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1、RaisingFreshFishinYOUrHomeWaters养鱼S#AprojectofVolunteersinAsiaby:BrendaBorta,JackRuttle1andMarcPodemsewspInc.33Ea8tMinorStreetEmmaws,BA18049USAbo,Inc.BrendaBortzJackRuttleMurcPodsmsWIWBEAF1SHFARMERStManypeoplethinkoftishasapotentialcrop.Ru:thatsjustwhatcarp,catfish,trout,andbassare.Tillrecently,fi3h
2、hasbeenawiIdfoc:dinthiscountry-huntedandcaddhtinopctnwater:,thentakenhomeortomat.Butallthatischanging.Wildstockisbeingdcletrdbyoverfishingandcou!;mirlatcclbyindustry,andthecostottrcshandfrozenfishkeepsclinbing.21.uckily,theresahappyendingtothisfishstory.Inotherlandspeoplehavebeenstocking,breeding,fe
3、ed-ing,andharvestingfishforcenturies.Andmorerecently,Americansin-tistshavebeguntodomesticatede,siratlenativespeciesliketruutandr%,tfish.Puttingthisknowhowtowork,CUmmer1.iaIfarmsnowraisehugenumbersoffishmuchlikeagribusi-nesserodeextieandchickens.Attheoth,.extreme,countrypeopiestillen,Olthefarmpond-st
4、ockedfor;ecre,Itionandoccasionalmeals,butnottrulycultured.Now,though,theresamiddleground.Itsabackyardfishculture,;Imethodthatletsyougrowfish1ikeagardencrop.1.ikethefoodsyougrowin4,Ihcfishinyourwatergardenwillneedregularattentionandfeedingorfertilization.Caredforinthisway,apondthesizeofamodestswimmin
5、gpoolcansupplyenoughfishforafamily,Artdatypicalfarmpondcanyieldenoughtohaveplentyleftoverforsale.Backymlfishvs.barnyardanimaleFormanypeople,acropoffishcanalsoturnouttobethebestchoiceinlivestock.Highlydigestibleandlow,infat,fisharerichinprotein.Andtheirproteincomesclosert.meetingthebodysneedsthanmeat
6、proteindoes.Sincefisharecoldblooded,theydontburnfoodjusttokeepwarm.WhichmeanstIicyarconeoftIitsmostenergyefficientlivestockaround.Andunlikebarnyardanimals,theyreabsolutelyquidandodorless.Sincetheresnopenormanurepiletooffendtheneighbors,raisingfishis.analmostinvisiblewilytogrowSonirofyourownnitintown
7、orinthesuburbs.GREATINGAB1.ANCEDJtlikeorganicgardening,fishculturrinvolvesworkingwithawholelivingsystem.Ihcwaterthatwillbeyourgrowthmediumismuchmorethantheequivalentofnourishinggardensoil.Itsalsotheatmospherethatprovideslife-givingoxygen.Manyforcesinteractinthistotalen-vironmtnt,andasabeginnerinaqua
8、cultureyou11wanttoknowaboutthosethatdirectlyaffectfish.Cleanwaterisamustinfishcul-ture,andfortunatelythewaterinmostfarmponds,ruralstreams,springs,andwellsisnaturalIyclean,Keepinmind,though,thatthekindofwaterbestforfishfarmingisfarfromcrystalclear.healthybloomofalgaeisvitaltoahigh-yieldingsys-tcm,and
9、thesemicroscopicpeagreentoruddybrownplantscanmakewaterlooksoupy.Ifyoususpect,however,thatyourwatersourcecontainsman-madepol-Iutants,youshouldhaveitanalyzed.YourcountyAgriculturalExtensionAgentoryourstatesFishandCameCommissionpeoplecantellyouhowtodothis.Youmustalsobealerttonaturalsourcesoftrouble.Eve
10、nordinarysoi1aidec!byerosionortherootingofduckscanfoulwatertoonluchforthefishesliking,Inheavi1ystockedlx)ndg,droppingsfrmthefishthem-selvescangetthickenought,tnclog110withtinyparticles.Uncon-SUmCdbitsoffoodcandothesamething.Happily,theseprrblemsarent72*common-especiallywhenotheror-g;Inismsintheponda
