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ReportonRampUsebyNZSLPupsinthe2017/18SeasonintheAucklandIslands
Preparedby:ThomasBurnsMay,2018
Figure1.ANZSLpupusingawoodenramptoexitamuddypoolinSandyBay,Enderby.
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IntroductionThehabitatoftheAucklandIslandsbreedingcoloniesofNewZealandsealionscontainaseriesofwaterwaysincluding:streams,poolandpeatbogs.Thesteep,highsidesandundercutbanksofthesewaterwayscanproveinescapabletothepupsastheyventureoffthebeachinlateJanuary.Manyofthesewaterwayshavenoviablemeansofescapeforthepupsandconsequentlytheydrown(Childerhouseetal.2014,2015,2016).Sealionresearchersontheislandduringthebreedingseasonhavehelpedtoreducethismortalitybyrescuingtrappedpupsmanuallyandinstallingwoodenrampstohelpthepupsself-rescue(Figure1).Monitoringoftherampsbycamerashasoccurredsincethe2013/14season(Childerhouseetal.2014,2015,2016).EnderbyIslandhas15permanentandtemporaryrampsinstalledinSandyBay(Figure2.)Fourofthesewerenewinthe2017/18season.DundasIslandhas9rampsofvariousagesinstalledinit'swaterways(Childerhouseetal.2016).
Figure2.BluemarkersshowthelocationoframpsatSandyBay,Enderby.
AimThemonitoringoframpsfrom2017-18NewZealandSealion(NZSL)seasonwasusedsolelytoassesstheusefulnessofagivenrampanddetermineanyimpactscausedbynewrampsaddedintheseason.Inthe2016-17NZSLseasonnonewrampswereinstalledandthereforenomonitoringusingmotionactivatedcameraswasundertaken.
RampInstallation&MonitoringIfanareaofwaterwayhabitatonEnderbyIslandwasconsideredtoposearisktotheNZSLpupsthentheinstallationofarampbythefieldteamwasconsidered.Theassesmentwassubjectivewithseveralfactorstakenintoaccountincluding:thesteepnessandheightofthebankssurroundingawaterway,theproximityofpupstothewaterwayandwhetheranypupshadalreadybeenrescuedmanuallybythefieldteamfromtheareapreviously.Ifarampwasinstalledthenamotionactivatedtrailcamerawasinstalledfacingtherampandsettoeitherrecordingstillimagesorvideo.Thefootagecouldthenbereviewedtoseeifpupshadusedtheramptoexitorenterthepoolandiftherampcausedanyunforseendisturbanceorinjurytothepupsorotherwildlife.
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Results&ObservationsFournewrampswereinstalledinwatewaysinthe2017/18fieldseason.Theserampswereobservedusingthemotionactivatedcameras.Onlyonepupwasrecordedfallingintoahole,apparentlybyaccident.Howeveralltherampswereobservedtobeusefulandallowedpupstoexitthewaterwayviatheramp,asummaryofthismaybeseenbelowinTable1.Table1.ThenumberofNZSLpupsusingrampstoescapewaterwaysatSandyBay,Enderby2017/18
Ramp GPSlocationDate
installed
Periodcamera
monitoredfor(hr)
Pupsexitedusingramp
Pupsenteredpool
intentionally
Pupsobservedfallinginpool
Notes
2018-150.498970°S,166.284910°E 28/01/18 79.9 6 0 1
Thecamerawasknockedaskewduringthenightof28th,thiswascorrectedandtheperiodomittedfrom
monitoringtime.
2018-2 50.499090°S,166.284320°E
29/01/18 62.6 10 0 0TheIRflashwastoobrightrenderingmonitoringat
nightuseless.
2018-3 50.499900°S,166.292740°E
23/02/18 105.8 12 0 0Duetoanerrorthecameraonlyrecordedeventsat
night
2018-4 50.499910°S,166.292830°E
24/02/18 91.0 9 7 0
Pupsintentionallyenteringthepoolusedboththerampandthebankadjacenttothe
ramp.
