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页面关键字： highcostofaquaculture highcostofaquaculture aquaculturecanbesimplydefinedastherearingorfarmingofaquaticspeciesundercontrolledconditions.itisarapidlygrowingindustry,accountingforoverone-thirdofalldirectfisheriesconsumption.aquaculturehasoftenbeenconsideredasingleactivity.butitrepresentstheaquaticcounterpartofallterrestrialagricultureundertheonename. fishhavebeentakenfromtheworldsoceans,lakes,riversandwaterwaysandkilledbyhumansforfoodformillennia.inthelastfiftyyears,demandforaquaticfoodshasincreased,andatthesametime,newtechnologieshaveimprovedourabilitytofindandcatchfishandotheraquaticlife.overthelatterhalfofthe20thcenturywildcatchesoffishhaveincreasedbyapproximately500percenttonearly100milliontonsperyear.thishasledtorapidlydepletingfishstockswithsomewildfishpopulationsdecimated. itisnotjustthefishpopulationsthatwereintentionallyfishedthataresuffering.otherfishandsealife,suchasseaturtles,sealionsanddolphinsarecaughtandthrownbackintothewaterdeadordying.theseunintentionallyfishedspeciesarecalledby-catch.itisestimatedthatonethirdofthewildfishcatchisby-catch. aquacultureisanimportanteconomicactivityinmanycountries.itcanoffersomegoodopportunitiestocontributetopovertyalleviation,employment,communitydevelopment,thereductionofover-exploitationofnaturalresources,andfoodsecurityintropicalandsub-tropicalregions.but,initscurrentform,isthecosttoohigh?issuesofconcernincludethosethatrelatetogenetics/escapement/geneticallymodifiedorganisms,aquaticnuisancespecies,aquatichealth,andaquacultureeffluents. aquaculture,likemanyotherfarmingactivitiesisdependentupontheuseofnaturalresourcessuchaswater,land,seedandfeed. pollutionisoneofthemajorconcernsforaquaculture.imaginetherawsewagethathalfamillionpeoplewouldcreateinonedayandimagineifitwerepumpeddirectlyintotheoceanwithouttreatment.inmanyplacesaquacultureisresultinginanequivalentsituation.forexample,therearepresentlyover85opennetcagefishfarmscurrentlyoperatinginthecoastalwatersofbritishcolumbia,canadaproducingwastethatisroughlyequivalenttotherawsewagefromacityof500,000people. aquaculturebringswithithumanhealthrisks.astudyreleasedinaugust2004inthejournalenvironmentalscienceandtechnologyfoundmuchhigherlevelsofsomechemicalflameretardantsinfarmedsalmoncomparedtomostwildsalmon.also,thefoodforsalmonfarmedinaquaculturesystemsdoesnotcontainthenaturalsourcesofcolourandasaresultthesalmonfleshisanunappetisinggreycolour.tomaketheirproductmoremarketable,aquaculturefarmmanagerschoosewhatcolourtheywanttheirsalmonbyaddingchemicalstothefishfeed. thegrowingaquacultureindustryisassociatedwithanumberofenvironmentalandsocialissuesincluding:(source:worldwildlifefundfornature) aquacultureatinappropriatesitescanleadtohabitatconversionandon-goingoperationalimpacts aquaculturepotentiallyhasseveraladverseeffectsonwildspecies,includingdiseasetransmission,escape,andcaptureforbroodstockorrearingamongothers productionofnutrient-loadedeffluentcanleadtoeutrophicationofnearbywaters prophylacticuseofchemicals,includingantibioticscanharmwildlifeandtheenvironment,andmayleadtoantibioticresistance massivewaterusecanresultinwatershortagesaswellassaltwaterintrusionandotherhydrologicalchangesorwastedisposalissues relianceonhighprotein,fishmeal-basedfeedforcarnivorousspeciesoftenrequiresmanypoundsofwildfishtoproduceonepoundofedibleaquacultureproduct theconflictovertheuseandconversionofnaturalresourcesaswellasaccesstoremainingresourcesandtheprivatisationofpubliccommonshasresultedinphysicalconflictandevenmurderinsomecountries inflationinthecostofkeylocalgoods(egfood,labour,land,orotherinputs)disproportionatelyaffectsthosenotassociatedwiththeindustry,particularlythepoor. thedeclineinfisheriesinsomeareasisduetodirectenvironmentalimpactsofaquacultureoritsindirectimpactsonthemarketpriceoflocalcatch. supportedbypromosales-promotionallanyardsandconferencegear. homeaboutuscontactus
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