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Cefas contract report
FES220: A review of the land-based, warm-water recirculationfish farm sector in England andWales.
Authors: Keith Jeffery, Nicholas Stinton & Tim Ellis
Cefas Weymouth Lab, Barrack Road, The Nothe, Weymouth,Dorset, DT4 8UB
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1 Executive summary
ThewarmwaterRecirculationAquacultureSystem(RAS)sectorhasshownconsiderablegrowth
withinEnglandandWalesoverthelastdecade.Environmental,politicalandsocialfactorswithin
Englandarecombiningtoprovideconditionsfavourabletofuturedevelopmentofthesectorwhich
ticksmanyboxesforenvironmentalandsocialsustainability.RASrepresentahighlyproductive
meansofgrowinganimalproteinonsmallareasofland.Ifenergy(fossilfuel)useandtheassociated
carbonfootprintcanbereduced,RASsystemswouldappeartomeettherequirementfor
sustainableintensification,recognisedasakeymeansofaddressingfoodsecurity1
.
Nevertheless,itmustberecognisedthatfinancialviabilityofRAShassofarbeenmarginal.RAS
businesseshaveapoorrecordforlongevity,andanumberofventureshavefailed.Thisproject
identifiedpoorsystemdesign,lackofattentiontoeconomicfactors(e.g.electricitycosts),andlow
demandforproducts(resultinginlowpriceandsalesvolume)asthecausesoffailure.However,this
pessimisticviewoftheUKexperiencemaybeskewedasthesectorhasbeennumericallydominated
byfreshwatertilapiasystemswheresystemdesignissueswerecommon; veryfewseawater
systemsproducinghighervalueproductsareoperatingtojudgetheviabilityofmarineRAS.
Newentrantsneedtoproceedwithcautionandoptimisesystemdesign,economiesofscale,input
costs,andmarketingandsalesplans.Inaddition,experiencedstaff,systemflexibilityandfurther
developmentofsurroundingindustry(i.e.frysupplyandtechnologicalprogress)remaincriticalifthe
RASsectoristogrow.Issuesthatremaincanbeaddressedthroughacombinationofresearchand
developmentandadoptionofaccreditationandqualitylabellingschemes.
Grantawarders(andinvestors)shouldensurethatapplicantshaveresearchedsystemsadequately,
havefirsthandexperience,andthatbackupsystemsareinplace.Applicantsalsoneedtominimise
inputcostsandproducerealisticbusinessplansthataddressmarkets.Pilotstudiesshouldbe
encouraged.Projectsshouldnotbedismissedthatareinnovativeortransfertechnologyfromother
industriestosupportsustainability.
1
GodfrayHCJ,BeddingtonJR,CruteIR,HaddadL,LawrenceD,MuirJF,PrettyJ,RobinsonS,ThomasSM,ToulminC(2010)Foodsecurity:thechallengeoffeeding9billionpeople.Science327:812818
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Table of contents
1 Executive summary ...................................................................................................................... 12 Introduction ................................................................................................................................... 2
2.1
Disclaimer
..............................................................................................................................................
4
3 Methodology .................................................................................................................................. 54 Status and prospects of the warm-water RAS industry in England and Wales. .................... 7
4.1 NumbersofRASsitesinEnglandandWales......................................................................................... 7
4.2 ProductionoftablefishinRASinEnglandandWales.......................................................................... 8
4.3 RAScontributiontotablefishproduction............................................................................................ 9
4.4 TheRASindustryinEurope................................................................................................................... 9
4.5 ProspectsfortheRASsectorinEnglandandWales........................................................................... 11
4.6 ProspectsforRASuseintheScottishsalmonsector.......................................................................... 11
5 Technology, performance and operat ion of RAS .................................................................... 125.1 ThefundamentalsofRAS.................................................................................................................... 12
5.2 Mechanicalfiltration........................................................................................................................... 14
5.3 Biologicalfiltration.............................................................................................................................. 15
5.4 Aeration/oxygenation ......................................................................................................................... 16
5.5 Heating................................................................................................................................................ 17
5.6 Sterilisationofinlet/returnwater....................................................................................................... 17
5.7 Pumping.............................................................................................................................................. 18
5.8 Tanks................................................................................................................................................... 18
5.9 Pipework............................................................................................................................................ 18
5.10 Monitoringsystems............................................................................................................................. 19
5.11 Automaticfeedingsystems................................................................................................................. 19
5.12 Watersources,replacementanddischarge....................................................................................... 19
5.13 Lessonstobelearnt............................................................................................................................ 20
5.14 NextgenerationRAS........................................................................................................................... 22
6 Financial sustainabi li ty of RAS ................................................................................................. 24
6.1 Fundingsources.................................................................................................................................. 246.2 Buildandsetupcosts......................................................................................................................... 24
6.3 Runningcosts...................................................................................................................................... 24
6.4 Planned vactualsalesprice............................................................................................................... 27
6.5 Productioncosts,paybackandaccountingrateofreturn.................................................................. 27
6.6 Literaturereviewfindings................................................................................................................... 28
6.7 Overallassessmentoffinancialsustainability..................................................................................... 29
7 Factors leading to his tor ical failure of some RAS ................................................................... 307.1 Top10criticalfactors...................................................................................................................... 30
7.2 Additionalfactorscontributingtofailure............................................................................................ 31
7.3 Markets............................................................................................................................................... 31
7.4 Addingvalue:processing,accreditationschemesandbranding........................................................32
7.5 Economiesofscale.............................................................................................................................. 338 Sustainabi li ty issues relating to RAS ....................................................................................... 34
8.1 Environmentalprotection................................................................................................................... 34
8.2 Naturalresourceuse........................................................................................................................... 36
8.3 Socialissues......................................................................................................................................... 39
8.4 Employment........................................................................................................................................ 42
9 Strengths, weaknesses, oppor tuni ties and threats to the RAS sector. ................................ 439.1 PEST Analysis...................................................................................................................................... 43
9.2 SWOTAnalysis..................................................................................................................................... 44
9.3 IdentificationofR&Drequirements.................................................................................................... 45
10 Conclusions ............................................................................................................................. 4610.1 Acknowledgements ............................................................................................................................. 47
11 Annex 1: Line graphs i llustrating operating periods of indiv idual farms ......................... 48
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2 Introduction
MostoftheexistingUKfinfishaquacultureindustryisbaseduponopen,flowthroughsystems
where
natural
water
bodies
provide
a
clean
water
supply,
and
remove
and
assimilate
wastes.
Such
culturesystemshavebeencriticisedastheyaredependentuponthissubsidyfromnatureand,if
intensive,canincuranenvironmentalcostonthesupplying/receivingenvironment2
.Analternative
modelforintensivefinfishproductionisclosedRecirculationAquacultureSystems(RAS).InRAS,
waterisrecirculatedandtechnologyisusedtoremovewastesandmaintainoxygenlevels.RASare
oftenperceivedashavingstronggreencredentials3 andRASproductsarepromotedassustainable
byenvironmentalorganisationssuchasSeafoodWatch4andGreenpeacebecause,asclosed
systems,they
abstractlittle,ifany,waterfromnaturalwaterbodies
produceminimaleffluent,withreadilymanagedwastestreams
reducethepotentialenvironmentalimpactsfromescapeeandpathogenrelease
RASalsooffermanypotentialbenefitstotheproducerandsupplychain:
controlofthefishesenvironmentallowsconsistentandpredictableproduction,essentialfor
modernfoodproduction;
removalofdependenceonanatural,clean,flowingwatersupplyeliminatesseasonalvagaries
(e.g.floods,droughts)associatedwithnaturalwatersupplies,widenspotentiallocations,and
enableslocationclosertomarkets;
improvedbiosecurityinclosedsystemsreducestheriskofpathogeningressanddisease
outbreaks;
closedsystemseliminatelossesto,andconflictswith,predators;
containmentwithinbuildingsaidstemperaturecontrol,therebyavoidingseasonalityin
production;
heatingallowsalternativetropicalfastgrowingspeciessuchasNiletilapia(Oreochromisniloticus)tobefarmed.
2PelletierN,TyedmersP(2008).Lifecycleconsiderationsforimprovingsustainabilityassessmentsinseafoodawarenesscampaigns.
EnvironManage42,918931.3LittleDC,MurrayFJ,AzimE,LeschenW,BoydK,WattersonA,YoungJA(2008).OptionsforproducingawarmwaterfishintheUK:limits
togreengrowth.TrendsinfoodScience&Technology19,255264.4Pelletier&Tyedmers(2008).op.cit.
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Despitetheseapparentbenefits,RASmayattractcriticismonenvironmentalgroundsduetohigh
energyusageanditsassociatedenvironmentalimpacts(carbonandacidificationemissions)5 and
forethicalreasonsRASaretypicallyintensivesystems,whichmaybeviewedasfactoryfarms.
Overthelast10yearstherehasbeenanotableincreaseinboththenumberandsizeoflandbased,
warmwaterRASfarmsinEnglandandWales. In2000therewas acoupleofsmallscalefarms,buta
decadelaterthisisapproaching20farmswhichvaryinscalefrom10to1000tonnesp.a..These
newfarmsrepresentadiversificationintheUKaquacultureindustry,andprovideanadditional
routetoproduceahealthyfoodproduct,therebystrengtheningUKseafoodsecurity.However,
despitetheoptimismsurroundingRAS,anotableproportionhasgoneintoadministration6
7.
Variouspotentialfactorshavebeensuggestedanecdotallyascontributingtotherecurrentfailureof
commercialRASintheUK89:
poordesign
toohighrunningcosts
labourintensivetechnology
steeptechnicallearningcurves
lackofexperiencedstaff
overambitiousproductionschedules
overoptimisticmarketforecastsforproductsales
poormanagementdecisions
Todate,therehasnotbeenanobjectiveexaminationofthefactorsthatcontributetothefailure
(andsuccess)ofcommercialRASintheUK.ThisprojectwasfundedbytheDefraFisheriesChallenge
Fund,administeredbytheMarineManagementOrganisation(MMO,formerlyMarineFisheries
Agency)toaddressthisgap,andreviewthetechnology,operation,production,problemsand
sustainabilityofwarmwaterrecirculationaquaculturesystemsinEnglandandWales.Thisreportis
intendedtoprovideasourceofUKspecificinformationonRASforprospectivefarmers,investors,
policymakersandlobbygroupstoaiddecisionmaking.
5SeeEllisetal.(2011)InitialinvestigationofthesustainabilityofEnglishaquaculture.CefascontractC3743reporttoDefra.
6LittleDC,MurrayFJ,AzimE,LeschenW,BoydK,WattersonA,YoungJA(2008).OptionsforproducingawarmwaterfishintheUK:limits
togreengrowth.TrendsinFoodScience&Technology19,255264.7E.g.http://www.fishupdate.com/news/fullstory.php/aid/10782/Barramundi_farm_brings_in_administrators.html8http://www.slideshare.net/Cefas/largescaleintensiverecirculationsystemsandtheirpotentialdevelopmentwithinengland2373881
9Littleetal.(2008)op.cit.
