas from switching tomore profitable shrimp farming,which is highly damaging to theenvironment, officials said in May.

The Agriculture Ministry isnonetheless concerned that Thailandmaintain its position as the world’snumber-one shrimp exporter, saidDhammarong Prakobboon, director ofthe Fisheries Department.

Pongpol Adireksarn, the agricultureminister, has ordered the departmentto stop allowing shrimp farms in ricezones, where high salinity and effluentin the waste water from shrimpfarming damage the water table andagricultural soil. Pongpol said farmersshould be encouraged to move tosaltier areas in coastal regions.

“We want to solve problems ofenvironmental protection and ofcourse we want shrimp farming to besustainable,” Dhammarong said.

Shrimp farming has badly damagedmangrove forests in coastal areaswhere it became popular about adecade ago. Officials want to moveshrimp farming away from themangroves as well as rice land to areaswhere it will have minimal impact.

Thailand is the world’s number-one shrimp exporter, producingsome 300,000 tons of the worldannual demand of 800,000 tons.About 90 percent of shrimpsexported from Thailand come fromfarms.

Source: The Aquaculture News Vol. 6,No. 7, May 1998.

Thai Government Making Efforts to Limit Shrimp FarmPollution

Customers are primarily speciality seafood distributors, foodretailers and broadline distributors. In 1997 the company’ssales exceeded US$12 million.

The acquisition of ACI complements existing CDCaquaculture activities, in particular, Lake Harvest Aquaculture(PVT) Ltd., a Zimbabwean tilapia operation based on LakeKariba. This project will benefit from the technical andmarketing capabilities which ACI has developed.

CDC is the British overseas development finance institutionwith headquarters in London and 27 overseas offices. At theend of 1997 its investments totalled US$2.6 billion in over 400businesses.

Source: Fish Farmer International 12, no. 2, March/April 1998.

Biggest Fish Farm in theWorldAzerbaijan—May 25, 1998

A ccording to the newspaperAzadlyg, Azerbaijan plans to

build the biggest fish farm in theworld by the first quarter of the year2000.

Reportedly, the US$5 million farm,to be sited on the Kura river, willproduce some 15 million sturgeon peryear. If approved, an internationaltender will be held. It is thought thatthe Azerbaijani government hasalready held talks with the WorldBank.

Source: Fish Info Service, www.sea-world.com. Reprinted with permission.

Aquanews ~ Summer 1998

African Catfish Spread inAsiaDr. Hans A.J. Middendorp reportspromising progress with intensiveculture in Bangladesh

African catfish today seemstriumphant all over southeast

Asia, and has now spread across thebreadth of southern Asia as well. Thestory goes that only a few fish wereoriginally introduced to Indo-Chinafrom Africa by the French in the 1950swhere it hardly survived the Indo-China wars.

From Vietnam, it reached Thailandin the early 1980s, where hybrids ofAfrican catfish, Clarias gariepinus, andthe local ‘Pla duk oui,’ Clariasmacrocephalus, have since successfullytransformed catfish rearing into a bigbusiness. . . .

African catfish, or magur, as it iscalled on the Indian subcontinent,

reached Bangladesh in 1991. Africanmagur fingerlings were introducedfrom Thailand by officials from theMinistry of Fisheries and Livestockand were successfully bred in Jessorein 1992. Since then, an importantcatfish fry export business has been inoperation from Jessore, with manythousands of catfish fingerlings beingsold every year to West Bengal andAssam. Surprisingly few magur areactually reared to market size withinBangladesh, as it fetches relatively lowmarket prices compared to the Indianmajor carps.

African catfish fingerlings werebrought to Andrah Pradesh fromJessore soon after introduction toBangladesh. The area around Kollerulake in Andrah Pradesh has become animportant aquaculture producer ofIndian major carps (rohu, catla andmrigal) and farmed carps fromAndrah Pradesh are routinely . . . continued on p. 9

exported to Dhaka, at an estimateddaily contribution of between 20 and30 per cent of the Dhaka fishwholesale market. African magurfingerlings may have reached Kolleruon the return trade.

From Andrah Pradesh, catfishfingerlings reached Kerala in 1993 orearly 1994. It can be safely assumedthat African catfish also found its wayto Tamil Nadu in the same period. Itwas certainly bred in Kerala in 1995,where it seemed to be welcomed bythe market. As one aquacultureentrepreneur in Kerala stated at theend of 1996: “Any fish which will fetchmore than 70 rupees (US$2) per kg isinteresting for culture”.

