Installation manual

Echosoundertheory
Biomass
ProvidedthatyouuseanES70withasplitbeam
transducer,orhaveavalidbiomasslicenseonasingle
beamtransceiver,youwillhaveaccesstotheBiomass
informationpane.
Thisbiomassvalueisanindicatortohowmuchsh
youcurrentlyhaveinthecurrentechogram,orinthe
zoomedarea.Everysingleshwillemitanecho,and
thesumofalltheseregisteredechoesarepresentedas
anumber.Smallerorganismssuchasplanktonwillalsoemitechoes,buttheseareso
weakthattheywillhardlyinuenceonthetotalbiomass.
TheES70recordsallthetargetsfromthesmallestplanktontothelargestwhale,and
providesthesendingsasanumber.Forallpracticalpurposesthisnumberwillprovide
youwithinformationabouttheshabundancetoallowyoutodecideifitpaysoff
tostartshing.Youmustalsoconsiderifthisnumberisaresultoflargeamountsof
planktonorbait,orifthereisrealshbelowthekeel.Thenumberprovidedtodisplay
shabundanceisrelative,andaftersomeuseyourexperiencewillbeavaluablefactor
whenthedecisionismade.
Thebiomassvalueisalsousedbytheresearchestocalculatehowmuchshthereisin
theocean.Ifyouknowtheshspecieandthesizeofthesh,youcancalculatenumber
ofindividualshesforagivenvolumeofsea.Othermeanstoestablishthenalresult
aretrawlingandcatchdatafromthesherycommunity.
Note
IfyouhaveotherechosoundersorsonarsrunningasynchronouswiththeES70,the
ES70willalsomeasurethetransmitpulsefromthesecondarysystem.Thisiscalled
interference.
YoucanremovetheinterferenceusingthePing-PingFilterfunctionontheActivemenu,but
theES70receiverwillstillpickupthetransmitpulseandimplementitinthecalculations.
Afullsynchronizationofthevariousacousticinstrumentsisrequired.Ifyourownvessel
producesexcessivenoisethiswillalsobetakenintothebiomasscalculationsand
provideyouwithinaccurateinformation.
Relatedtopics
•Biomasslineonpage93
•Biomassinformationpaneonpage97
Dynamicrangeanddisplaypresentation
TheES70echosounderhasadynamicrangeof140dB.Thismeansthatthesounder
canreceivebothverystrongandveryweakechoes.Actually,theES70willdetect
echoesfromplanktontowhales,bottomonmostdepths,andpresenttheinformationfree
fromdistortion.Asacomparison,ouroldechosoundersES380andET100had-using
analogueTVG-adynamicrangecorrespondingtoapproximately65dB.
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