Simrad EK15 - Biomass; Dynamic Range and Display Presentation

Echosoundertheory
Biomass
ProvidedthatyouuseanEK15withasplitbeam
transducer,orhaveavalidbiomasslicenseonasingle
beamtransceiver,youwillhaveaccesstotheBiomass
informationpane.
Thisbiomassvalueisanindicatortohowmuchsh
youcurrentlyhaveinthecurrentechogram,orinthe
zoomedarea.Everysingleshwillemitanecho,and
thesumofalltheseregisteredechoesarepresentedas
anumber.Smallerorganismssuchasplanktonwillalsoemitechoes,buttheseareso
weakthattheywillhardlyinuenceonthetotalbiomass.
TheEK15recordsallthetargetsfromthesmallestplanktontothelargestwhale,and
providesthesendingsasanumber.Forallpracticalpurposesthisnumberwillprovide
youwithinformationabouttheshabundancetoallowyoutodecideifitpaysoff
tostartshing.Y oumustalsoconsiderifthisnumberisaresultoflargeamountsof
planktonorbait,orifthereisrealshbelowthekeel.Thenumberprovidedtodisplay
shabundanceisrelative,andaftersomeuseyourexperiencewillbeavaluablefactor
whenthedecisionismade.
Thebiomassvalueisalsousedbytheresearchestocalculatehowmuchshthereisin
theocean.Ifyouknowtheshspecieandthesizeofthesh,youcancalculatenumber
ofindividualshesforagivenvolumeofsea.Othermeanstoestablishthenalresult
aretrawlingandcatchdatafromthesherycommunity.
Note
IfyouhaveotherechosoundersorsonarsrunningasynchronouswiththeEK15,the
EK15willalsomeasurethetransmitpulsefromthesecondarysystem.Thisiscalled
interference.
YoucanremovetheinterferenceusingthePing-PingFilterfunctionontheActivemenu,
buttheEK15receiverwillstillpickupthetransmitpulseandimplementitinthe
calculations.
Afullsynchronizationofthevariousacousticinstrumentsisrequired.Ifyourownvessel
producesexcessivenoisethiswillalsobetakenintothebiomasscalculationsand
provideyouwithinaccurateinformation.
Relatedtopics
•Biomasslineonpage121
•Biomassinformationpaneonpage125
•Echogramdialogboxonpage206
Dynamicrangeanddisplaypresentation
TheEK15echosounderhasadynamicrangeof80dB.
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