•  Myname’sMaddieBeange&I’mresponsiblefortheresearchandtheinternshipprogramsofPRETOMA&TurtleTrax’sfourseaturtlenesAngbeachconservaAonprojects

•  TodayI’mgoingtotalkaboutoliveridleynesAngbehaviouratoneofthoseprojects:Corozalito

•  I’lldescribehownesAngacAvityhasdevelopedoverthe8yearsofmonitoringthebeachandthenpresentsomeexciAngresultsfromourtaggingstudy

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•  Oliveridleysaretheleaststudiedspeciesofseaturtlebecausetheyarethemostabundant,andthuslowestpriorityforconservaAon.

•  OliveridleysareinteresAngbecausetheyhavethemostcomplexreproducAvesystem,whichissAlllargelynotunderstood.

•  EarlystudiesfocussedonarribadanesAngbecauseitissuchauniqueandunbelievablymassivephenomenon.

•  NowwearestarAngtocatchuponsolitarynesAngresearch,whichisimportantbecauseonaworldwidescaleitmakesupforthesameamount,ifnotmore,nesAng.

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•  Hereisamappublishedinthe10thvolumeoftheSWOTReport,showingCostaRica’sseaturtlenesAngacAvity.

•  ThePacificcoastofCostaRicaisanimportantareaforeasternPacificoliveridleynesAng.

•  InthenorthareNanciteandOsAonal,whichareestablishednesAngbeaches.OsAonalgetssomeofbiggestarribadasintheworld&theeventsoccurmonthlythroughoutyear.

•  SolitarynesAngoccursalongtheenArecoast.

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•  EarlystudiesfromOsAonalandNancitesuggestedtheoliveridleyspeciesisreproducAvelypolymorphic(Plotkinetal1997&Kalb1999).

•  TheyindicatedonepopulaAonexhibitsthearribadanesAngphenotype-characterizedbyinternesAngperiodof30daysandhighernesAngsitefidelity.

•  AseparatesolitarypopulaAonexhibitsthesolitaryphenotype-characterizedbyaninternesAngperiodof15-20daysandlowernesAngsitefidelity.

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•  However,recentstudieshaveshownthatindividualoliveridleyscannestbothsolitarilyandinarribadaswithinandbetweennesAngseasons.

•  Forinstance,thisNancitestudypresentedatthe33rdsymposiumbyLuisFonsecafoundthat30%oftherecapturedturtleswereobservedswitchingnesAngbehaviours.

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•  SoitappearsthatoliveridleyshavetheabilitytodisplaybothreproducAvestrategies.

•  ItislikelythatsolitarybehaviourisdependentoninternalsAmuli(physiological),explainingtheshorterinternesAngperiodof22days.

•  Ontheotherhand,thearribadabehaviourislikelydependentonexternalsAmuli(environmentalorotherturtles)toenablesynchrony.

•  TheadaptaAonoftheabilitytodelayoviposiAonbyretainingeggsallowsoliveridleystowaittonestinsynchrony,andexplainsthelongerinternesAngperiod.

•  ItisunknownwhetheroliveridleyindividualsprimarilyexhibitonestrategythroughoubtheirreproducAvelifestagedependingonlocalpopulaAondynamics,withonlyasmallporAonwhouseboth…

•  OrifthemajorityofthepopulaAoncommonlyswitchesbetweennesAngbehavioursthroughouttheirreproducAvelifestage.

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•  TheuniquenesAngdynamicswe’veobservedatCorozalitocouldshedlightonthiscomplexoliveridleynesAngbehaviour.

•  PRETOMAstartedmonitoringthebeachin2008.•  InthenextfewslidesI’llgiveanoverviewofthedatafromthefirst4seasons,

whichwaspresentedat32ndISTSinMexicobySandraBuenoviejo.

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CorozalitoisonthesouthernNicoyaPeninsula(SNIP)ofCostaRica,about40kmsoutheastofOsAonal

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Itisthefurthestnorthofthe4SNIPnesAngbeachesmanagedbyPRETOMAandTurtleTrax.

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CorozalitoseesthehighestlevelsofsolitarynesAngofthefourbeaches.(TherecordednumberofnesAngeventsappearslowerin2008becauseCorozalitowasmonitoredforonly3months,whiletheotherprojectwereopenfor6months)

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•  WefirststartedtheprojectatCorozalitobecauselocalshadreportedsmallarribadaseventshadstartedtooccuroverthelastdecade.

•  In2007theyesAmatedaneventinJanuarywasmadeupofabout5000turtles.

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•  Weranapilotprojectin2008,monitoringthebeachfor3monthsfrommid-Augusttomid-November.

•  Weobservedapeaknightof89nesAngeventsonAugust27thandasmallarribadaeventonSeptember25th.