11、redoingtheirwork.Temperatureiscrucial.Becausefisharecoldbloodedanimals,theycanbegrownonlywhenandwheretheclimateandwatersupplycooperatetoprovidewatertemperatureswithintheirgrowingrange.Moreover,eachkindoffishfavorsaspecificitimperatureringe.Someflourishonlyincoldwaters.OtherswontgrowandreproduceWellu
12、nlessthewaterisverywarm.Thewatertemperatureyouwillhavetoworkwithcanbecloselytiedtothetemperatureofyourwatersource,Ifym-sourcewaterflowsfastfromanundergroundsupply,itstemperaturewillberough1ythesameasthatofthegroundwaterinyourarea.(SeeFig.1,)Ontheotherhand,ifyourscrurctwatertricvklcsfrombe1owemendrat
13、herthangushes,itwillbewarmedsomewhatasitpassesslowlythroughthegroundbelowthefrostline.irtemperaturealsogreatlyinflu-encespondwatertemperatures.saruleofthumb,watertemperatureinapondtendstnapproachtheaver-ageairtemperature.Ibgetagoodideaofwhatthatis,scanthetableofaveragemonthlytemperaturesforyourarea.
14、(GetthisfromthenearestU.S.WeatherBureau.Or1ookitupatthelibraryinTheClimdictlasqfthiUStsorinagoodalmanacorencyclopedia.1Sincepondwaterrespondsslowlytochangesinairtemperature,thewatertemperatureinyourpondwillbeslightlybehindthetemperatureriseinspringandthedropinfall.Forthesamereason,pondwaterisusu-all
15、ycoolerthanthehottestairduringthedayandwarmerthanthecoolestairatnight.Thedeeperthepond,thelessthechangeinwatertemperaturebe-tweennightandday.Insmal1ponds,however,watcrtemperaturecanchangeafairamountonasummersdayandwillfollowseasonalchangesinairtemperaturemoreclosely,Thismeansthattobeonthesafesideinc
16、hoosingfish,youshouldknowbothaveragemonthlyairtemperaturesandtheapproximatehighesttemper-atureyourpondwaterisapttoreachinthesummer,(FishCommissionpeoplecanhelpyouwiththatesti-mate.)sallthissuggests,eachregionhasagrowing?ieasonforfish,Thoughpondsize,source-watertemperature,andclimateaffectthelengthof
17、thisBeason,itwillcorres-pondrough1ytothefrost-freeperiodrdeninginyourarea,Hocloseitcomesyou11havetodeterminefromepg.Sence1mantinwinter,a1gaewillgrowa1it-tie.Watertcmpcrturtwillcentt_01therateoftrllactivityatanytimr.Averyroughrultbisthatthesptaectof1ifeproct*sstlsinfishandalgatdou-blcstV.i+heach15Fri
18、seinttmptra-turc.Oxygenisbitaltohighyit+lsinfishculture.Unlike:1ir,waterhasverylit-tieabilitytoholdoxygen.In5partsofair,1partisoxygen.Kr(i1IGl-1ionpartsofwater,only11)ICoxy-gen.Andsotheavailabilityofoxygenisoftenwhatputsalimitonhowmuch1ifeapondcansuppert.Someoftheoxygenusedupbypondlifeisrcplattctfro
19、mtheair.Coolerwaterwillholdmoreoxygenthanwarmwater.Sowhenoxygenlevelsfallbelowthenormatagiventemperature,oxygenmoleculesmoveintospacesinthewaterfromtheairaboveit.At50Fwaterwillhold11.3ppm(partspermillion)ofoxygen.AT60*Fthesaturationpointis9.6ppm,at70F-9ppm,at80F_8ppm.andat900F-74ppm.Nowitsmucheasier
20、forrelativelyshallowpondsof3to5feetindepthtomaintainthesefulloxygenlevelsnaturally.Thatsbecauseshallowpondshavealargesurfaceareacom-paredtovolume,soalargerportionofwaterisincontactwiththeair.Windalsocanhelpgreatly.First,bymakingripplesorwaves,itmag-nifiesthesurfaceareaofapond,Second,windsteadilybrin