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2.1 DisclaimerWhilsteveryefforthasbeenmadetopresentanaccuratesummaryofinformation,Cefasandthe
authorscannotbeheldresponsibleforinaccuraciesoromissions.ReadersinterestedinRASare
encouragedtoconducttheirowninvestigationsand/orseekspecialistadvice.
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3 Methodology
Theprojectwascomposedoffoursuccessivestages:
a
desk
based
literature
review;
identificationofallwarmwaterRASfarmsinEnglandandWalesregistered(andderegistered)
between2000and2010,andcollationofproductiontoassessthecontributiontothefinfish
supplychain.[TheCefasFishHealthInspectorates(FHI)LiveFishMovementDatabase(LFMD)
wasusedtoidentifyallregistered(andderegistered)warmwaterRASfarmsinEnglandand
Walesandrelevantdatawasextracted];
asurveyofrepresentativesofthewarmwaterRASindustry, i.e.farmersandconsultants,to
gatherinformationontechnology,operation,production,problemsandsustainability.
collationoftheinformationintothisreport,andreviewbyrepresentativesoftheindustry.
TheaimofthesurveywastocoveralargeproportionoftheRASsitesinEnglandandWalesand
includebothoperatingandnonoperating(inreceivershiporceasedtrading)sites,togatherdiverse
feedbackontheissuesfacedbythissector.Theapproachtothesamplingmethodologywas
discussedwithaCefasstatisticianandrecommendationsincorporated.
Ofthe29farmsidentifiedonthedatabase,asampleoffarmswasselectedforpreliminary
discussion(n=18)andthesewerecontactedbytelephonetorequestagreementtoparticipate.Two
farmswereunwillingtoparticipateinthesurvey. Ascheduleoffieldvisitswasthenarranged.
Duringschedulingtwofurtherfarmerswithdrewfromthesurvey,astheywereunavailableinthe
allottedtimeframeorwerenolongerabletoproviderequiredinformation. Itwasjudgedthatthe
remaining14farmswereadequateforthereview.Productionfiguresandotherrelevantdatawere
gatheredduringtheinitialtelephoneconversationsforthenonparticipantsandareincluded(with
permission).
ThefieldvisitswereconductedoveratwoweekperiodinlateAutumn2010.Fourteensites
producingavarietyofspecies,locatedthroughoutEnglandandWales(e.g.Devon,Cambridgeshire,
York,DurhamandAnglesey)werevisited(Table1).Theschedulewasarrangedtominimise
travellingwherepossible,andvisitswerecombinedwiththeroutineannualFHIinspectionwhere
applicable.
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SitevisitswereconductedbytwoCefasprojectstaff(theprojectleaderandanexperiencedRAS
operator),andcomprisedaninspectionofthesiteandrecirculationsystemandasemistructured
interviewwiththefarmmanger. Theinterviewwasstructuredaroundaquestionnaireproviding
promptsforthemainissuesidentifiedfrompersonalknowledgeandtheliteraturereview.The
presenceoftwoprojectstafffacilitatedcaptureofinformation. Farmerswereadditionallyaskedto
identifyandranktheirTop10criticalfactorsforthesuccessorfailureofawarmwater
recirculationfishfarmfromalistof34putativefactorsidentifiedfromtheliteratereviewand
personalknowledge.Spacewasprovidedtoaddadditionalfactorsandcomments. Production
figureswerecollecteduptoandincluding2010;forsitesthathadceasedoperating,finalproduction
wasrecorded.
RASconsultantswerepresentattwoofthefarmsites,andtheirinputwasgatheredfollowingthe
samesemistructuredinterviewformat.
Table1:BreakdownofRASoperatorsinterviewed,byspeciesfarmedandoperationalstatus.
Typeoffarm Operational Closure
Imminent
Non
operational
Total
Tilapia 3 2 1 6
Tilapia&catfish 1 1 1 3
Turbot 1 1
Turbot,sole,prawn&seabass 1 1
Seabass&turbot 1 1
Barramundi 1 1
Prawn 1 1
Totals 7 4 3 14
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4 Status and prospects of the warm-waterRAS industry in England and Wales.
Detailsofallwarmwaterrecirculationfishfarms(thoseproducingfoodfish)registeredinEngland
andWalesbetween2000and2010wereextractedfromtheLFMDandsupplementedwithsite
specificdata.DataforWaleswasincludedalongsidethatforEnglandduetothecoverageofthe
database,andthenatureandimportanceoftheseoperations.
4.1 NumbersofRASsitesinEnglandandWalesWithinEnglandandWales,29warmwaterRASsiteswereregisteredduringtheperiod20002010
(Table2).Thesehavetargetedavarietyofspecies,withaclearinclinationtowardstilapia.Ofthese
29sites,only18arestilloperationaland11haveceasedoperating.
Table2: Numbersofwarmwaterrecirculationfishfarmsitesregisteredbetween2000and2010,
andcategorisedaseitheroperationalin2010ornonoperational.NB:Datacontainsonehatchery
thatmovedlocation.
Speciesheld Numbersites
registeredbetween
2000and2010
Sites
operationalin
2010
Sitesnot
operatingin
2010
England
Tilapia
18
9
9
Tilapia&catfish 3 3 0
Barramundi 1 0 1
Hybridstripedbass 1 0 1
Prawns 1 1 0
Turbot 1 1 0
Grasscarp 1 1 0
Subtotal 26 15 11
Wales Sole,bass,prawns&turbot 1 1 0
Turbot&bass 1 1 0
Bass 1 1 0
Subtotal 3
3
0
Total 29 18 11
ThewarmwaterRASindustryinEnglandandWaleshasshownconsiderabledevelopmentoverthe
lastdecade,witha10foldincreaseinthenumberofoperatingfarms(Fig1A).However,thismarked
increasedoeshidethefactthataround40%offarmshaveceasedoperating(Fig1B).
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5
0
5
2000 2002 2004 2006 2008 2010
B
0
5
10
15
20
2000 2002 2004 2006 2008 2010
NumerofoperatingR
ASfarmsinE&W
A
Newinyear
Ceasedinyear
Figure1:
A:
Number
of
warm
water
RAS
farms
operating
in
England
and
Wales
in
the
years
2000
2010.B:Foreachyear,thenumberofnewRASfarmsregistered,andthenumberthatceased
operating.
Simplelinegraphsareincluded(Annex1)toillustratesitenumbersbyspeciesfarmed,andthe
periodofproductionofeachsite.
4.2 ProductionoftablefishinRASinEnglandandWalesAnnualproductiondataforthedifferentRASfarmswasextractedfromthelivefishmovements
database(LFMD).ThiswassupplementedwithdatacollectedduringinterviewswiththeRASfarmers
(Figure2).
0
200
400
600
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Annualprodu
ction
(tonnesp.a.)
Welshseabass
Englishcatfish
Englishbarramundi
Englishtilapia
Figure2:AnnualproductionoftablefishinRASbyspeciesandcountry,fortheyears20002010.
Please
note
production
of
other
species
is
not
included
as
it
is
negligible.
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Atthatstartofthedecade,RASproductionamountedto2tonnesofcatfish.Attheendofthe
decade,RASproductionwasover600tonnes,whichequatestoan80%p.a.increaseinoutput.
Productionin2010wascomprisedalmostentirelyofseabass(77%)andtilapia(23%).Therewasa
notableproduction(400tonnes)ofbarramundiin2008fromasinglefarm,whichthenceased
production.
4.3 RAScontributiontotablefishproductionAlthoughproductionfromRAShasincreasedmarkedly,itisstillonlyaminorcontributortotablefish
productioninEnglandandWales(Figure3).Tablefishproductionisdominatedbyrainbowtrout,
withRAS(allspeciescombined)contributingapproximately12%.Nevertheless,differenttrendsare
apparent:RASproductionhasbeenincreasingagainstabackdropofdecliningtroutproduction.
0
1000
2000
3000
4000
5000
6000
7000
8000
1994 1996 1998 2000 2002 2004 2006 2008 2010
Tonnesp.a.
E&Wtabletrout
E&WRAStablefish
Figure3:AnnualproductionoftabletroutandtablefishinRASinEnglandandWales1994201010.
4.4 TheRASindustryinEuropeAlthoughtherehasbeenanincreaseinRASproductioninEnglandandWalesoverthelast10years,
itcannotbeassumedthatthistrendwillcontinue.TheBeneluxcountriesandDenmarkhavea
similarclimate(andgeography)toEnglandandWales,andleadEuropeintheproductionoftable
fishinRAS11
.(PossiblecontributingfactorstoenthusiasmforRASfishfarming inthesecountries
are:adietwithatraditionalfishcomponent;lackofuplandareasforcool,cleanwatersupplyfor
salmonidfarming;coastlineinappropriateforcageculture;astrongenvironmentallobby;along
10Source:FHIproductionfigures,FinfishNewsandcollectedduringsurvey.
11MartinsCIM,EdingEH,VerdegemMCJ,HeinsbroekLTN,SchneiderO,BlanchetonJP,dOrbcastelER,VerrethJAJ(2010)New
developmentsinrecirculatingaquaculturesystemsinEurope:aperspectiveonenvironmentalsustainability.AquaculturalEngineering43,
8393.
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standingeelfarmingsectorwhichusesRAS).Experiencesfromthesecountriesmeritconsideration
whenreflectingonthepotentialfuturedevelopmentoftheRASsectorinEnglandandWales.
IntheNetherlands,thefinfishaquaculturesectorisuniquewithinEuropeasitisbasedalmost
entirelyonthecultureofvariousspeciesinRAS.ProductionoftablefishinDutchRAS(ca.8,000
tonnesp.a.,Table3)exceedsthetotalproductionofalltablefish(flowthroughandRAS)inEngland
andWales(5,500tonnesp.a.,Figure3).
However,theDutchRASindustryhasshownaveryrecentdownturn.Thenumberoffarmshas
halved,andproductioncapacityhasreducedbymorethan16%within2years(Table3).Various
reasonshavebeenproposedforthisdecline12
:
issuesoverthesustainabilityofeelproductionduetodependenceonendangeredwildelvers
highproductioncostsforspeciessuchasturbot,soleandtilapia
novelspecies,e.g.whitelegshrimp,beingunabletoestablishinnichemarkets
Table3:Production(tonnesp.a.)ofthemostimportantspeciesinDutchRAS13.
Species
20072008 Expectedforendof
2009
%Change2007
08/2009
No.of
farms
Production No.of
farms
Production No.of
farms
Production
Eel 43 4250 19 29%
Africancatfish 18 3100 56 1000 6772% 68%
NileTilapia 4 840 0 0 100% 100%
Turbot 4 210 2 210 50% 0%
Barramundi 2 135 0 0 100% 100%
Pikeperch 2 130 3 130 +50% 0%
Doversole 1 10 1 20 0% +100%
European
catfish
1 100 2 3000 +100% +2900%
Totals 75 8775 33 7360 56% 16%
AtilapiafarmingprojectwaslaunchedinBelgiumin2006,whichclaimedtobethelargestRASinthe
world;theprojectcost15millionandplannedproductionwas3000tonnesp.a..However,itwent
intoadministrationin200914
,andthefailurewasattributedtodiseaseproblemsandthelowprice
ofcompetingfishproducts15
.