•  Wedidn’tseeanypeaksinOctober,soweweresurprised/frustratedwhenthelocalsreportedamuchlargereventtheweekaferweclosedtheproject.TheyesAmatedthesizewassomewherebetweentheprevious2arribadaevents.

(Thechartsupto2013shownesAngacAvityrecordedperday,ratherthanpernightwhichiswhythenumbersonthechartdon’texactlyrepresentthoseonthetable)

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•  ThenextyearweextendedmonitoringduraAonatCorozalitoto7monthssowewouldn’tmissanything.

•  Unfortunatelytherewerenosignificantpeekeventsthatyear.•  ThehighestnightofnesAngin2009wasof40nesAngevents.

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•  In2010therewere2nightsofover60eventsatendofAugustandinmid-September.

•  AttheendofOctoberwecounted120eventsin1night,whichwecategorizedasanarribadabecauseitwasgreaterthan100nesAngeventsinanight.

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•  Finallyin2011our3yearsofpaAencewasrewardedwiththebigarribadaeventwehadbeenwaiAngfor.

•  Corozalitohadthelargesteventwehadseen,withanesAmated5000nesAngover2nightsinlateSeptember.

•  LocalsreportedasecondsmallereventinearlyJanuary,aferwehadclosedtheproject.

(TheseyearstheesAmateofarribadasizeisnotanaccuratenumber.Itisthenumberofallthefemalescountedduringpatrols.WepresentthenumbertogaugerelaAvesizesofeventsbetweenyearratherthanabempAngesAmateanaccuratenumberoffemales).

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•  FromthefirstfouryearsofmonitoringCorozalito,weconcludedthatthisbeachhasincrediblyuniqueoliveridleynesAngdynamics.

•  ThebeachwascharacterizedbyhavingsporadicoccurrencesofoneortwomassnesAngeventsperyear.

•  Toourknowledgethistypeofbeachhadnotbeenpresentedinpreviouslypublishedliterature.

•  WespeculatedthatCorozalitocouldbeayoung,growingoliveridleyarribadabeach.

•  Aswehadrecordedunder2000solitaryeventsatthisbeacheveryyear,wewereinterestedinstudyingwheretheturtlesnesAnginthemasseventwerecomingfrom.

•  Theycouldbe“arribadaturtles”migraAngfromarribadasinOsAonalwithinanesAngseason.AlternaAvely,theycouldbe“solitaryturtles”fromCorozalitoandsurroundingsolitarynesAngbeachesswitchingnesAngbehaviourstojointheCorozalitoarribadaevents.

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Inthepast4yearsofconAnuinginvesAgaAonsatCorozalito,we’vefocussedon3primaryobjecAves

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1.  MonitoranddefinenesAngacAvitytostudyhownesAngdynamicdevelopsatthebeach

2.  DesignandimplementanarribadaprotocolsowecancomeupwithmoreaccuratesizeesAmates

3.  StudywherethearribadaturtlesarecomingfrombyIncreasingresources(people&equipment)tobeabletocheckarribadafortags,andtaggingarribadaturtles.

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•  InaddiAontoconducAngtwo4-hournightpatrolnightly,weputgreaterpriorityonconducAngmorningcensusesEVERYDAY.

•  Corozalitoisawonderfulbeachtostudybecauseshort(800m)andflat,makingtrackseasytocountcomparedtoourotherprojectsatmuchlongerbeaches.

•  HoweverthetownofCorozalitoisa30minwalkaway.Theresearchteamhastocrossarivereitherwaytheygettothebeach,andonnightswithbigrainstormstheroadisnotpassable.

•  ByconducAngmorningcensuswecangetdatafromnightswedon’tmakeittothebeach,andalsocheckthestatusofthenestslefinsitu.

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•  Wedefineanarribadaeventasanight(orconsecuAvenights)withmorethan100nesAngevents.

•  IfnesAngacAvityincreasesbeyondthelevelinwhichtrackscan’tbecountedindividually,weswitchtothearribadaprotocol.

•  Weusealoosethresholdof50turtlesonthebeachatoncetoswitchtoarribadamethod.Wefindthatwecancounttracksindividuallyifthereareupto100eventsinanight

•  WeuseasimpleINSTANTANEOUSCOUNTMETHOD,counAngallturtlesonthebeachinoviposiAonevery2hours.

•  FromtheequaAonabovewecomeupwithanesAmateofnumberoffemalesthatnestineachevent.

(EquaAonbasedoffofthatdescribedinGates&Valverde1996.Twas15min).

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•  WetagthesecondscaleoneachfrontflipperwithinconnelmetaltagsfromNaAonalBand.

•  From2012-2015wetagged2751turtlesnesAngsolitarilyonPRETOMA’s4nesAngbeaches.Corozalitoislimitedto2-3turtlespernightduetofunds.