21、gsfreshairinto*ontactwiththewater,thussteppinguptherateofoxygenex-changefromrichtodepletedareas.(1.argerpondstakeadvantageofwindbest,becausetheygivemovingairmorechancetokickupwaveo.)irladditiontoair,anothersourcechargeswaterwithoxygen.Itstheprocessofphotosynthesis,Wheneveroxygeniousedupinihewaterbyb
22、acteriabreakingdownor-ga11icmatter-orbyhigherformaofanimalandplantlife-carbundioxide4isproduced,Thisabundantgas,togetherwithsunlightandwater,isusedbyplantstomaketheirfoodviaphotosynthesis.ndsoforeachmoleculeofcarbondioxideplantstakein,theyreturnamoleculeofoxygentothewater.Themostimportantplantscon-t
23、ributingoxygentowaterarealgae,andunderidealconditionsalgaeandstillormovingairwillkeep:Ipondsupplied,Buttheamountofoxygenacultivatedpondwillneeddependsonhowmuchfishyouplantogrowinit.TheoreticaNyatleast,yourgoalinfishfarmingoughttobefirst,tofindthoanwntoffishthattheoxygeninyourwatercansupport,andbeyon
24、dthat,tofindwaystomaketheagatbpopulationhealthiersoitcandonatemoreoxygen.Butallthisiseasiersaidthandone,formanyfactorsmakeitdifficulttot.outItOili1fixtbdam、UnIofoxygc*tfromZdgiIcB.IiiktlofthtsnlNlytypc*SmakesOXYKViitiIdifftbrtbntriltt*.li)o,itsitiiposiblttotcI;rotwhichspecieswillgthtintoyourpond,ort
25、otc41howtoCreiltcthet.onttitionsthatdtGrablr*typcswi11like.Moreovt*r,forPOapparenreasontheClOlllitlilltspecaic5inyourpondmaychange-SlOWljiISthC!SUiISOtlprogresst5.Anothervari;rMisthevtb：Ither,fortherattbofp:Iotosynthesisde-pendsdirec11yonthesun,Typically,theoxygenI、WISinyourpondwiltchangeevenDniCICN
26、day.Ijymid-morningthedjtjwillb1hi114litwork,andtherewillheplentyofoxy-gen,Byearlyafternoonthedissolvedoxygenwillbeatmaximumconcen-Iration.Yourpondshouldstaysatu-ratedwithoxygennearlytosunset.Whenthetemperaturesarerightatthosetimes,youcanbesurethefisharefeedingactivcr.*andgrowingwell,eventhoughyoucat
27、tseetheminthepeasoup-greenthrIter.Atsunset,naturaloxygenproduc-tionstops,butoxygenusebyallpondlifegoeson.Bythenextmorning,nlevelswillbelowbuttolerablerfish,andatsunrisetheasterwillbegintobechargedb：thealgae.Onacloudyday,ofcourse,theagaewilgeneratemuchIessoxygcn,andtherewillbemuchlesstotideoverthepon
28、dpopulationatnight.Coolweatheralsowi11slowphotosy11-thesisslightly.Thef4chainisanothermajorforceatworkinthea+rntice11viron-ment.Asthetermimplies,al1lifeinthewaterislinkedtogether.ndeveryplantandanimalisdestinedtobeeatenbythebeingonthenexthigherlevelofthechain.Interest-ingly,acreaturessourceoffoodrat
29、herthanitssizeiswhatfixesitspositiononthefoodchain.Becausealgaemaketheirfoodfromgas,light,andwater,theyareatthefirstlevel.Andbecausesomeverylargefishfeeddirectlyonmicanedzoopfisharethemselvesquitelowonthedpond,itstheseplanktonfeedersthatwillgrowbestwiththeleastattentiontosupple-natdfoodsinthebecause
30、likegrassinasuppliedbynatureorbyyou,therewillbearichbloomofalgae.Andthealgalpoptionwillexpanduntilallfreenutrientsareal1ofthesefish,you11needcommercialfeedblends-readilyavaiIablefrom1ives-tockfeedsuppliers.Actually,togetbumpercropsof1It,ayfish,supple-mentingnaturalfoodsisnearlyal-waysessential.Thene