12http://www.oecd.org/dataoecd/19/21/45032957.pdf
13 TheDutchcaseforpracticesinfinfishaquacultureusingRAS,Schneider,Oetal,Abstractat8thInternationalrecirculatingaquaculture
conference.14http://www.fishnewseu.com/latestnews/world/2097endofthelineforvitafish.html
15http://www.fishnewseu.com/latestnews/world/1684priceofcodblamedforbankruptcyofvitafishtilapiafarm.html
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4.5 ProspectsfortheRASsectorinEnglandandWalesTheDutchRASindustryproducingmorethan10timesthatoftheEnglishandWalesRASsector
indicatespotentialforfurtherexpansionintheUK.However,itmustalsoberecognisedthatDutch
RASproductionisdwarfedbycagefarmedsalmoninNorway(800,000tonnesp.a.)andScotland
(145,000tonnesp.a.)16
.Historically,RAShaveapoortrackrecordintheUK,withfewfarms
persistingformorethanafewyears;thisisnotuniquetotheUK.RASproductsmayalsohaveto
increasinglycompetewithcheapimports,suchasPangasiuscatfishfromAsia(alsoknownasbasa,
rivercobblerorpanga).Consequently,projectingthefuturesizeof,andproductionfrom,theRAS
sectorinEnglandandWalesisextremelydifficultwitheithergrowthordeclineforeseeable.The
commercialviabilityofRASintheUKwilllargelydependupondomesticdemandforRASproducts
andfarmgatepricesachievable.
4.6 ProspectsforRASuseintheScottishsalmonsectorScottishsalmonproductioncanbeviewedasa3stageprocess:thefreshwaterhatchery,freshwater
ongrowing(smoltproduction),andmarine(seacage)production.Allthreestageshavetraditionally
beenbaseduponopensystems:assalmonareacoldwaterspeciesanddonotneedadditionalheat,
openflowthroughsystemsaregenerallyacceptedasbeingmorefinanciallyviablethanRASculture.
However,duetoenvironmentalconcerns,thereisincreasingpressuretoproducesalmoninclosed
containment
systems
and
research
is
ongoing
in
North
America
17
to
develop
and
make
these
systemscommerciallycompetitive.IntheFaroeIslandsandNorwayfreshwaterproductionhasbeen
shiftingtowardsRAStechnologytoalleviateproblemsassociatedwithfreshwaterresources,i.e.
shortage,poorqualityandvariabletemperature18
.IthasbeensuggestedthatRASproductionoffers
benefitstotheindustrythroughimprovedfreshwatergrowthratesandsmoltquality(improved
survivalandgrowthratesonceinseacages)19
.However,arecentreportbytheScottishSalmon
ProducersOrganisation(SSPO)considerslandbasedRASforongrowingstagesnotfinanciallyviable,
withthehighenergyuseandcarbonfootprintmakingitanenvironmentallyunfriendlyoption20
.
162008Europeanfinfishaquacultureproduction.FinfishNews9,5455.
17http://www.fishupdate.com/news/fullstory.php/aid/15659
18MartinsCIM,EdingEH,VerdegemMCJ,HeinsbroekLTN,SchneiderO,BlanchetonJP,dOrbcastelER,VerrethJAJ(2010)New
developmentsinrecirculatingaquaculturesystemsinEurope:aperspectiveonenvironmentalsustainability.AquaculturalEngineering43,
839319Martinsetal.(2010)op.cit.
20http://www.scottishsalmon.co.uk/userFiles/885/Salmon_Annual_Report_2009(1).pdf
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5 Technology, performance and operationof RAS
Arecirculatingaquaculturesystemisanartificialgrowingenvironmentthatrecyclesusedwater.As
waterisretained,RASpotentiallymakesheatingwaterforfishfarmingcosteffective21
. Awarm
waterRASallowstheproductionoftropicalspeciesincoolerclimates.Itmayalsobeusedfor
temperatespecies:asfisharecoldbloodedanimals,growthrateislinkedtotemperature,so
increasingthewatertemperatureaboveambientincreasesgrowthandproduction.
Waterqualitydoesneedtobemaintainedtoprovideoptimumconditionsforfishgrowth,and
assurefishhealthandproductquality.Thisisachievedbyremovingthewasteproducts(uneaten
food,faecesandexcretedmetabolites)bytreatingthewaterusingfiltrationandcleansing
technology.Thesystemwaterpassesthroughthetreatmentprocessmanytimesperday,ata
recirculationratetypicallyequatingtoonesystemvolumeevery1to2hours.Inaddition,a
percentageofthetotalvolumemustbereplacedwithnewmakeupwatertopreventexcessive
buildupofnitratesanddissolvedorganiccompounds.WhenRASsystemswerefirstbeing
developed,theyweredescribedintermsofthevolumeofwaterexchangedduringeachcircuit(e.g.
10%ofsystemvolume/pass).CurrentRASrequiremuchlessmakeupwater,andaredescribedby
thedailyreplacementrate(e.g.5%systemvolume/day)22.
AlthoughRASofferanumberofadvantagesasdescribedaboveandintheIntroduction,theyalso
sufferfrompotentialdrawbacks:
largesetup/investmentcosts,withaneedforbackupsystems.
highrunningcosts
productionlimitedbythecapacityofsystems:theloadthatfilterscanprocesswilllimitthe
productionofaRAS
shorttermincreasesinfishproductionarelimited: thebiofilterneedstimetoadaptand
changecapacitytodealwithwastes
experiencedstaffareneededtorunRASwhichactaslifesupportsystems
5.1 ThefundamentalsofRAS
21LittleDC,MurrayFJ,AzimE,LeschenW,BoydK,WattersonA,YoungJA(2008).OptionsforproducingawarmwaterfishintheUK:limits
togreengrowth.TrendsinfoodScience&Technology19,255264.22http://www.slideshare.net/Cefas/largescaleintensiverecirculationsystemsandtheirpotentialdevelopmentwithinengland2373881
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InRAS,thewaterfromtheproductionunitsistreatedtoremovesuspendedsolidparticles(uneaten
food,faeces),toremoveorconvertdissolvedchemicalwastesandgasses(e.g.ammonia,nitriteand
CO2)andtoincreasedissolvedoxygenlevels,beforereturntotheproductionunits. Thefiltrationis
carriedoutbytwomainprocesses:
Mechanicalfiltration,wherebythesuspendedsolidsareremoved(c.f.asieve)
Biologicalfiltration,wherebythedissolvedsubstancesandorganicchemicalwastesare
convertedtolesstoxicsubstances.Biologicalfilters,throughtheirdesign,usuallyalso
increaseoxygen,andreducecarbondioxide,levels.
RASmayalsouseadditionalprocesses:aeration/oxygenation,sterilisation(toremovepathogens
andundesirablebacteria),chemicalbuffering(ofwaterqualityparameters),etc. Theseadditions
dependontherequirementsandtheloadingofthesystem23.AlthoughloadingofRASisoften
consideredintermsoffishbiomass,itisprimarilytheamountoffoodthatisthelimitingfactor24
:
foodmassdictatesthemetabolicrate(andoxygenrequirements)ofthefish,therateofwaste
production,andthefishbiomassthatcanbeheldinthesystem.
Figure4:Featureofrecirculationaquaculturesystems
23withaerationstockingdensitiesof5060kg/m
3(50kg/m
3isthemaximumcapacityusedinthedesign)canbeachievedwhilst
maintaininghighfishwelfarestandards.Higherstockingdensitiesupto120kg/m3canbeachievedwiththeuseofoxygenTilapiainfo
packUniversityofStirlinghttp://www.tilapiascotland.org/resources24Ellisetal.(2010).Sustainablefinfishaquacultureworkshop.FinfishNews9,422.
Production units
Mechanicalfiltration
Sterilisation
Water eitherpumped orvia gravity
Waterreturn bygravity
Oxygenationand/ or aeration
Water pumped tonext stage
Chemicalbuffering
Biologicalfiltration
Additionalapplications
Basicprocesses
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5.2 MechanicalfiltrationWhatevertheRASdesign,theremovalofsuspendedsolidwaste(SSW)bymechanicalfiltrationis
oneofthemostimportantpartsofwatertreatment.Alldesignsshouldaimtokeepsolidwastesas
intactaspossiblepriortomechanicalfiltration.IfSSWarebrokenup,thesmallerparticlesarenotas
easytosieveout,andthelargersurfaceareafacilitatesdissolvingofsolubleorganiccompounds.
Dissolvedorganicsaddtotheloadonthebiologicalfilterandencouragethegrowthoflessdesirable
heterotrophicbacteriawhichincreasetheoxygendemandofthesystemandcompetewiththe
nitrifyingbacteriainthebiofilter.
TherearemanytypesanddesignsofmechanicalfiltrationtoremoveSSW,suitedtodifferent
operatingsystems. Thetwokeyfactorstoconsiderwhenselectingmechanicalfiltrationare:
theexpectedSSWloading
theflowrateofwaterthatthefilterwillhavetoprocess.
ThemechanicalfiltershouldremoveSSWasquicklyaspossiblewithoutdamagingtheparticles.
Variousmechanicalfiltrationmethodsareavailable:
drumfilters
screen/beltfilters
beadfilters
sandfilters
vortex/settlementfilters
ForlargescaleRAS,onlydrumfiltersofferapracticalmethodforremovinglargequantitiesofSSW
atahighflowrate.Drumfiltershavetheaddedadvantagethat,dependingonthescreenareaand
meshsize,ahighpercentageofSSWcanberemoved. Screen/beltfiltersaregenerallydesignedfor
lowflowrates.Intheotherthreemethods,SSWaretrappedinthefilterbutnotremovedfromthe
systemimmediately,whichallowsleachingofsolubleorganiccompounds.Thelatterfourmethods
arethereforegenerallyonlysuitedforsmallerRASorthosewithalowloading.
Industryobservations
AllsitesvisitedrecognisedthatpromptremovalofSSWwasanimportantfactor.Approximatelyhalf
ofthesitesuseddrumfilters.Althoughtheygenerallyhadnoproblems,oneissuewasinappropriate
selectionofdrumfiltersbythesystemdesigner,i.e.undersizedfiltersortoofinemeshinscreens,
whichresultedinthedrumfiltershavingtorunconstantly.Constantcleaningofdrumfilterscreens
requiresahighwaterusageand,wheretapwaterwastheonlysupply,thisbecameasignificant
cost.Nevertheless,thisprovidedtherouteforwaterexchangefortheRASand50%ofthesesites
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installedawaterrecoveryprocessfordrumfilterscreenwashing. Asdrumfiltersareexpensive,
mostRAShadtobeoperatedasasingleunitratherthanseveraldiscreteunits;thiswashighlighted
bysomefarmersasundesirable,asithasimplicationsfordiseasespreadandcontrol,andtherewas
lessflexibilityinthesystem.