There is a clear interest in rearingAfrican Magur in south India, althoughnobody yet seems quite clear on theappropriate rearing techniques. Catfishrearing is certainly different from a

It’s High Time for a NewFeedUnited States—June 6, 1998

K entucky State Universityresearchers are feeding 150 blue

catfish a fish meal diet mixed withhemp - with positive results so far.

Using hemp meal provided by CraigLee, of the Kentucky Industrial HempAssociation, the researchers will startanother study on channel catfish inJune using formulations closer tocommercial feed; they will trysubstituting hemp meal for soybeanmeal, a main ingredient in fish feed.

At the moment, US-producedsoybean meal, about 50-60% of thefish food market, costs about US$170a ton, plus delivery. Hemp meal, withits higher shipping cost, is aboutUS$1,200 a ton. Most hemp seed nowcomes from China, because growinghemp is illegal in the US.

However, hemp meal could replacefish meal (another fish feed ingredient)in the future; because of El Nino’schanges in ocean temperature, fishmeal has skyrocketed to US$600 a ton.

Source: Fish Info Service, www.sea-world.com. Reprinted with permission.

T he V Central AmericanSymposium on Aquaculture,

“Aquaculture & The Environment:Together Into The New Millennium,”sponsored by the Asociacion Nacionalde Acuicultores de Honduras(ANDAH), the Latin AmericanChapter of WAS, and the PD/A CRSP,will be held 3-5 March 1999 at theCentro Social Hondureño Arabe in SanPedro Sula, Honduras. The VSymposium will have a full programon Tilapia and Shrimp and will draw alarge attendance from internationalaquaculture professionals.

The IV Central AmericanSymposium on Aquaculture, held 22-24 April 1997 in Tegucigalpa,Honduras, was a tremendous successwith double the number of attendeesfrom the III Symposium. The IVSymposium included a full programon tilapia as well as shrimp. ANDAHand the Latin American Chapter ofWAS worked together to produce theIV Symposium.

Because the conference andexposition have grown so much, the VSymposium has been moved to SanPedro Sula in the northern part ofHonduras. San Pedro Sula is the

V Central American Symposium on Aquaculture

industrial center of Honduras withone of the largest and most modernports in the Central American region.San Pedro provides better meetingfacilities and hotels. It is situated closeto the Caribbean beaches, the beautifulBay Islands and the Copan ruins, aswell as other sites of interest. SanPedro makes an ideal starting pointfor your pre- or post-conferencevacation. It is easy to fly into SanPedro Sula from just about anywhere.

There will be three full days ofconferences, exhibits, receptions andtime to meet with others in the shrimpand tilapia industry. The Program willinclude a full range of presentationson shrimp and tilapia production byleading experts from around theworld. All aspects of shrimp andtilapia production will be addressed.There will be industry tours forshrimp and tilapia on the day after theSymposium ends (6 March).

For further information:USA: John Cooksey; Tel: +1-425-485-6682; Fax: +1-425-483-6319; email:worldaqua@aol.comHonduras: Alberto Zelaya; Tel: +504-882-0986; Fax: +504-882-3848; email:andah@hondutel.hn

Estuarine water qualitysignificantly affects shrimpculture, which in turnaffects estuarine waterquality. The potential fordevelopment of shrimpfarms along an estuary willbe dictated ultimately byestuarine water quality,which itself is controlled bynutrient inputs from riverdischarge, shrimp farms,terrestrial agriculture,rainfall runoff, municipaldischarge, and exchangewith the Gulf of Fonseca.

Honduras project researchon environmental impactsof shrimp culture focuses onmonitoring water quality inshrimp farming estuariesand on estimating theassimilative capacity ofthese estuaries. On a weeklybasis, estuarine watersamples are collected andtransported by participatingfarmers to the DIGEPESCA-ANDAH-PD/A CRSP

waterqualitylaboratory,La Lujosa,Choluteca,wherechemistsDeliaMartinezand EneidaRamírez andtechnicianJaime Lópezareresponsible

for water quality analyses. During the pastyear ANDAH has provided funds to enlargethe lab and to drill a new well, and the PD/A CRSP has purchased additional lab andcomputer equipment, and lab supplies.