31、xtpointtorememberisIhzlifeedingatproductiveratesstimu-Iatesrapidgrowthandhigherwastelevels.Sincemoreoxygen8iiibeneededbythefast-growingushantoreadytheBystemtoabsorbtheirwastes,youmightneedtofertilizewithmanure.Thelife-givingnutrientsthusprovidedwillmultiplyal-gae,zooplankton,andbacteria,Thesewillfee
32、donthedetritusandprovidemoreoxygenandfeefish.Todetermineifyoudoneedtoaddfertilizer,thereisasimpletestyoucanmake.Ifyouralgaeareadequate,theyshouldbesothickthatyoucantseeanydeeperthan15to18inchesintothewater,Tofindoutifthisisso,marktheinchesoffstickandIai1atincanend.Thenushtheintothewatr=:untilfromsig
33、ht.NextcheckthehighwIfthelidisvisyoushouldferti1izewithmanure.Foreachacreofpondsurface,use500)sndplacethemintheemanureifneeded,butbeManuringwillbemostsuccrssfulinpondswherewarmwaterfishwillgrow.Inlargepondswithwatr:rttlm-PtraturesbetweenFiO*FandIiOEyoumayhavetroubtogettingathickbhomofalgaeevenifyoua
34、ddmuchmanure.ButthenthetroutandolhtbrcoldwaterspeciesyouwouldgrowtherepreferCrwateranyway.Aerating:Youcansuppkmttitoxy-gencontributedbyairat!lalgaebypayingattentiontothetyenclosureyouchoose,toandtomechanicaldevicesthathelpoxygenexchange.Fori11stance,byimpoundingasectionofstreamwithIadamornetlikefenc
35、e,youcantiakafishfarmthatisalwaysbeingSUPPliedwithfreshlyoxygenatedwater.(Tbmbling,rollingfast-movingwaterbreaksintowavesCanclsplashesthattakemoreoxygenfromtheair.)Ifyoudofarmastreamorbrook,however,youwonteasilyreapthebenefitsoffertilization,fortheman-urewi11bewashedfardownstream.Thesamethingcanhapp
36、entoyourfishfoodunlessyoudeviseaStatio-naryfeederthatcanresistthecur-rent.Rememberthatyourwastedfeedorfertilizerispollut.iforyourneighbordownstream.Andthatadd-ingthesematerialswithoutbeingsureoftheireffectsanddestinationisillegalaswel1aswasteful.AbettersystemwouIdbetotapaportionofthestreamwaterviaao
37、rditch.Youmightmuteitthmuomal!pondbby,thenbacktotheBEtream,thekiarncpoten-tialproblemsexist,thiskindofsetupismoreeasilycontrolled,Youcanregulatetheamountofwaterandrateofflow.Andwhenstormsswe11thestreamwithwater,mud,andde-bris,youcandisconnectyourencto-W?.ofthestreamyounbycreatingasmallwaterfallorspi
38、llwayoverrocks.Thiswayyoucanchargea9smallamountofincomingwaterasitentersarelativelylargepool.Thiswateralsowillbringinsomeoxygen-makingalgaeandsomefishfoods.Iftheenclosureismuchlargerthanthestreamandmuchofthewaterremainswithinitforaweekorso,youmightencouragemorealgaewithtowlevelfertilization.Totakefu
39、lladvantageofaeration5ywind,makethesurfacearealargerratherthandeepenthewaterwhenyouwanttoincreaseyourpondsvchme.Also,autlocationswheretreesorbuiIdingswillkeepwindorsunfromthesurface.Thewatersurfaceshouldntlietoofarbelowthebankseither-especiallyinsmal1ponds.Insomepartsofthecountrymechanicalaeratorsma
40、ybeneces-saryifyourestockingandfeedingapondforhigherproduction.Theamountofsupplementaryaerationyouneedwilldependuponyourpondsnaturaloxygenlevels-linked,ofcourse,towindandphotosynthesis-andonthequantityoffishyouvestockedpercubicfootofwater,Thoughmechanicalaeratingeasilyremovesanydoubtsaboutadequateox