Inadditiontoallowingpupstoexitthewaterways,pupswereobservedpurposefullyenteringthepoolusingaramporthenearbybank.Noinjuryorsimilarnegativeinteractionwasobservedasaresultoftheramps.AlloftherampsshowedAucklandIslandtealusingthemwithnoilleffects.Noadverseenvironmentalimpactswereobserved.Anadultfemalesealwasobservedoncamerausingoneoftherampstoenterandthenexitasteepsidedstream.Pupswereobservedoncamerausingtherampsinshallowerpoolsmoreassteppingstones,ratherthentraversingthefulllengthasconstructionintended.Indeeperpoolspupswereobservedusingthefulllengthoftheramptoclimbout,evenataasteepincline.Nonewrampswereinstalledinthe2016/17season
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Conclusions
• Rampsdoallowpupstoexitfromsmallandlargewaterwaysincludingpools,bogsandstreams.
• Pupswillfallintowaterwaysbyaccident.
• Rampscausenoapparentharmtosealsorotherwildlife.
• Rampdesigncouldberefinedandimprovedtoallowbetteraccessbypups.
• Pupswillentersomewaterwayswillinglywhererampsareinstalled,thismayormaynotbebecausetheyhavedeterminedorhavelearntthatthesepoolsareabletobeeasilyexited.Thisappearstobemorelikleyinpoolratherthenstreamhabitat.
• Usingmotionactivatedcamerastomonitorrampsisausefulwaytoobservethatramps:
allowtheescapeofpups,causenoharmtowildlife,areusedbythepupsindifferentwaysandthereforeinformthewaysthattherampscouldbeimprovedtohelpeasepupspassage.
• Usingmotionactivatedcamerastomonitorrampsdoesnotallowancountorestimateof
thetotalnumberofindividualpupssavedfrombogs.
DiscussionRampsremainusefulforallowingpupstoescapefromwaterwayswheretheywouldnototherwisebeableto.Whileonlyoneeventwaspickeduponthemonitoringcameraswhichshowedapupfallingintoawaterway.Thisislargelyduetocamerapostionandthefieldofviewnotbeingabletocovertheentirewaterway,onlytheexitramp.IfaccuraterampusagedataisrequiredfromalltheexisitingrampsonEnderbyalargernumberofcameraswillneedtobeputout,foralongerduration.Ifdataisneededontheabsolutenumbersofpupsthataresavedfromdrowningbytheuseoframps,thenanewrobustmethodologywillberequiredthattakesintoaccount:
o Individualpupsthatusetheramp(s)morethenonce,o Pupsmayviewa‘rampedpool’asasafehabitatandthereforeutiliseitasaplay
poolandenter/exitthepoolmultipletimes.o thepossibilitythatdeadpupsmayprovide‘steppingstones’tothelivepupsand
thereforereducethetotalnumberofpotentialdeadinagivenpool.Evenwiththeinstalledramps,manualrescuesofpupsbytheNZSLfieldteamisstillimportantbecause:theNZSLcolonycanmovethroughdifferentareasofSandyBayyeartoyear,alsothenatureofthewaterwaysmeanstherearesomechangesyeartoyearinthehabitat(eg.Streambankscollapsing);andthefluctuationofwaterheightswithinpoolsfollowingheavyrainorlackthereof,canmeansomepoolsbecomemore/lessdifficultforpupstoescape.Inthis2017/18season14pupsweremanuallyrescuedfromwaterwaysonEnderby(S.M.Michael,personalcommunication,May14,2018).OnDundasIslandthisseason29pupsweremanuallyrescuedfromwaterwayseventhoughthefieldteamwasonlypresentforseveraldays.ThisnumberislikelyduetothelargerNZSLcolonyhereandalsoitoccuredatthepartoftheseasonwhennaïvepupsfirstmoveontotheswardandamongthe
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waterways.DundasissignificantlysmallerandthehabitatappearstobelesschangeablethenEnderby.Ifagreaternumberofnewrampsareinstalledherehereitshouldmeanminimalornoeffortisneededbyafieldteamtorescuepupsshouldbesufficient.Thisisimportantasafieldteamisnothereformostoftheseason.Thecamerasdemonstratedthatpupswouldenterpoolswillingly,possiblybecausetherewasarampandthusarouteofexitnearby.Thiswillskewanynumbersofpups‘escaping’thewaterwayusingtheramp.Howeveritdoesnotnegatetheneedforarampinthatpool.InadditionthisphenomenonwasonlyobservedinthepoolhabitatratherthenthesmallerpitsinstreamsRampConstructionRampconstructionneedstoberobustbecauseadultanimalsmayusethem.Theexisitngwoodandnailconstructionseemssuitablebutthisshouldbekeptinmindforfuturedeign/construction.Inshallowerpitswithshorterramps,pupswilloftenusetherampasasingleflipperholdandmorelikeastepthenaladderorramp.Aphysicalstep,or‘rock’substituemayprovideanalternativemethodofexit.Whenexitingfromdeeperpits,pupswillusethelengthoftherampasintendedtoclimboutofthehole.Inbothscenariosaboveawiderrampwouldprobablyallowaneasierpathforthepuptoexitandtheexisitingrampsmaybeslightlytoonarrow.Howeveritisworthnotingthatsomeholesaresimplynotwideenoughtofitawiderramp.EnvrionmentalImpactRampsputintopoolsorbogshaveminimalenvironmentalimpact,theyareeasiertoinstallandthehabitatislesslikelytochange.Rampsputintostreamhabitatoftenrequiremorethoughtanddiscretionintheirplacement.Thisisbecause:thereisusuallylessroomtoinstallthem,therampmayhindertheflowofwaterandbecausethemovingwaterinastreammaycausethebankstructuretochangeyeartoyear.Inseverallocationswehavemovedtoamobile/temporaryrampthatisinstalledandremovedeachseason.Thisisonlyapplicablewithanannualsealionteamandbecausethesitesinquestionareonlyproblematicearlierintheseasonandarenolongerathreatoncethefieldteamhavelefttheisland.AsmentionedthereissomeuseoftherampsbyAucklandIslandtealbutnonegativeinteractionshavebeenobserved.LimitationsThereweresomecamerasthatwerenotperformingoptimally(thismayhavebeenuser,hardwareorsoftwareerror).Thecamerasshouldbere-checkedtoconfirmtheyarefullyfunctioning.Cameraswouldsometimesshootonafalse-positivewherethewind,grassorsealionmovingthestakecausedthesensortoactivateeventhoughtherewasnosealinthefieldofview.Thisincreasesthetimespentondataanalysisandreducebatteryandcardlife.Itwasalsodifficulttoensurethecamerawaspointingexactlywhereneeded.InordertoincreasestabilityandtoprovidemorecontroloverthedirectionthecameraisfacingIsuggesttrialingarobustball-headmounteitherattachedtostakeorapeggeddowntripod.
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Recommendations
• Tomitigatepupmortality:o InstallnewrampsontoDundasislandandfixorremoveexistingrampswhere
necessary.(Thiswillrequirenewmaterialstobesentdown).o ContinuetousetheexitingrampsonEnderbyandimplementnewrampswhere
necessary.
• Investigateinthefield,theuseofphysicallywiderrampstoseeifpupsfinditeasiertomoveupthem.
• Investigateinthefield,othermethodsofexitfromtheholes(eg.singlestepsorboxesinthe
shallowerpools).
• Ifdetailedinformationisrequiredonrampusebypupsthenmorecameras,deployedforlongerareneeded.
• Ifanestimateoftotalpupssavedfromdrowningisneededthenanewmethodforassessing
thisneedstobedeveloped.
SummaryRampsremainavaluablemanagementtoolforallowingNZSLpupstoescapewaterwaysandrampinstallationanduseshouldcontinue,withrefinementsif/wherenecessary.Monitoringoftherampswithmotionactivatedcamerasallowstheusefulnessandimpactofagivenramptobeassessed,howeveramuchmorerobustmethodisneededifabsolutenumbersofpupsusingtherampsisrequired.
ReferencesChilderhouseS,HamerD,MaloneyA,MichaelS,DonnellyDandSchmittN(2014)FinalreportforCSPproject4522NewZealandsealiongroundcomponent2013/14.DepartmentofConservation,Wellington,NewZealand.ChilderhouseS,MichaelS,AdamsL,BurnsT,CockburnS,HamerD,MaloneyA,PugsleyC(2015)FinalReport:NewZealandsealionresearchattheAucklandIslands2014/15.BluePlanetMarine2015,DocumentReferenceNumber:BPM-15-FinalReportforNZsealionresearchattheAucklandIslands2014-15v2.2ChilderhouseS,MullerC,BurnsT,FrenchR,KayE(2016)FinalReport:NewZealandsealiongroundcomponent2015/16.BluePlanetMarine2016,DocumentReferenceNumber:2015/16BPM-16-FinalReportforCSPProjectNZsealiongroundcomponent2015-16v1.32/06/2016
