Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
24PACIFICFISHERIESREVIEWspecialsupplementtoJuLY2012Fishermenx19snewsOPERATIONSWhatx19sUnderyourBoatHydro-acousticmonitoringSplitbeamBroadbandCHIRPandSpeciesIdentifcationByMikeHillersbuildingAneWtrAWleroranytypeox3shingves-selisacomplexevent.Unortunatelywiththeexceptionoaewbeautiulmulti-purpose58-ootlimitvesselstherehavenotbeennewtrawlersbuiltortheBeringSeax3sheriesinquitesometime.Tishasreducedtheexamplesoincremen-talchangeandimprovementusuallyavailableinax3shingx1eetgeneratingsolidincome.Fortunatelytherewillbearesurgenceonewbuildactivityandthex3rsttobuildwillbetheinnovatorsandtherisktakers.Tesecommentsaredirectedtothisgroupoinnovatorssothatthepotentialriskisdiminished.WhileIdonotproesstohaveknowledgeonengineefciencyadvancesindeckorprocessingmachineryormanyotheothersystemsneededtoassembleamodernx3shingves-selIwilllayclaimtoexpertisewithrespecttothehydro-acousticmonitoringequipment.Tisisthex18x3sh-x3ndingx19equipmentneededtolocateidentiyanalyzeandcatchx3sh.Iamalsoawareodevelopmenttrendsthatmakemebelieveinauturethatholdstremendouspromise.Ax3shingvesselisaplatormwithmultiplesystemsdesignedtoperormmanytasksresultinginhigh-qualitydeliverableoodproducts.Keytoasuccessulresultistheabilitytolocatex3shidentiythetargetspeciesanalyzethetargetspeciestodeter-minesizeandalsoidentiythenon-targetedorby-catchspecies.Tisisbestaccomplishedwithqualityhydro-acousticsystems.Conventionallythesearehull-mountedbutmoreandmoresys-temsarebeingtrawl-mountedandintheuturethesewillberemotely-mountedastheexplosioninAutonomousUnderwa-terVehicleAUVtechnologymakesitswayintothecommer-cialx3shingindustry.ForthenewbuilddiscussionIwillocusonthetechnologicaladvancementsinthehull-mountedsystems.Fishsizinghasbeenaccomplishedandrex3nedsincetheadventosplitbeamtechnology.Tistechnologywasintroducedtothecommercialx3shingcommunityinthemid1980s.Split-beamtechnologymergedknowledgeothetransducerx19ssourcelevelandbeampatternwithaphasemeasurementorcomparisonothex3shechoondix4erentquad-rantsothetransducer.Teresultisatargetstrengthx1eSmeasurementthatcanbeconvertedtoalengthorweightothex3shithespeciesisknown.Tespeciesisinputasax1cguessx1dhow-ever.Teresultitheechoisorexampleacodisalengtho60cm.Ithatsameechoisromamackerelhoweveritisasubstantial3metersinlengthTisisbecauseamack-erelhasalowerx1eSthenacod.Since3-metermackerelarenotarealitythesituationneedsaneducatedandastuteoperator.Tespeciescanbeselectedromalistinasplitbeamechosounderbutthenalltargetsarejudgedtobethatspecies.Clearlyanacousticsolutiontoidentiythespeciesoindividualtargetsisneeded.Speciesidentix3cationisthex1cHolyGrailx1dox3sheriesacous-tics.Signix3cantworkhastakenplacetoachievethisquest.Tebestsciencehasaconsistentwatervolumebeingsimultaneouslyx1cpingedx1dwithmultiplerequencies.Tismeansorexamplesplitbeamtransducersoperatingat18kHz38kHz70kHz120kHz200kHzand333kHzandhavingbasicallythesamebeamanglesx1cpingingx1donthesamex3shatthesametime.Tissystemworksbecausex3shresonatewhentheyarex1cpingedx1danddix4erentspeciesresonateatdix4erentrequencies.Iyouareusinga70kHzanda120kHzechosounderandthetargetreso-natesbestat70kHzthenyouwillseeagreaterechoresponseonthe70kHzthenyouwillonthe120kHz.Temorerequen-ciesyouhaveavailablethegreateryourabilitytoascertaina