Another component of the Hondurasproject shrimp research effort addressesproduction system optimization. BecauseDIGEPESCA does not have a brackish waterresearch station, pond research is conductedon ANDAH members’ farms in a trulycollaborative partnership between farmersand CRSP researchers. Pond trials aredesigned jointly by Honduras projectresearchers and farmers. Farmers provideponds, all pond inputs, and daily pondmanagement, while the CRSP conductswater quality analyses at the La Lujosa laband analyzes and reports research results.Results of research conducted on feedingrates and water exchange rates have shownthat both can be decreased without affectingshrimp production.

In the coming year, Honduras projectresearchers hope to regionalize projectactivities to Nicaragua and Costa Rica.Project personnel have submitted proposals

to initiate shrimpresearch andestuarinemonitoring inNicaragua basedupon the Hondurasproject model. Andin Costa Rica, theCRSP hopes towork with EscuelaAgrícola de laRegión TropicalHúmeda (EARTH)on research related to pond management strategies. With theimplementation of these activities, the Honduras PD/A CRSPwill achieve a truly regional impact.

Fresh and Brackish Water Aquaculture in Honduras. . . from p. 1

Honduras project staffinclude: Claude Boyd ,Carolina Cardona, FedericoCharres , Nelson Claros ,Bartholomew Green, JaimeLopez, Delia Martinez, MarcoPolo Micheletti , RenePalacios, Eneida Ramírez, andDavid Teichert-Coddington.

Despite the appeal of working with native species,the University feels that it cannot ignore provenaquaculture species such as tilapia, and otherprojects include efforts at the farm level tomasculinize tilapia with immersion treatments. Thiswork relies heavily on students, who work asvolunteers. Last year there were ten studentsinvolved in the project, and this year Gabriel has 15

students working for him. Gabriel is currently selectingbroodstock to find the best masculinizing technique toproduce large quantities of tilapia and bring this technologyto the farm level.

Gabriel also expressed an interest in forging connections tothe project with interested OSU faculty. Such a connectionwould offer both OSU and the University of Tabasco aninvaluable exchange of knowledge and resources.

. . . from p. 3Finding a Natural Niche for Aquaculture in Southern Mexico

Water quality laboratory at La Lujosa, Choluteca

Assimilative capacity is thenutrient load that can besustained without degradingreceiving water qualitybelow acceptable levels.Determination of estuarineassimilative capacity is along-term effort because ofseasonal and annual variationsin water quality, and becauseassimilative capacity is afunction of position in theestuary.

Aquanews ~ Summer 1998

Notices of PublicationCRSP Research Report 98-124

SMALL-SCALE FISH FARMING IN RWANDA:ECONOMIC CHARACTERISTICS*

Nathanael HishamundaDepartment of Agricultural Economics and Rural SociologyAuburn University, AL 36849-5419

Maria ThomasWork/Study ProgramTuskegee UniversityTuskegee, AL 36088

David BrownHumphrey High SchoolHumphrey, AR 72073

Carole EngleDepartment of Aquaculture and FisheriesUniversity of Arkansas at Pine BluffPine Bluff, AR 71611

Curtis JollyDepartment of Agricultural Economics and Rural SociologyAuburn University, AL 36849-5419

polyculture of rohu, catla, mrigal and sometimes commoncarp and silver carp and grass carp as well, as is customaryon the subcontinent. In Kerala, a fish feed industry is startingto develop, mixing imported fish meal from Chile with localingredients. Although the feed industry presently mainlytargets shrimp culture (Penaeus monodon), it could easilyproduce good quality catfish feed. . . .

In Bangladesh, however, culture of catfish to marketablesize has not really become established yet. For one thing,quality pelleted fish feed is not easily available, and it issuspected that some Bangladeshi feed companies produceso-called fish meal from locally-dried trash fish treatedwith pesticides, rather than using high quality fish meal.Also, policymakers seem to insist on the superior taste ofthe indigenous small catfish and snakehead species.

It is true that the market price of African catfish ispresently well below the market value of the traditionallyhigh-valued rohu and catla, but this does not necessarilymean that culture of catfish is therefore not economic.