ThreesmallersiteshadusedalternativessuchasbeadfilterstoremoveSSW.However,asthe
quantityoffish(andfeed)increased,thesefilterscouldnotcopewiththeSSWloading,andwere
typicallyreplacedwithdrumfilters,whichwasacostlyprocess. Twositesusedscreen/beltfilters;
althoughonefoundthemgenerallyadequate,theothersitehighlightedthemasamajorproblem
theywereinadequatefortheirroleandrippedandfailedonaweeklybasis. Thereplacement
screenscouldonlybesourcedfromaspecialistsupplierandprovedveryexpensive(1,8002,000
ea)andtimeconsuming(taking3menhalfaday)toreplace. Onesiteusedvortex/settlement
methodstoremovesolidsandfoundthisadequateatthemodestscaleofproduction,providedthe
solidswerebackwashedoutregularly.
5.3 BiologicalfiltrationBiologicalfiltersaregenerallyplaceddownstreamofthemechanicalfiltersotheydonotbecome
cloggedwithSSW.Nitrifyingbacteriawithinthebiofilterconverttoxicammoniatonitrite,andin
turnnitrate25
.Thebasicprincipleofbiologicalfiltrationistoprovideasurfacefornitrifyingbacteria
togrow.Thisisachievedbyusingasubstratumwithaveryhighsurfacearea:volumeratioto
maximisetheamountofbacteriawithinalimitedspace.Therearemanydifferentdesignsof
biofilter:theinstallationofofftheshelfsystemsistheexception,andmosttendtobebespoke.
Manybiofilterscombineasubmerged(wet)stageandatrickle(nonsubmerged)stage. The
submergedstageusuallycomprisesavesselcontainingplasticfiltermediaspecificallydesignedfor
itshighsurfaceareawithaflowpassingthroughthevessel. Mostdesignsalsousestrongaerationto
constantlymixthemedia(afluidisedbiofilter)whichgivesvariousbenefits:
filtermediaiskeptclean,preventingSSWsettlementandheterotrophicbacteriabuildup
mixingensuresallmediaisutilisedbynitrifyingbacteria
increasedoxygen(O2)levelswithinthefilterensuresahigherconversionofammoniatonitrite
andinturnnitrate(nitritetonitraterequiresahighO2environment).
CO2andanyotherundesirablegassesaresloughedoffbytheaeration
25ammoniaispresentintwoforms free(NH3)whichisverytoxictofish,andionized(NH4
+)whichisstilltoxicbutlessso.Thehigherthe
pH,thegreatertheratioofthemoretoxicfreeformtotheionizedform.Nitrosomonasbacteriaoxidizeammoniaintonitrite(NO2)bytheadditionofoxygen,andNitrobacterbacteriaoxidizenitriteintonitrate(NO3
).Thesetwotypesofbacteriaarereferredtoas"nitrifying
bacteria,"http://www.pondsystems.com/news_biofilt.html#TheNitrogenCycle
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O2levelsinthewaterareboosted(forreturntothefish)
Trickle(nonsubmerged)filtersagainmakeuseofspecificmediabutthesearefreestanding,either
withinavesselorstackedwithcurtainsides,ratherthansubmerged. Tricklefiltersaregenerally
positionedafterafirststagesubmergedfilterandoftenusegravitytofeedwatertothetopofthe
filterwhichthensimplytricklesdownthroughthemedia. Themainadvantageofatricklefilteris
thehighsurfaceareaincontactwithairwhichallowsbothdegassingandaerationofwaterand
providesanoxygenrichareatocompletetheprocessofconvertingammoniatonitrate.
Industryobservations
Approximately60%ofsitesvisitedusedfluidisedbiofiltersofvariousdesignsandcapacities.One
commercialmedia(KaldnessK1plasticmedia)wascommontoallsystems.Sitesproducingtilapia
justusedasubmergedfilter(notricklefilter).AllseawaterRASusedtricklefilters,andnoissues
werehighlightedwiththese.
Acommonfindingwasoverexpectationofperformanceofbiofiltersintheoriginalsystemdesign,
withtheinstalledbiofilterfailingtodeliveranticipatedperformance.Nearlyeverysitehadto
increasebiofiltercapacitybyaddingmoremediaand/orincreasingthefiltersize.Factorsthat
contributed
to
reduced
performance
were:
inadequatemechanicalfiltration,soSSWaddedtothebiofilterloading
lowerthanexpectedoxygenlevels
inadequateflowratesthroughtheRASwhichallowedammoniatobuildupinproductionunits
andreachthebiofiltersatahighlevel.(UnprocessedSSWcouldalsobuildup).
deadspotsinfilters.
5.4 Aeration/oxygenationAdequateoxygenlevelsareobviouslycriticalforfishproduction,healthandwelfare,aswellas
biofilterperformance.Variousmethodsareemployedrangingfromaerationviadiffusersdelivered
fromacompressor/blowertotheapplicationofpureoxygenviafinediffusersorinjectionsystems.
Carehastobetakenwiththeapplicationofpureoxygenasoveroxygenationispossible;an
automaticmonitoring/controlsystemthatdosesthecorrectamountisrequired. Itispreferableto
applyoxygeneitherdirectlytotheproductionunitortothereturnwaterratherthanthewholeunit.
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Industryobservations
Allsitesusedaerationasthemainsourceofoxygen,andalsotooperatefluidisedbiofiltersand
opposingflowproductionsystems(whereaerationcreatesopposingcircularcurrentsalong
productionunitsinordertodistributefishmoreevenly). Severalsiteshadneededtoincrease
aerationabovethatoriginallydesignedandinstalled. Atleastonesitehadexperiencedthetotalloss
ofabatchoffishwhichwasattributedtolowoxygenlevelsduetoinstallationofaninadequate
aerationsystemwhichhadsincebeenupgraded. OnesitemoveditsairblowersoutsidetheRAS
buildingtoreducehumidityandimproveturnoverofairandreduceCO2buildupwithinthewhole
building. Onesiteinstalledahydrogenperoxidedeliverysystemforbothroutineandemergency
oxygenation,whichwasconsideredtobeasimpleandeconomicalsolutionforthatsite.
5.5 HeatingHeatingcanobviouslybedeliveredinnumerousways;spaceheaterswereusedbythe65%ofsites
asitisgenerallyconsideredmoreeconomicaltoheattheentireunitthanjustthewater.This
assumesthatthebuildingiswellinsulated.Thespacetoheatisthereforeafactortoconsiderinthe
initialdesign:thereshouldnotbeanexcessivespace(airvolume)toheat,althoughthereshouldbe
sufficientexchangetopreventCO2buildup. Nevertheless,approximately80%ofunitsusedpre
existingbuildingssotheairspacedwasalreadyfixed;onesitehadinstalledlowerceilingstoreduce
it.
At
60%
of
sites,
space
heaters
were
situated
in
the
main
production
building;
however
3
sites
had
movedthemoutsidethebuildingtodirectfreshairintothebuildingandprotecttheheatersfrom
thehumidenvironmentinsidetheRASbuilding.
Onesiteusedtheheatgivenoffbyonsitegenerators. Heatrecovery(fromwastewateror
ventilatedair)wasinstalledatseveralsites.Onesiteexpendedconsiderableeffortinrecovering
dischargedheattoreduceheatingcosts,and4ofthelargersites,whereheatingwasrecognisedasa
significantcost,wereexploringheatrecovery.
AlmosteverysitesituatedheadertanksfornewmakeupwaterinsidetheRASunitsoitcouldwarm
up,butoftenthewaterwasincirculationbeforeithadreachedtemperature.
5.6 Sterilisationofinlet/returnwaterWaterissterilisedtokillpathogens,removeundesirableheterotrophicbacteriaandimprovewater
quality.ThetwomainmethodsareexposuretoUVlightandozone.Bothmethodshavetheir
advantagesanddisadvantagesandsuitabilitydependsonthesituation. UVisgenerallythecheaper
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option,butisonlyeffectivewithclearwater;inturbidwaterpenetrationofUVisinsufficient. Ozone
ismoreexpensiveandhasobvioushealthandsafetyimplications,butitismoreeffectiveandworks
inturbidwater.Ozonemayhavetheadditionalbenefitofimprovingwaterqualitybyremoving
flavourtaintssuchasgeosmins26andorganictoxins.InseawaterRAS,ozoneisoftencombinedwith
proteinskimmerstoboosttheirperformanceinfractionalremovalofproteins.Onesiteusedozone
todisinfectincomingwaterwhichwasdrawnstraightfromsea.
5.7 PumpingPumpingofwatertoensurecirculationofwaterwithinRASisobviouslyanextremelyimportant
factorforbothdesignandoperation.Therightpumpneedstobeselected:undersizedpumpsresult
inapoorturnoverinthesystemandleadtounderperformingfilters,waterqualityissuesand
reducedproduction.Oversizedpumpsareuneconomicaltorun. Thereisawidevarietyofpumps
availablefordifferentpurposes:
highpressurepumpsaremoresuitableforaringmainsystem
liftpumpsaresuitedtomovinglargevolumesofwaterbutwithlittleheight(head)
sludgepumpsaredesignedtomovehighlyviscoseliquidsladenwithsolids.
Approximately30%ofsitessaidtheyhadthecorrecttypeandsizeofpumpsinplace.Asmall
numberofsiteswouldhavepreferredtohaveaseriesofsmallerpumpstogivegreaterflexibilityin
thesystemandactasbackupsincaseoffailure. Three(cooperating)sitessharedasparepumpas
contingencyforpumpfailure.
5.8 TanksTankandholdingsystemsvariedacrosssites.However,themostcommontypesfortilapiaunits
wereabovegroundrectangularconcreteorfibreglassraceways.Marinesitesmostlyoperatedeither
circularorhexagonaltankswithonelargesiteconstructingtankspartiallybelowgroundlevel.
Smallersitesusedavarietyofcircularfibreglassholdingunits. Depurationtanksusuallyinvolveda
separatefiltrationsystemusingnewcleanwatertosupplysmallerfibreglasstanks.
5.9 PipeworkPipeworkisoftenoverlookedwithinthedesignofanRAS.Inadequatepipeworkandfittingcanslow
flowrates. Itisdifficulttocleanclosedpipeworkso,wherepossible,openchannelsshouldbeused
26SchraderKK,DavidsonJW,RimandoAM,SummerfeltST(2010).Evaluationofozonationonlevelsoftheoffflavourcompoundsgeosmin
and2methylisoborneolinwaterandrainbowtroutOncorhynchusmykissfromrecirculatingaquaculturesystems.AquaculturalEngineering43,4650.