41、ygen,youdbeststartsmall,forthecostoftheaeratorandthepowertofuniteasilycanbecomeoneofyourbietexpensesinfishculture.Inverysmallgrandstrybubblingaerators-thekind(1,tenuwdinaquariumtarke,TheyarecheapandUIWrittkpov?r.Ina490Square-footpond,trytwowithfouraerationtubesoneach.Inalargerpond,youmighthave:touse
42、Purfaceaerators,whichchurnorspraythr*water.Fig-powerofaeratorforboostyourpondsoxygenduringthedogdaysofsummer.Thereasonisthatinsunnyandveryhotweatheralgaebegintogrowmuchmorevig-orouslythanusual.Thenwhtwcloudyandperhapsslightlycoolerweathersetsinforafewdays,oxy-genproductiondropssuddenly.Sincethewryhi
43、ghoxygendcrnxctofthe*expandedpopulationcantbemet,somepond1ifewi11die.Thisisthetimewhenfishkillsaremostcommon,andinsomeplacestheyoccurregularlyonceortwiceaseason.Theproblemiswor;atnightawlishcightent-rlbcte7ayofthedeadalgae,inasitu,rtionlikethis,a1/20h.p.aeratormaysupplyenoughoxygentosiIpportseveralh
44、undredpoundsoffish,usingjustttsofpoweradayAt3centsakiIowatthour,12cenl9adayisasmal1pricetopayfortidingyourfishthrough.Anotherremedyifoxy-get7levelsbecomeperiIouslylowistoharvestaomcfish.Thiswillquicklyreducethedcmanoontheoxygensource,IPUTTIp:scINAkI$HPONDOneofthemissionsoftheSoi1ConservationServicei
45、stohelpndsthatwilllast.SiSenkxalkxdkkmifyourprojectisforvnutodoyourself,ystateshaveIaiVSthatregu-latethewwofwaterandthedesignandconstructionofponds.Somere-q+ethatplansforadambeap-provedbyastateagencybeforeaconstructionpermitisgranted.Sobeforeyoustartbuildingapond,Endoutwhatlawsapplylocally.Priortota
46、lkingwithanyoneattheSoilConservationService,you11wanttogiveyoursituationsomethought.Herearesomemajoras-pectstoconsiderandsometerh-niquesyoumightfinduseful.Selectingudte:Tofillyourpondandreplenishwaterlostbyevapora-tionandseepage,locateitnearade-pendableSOWCofgoodwater,P0+siblesourcesaresprings,wells
47、,streams,andtherunofffromrain.Runoffistheleastdependable,andinareasof1ightrainfal1apondfilledbyrunoffmustbeoversizedtocarrythefishthroughdrought.Thesoi1atyoursite-lustbeabletoholdwater,oryouhavetosealthepondartificially.Clayandsiltyclayaregoodforwnds,andsandyclaysometimesholdswateradequately.Butarea
48、swithrockout-croppings,limestone,shaleledges,orgravelrequiresealing.Foragoodpreliminarysoi1test,wetahandfulwithjustenoughwatertodampen.Thensqueeze.Ifthesoi1holdsitsshapeafteryouopenyourhand,itsprobablygoodforapond.Therearetwobasictypesofponds.Impoundingpondsarebestsuitedtohillyareas.Theyusedamsorban
49、ksofearthtobloc：:offtheopeningbetweentwobanksorslopesandareusuallyeasiertobuildbe-cituselessearthmustbemoved.Mostofthereservoircreatedisabovethenaturalgroundlevel,thoughthesizeordepthcanbein-creasedbyexcavation.Excavatedpondsarepitsdugbelowthepondsurface,usuallywherelandisfairlyflat.Thereisnodefiniteruleforchoosingbetweenthetwotypes,Butifthelandsur-roundingyoursiteslopesmorethan4percent,animpoundingpondislikelytowork.Todeterminetheslope,driveastakeintoyoursiteatthehighestpointyouexpectthewatertoreach.Thendrivemotherstakeinabout10