Others seem convinced that the African catfish is avoracious predator, capable of decimating the local fish faunalike the Nile perch in Lake Victoria. The truth is that an

A survey was conducted of 156 cooperative and 111individual Rwandan fish farmers to estimate the costs andreturns of aquacultural and agricultural crops. Enterprisebudgets were developed for both individually andcooperatively produced fish, sweet potatoes, Irish potatoes,cassava, taro, sorghum, maize, peas, beans, soybeans,peanuts, rice, and cabbage. With the exception of Irishpotatoes, all enterprises showed positive income abovevariable costs and positive net returns to land, labor, andmanagement. Fish production yielded the highest incomeabove variable costs and the highest net returns if fingerlingscould be sold. If only food fish could be sold, cabbage wasthe most profitable crop. Sweet potatoes produced thehighest yield of carbohydrates and soybeans were the leastexpensive source of protein. This study demonstrated thatthe cash income per unit of land generated by fish productionis superior to other crops raised in the marais in Rwanda.While aquaculture is often considered a source of animalprotein for household consumption, a high potential alsoexists for cash income generation.

*To order this publication, contact:Publications/Information ManagementPD/A CRSP400 Snell HallOregon State UniversityCorvallis OR 97331, USA

African catfish is an extremely opportunistic, omnivorousfeeder. It depends largely on its barbels for scavenging thebottom, as its eyes are very small. Admittedly, it will eatother small fish when they happen to be in front of its mouth,but it is not the dedicated piscivorous eradicator somepeople think. . . .

The recently-introduced Thai catfish, Pangasius sutchi,certainly is more acceptable in Bangladesh, through itssimilarity to the indigenous Pangasius pangas (simply called‘pangas’ in Bangladesh). Very large pangas, of up to 20 kgor more, are occasionally caught from the big rivers,fetching very high prices. However, it is a mistake to thinkthat farmed pangas will fetch similarly high prices oncethey become available in larger quantities and at muchsmaller sizes than their wild cousins are caught. Forexample, pangas reared in cages near Jessore fetched onlyabout US$ 2.5 per kg (400 g average size) in 1997, whilepangas fingerlings were sold at 7 BDT per piece (US$ 0.17)in Jessore in 1996, three times the price of carp fingerlings.

African magur is well-suited to the social conditions inBangladesh. It has a low mortality rate and grows very fastwhen fed well. It is best reared in small ponds or ditches,or even in cement tanks. The numerous borrow-pits forhouse construction, which are usually deep and steep and

. . . continued on p. 10

African Catfish Spread in Asia. . . from p. 7

Notices of Publication (cont.)

CRSP Research Report 98-124a

SMALL-SCALE FISH FARMING IN RWANDA:DATA REPORT*

Nathanael HishamundaDepartment of Agricultural Economics and Rural SociologyAuburn University, AL 36849-5419

Maria ThomasWork/Study ProgramTuskegee UniversityTuskegee, AL 36088

David BrownHumphrey High SchoolHumphrey, AR 72073

Carole EngleDepartment of Aquaculture and FisheriesUniversity of Arkansas at Pine BluffPine Bluff, AR 71611

Curtis JollyDepartment of Agricultural Economics and Rural SociologyAuburn University, AL 36849-5419

This data report presents information collected in asurvey of 267 fish farmers in Rwanda in September 1991.The findings are discussed in CRSP Research Report 98-124entitled, “Small-Scale Fish Farming in Rwanda: EconomicCharacteristics” (Hishamunda et al., 1998). The Research

Report contains enterprise budgets for individual andcooperative enterprises that raised fish and alternativecrops. These enterprise budgets demonstrate that fishproduction yielded the highest net returns to land, labor,and management. Additionally, the Research Reportcompares the carbohydrate yield and protein costs of fishwith those of alternative crops, and concludes that sweetpotatoes produced the highest yield of carbohydrates andthat soybeans were the least expensive protein source. Theresults of the study demonstrate that fish culture is asuperior production system in terms of cash income perunit of land when compared with other crops raised in themarais, or valley lowlands, in Rwanda.

This data report presents information collected in thesurvey that, while supplemental to the original researchobjectives, may be of interest. Section 1 contains 15 tablesand 3 figures, which summarize the supplemental datacollected by the survey instrument. The questionnaire itselfcomprises Section 2. Section 3 contains the criteria whichwere used to classify survey responses as unreliable, factorsfor converting various measures of crops and inputs intokilograms, and secondary data from the literature whichwere used to compare the nutritional values of variouscrops in the Research Report. Sources of secondary dataused in the study are listed in the Literature Cited section.