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toenableroutinecleaning,especiallyfordirtyreturnwater. Atoneofthesites,deepchannels
returnedwastewaterataslowratetothefilters:thisallowedSSWtosettlewhichaddedto
maintenanceandleachedorganiccompoundswhichincreasedbiologicaloxygendemand.The
inappropriatelocationofpipeworkcancauseoperationalissues:at2sitesitwaspositionedontop
oftheproductionunitswalls:thisreducedaccessandwasthereforeconsideredapoordesign.
Overhalfofthesiteshadchangedpipeworktoimprovesuchaspects,whichrequiredextratimeand
expenditure.
5.10 MonitoringsystemsAlarmedmonitoringsystemsareobviouslyacriticalpartofanyRASdesign.Incomparisontoa
simpleopen/flowthroughfishfarm,therearealotmoretechnologicalcomponentsthatcanfail,the
responsetimeisshorter(duetotypicallyhigherfishdensities),andthereislikelytobemorethan
oneissuetoresolveifsystemsstop.Acomprehensivealarmsystemshouldcoverelectricitysource,
allpumpsandtheiroutput,otherkeyequipment,oxygenlevelsinall(oratleastthelargest)
productionunits,andpH.Thealarmsystemshouldbelinkedtodialoutcontrol.
Nearlyallofthesitesdidhavealarmsystemscoveringtheelectricitysupplyandpumps,butdiffered
inwhatelsewascovered. Allbuttwositesdialledouttoalistoftelephonenumbers;theexceptions
used
an
onsite
audible
alarm
with
the
disadvantage
of
requiring
personnel
to
be
within
ear
shot.
5.11 AutomaticfeedingsystemsAutomaticfeedingsystemswereusedonrelativelyfewsites.Theseweresuggestedasbeneficialby
freeingupstafftimeandallowingfeedingtobecontrolled(amountandtiming)whichcanbe
importantforensuringconsistentwaterqualitywhenrunningRAS.
5.12 Watersources,replacementanddischargeThefreshwatersitesvisitedwereeitherusingmains,springorboreholewaterandweretypically
onlyreplacingbetween1to10%ofsystemwaterperday.Twocoastalseawatersitespumped
seawaterashore,whilsttheotherinlandsitesmixedtheirownfrompurchasedsaltandmainswater.
Theseawatersitesreplaced210%ofsystemwaterperday.
Dischargeofreplacedwater(usuallydrumfilterbackwash)wasmostcommonlytoasettlementtank
orlagoonandoccasionallytoasewer.Anyexcesswateraftersettlementwasdischargedtoamains
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sewer,intoaconstructedwetlandareaordrainageditch.Theconcentratedsettledsolidswere
disposedofbyspreadingontofieldsorbeingtakenawayforoffsitedisposal.
5.13 LessonstobelearntThemajority(80%)ofsitesthatusedapreexistingbuildinghadtoaccommodateaspectsofthe
buildingdesign(e.g.lowceilingsandsupportpillars)intothesystemlayout.Thedisadvantagesof
usingapreexistingbuildingwillbesitespecific,andmustbebalancedagainstthecostofacustom
madebuilding.
RASmustbeconsideredasaselfcontainedecosystem,withthebiofilteratitscore.Akeyfactorthat
washighlightedbysomeofthesitesisthatRASmustberunasfixedoperations,i.e.inputs(i.e.
feed)andoutputs(harvest)mustbeconsistenttoensurereliableproduction.
ToensurethattheproductionpotentialofaRASisreached,itmustbedesigned,constructedand
operatedwell.Everysitevisitedrecognisedthatdesign,constructionanduseofcorrect/adequate
equipmentwereextremelyimportantinrunningaRAS:wheretherehadbeenfailures,aproblem
withoneofthesefactorshadbeenamajorcontributor.
A
high
percentage
of
sites
identified
poor
design
of
the
RAS
itself
as
the
main
cause
of
ongoing
issues:thesetendedtoemergeasthebiomassintheRASincreased,andrequiredaconsiderable
amountoftimeandmoneytoaddress. Examplesofdesignerrorswere:
ammoniabuildupinproductionunitsduetoinadequatewaterflowthroughthesystem
oxygenlevelsbecominglowasbiomass/feedingrateincreasedduetoinsufficientaeration
pHdroppingcausedbyCO2buildupduetoinadequateventilation/aeration(couldalsobe
addressedbybuffering)
onesitestoppedusingaventurideliverysystemasthiswascausinghighlevelsofO2
(supersaturation).
MakingchangestoRASonceinuseisobviouslyundesirable: ontopoftheadditionalcost,itis
logisticallydifficultandcancompromiseproduction. Somefundamentalflawscouldnotberectified
withouttotalshutdownoftheRAS,whichwasnotarealisticoptionforarunningbusiness. Onesite
didhavetoresorttototalshutdowntoaddressfailingdesignandpoorconstruction,whichpushed
thebusinesstowardsfinancialfailure.
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Approximately60%ofRAShadbeendesignedtorunasonelargesingleunit.Althoughthismay
economiseonconstructioncosts,itwasrecognisedasacompromiseasitmakessystemsinflexible.
Anexampleiswhensmallfryneedtobeongrown(ratherthanfingerlings) fryrearingfacilities
separatetothemainproductionRASneededtobesetupbysomesites. Inhindsight,approximately
30%ofsiteswouldhavepreferredsmaller,separateRASdespitetheadditionalcapitalinvestment
required,togivegreaterflexibilityandmanageability,particularlywhilenewbusinessventureswere
findingstheirfeet.
RASoftenseemtobedesignedtorunatthelimitofcapacity,withfiltrationjustadequateto
managethemaximumbiomass/feedloadingonasystem. RunningaRASatthislevelleavesno
margin forfluctuationsinwaterquality,errorinpractices,maintenance,andforunforeseenevents
suchasequipmentfailure.Therealityisthatthingswillnotproceedsmoothlyatalltimes,andspare
capacitydoesneedtobebuiltintothedesign.
Sitesthatconstructedvessels(forfishandfilters)ofconcretewereparticularlyrestrictedcompared
tositesconstructedoffreestandingvessels. Concreteproductionunitsweregenerallyofaraceway
design,butonesiteusedlargeconcretecirculartanks.Modificationstothefiltrationunits,
frequentlyidentifiedassitesapproachedtheirexpectedmaximumbiomass(andfeedingrate),were
particularly
difficult
and
restricted
if
constructed
from
concrete.
However,
concrete
may
be
the
only
viableoptionforlargeRAS.Notably,atonelargesiteconstructedofconcrete,thefiltrationhadbeen
carefullydesignedandwasworkingwellwithinexpectedparameters.
Forgettingoperationconsiderationsduringdesignledtotwocommon,andpotentiallyimportant,
designflaws:
storagecapacityforinletwaterisoftenunderestimated,somakeupwaterdoesnothave
sufficienttimetowarmuptotemperaturebeforeuse
alackofcapacitytoretainwaterwhentanksneededtobedrainedforharvestormaintenance.
Ifdrainedtankwaterislostfromthesystem,thenitmustbereplaced.Replacementmay
representasignificantcostintermsoflostwaterandheat,ontopofthetimeforreplacement
(particularlyiftapwateristheonlywatersource).
Examplesofotherdesignflawsrelatedtoignoringhowstaffwouldaccessareas,conductroutine
activitiesandmaintenance:
pipesfittedtotopsofwallspreventedaccessalongthem
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hexagonaltanks,neatlyfilledspace,butpreventedaccesstothoseinthemiddle
awalkway,postfittedtoprovideaccess,necessitatedstaffhavingtooperate4mabovethe
watersurface,makingactivitiessuchasmortalityremovalverydifficult.Thistrickyoperation
wascompoundedbytheoutletsbeinginstalledatthebottomofthevessels.
tankshape(e.g.hexagonalwithawkwardcorners),makingconfinementofthestockdifficult
duringharvest
lackofanyprovisionindesignformechanisedharvest,necessitatingmanualhauling.
InconclusionthemajorityofRASoperatedwellandproducedfishoncetherightcombinationof
mechanicalandbiologicalfiltrationwasinplace.Sitesthatachievedtherightfiltrationfromthe
outsetwereaminority;mostrequiredconsiderableadaptationandmodificationstoapoorinitial
design.Underestimatingfiltrationcapacityfortheproductiontarget(=overestimatingproductionfor
thedesignedfiltrationcapacity)wascommon.Whetherinitialdesignwasgoodorbad,changes
alwaysneededtobemade;minorchangescanbeaccommodated,butlargeunforeseenchangescan
provecostly. Poorconstructionwasaproblemforsome,butnotall,sites.
5.14 NextgenerationRASActiveresearchisongoinginEurope,NorthAmericaandelsewheretofurtherdevelopRAS.Progress
isbeingmadeinareassuchasdenitrificationreactors,sludgethickeningtechnologiesandozone
treatments.Thesewillallcontributetoreducingwateruse,wastedischargeandenergyuseinRAS
(recentlyreviewedbyMartinsetal.2010)27
.However,whilstsuchdevelopmentsofferpromisefor
thenextgenerationofUKRAS,theyarenotyetwidelyavailabletotheexistingsector.
Nitrogenouswasteremoval:Twonewapproachesarebeingappliedtoremovenitrogenouswastes
fromRAS.Thefirstisbasedonrecentdevelopmentsindeammonificationinotherwastewater
treatmentapplications.TheEUFP7DeammRecircprojectisdevelopingdeammonificationreactors
forfresh andseawaterRAS,whichconvertammoniatonitrogengasinonestep.Ifthetechnology
isproven,deammonificationreactorscouldbenefitcommercialRASbyreducing:theneedforclean
makeupwaterandassociatedpumpingandtreatmentcosts,oxygenandbufferingchemicaluseand
cost,carbonfootprint,andlevelsofnitrateineffluent28
.Thesecondapproachisdenitrification
reactorswhichremovethenitratethatbuildsupinRASbyconversiontonitrogengas.Varioustypes
ofdenitrificationreactorshavebeendevelopedthatallowhighnitrateconcentrationstobe
27
Martinsetal(2010)NewdevelopmentsinrecirculatingaquaculturesystemsinEurope:Aperspectiveonenvironmentalsustainability,AquacultureEngineering43(2010)8393.28http://deammrecirc.com/Project Description
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counteracted,e.g.theupflowsludgeblanketdenitrificationreactor.Martinsetal(2010)discussthebenefitsofthesesystems andsuggestthat installationcostsarerewardedbyloweroperatingcosts
duetoreduced waterexchange.However,boththesenewapproachestoremovenitrogenand
reducewaterreplacementmayprecipitateotherproblemssuchasaccumulationofgrowth
inhibitingfactors(anareathatrequiresfurtherresearch).
Suspendedsolidswastetreatment:Sludgethickeningtechnologiessuchasbeltfilters,geotextile
bagsortubesallhelptodewaterandreducethevolumeofSSWthatneedsstorageanddisposal.
Thesetechnologiesmayalsochangethewasteintoaformmoresuitableforuseasafertiliserorin
integratedaquaculture.
