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1FOAM,anewsimplebenthicdegradative2modulefortheLAMP3Dmodel:an3applicationtoaMediterraneanfishfarm4PatriziaDeGaetano1,AndreaM.Doglioli2,MarcelloG.Magaldi3,PaoloVassallo4,MauroFabiano451DIFI,DipartimentodiFisica,Universita`diGenova62Aix-MarseilleUniversite´;CNRS;LOB-UMR6535,Laboratoired’Oce´anographieetde7Bioge´ochimie,OSU/Centred’Oce´anologiedeMarseille83RosenstielSchoolofMarineandAtmosphericScience(RSMAS),DivisionofMeteorology9andPhysicalOceanography(MPO),UniversityofMiami104DIPTERIS,DipartimentoperloStudiodelTerritorioedellesueRisorse,Universita`di11Genova12Correspondingauthoraddress:13PatriziaDeGaetano,DIFI,DipartimentodiFisica,Universita´diGenova,ViaDode-14caneso33,16146Genova,Italia.15Phone:+390103536385Fax:+390103536354E-mail:degaetano@fisica.it16Runningtitle:FOAM,FiniteOrganicAccumulationModule17Keywords:Biodegradationmodeling,Aquacultureimpact,MediterraneanSea,18Husbandry,Net-pen,Organicmatter.19PreprintsubmittedtoAquacultureResearch1December12,2007
201222324252627282920313233343536373839304AbstractThemodelingframeworkalreadyintroducedby(Dogliolietal.,2004a)topredictthepotentialimpactofamarinefishfarmisimprovedfollowingdifferentdirections.Namely:(i)realhistoriccurrent-meterdataareusedtoforcethesimulations;(ii)set-tlingvelocityvaluesspecificallytargetingMediteranneanfishspeciesareused;and(iii)anewbenthicdegradativemodule,FOAM,isaddedtothemodelingframework.FOAMusestheoutputoftheotherfunctionalunitsofthemodelingframeworktocalculatetheorganicloadontheseabedatthenetofthenaturalremineralization.DifferentremineralizationratesreflectthesedimentstresslevelaccordingtotheworkofFindlay&Watling(1997).Organicdegradationforbothuneatenfeedandfaecesisevaluatedchangingreleasemodality(continuousandperiodical)andvaryingthesettlingvelocities.Itisfoundthatthemaximumimpactonthebenthiccommunityisobservedeitherforquickly-sinkinguneatenfeedreleasedtwiceadayorforlessintensenearbottomcurrentconditions.Ifboththeabovementionedscenarioscoexist,ahighstresslevelisestablishedinthesediment.Themodelalsosuggeststhatademand-feedingofthefishinthecagecansignificantlyreducethefarmimpact.Theseresultsshowhowthenewandmorecompletemodelingframeworkherepresentedisabletoimprovetheobjectivityindecisionmakingprocessesanditmaybesuccessfullyusedforplanningandmonitoringpurposes.2
411Introduction42Theincreaseinglobalfishconsumptionandthedecreaseofwildfishstocksarethe43mainreasonsbehindthecontinuousdevelopmentofmarineaquaculture(FAOFish-44eriesDivision,2006,http://www.fao.org/docrep/009/a0874e/a0874e00.htm).45Theworldwideexpansionofthemarinefishfarms,however,hasalwaysbeengener-46atingconcernonthepossibleimpactsforcoastalecosystems.Alreadyin1995,the47FoodandAgricultureOrganization(FAO)oftheUnitedNationsadoptedaCodeof48ConductforResponsibleFisheries.TheCodeprovidedthenecessaryframeworkfor49nationalandinternationaleffortstoensuresustainableexploitationofaquaticliv-50ingresources.Aparticularattentionwaspaidtotheaquaculturegrowthinaccord51tothesustainableandintegrateduseoftheenvironment,takingintoaccountthe52fragilityofcoastalecosystems,thefinitenatureoftheirnaturalresourcesandthe53needsofcoastalcommunities.In2001,followingthesamedirection,theEuropean54Unionstartedtosetupastrategyforasustainableaquaculturedevelopmentwith55theBiodiversityActionPlanforFisheries(COM(2001)162)andtheEuropean56StrategyforSustainableDevelopment(COM(2001)264).Thesetwodocuments57ledtothemorerecentandspecificStrategyfortheSustainableDevelopmentof58EuropeanAquaculture(COM(2002)511).59Marineaquacultureoperationsarestillveryexpensiveandtheonlymeanto60sustainprofitabilityistointensifyfishproduction.Unfortunatelythisintensifica-61tionincreasesthealreadyexistingconcernsaboutreachingandgettingoverthe62naturalcapabilityoftheenvironment.Thescientificliteraturehasidentifiedinthe63releaseofparticulatewasteproductsthemaincauseofenvironmentalimpactdue64tothepresenceofmarinefishfarms(Halletal.,1990;Holmer&Kristensen,1992;65Karakassisetal.,2000).Theparticulatewastesincreasetheorganicloadonthe66benthicenvironmentandmightdeterminechangesinthecommunitystructureand67inthebiodiversityofthebenthicassemblages(Tsutsumietal.,1991;Wuetal.,681994;Vezzullietal.,2002,2003).Thereforeweareinneedforpredictivetoolsable3
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