*To order this publication, contact:Publications/Information ManagementPD/A CRSP400 Snell HallOregon State UniversityCorvallis OR 97331, USA

not at all appropriate for carp culture, should be excellentfor rearing magur. It likes a muddy bottom, and poor waterquality or even oxygen depletion is not a serious problem.Given the scarcity of land, African magur rearing is one ofthe few aquaculture options open to poor people who onlyhave the land around their one-room hut.

However, one drawback is that magur productiondepends on regular feeding rather than natural productionof phytoplankton, which is the basis for carp polyculture.When good fish feed is available in adequate quantities,African catfish may reach a marketable size of 400 gwithin two months of stocking, or reach one kg in four orfive months (estimated price at the fish pond: aboutUS$1.5/kg). . . .

The Department of Fisheries and NGO s active inaquaculture development should realise that it is far toolate to stop the introduction of African catfish inBangladesh, or in South Asia for that matter, while it hasthe potential of boosting animal protein production in this

densely-populated country.Inland aquaculture and inland open water fisheries in

Bangladesh already depend largely on exotic fish species,notably common carp and silver carp, Nile tilapia and Thaisilver carp. And the reared stocks of rohu, catla and mrigalhave become so inbred, that the Fingerling Producers’Association in Jessore is crying for governmentintervention. “Wild type” Indian major carps have becomeextinct, at least in southern Bangladesh.

Proper extension support is needed, in order to teachpond operators the rearing methods for African magur.Backyard magur hatcheries already exist; now backyardproduction units should be encouraged. Most importantly,good pelleted fish feed should be available locally, in orderto support the development of this branch of theaquaculture industry.

Excerpted from: Fish Farmer International 12, no. 2, March/April 1998.

African Catfish Spread in Asia. . . from p. 9

Aquanews ~ Summer 1998

Upcoming Conferences and Expositions

Date Topic/Title Event Location Contact Information

Aug 23-26 Seafood Africa '98 Johannesburg,South Africa

Tel (27 3)-3354-1890; Fax (27 3)-3354-1962

Aug 26-28 IFA '98 Sao Paulo, Brazil Royal Dutch Jaarbeurs, PO Box 8500, 3503 RM Utrecht, TheNetherlands; Tel +31-30-295-5662; Fax +31-30-295-5709; emailifa.brasil@jaabeursutrecht.nl

Aug 30-Sept 3

3rd International Symposium on AquaticAnimal Health

Baltimore, MD,USA

Division of Comparative Medicine, Johns Hopkins UniversitySchool of Medicine, 720 Rutland Ave, Baltimore, MD 21205,USA; Tel 1-410-955-3273; Fax 1-410-550-5068; emailwellfish@welchlink.welch.Jhu.edu

Sept 2-4 FishEco ‘98, International Symposium onFisheries and Ecology

Trabzon, Turkey Dr. A C Dincer, Faculty of Marine Science, Karadeniz TechnicalUniversity, 61530 Camburnu, Trabzon, Turkey; Fax +90-462-752-2158; email fisheco@risc01.bim.ktu.edu.tr

Sept 16th Lowell Wakefield FisheriesSymposium & 1998 Joint Meeting of AFSWestern Division, Alaska Chapter & N.Pacific Intl. Chapter

Fairbanks, AK,USA

Brenda Baxter, Coordinator, Alaska Sea Grant College Program,University of Alaska Fairbanks, PO Box 755040, Fairbanks, AK99775-5040 USA; Tel 1-907-474-6702; Fax 1-907-474-6285.

Sept 22-24 Feria International Aqua Expo '98 Guayaquil, Ecuador Tel (593-4)690739/40; Fax (593-4)281741-298357

Oct 1-3 II Simposio Internacional de Acuicultura Mazatlan, Sinaloa,Mexico

Tel 52-(67)-17-27-20/21; Fax (67)-14-08-85

Oct 6-10 1st Latin American Shrimp CultureCongress and Exhibition

Panama City,Republic ofPanama

Grupo de Ferias, Congresos Y Eventos, S.A. P.O. Box 7277,Panama 5, Rep. de Panama; Tel (507) 269-3995/264-7227; Fax(507) 264-6983; email gfce@sinfo.net.www.expoferia.com/camaron.