Effluenttreatment:Constructedwetlandsandmicroalgalcontrolledsystemsarecommonlyusedto
treatmunicipalwastewaterandofferopportunitiesfortreatmentofwastewaterfromRAS.
Energyefficiency:ResearchbeingcarriedoutattheFreshwaterInstitute(Virginia,USA)on
improvingthesustainabilityoflandbasedclosedcontainmentsystemsforsalmonidtablefish
productionistargetingthepotentialforgreaterenergyefficiencyinwaterrecirculationsystems
throughimprovedlowliftpumpingandgastransferprocesses.TheUSDepartmentofAgriculture
scientistshaveshownthatacombinationoflowheadpumps,properplumbingandlargerdiameter
pipesused30%lessenergythanhighheadcentrifugalpumps.
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6 Financial sustainability of RAS
Theaimofthissectionistoprovideanoverviewofthefinancialexperiencesofthe14different
warm
water
RAS.
It
should
be
noted
that
the
extent
and
detail
of
the
financial
data
provided
varied
betweenintervieweesduetoconfidentiality,positionwithinthebusiness,andavailablerecords.
6.1 FundingsourcesFundingoftheoperationsvariedconsiderablybetweenbusinessesfromthosewhojustusedtheir
ownmoneytomixturesofinvestorfunding,bankloans,mortgagesandgrants. Approximatelyhalf
hadborrowedinoneformoranothertogetthebusinessupandrunning.Fewerthanhalfthesites
hadobtainedsomesortofgrantfunding:grantsvariedfromaslittleas1,000tomany100,000s
forthelargestsites.Accesstocontingencyfundingwasmentionedasimportantbyonesite.
6.2 BuildandsetupcostsThescaleofthesitesvisitedvariedfromthosecosting70,00080,000builttoproduce1050
tonnesp.a.,tositescosting10to14milliondesignedtoproduce1,000tonnesp.a..
Underestimationofthebuildandsetupcostswascommon,withfiguresforoverspendvarying
between15and40%.Thereasonsgivenvariedandincluded:
designsnotincludingcostofinstallationofspecificelectricalsupplies
additionofsupplementarydenitrificationfilters
modificationstofaultysystems.
6.3 RunningcostsElectricity:Mostofthesitesvisitedconsideredelectricitytobeamajorcost:typicalfiguresquoted
were15 20%ofrunningcosts.Monthlycostsof500 1000weretypicallyquoted,evenbysites
producinglessthan100tonnesp.a. Somesitesexpressedconcernthatinappropriate,power
hungrypumpshadbeensupplied,whichunnecessarilydoubledtheelectricitybill. Somesiteswere
investigatingtheuseofalternativeenergysources.
Heating:Thenecessityforsupplementaryheatingvariesbetweensitesandwithspeciesheld.
However,mostsitesconsideredthatheatingwasaminorcost,andthelargestsitedidnotconsider
heatingasignificantcostatall. Figurestypicallyquotedwere5%ofrunningcostsor50%ofpumping
costs.Withgoodinsulation,alotofthesitesonlyusedsupplementaryheatingfor2 4monthsin
winter.Somesmallersitesfoundcheaperalternatives,e.g.
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burningwoodchip
switchingfromanLPG(liquidpropanegas)heatsourcetodiesel.
Water:Agoodsupplyofwateriscriticalevenforarecirculationsystemasitisrequiredfortopup,
emergencyuse,shippingetc. Waterquantityandqualityissuesmustberesolvedbeforelocatingan
aquaculturefacility29
.Themajorityofsiteshadnoissueswithsupplyandoftenbenefittedfrom
agriculturalrates. Watersupplycostsdidnotrepresentasignificantproportionofrunningcostsfor
themajorityofsites. However,asmallnumberofsitesdidexperienceunexpectedwatercosts,e.g.:
aswitchtomainswatersupply
makingupsaltwateronsite,costingupto2.10perm3
underestimatingthecostofpumpingwaterfromthesourceintothefarm.
Staff:Responsesvariedbetweensites:somethoughtstaffcostswerenothigh,whileothers
emphasisedthetimecommitmentinrunningRASandtheneedfortrained,experiencedbackup
availableatalltimes.Onesite,betweendevelopmentphases,didexpressconcernaboutthe
intensityofmanpowerrequired.Entrylevelpayintoaquacultureisacknowledgedtobelow30
and
manysiteshavebenefittedfromcheapeastEuropeanlabour. Twolargersites,inoperationwith
goodfinancialmanagementsystems,bothestimatedstaffcostsat15%ofrunningcosts.
Fry:Ofthe14RASsitesvisited,5hadsourcedUKfryandonehadusedtheirownbroodstock,while
10hadimportedeggsorfry. SomesiteshadongrownbothimportedandUKfry.Frysupply
thereforefrequentlynecessitatedimports,duetoalackofUKhatcheries.Fryhadbeenimported
fromFrance,Holland,Israel,USA,SouthAfricaandIndonesia.Themethodofshippingvaried:road
deliveryfromEuropeancountriesandairfreightfromfurtherafield.Althoughfrywouldhavebeen
movedatasmallsize,transportinwateraddstoshippingcosts. Onelargersitestatedthatfrycosts
were8%oftotalrunningcosts.
Feed: Thepriceofaquafeedwasaconcerntoallbusinessesandcomprisedasizeableproportionof
runningcosts.Theactualcostsoffeedsvariedbetweenthespecies,anddidnotcorrelatewiththe
percentageofrunningcostsquoted,varyingbetween20%and40%ofrunningcosts.Factors
thoughttocontributetorelativedifferencesbetweensitesincludeeconomiesofscaleinfood
purchase(bulkbuying),howmuchthefishwerefed(%bodyweightperday),aswellasthe
magnitudeofothercostcategories. Issuesaroundfeedcostsincluded:
29http://www.aces.edu/dept/fisheries/aquaculture/documents/Wheaton.pdf
30http://www.sparsholt.ac.uk/pages/template.aspx?idSection=69&idPage=139
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largeincreasesinfeedpricesoutsidefarmercontrol
aswitchindietsnecessitatedbynutritionalproblemswhichincreasedfeedcostsfrom1,000to
1,600/tonne.
onetilapiafarmer,experiencedinsourcingterrestriallivestockfeedexpressedfrustrationatan
inabilitytosourcehisowningredientsandconsideredthataquafeedsupplyoptionsweretoo
limited.
producersofturbotandbarramundiexperiencedproblemsinsourcingappropriatediets
becausetheyweretheonlymarketintheUK.Thisalsomeanttherewasnochoicein
formulation.
Maintenance:Thereliabilityofequipment,itslifespanandthemaintenancecostsneedstobe
knownandassessedbyalloperatorspriortopurchase.Examplesofmaintenancecostissuesraised
are:
Pumpmaintenancecostswerehighlightedbyseveralsites
Onelargefarmhadtoreplacefilterbeltsonanalmostweeklybasis.Thistook3mendayeach
andcost1,800 2,000atime.Althoughacheaperbeltsupplywaseventuallyfound,thetime
andcostshadalreadyhadacripplingfinancialimpact.
Solidswaste
disposal:
Disposalofsettledsolidsfrommostfreshwaterrecirculationsystemswasnot
seenasasignificantcostastheywereabletospreadontofields.(Somesitesdidmentionthatthe
systemsadoptedhadincreasedtheirassociatedpumpingcosts). However,forsaltwatersites
disposalwasfarmorecomplicatedduetothepresenceofsalt.Foronesitepumpingoutthe
settlementtankapproximatelyeverytwomonthscost1,500atime.Inaddition,regulatorshave
notappliedpolicyuniformlyacrossregionswithsomefreshwatersiteshavingtheirwaste
categorisedasindustrialwastewhichrequiresaspeciallicensecosting4,000p.a..
Mortalitydisposal:Disposalofmortalitieswasconsideredaminorissuebysomesitesthathad
readyaccesstofacilities,whileotherssuggestedthatitincurredasignificantcostalthoughthiscould
notbequantified.
Rental:Over90%ofthesitesownedtheirownbuildingsoconsequentlyrentalcostswerenotan
issueandalmostallofthesehadutilisedexistingvacantbuildings. However,foronelargersite,
rentalcostswereconsideredexcessiveatapproximately25,000permonth.
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Oxygen:Oxygenwasnotusedatmanyofthebusinesses,butdidamounttoupto5%ofrunning
costsatsomesites.Onefarmmentionedhydrogenperoxideuse,butthiswasnotconsidereda
majorcost.
Unexpectedcosts:Sitesoftenfoundrunningcostsweregreaterthaninitiallybudgeted,which
occurredduetoavarietyof,oftensitespecific,reasons:
salescosts(formarketing,packaging,icemachinesanddelivery)werecommonlywrongly
anticipated.Onesitequotedsalescostsat0.25/kgoffish.
supermarketcompliancecosts
modificationofnewlyinstalledsystemsandadjustmentstotechnology,e.g.deliveringadditional
ozonetoproteinskimmers.Therewastypicallyasignificantadditionalsetupcosttoaddress
teethingtroubles.
Biofilterscouldrequireuptoseveralhundredm3ofmedia,costingupto300/m3
frycostshigherthananticipated
6.4 Planned vactualsalespriceAlthoughonesiteachievedandonesiteexceededtheirpredictedsalesprices,manyofthesiteshad
beenunabletoobtaintheirplannedsalesprice.Onesiteplannedasalespriceof16/Kg,revisedthis
downto6/Kg,butthebestpriceachievedwas3.20/Kg,withafinalaverageof2.40/Kg.Prices
quotedwereclearlyhigherforpremiummarinespeciessuchasturbotandbass.Sitesproducing
lowervaluespeciessuchastilapiaorcatfishindicatedthatsalesat3.00/Kgwouldprovideaviable
business,butmanywerestrugglingtoachieve2.20 2.80/Kg. Thepressuresandproblemscaused
bysupermarketswerementioned,e.g.promotionalofferswhichreducedpricesthefarmers
receivedandcausedashorttermincreaseinsales.Severalsiteshadmanagedtoobtainhigher
pricesbydeliveringtolivefishmarkets.
6.5 Productioncosts,paybackandaccountingrateofreturnAccuratefiguresforfinancialappraisalweredifficulttoobtainwithmanyfarmerseitherunwillingor
unabletosupplythese.Insomecasesfigureswerewithaccountants.However,threesitesnolonger
inoperationquotedproductioncostsofbetween1.50/Kgfortilapiaand7.70/Kgforturbot.
Paybackistheperiodtakenforaprojecttorecoveritsoriginalcostinfuturecashflows.Twosites
mentionedthattheyhadexpectedtoachievethiswithintwoyearsbutapaybackperiodof5years
wasmorerealistic.Onesite,currentlybetweendevelopmentphases,wasconcernedaboutthe
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lengthoftimebeforeareturnwasachieved(interpretedbyinterviewerstomeanachieving
payback).
