DifferencesBetweenSmith-RootPuntledgeRiverandUMTTestArrays

VarioustypesofelectricaldeterrencearrayswereusedbySmith-RoottoevaluatePacificharborsealdeterrenceinthePuntledgeRiver,Courtenay,B.C. ThesealstudieswereconductedinpartnershipwithDepartmentofFisheriesandOceansCanada. FPOMwasprovidedwithaDecember2008DraftReport. ThisReport,co-authoredbySmith-RootandDFO,wasfinalizedinFebruary2009. TheFinalReportisattachedasaPDF.

ThepurposeforconductingtheUMTtrialsistofieldvalidateprevioustestresults(fromresearchoncaptivefishinclosedenvironments)inareaswithflowingwateramongfishundergoingactivespawningruns.

ThearraysandelectricfieldgradientstestedinthePuntledgeRiveraresubstantiallydifferentthanthearrayandfieldlevelstobeevaluatedintheUMTatBonnevilleDam. Themajordifferencesare:

Electrodes:

  • PuntledgeArray: Crude,0.5-inchround,coppercables.
  • UMTArray:Flat,steelplateswhichproducemoreuniform,homogenousfields. Platescontained within an insulatedframe in the UMT.

FieldOperationTime:

  • PuntledgeArray:Continuouslyoperatedduringtest.
  • UMTArray:Operatedin½hourblocks.

ElectricFieldTestLevels:

  • Fieldstrengthof0.6V/cmfieldat0.4milliseconds(ms)pulsewidth2Hz(twopulsespersecond)successfullydeterredCaliforniasealions,evenwithfoodpresent.
  • PuntledgeArray:Voltagegradientupto1.8V/cmwithpulsewidthsrangingfrom3to5ms. Pulsefrequenciesof2Hz.
  • UMTArray:Initiatetestat0.6V/cm. Increasestoamaximumtestlevelof1.2V/cmwillbedependentuponfishreactions. Pulsewidthswillcommenceat0.4ms. Pulsefrequenciesof2Hz will be used for all tests.

Environments:

  • PuntledgeArray: Varyingwaterdepthduetotidalfluctuations. Also,metalsuspectedtobeembeddedinstreambottommayhavecaused“shorts”whichalsodilutedthefield. Waterconductivitywasonly28to37µS/cm. Voltageatthearraywasincreasedtoaccountforthesefactors.
  • UMTArray: Theconstantwaterelevationandinsulatingstructureshouldprecludetheneedtomodifyfiledstrength. Conductivityistypically100to120µS/cmandhigher. Field strengths are expected to remain constant during study blocks.

EffectsonFish:

The Puntledgestudyusedafieldthatoperatedconstantlyata3-mspulse-widthfieldandhigher. Notsurprisingly,aDIDSONcamerashowedthat11of14Chinooksalmonadultsappearedtoturnor“stall”astheyapproachedthecablearraywhile3fishpassed(seepage16ofattachedPDF).

AsdescribedintheMinutesofthesecondSeaLionPartner'sForum(1/28/09),thesefishwerenotradio-taggedandtheirultimatefateswerenotdiscernible. Inasuiteofpreviousstudieson100captiveCowlitzsteelheadexposedtomultiplecombinationsoftreatmentsingroupsof6,Smith-Rootscientistsobserved2of6fishtotemporarilyturnafewtimesinafieldhavingavoltagegradientof0.7to0.9V/cmandapulsewidthof4ms. Butthesefishallpassedthroughthearraywithin5minutes.

Inthisunpublishedstudy,notemporaryturningordiversionarybehaviorwasobservedatvoltagegradientsupto0.9V/cmatpulsewidthsupto2msinduration…levelsmuchhigherthanthoseproposedasstartingpoints(0.6V/cmat0.4mspulsewidths)for2010UMTresearch. Itisnotarareeventtoseefishhesitatewhentheyapproachanewenvironment.

IntheSmith-Rootsteelheadresearch,completefishdeterrencerequiredpulsefrequenciesof5Hzandpulsewidthsof5ms(levelswaybeyondthe2Hzand0.4msfieldstobetestedintheUMT). InthecaseoftheunmarkedPuntledgeChinooksalmon,itisnotknownifanythe11of14stalledor"turningfish"representedmultipletrialsbythesameindividual.

Summary:

MuchwaslearnedfromPuntledgesealdeterrencetrials. Despiteahostofchallenges,79%ofthesealswerestoppedwiththeSmith-Rootarray(asdiscussedwiththosemanagerspresentatthe1/28/09SeaLionPartner’sForum). Amajorconclusionwasthatadditionalresearchisneededtoperfectatechnologyforselectivedeterrenceofpinnipeds,especiallyinenvironmentswherewatervolumesandconductivitiesfluctuate.

IncomparingPuntledgeresultswithUMTresearchplans,thereshouldbenoexpectationforasimilaroutcomeintheconstantwatervolumesandlowerfieldstrengthstobeevaluatedattheUMTsite. Itisnotvalidtoexpectthekindoffieldlevels,watercharacteristicsoroutcomesintheUMTthatwereexperiencedinatidallyinfluencedareawithacrudeelectrodearrayintheconstantlyoperatedelectricfieldtestedinBritishColumbia.

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