Oct 7-10 Aquaculture Europe 98 Bordeaux, France Aquaculture Europe 98 Secretariat, EAS, Slijkensesteenweg4, B-8400 Oosetende, Belgium; Fax 32 59 32 10 05; emaileas@unicall.be

Oct 7-10 Bordeaux Aquaculture 5th BiennialConference, Workshop & Exhibition

Bordeaux, France BCS, Palais de Congrès, 33300 Bordeaux Lac, France; Fax +33-5-56-43-17-76

Oct 8-11 Agritech '98 & Fisheries '98 Surabaya,Indonesia

Tel (852)-2851-8603; Fax (852)-2851-8637

Oct 15-17 Fish Expo Boston Boston, MA, USA Diversified Expositions; Tel 207-842-5508

Nov 2-7 I Congreso Sud Americano de Aquicultura;X Simpósio Brasileiro de Aquicultura; VSimpósio Brasileiro Sobre Cultivo deCamarão; Feria Internacional deAquicultura.

Pernambuco,Recife, Brasil

Tel (55-81)-445-2200

Nov 11-14 5th Asian Fisheries Forum Chiangmai,Thailand

Dr. Padermsak Jarayabhand, Aquatic Resources ResearchInstitute, Chulalongkorn University, Bangkok 10330, Thailand;Tel 66-2-2188160-62; Fax 66-2-2544259; emailardic@chulkn.car.chula.ac.th

Nov 13 Asian Fisheries Society, Symposium onWomen in Asian Fisheries

Chiangmai,Thailand

Asian Fisheries Society, MC PO Box 2631, 0718 Makati, MetroManila, Philippines; Tel 63-2-818-9283; Fax 63-2-816-3183; emaile.tech@cgnet.com

Nov 16-18 IV Simposium Internacional de NutriciónAcuícola

La Paz, BajaCalifornia, México

Tel (8)-352-63-80; Fax (69)-88-01-57/58

Nov 19-21 Fish Expo Seattle Seattle, WA, USA Diversified Expositions; Tel 207-842-5508

Dec 2-5 ExpoPESCA ‘98, Latin America's Total FishShow

Santiago, Chile Sue Hill, Emap Heighway, Meed House, 21 John St., LondonWC1N 2BP, England; Tel 44-171-470-6340/6302; emailsueh@meed.emap.co.uk

Pond Dynamics/Aquaculture CRSPOffice of International Research and DevelopmentOregon State University400 Snell HallCorvallis OR 97331-1641

Director: Hillary S. EgnaAquanews Editor: Danielle Z. ClairStaff: John Baker, Kris McElwee, andMatt Niles

Aquanews is published by the InformationManagement Component of the PondDynamics/Aquaculture CollaborativeResearch Support Program, Office ofInternational Research and Development,Oregon State University, 400 Snell Hall,Corvallis OR 97331-1641.

The Pond Dynamics/AquacultureCollaborative Research Support Programis funded in part by the U.S. Agency forInternational Development under CRSPGrant No. LAG-G-00-96-90015-00 and byparticipating U.S. and Host CountryInstitutions.

Oregon State University is an AffirmativeAction/Equal Opportunity Employer.

Workshops and Short Courses

Date Title/Topic/Site Contacts

Year-round Work Experience in Hatcheries Techniques/Asian Institute of Technology, Thailand

Training and Consultancy Unit, Aquaculture and Aquatic ResourcesManagement Program, School of Environment, Resources andDevelopment, Asian Institute of Technology, PO Box 4, KlongLuang, Pathumthani 12120, Thailand; Tel (66 2) 524-5445; Fax (66 2)524-5484; email tcuaasp@ait.ac.th

Year-round Training & Research in Fisheries & StockMgmt/Wageningen Agricultural University,the Netherlands

G. van Eck, Dept of Fish Culture & Fisheries, PO Box 338, 6700 AHWageningen, The Netherlands; Tel 31-8370-8330; Fax 31-8370-83937;email gerrie.van.eck@alg.venv.wau.nl

Year-round Tropical Aquaculture Advanced Training ina Third Country/Escuela AgricolaPanamericana (EAP), Honduras, and AsianInstitute for Technology, Thailand

Zentralstelle fuer Ernahrung und Landwirtschaft (ZEL)Feldafing/Zschortau, Deutsche Stiftung fuer InternationaleEntwicklung (DSE), D-82336 Feldafing, Germany; Tel ++49/8157/38-0; Fax ++49/81 57/38-227