Accountingrateofreturnmeasuresthepercentagereturntheprojectachievesoveritslifeinterms
ofprofitability.Twositesthatarenolongeroperatingdidprovidecrudefiguresonrateofreturn
statingthatitwasjust2550%ofthelevelspromisedbythesystemsalesperson/installer.
Thelargescale,operatingsiteswithbetterfinancialmanagementdidnotquotefigures,butwere
optimisticandfirmlybelievedinthefutureofRAS. OnedidindicatethatthecurrentRASsystems
didneedtoevolvefurtherforanother10yearstoassurefinancialsustainability.Oneinterviewee
gavethemainreasonhesoldupasteethingproblemsthatwentontoolongsoheendedupwith
halftheexpectedsalesanddoublethecosts.
6.6 LiteraturereviewfindingsTheUniversityofStirling,hasexaminedthepotentialfordevelopmentofwarmwaterproduction
systemsasadiversificationrouteforUKagriculturalfarmers31
.Onepartoftheprogrammelookedat
theeconomics,withsensitivityscenarios.Usingtypicalfarmgatepricesfortilapiaof3.00,3.70
and4.50/Kg,salespriceemergedasthemostcriticalsensitivityitem. Manyofthetilapiafarmers
interviewed
in
the
current
study
had
struggled
to
achieve
even
the
lowest
modelled
sale
price.
TheStirlingresearchshowedthatcontinuousproductionwasmoreprofitablethanbatch
production:forprofitablebatchproduction,thesmallestunitswouldneedtoachieveasalespriceof
3.20/Kgtobringthemtoprofitability,comparedto2.65/Kgforcontinuousproduction. The
analysisshowedthatprofitabilityiscloselyrelatedtoproductionscale,butalsoindicatedthatrisk
increaseswiththescaleofoperation.Theresearchalsopointedoutconsiderablescopefor
increasingprofitsbyincreasingenergyefficiencyandintegratingcombinedelectricityandheat
biomasssystems.
The(somewhatcrude)industrysurveyinformationsummarisedaboveandtheStirlingprojectdonot
supportstrongfinancialsustainabilityoffreshwaterRASinEngland. However,thesituationcould
changemarkedlyifsalespricesareincreasedbyexternaldrivers.Thepressureonwildfishstocksis
mountingasglobaldemandforseafoodproductsgrows32
,humanpopulationsincrease33
,andper
31http://www.tilapiascotland.org/relu32http://www.fao.org/docrep/007/y5767e/y5767e0d.htm
33http://www.statistics.gov.uk/cci/nugget.asp?id=1352
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capitademandincreasesduetotherecentmessageforincreasedfishconsumption34
.Therehave
alreadybeenpricesrises35
andshortages36
,whichcouldleadtohigherfarmgateprices.Thepromise
offeredbyRASisfurtherillustratedbyinvestmentinresearchanddevelopment,e.g.:
ArecentfeasibilitystudyofclosedcontainmentoptionsfortheBritishColumbiaaquaculture
industry37
comparedopencagestoRAS.Overall,thestudyfoundasignificantadvantagefor
cagesintermsofpretaxincome.AlthoughRAStechnologywasmarginallyviablefinancially,it
representedahigherlevelofrisk.RASbenefittedfrommoreefficientbiologicalfeedconversion
ratio(FCR),temperaturestability,andimprovedenvironmentalcontrol,butthiswasatthecost
ofhigherexpenditureoncapital,energyandlabourwhichimpactedoverallprofitability.
Nevertheless,aswithmostemergingtechnologies,oncewiderRASuptakeisachieved,capital
andoperatingcostsmaygodown.Ifclosedcontainmenttechnologiesachieveacriticalmassof
production,operatorsmaybenefitfromeconomiesofscaleforacquiringcapitalitems,and
increasingexpertisecouldreduceoperatingcosts38
.
InManitoba,Canada,amodelinlandrecirculationtroutfarmisbeingdeveloped,with
encouragementfromtheauthorities,fromwhichdataisbeingrecorded.
InNorway,NOFIMAhavejustopenedastateoftheartrecirculationaquacultureresearch
facilityandacknowledgethatrecirculationwillbeimplementedwithintheindustryinthenear
future39
.
6.7 OverallassessmentoffinancialsustainabilityHistorically,thefinancialviabilityofrecirculationaquaculturehasnotbeengood:itisadeveloping
sectorthathasmademanymistakes. Currentsalespricesformanyspeciesmakethereturnon
investmentmarginal.Howeverifcapitalcostsreduce,andtechnologyandenergyefficiencyreduces
runningcosts,theoutlookmayimprove.Furthermore,salespricesmayincrease:consumersare
becomingincreasinglymoreadventurouswiththeireatinghabitsandRASofferanopportunityto
growadiverserangeofspeciesclosetomarkets.Potentialinvestorsshouldthereforeproceedwith
cautionandpayparticularattentiontominimisinginputcostsanddevelopprudentbusinessplans
thatreflectthemarket.
34http://www.food.gov.uk/news/newsarchive/2006/mar/oilyfish
35http://www.talkingretail.com/news/industrynews/fishpricestoriseby5asdemandincreasesandinflationbites
36http://www.enn.com/top_stories/article/41773
37http://www.dfompo.gc.ca/aquaculture/libbib/nasapiinpasa/BCaquacultureCBeng.htm
38http://www.dfompo.gc.ca/aquaculture/libbib/nasapiinpasa/BCaquacultureCBeng.htm#executive39http://www.fishnewseu.com/index.php?option=com_content&view=article&id=4838:berghansenopensrecirculationresearch
centre&catid=46:world&Itemid=56
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7 Factors leading to historical failure ofsome RAS
7.1 Top10criticalfactorsDuringthevisits,the14intervieweeswereaskedtopickandranktheirtop10keyfactors
contributingtothesuccess(orfailure)ofawarmwaterRAStablefishfarm.Rankingswere
convertedtoscores(highscore=importantfactor)whichweresummedfordisplay(Figure5).
Government support
Lack of automation
Veterinary support
CertificationTechnical stock issues (e.g. maturation)
Survival rates
Added value/own processing
Lack of funding
Supplier support
Staff costs
Husbandry difficulties
Food costs
Disease
System failure
Scale of site
Food conversion rates
Supermarkets
Paperwork
Diet / nutrition
Product quality
Access to markets
Lack of backups (alarms)
Competition from cheap imports
Growth rate
Staff aquaculture knowledge
Water quality issues
Owner / manager experience
Planning
Sales price achieved
Choice of species
Demand for productElectricity/gas/heating costs
Fingerling supply (& price)
Marketing
System design
Rank score
Figure5: CriticalfactorsforthesuccessorfailureofwarmwaterRAS,asscoredbyRASindustry
interviewees.
Technical(systemdesign)andsomeeconomicfactors(marketing,energycosts,demandfor
product),alongwithfingerlingavailability/price,emergedasthekeyissues.Staffknowledgeand
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biologicalfactorsappeartobeconsideredaslesscritical;regulatoryandcertificationissuesappear
tobeofminorimportance.
7.2 AdditionalfactorscontributingtofailureOtherkeyissuescontributingtofailedoperationswereidentifiedduringinterviews.Theseare
categorisedinTable4.
Table4:OtherkeyissuesidentifiedduringinterviewsascontributingtofailedRASoperations.
Reasonsforclosingtheoperation Sitespecificproblems
Operationaldesignissues Inappropriatewatersupply
Cashflowanddebts Restrictedaccesstofacilities
Salesvolumes Sitetoosmall
Marketprices Wastetreatmentanddrainageproblems Overheads Distancefrommarkets
Systemspecificproblems Mistakesmade
Modificationstooriginalbuild Onlyconsultingonesupplier/designer
Inadequatefiltrationsystem Notpilotingbeforescaleup
Qualityofsystembuild Unrealisticexpectations
Pipeworkandflowdesign Notenoughattentiontodetail
Lackofautomatedsystemsforharvesting
andmortalityremovals
Inputsandcoststoohigh
Inflexibility
of
system
Not
checking
access
to
markets
Ofthemajorreasonsidentified,thetechnicalandeconomicreasons(costs)forfailurehavebeen
discussedabove.Otherissuesthatmeritdiscussionrelatetomarketsandeconomiesofscale.
7.3 MarketsFishfarmersnaturallyfocusonproducingfishandsalesisrecognisedasanareawheretheyoften
droptheball40
.Manysitesappearednottohaveunderstoodthemarketatthebeginningofthe
operationandhadconsequentlychangedorstruggledtofindoutlets. Fewoperationsappearedto
haveinvestedeffortinthefourPs(Product,Price,PlacementandPromotion)41
.
Intendedmarketsvariedbetweensites,largelyduetodifferencesinthescaleofoperation.
Smallersiteswereunabletosupplysupermarketswiththevolumesdemanded,sofocussedon
localorethniclivemarkets. Sitesthattargetedethnicmarketshadgoodinitialuptake,butthen
40http://aquaculture.ext.wvu.edu/r/download/59173
41http://www.eldis.org/go/topics/resourceguides/healthsystems/keyissues/marketdevelopmentapproaches/tools/4ps
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hitaceiling.Severalfoundtheprocessofdistributiontolocalorpremiummarketsonerousand
endedupsupplyingwholesalers,processorsorsupermarketsasalastresort.
Manysitesciteddifficultiesindealingwithlargersupermarketssuchasbeingunabletosupply
whentheydemanded,andcopingwithpromotions. However,contractshadbeensetupto
facilitatetwowaycommunicationandunderstandingoftheproblems supplybythefarm,and
thesupermarketsneedforpromotions.
Otherissueswithmarketsthatemergedduringinterviewsincluded:
Breakingin Someofthelargertilapiaproducersfeltthatthemarketwasthere,butwasdifficult
toaccess,possiblybecausetheydidnothaveadiversebasketofproductstooffer.
Dependence Afewsiteswerereliantonasingleoutletfortheirproduct,andwereleft
flounderingifthisavenueclosed.
Productquality Onesitereleasedfishontothemarketbeforethedepurationsystemwas
operationalandasaresultacquiredareputationfortaintedfishthatproveddifficulttoshift.
CompetitionThelowcostofimportsinrelationtodomesticproductionwasraisedseveral
times.
Twositesdidrecognisetheimportanceofmarketingtheirproducts:
Onesiteallocated10%ofproductioncoststomarketingand,asaresult,hadalwaysachievedor
exceededtheirfarmgateprices.
Anotherofthelargersiteshadadedicatedsalesmanagertokeepcustomershappywhichwas
perceivedasakeytosuccess.
7.4 Addingvalue:processing,accreditationschemesandbrandingNearlyalloperatingsitesdidtheminimumamountofprocessingtheysoldwholefishwith
negligibleamountsofdescalingandpacking.Afewsitesstatedthattheydidnotwanttoget
involvedinprocessing.Incontrast,severalsiteswerecontemplatingprocessing,withonegroup
consideringasharedfacility.
Approximatelyhalfofthesitesvisitedhadneverbeeninvolvedinanaccreditationscheme.Twoof
thelargeroneshadjoinedupwiththeQualityTroutUK(QTUK)scheme,andothersiteswere
consideringjoining.
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Somesiteswereconsideringdevelopingtheirown,orlocal(group)brands.Severaltilapiafarmers
consideredthathighlightingtheirproductsaslocally/regionallyproduced(e.g.bredinNorfolk,
raisedinSuffolk)wouldbeamarketableattribute.Severalfarmerswerekeentoconveythe
sustainabilityattributesoftheirproductsandmakethemostofgreencredentialsthrougheco
labelling42
.However,thiswasnotyetoccurring,becauseeithertheywereunclearofhowtogo
aboutit,oritwasbeingleftassomethingforthefuture.
7.5 EconomiesofscaleWhilstthisdidnotrankhighlyasatoptenfactor,thevastmajorityofsitessuggestedthat
economiesofscalewereveryimportantintermsoffinancialsustainabilityandcriticalinsupplying
supermarketchains.Afewnonoperationalsitesexpressedtheopinionthatiftheyhadpilotedthe
projectorstartedsmallthiswouldhavereducedthecostlymistakesmadelater.Twofarmers
expressedtheopinionthatbeingsmallhadreducedtheirlossestomostlytheirownlabour,
althoughoneofthesesitesdidqualifythisbysayingthathecouldhavehadaviableoperationif
productionhadincreasedfrom10to20tonnesp.a..
42MungkungRT,deHaesHAU,CliftR(2006).PotentialandlimitationsofLifeCycleAssessmentinsettingecolabellingcriteria:acasestudy
ofThaishrimpaquacultureproduct.IntJLCA11,5559.
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8 Sustainability issues relating to RAS
TheEUAquaculturestrategycallsfordevelopmentofasustainableindustry.Awidelyused
definition
of
sustainable
is
developmentwhich
meets
the
needs
of
the
present
without
compromisingtheabilityoffuturegenerationstomeettheirownneeds43.Sustainabilityisanidealaimedatensuringsatisfactoryenvironmental,social,andeconomicconditions,andcanbe
envisagedasaddressingfourobjectives44
:
effectiveprotectionoftheenvironment
prudentuseofnaturalresources
socialprogresswhichrecognisestheneedsofeveryone
maintenanceofhighandstablelevelsofeconomicgrowthandemployment.
EconomicissuesrelatedtoRASarediscussedabove;herewediscussenvironmentalprotection,
naturalresourceuse,socialissuesandemploymentinrelationtoRAS.
Nearlyallofthefarmsvisitedwereawareoftheenvironmentalandresourceusecredentialsoftheir
products,e.g.locallyproducedandlowfoodmiles,rearedonlowfishmealdiets,lowwaterusage,
efficientuseofspace.However,farmersoftenstruggledtodiscusssocialsustainabilityissues,but
didsowhenpromptedbyinterviewerswithexamples.
8.1 EnvironmentalprotectionRASfarmsscorestronglyintermsofenvironmentalprotection,largelyduetotheirinherent
features.
Finfishaquacultureisoftencriticisedovertheissueofescapeesandtheirimpactsonlocalstocks
thoughcompetition,interbreedinganddilutionoflocalgenepools.Duetotheircloseddesign,
typicallocationremotefromnaturalwaterbodiesandcultureoftropicalspecies,noneoftheRAS
siteshadexperiencedanyproblemswithescapees.
Openfinfishfarmsareoftenperceivedtoactasreservoirsofpathogensthatinfectwildstocks.
Again,thecloseddesign,locationawayfromnaturalwaterbodies,treatmentofeffluentandculture
oftropicalspecies,negatethisissuefortheRASfarmsvisited.
43http://archive.defra.gov.uk/sustainable/government/publications/ukstrategy/documents/NewGlossary.pdf
44http://archive.defra.gov.uk/wildlifepets/zoos/documents/zoo handbook/3.pdf
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ContainmentofwarmwaterRASwithinbuildingsalsoeliminatesinteractionswithwildpredators,
withnositereportingpredatorproblems.Twositesdidmentionaneedforpestcontrolandused
professionalcontractorstocontrolratsaroundthefarm.
Openaquaculturesystemsmaynecessitatemodificationstonaturalwaterbodiesandchangesin
flow,duetoconstructionofchannelsforabstractionanddischarge.Again,RASavoidsuchimpacts.
Inopenaquaculturesystems,dischargeofveterinaryproductscanbeaconcern.Again,thelocation
ofRASfarmsawayfromnaturalwaterbodiescoupledwithretentionofwaterwithinthesystem
eliminatesthispotentialissue.Furthermore,RASaregenerallydesignedtohavehighbiosecurity
beingwithinabuilding,drawingwaterfromsourceswithoutfishpathogensorsterilisingifdrawn
fromnaturalwaterbodies.Alargeproportionofthesitesvisitedhadthereforenotusedany
veterinaryproducts.
Inopen,flowthroughfishfarms,thereisdischargeofeffluentcontainingsuspendedsolids,
dissolvedinorganicanddissolvedorganicwastesintonaturalwaterbodieswhichcanreducethe
qualityofthelocalenvironment.Again,thelocationofRASfarmsawayfromnaturalwaterbodies
coupledwithtreatmentofwasteswithinthesystemeliminatesthisissue. RASdoneedtodischarge
a
small
percentage
of
the
recirculating
water
(
10%
/
day)
to
prevent
excessive
build
up
of
nitrates
andothercompounds.Thiseffluentcouldhavepotentialeutrophicationimpacts,butRAStendto
dischargetosewers,settlementtanks,ditches,orconstructedwetlandsratherthannaturalwater
bodies.Constructedwetlandsprovideanaturalmeansofcleaningeffluent,andcanprovideanew
habitatforwildlife.
RASsystemscaptureandconcentratesuspendedsolidswasteswhichrequiredisposal.SomeRAS
farmsusewastedisposalsystemsalreadyinplaceaspartoftheiragriculturalfarms;somespread
theirsolidwasteontofields(representingreuseasfertilizer);somehavewastetakenawayaspera
septictank;othershavehadthewasteclassifiedasindustrialwasteandhavetopayforaspecial
licenceanddisposal.
OneenvironmentalweaknessofRASistheirhighenergyuse(seebelow)whichcontributestoglobal
warmingduetotheburningoffossilfuels.RAStypicallyhavedoublethecarbonfootprintofflow
throughsystems45
. ThekeytoreducingcarbonfootprintofRASistoswitchtorenewableenergy
45SeeEllisetal.(2011)InitialinvestigationofthesustainabilityofEnglishaquaculture.CefascontractC3743reporttoDefra
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sources.Everysitevisitedhadinvestigatedorexperimentedwithalternativeenergysources,i.e.
woodchipburners,solarpanels/photovoltaics,windturbines,biogasplants,anaerobicdigesters,
groundsourceheatpumps, anduseofwasteheatfromanicerink.Althoughreuseofwasteheat
fromthirdpartysourcesmaybegreen,asymmetriesbetweenthecooperatingbusinesseshave
typicallymadepreviousattemptsunsuccessful46
.
OnepotentialadvantageofgrowingtilapiaintheUKoverimportofforeignproductionisthatthe
associatedfoodmilesaremarkedlyless.However,simplyfocussingonfoodmilestravelledbythe
finalproductignoresthemodeofproduction,modeoftransport,andtransportofinputssuchas
feedsandfry.OnestudyassessedtheglobalwarmingimpactsofcagetilapiaproductioninIndonesia
andtransporttoEurope47
.Inthecontextofthefullproductioncycle,transportationimpactswere
negligible,astransportoffrozenfilletsinoceanfreightedcontainersisefficient.ThismeansthatUK
productioninRAScontributedmoretoglobalwarmingthanproductioninIndonesiacombinedwith
importation48
.Nevertheless,RASproductionintheUKwasassociatedwithlesseutrophication.
FurthermoreaseparatestudyhasindicatedthatproductionofAfricancatfishinDutchRASresultsin
lowercarbondioxideemissionsthanPangasiuscatfishfarmedinpondsintheMekongDelta49alsotakingintoaccounttransportationcosts.
8.2
Natural
resource
use
RASsystemsareinamixedpositionintermsofresourceusage.Asintensivesystems,theydo
requireinputofnaturalresources,sotheemphasismustbeonmaximisingefficiency.
RASfarmsrepresentanefficientuseofland. Comparativeproductionfiguresfortilapiaare1340
tonnes/ha/yearforRASversus17.4tonnes/ha/yearforaconventionaltilapiafarm50
.
WateruseinRASisevidentlyefficientincomparisontoopen/flowthroughaquaculture:
comparativedataare0.5m3
/KgRASv31m3/Kgtilapiaproductioninaconventionalintensive
farm51
.RASalsocomparefavourablytoterrestrialanimalproductssuchaspigsandeggs52
.
46LittleDC,MurrayFJ,AzimE,LeschenW,BoydK,WattersonA,YoungJA(2008).OptionsforproducingawarmwaterfishintheUK:
limitstogreengrowth.TrendsinfoodScience&Technology19,255264.47PelletierN,TyedmersP(2010).LifecycleassessmentoffrozentilapiafilletsfromIndonesianlakebasedandpondbasedintensive
aquaculturesystems.JIndustrialEcology14,467481.48SeeEllisetal.(2011)op.cit.
49PoelmanM,SchneiderO,Abstractat8
thInternationalConferenceonRecirculatingAquaculture.
50Sustainablefinfishaquacultureworkshop.FinfishNews9,422;http://www.slideshare.net/Cefas/largescaleintensiverecirculation
systemsandtheirpotentialdevelopmentwithinengland237388151http://www.slideshare.net/Cefas/largescaleintensiverecirculationsystemsandtheirpotentialdevelopmentwithinengland2373881
52http://www.oecd.org/dataoecd/19/21/45032957.pdf
WarmwaterrecirculationfishfarmsinEnglandandWales Page36of48
7/28/2019 Fish Farm Fcf-recirculation
39/51
However,simplecomparisonsofvolumeofwaterusedinproductionaretoosimplistic53
.Themetric
forwateruse m3/Kgproduction doesnotaccountfortheimpactofabstractiononthesourceof
thewater(i.e.mains,groundwater,river,lake,sea)whichwillberelativetoitsavailability.
Furthermore,open/flowthroughaquacultureisanonconsumptiveuseofwaterasitispromptly
returnedtothesamewaterbodyfromwhichitwasabstracted;incontrast,RAScouldbeconsidered
asaconsumptiveuserofwater,althoughsomedischargedwaterwillfinditswaybackintothe
watertableviasewageworksorspreadingontheland.
RASfarmshaveahighenergyuseastheyrelyontechnologytomovewaterandmaintainitsquality.
EnergyuseacrosstheproductioncyclehasbeenexaminedinanumberofstudiesandRASfarms
typicallyrequire2to3timesmoreenergythanflowthrough/openaquacultures
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