•  In2014wecheckedarribadaturtlesfortagsandtaggedasmallsampleof53arribada-nesAngturtles.

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•  PickingupwhereIlefoffwiththeaccountoftheannualarribadaeventsatCorozalito….

•  WeobservedonepeakonAugust10thof71nesAngacAviAes.•  ThreemonthslateronNovember10thweobservedaneventofanesAmated2000

nesAngfemalesover2nights.(ChartrepresentsthenumberofnesAngeventsperday).

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•  In2013thenesAngacAvitylookedsimilartothatoftheyearbefore.•  TherewasanarribadaattheendoftheseasonofanesAmated1300femalesover

threenights.•  Thiswasthefirstyearweusedthearribadaprotocol,andwegotasimilar

esAmatedsizein2012and2013.•  However,whencomparingesAmatesfrombeforeandafer2013thedifferentin

esAmatemethodsshouldbeconsidered.(ChartrepresentsthenumberofnesAngeventsperday).

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Thisbringsusto2014,whichblewusawaywith4arribadas.ThemassnesAngeventsoccurredatamonthlyintervalbetweenAugustandNovember.

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•  ThefirstarribadaoccurredinAugustandwassmallenoughtocounteventsindividually.

•  WeusedthearribadaprotocoltoesAmatethesizeofthenextthreeevents.•  TheSeptembereventlastedlonger,withacAvitymorediffuselyspreadoverthe

week.•  TheOctobereventwasthelargestwehaveeverseenatCorozalito.Itwasshorter

andmoreconcentratedthantheSeptemberevent.•  November’seventwassmallerthantheprevioustwo,andthelastreportedofthe

season.(ChartrepresentsnumberofnesAngeventspernight)

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In2015wewereholdingourbreathforanotherbigyear.Butasusualtheoliveridleysprovedtobeunpredictable,andweonlyhadasmalleventof320turtles.

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•  Thatbeingsaid,therewasaclearpabernofmonthlypeaksthatleaduptotheNovemberevent.

•  Itappearedthatalthoughtheydidn’tprogresstoanarribada,therewassynchronousacAvityonamonthlyinterval.

(ChartrepresentsnumberofnesAngeventspernight)

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•  NowthatweareuptodateonCorozalito’sannualarribadas,Icanpresentmyfavouritepartoftheresults.

•  Before2014weweretoobusydevelopinganarribadaprotocolandrunningaroundcounAngturtlestobeabletodoanythingelse.

•  Finallyin2014,wehadenoughparAcipantstocheckturtlesfortagsandtagasmallsampleofarribadanesters.WhatwefoundwasexciAng.

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•  Weencounteredatotalof29previouslytaggedturtlesnesAnginthe42014arribadaevents.

•  Twooftheturtlesweretaggedduringoneofthe2014Corozalitoarribadas,andencounteredamonthlaternesAnginthenextarribada.

•  Theother25hadbeenoriginallytaggedwhilenesAngsolitaryonavarietyofnesAngbeaches.

•  Finally,2hadbeenoriginallytaggedinCamaronal,andwehavebeenunabletogetdatafromwhentheyweretagged.

(WehaveheardCamaronalalsogetssmallarribadas,andwedon’tknowifthe2turtleswereoriginallytaggedwhilenesAngsolitarilyorinoneofthesearribadas).

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•  Ofthe25turtlesthathadbeentaggedwhilenesAngsolitarily,3hadnestedinpreviousnesAngseasons,theoldestbeingfromCaletas6yearsbefore.

•  Theother22hadnestedduringthesameseasononavarietyofbeaches.Iwilltalkaboutthesebeachessoon,butfirstI’llpresentinternesAngperiod.

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•  InternesAngintervalofthe“switchingbeheviour”turtlesrangedbetween15and47days.

•  Thesmallsamplesizedoesn’tallowforastaAsAcallysignificantaverageinternesAnginterval.

•  Howevertheaverageintervaltakenfromthe24previouslytaggedturtlesthatwereencounterednesAngtwiceduringthe2014seasonwas26days.

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•  Comparedtothe“switchingbehaviourturtles”,solitarynesAngturtleshaveasimilarrangeandslightlysmalleraverageinterval.

•  ThechartbelowshowstheinternesAngintervalsofthe154solitarynesAngturtlesrecapturedatthe4PRETOMAnesAngbeachesbetween2012and2015.

•  **therewere2moresolitaryintervalsnotincludedonthechartbutincludedinthecalculaAonofaverageinternesAngperiod:53&70

•  TheaverageinternesAngintervalof22daysissimilartothosefoundinothersolitaryoliveridleytaggingstudies:

1.  24.5+/-7.1days,n=33atPlayaGrande,CostaRica.(Dornfeldetal2015)2.  22.35+/-7days,n=173inBrazil.(Matosetal2012)

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•  Finally,IwillfinishtheresultswiththelocaAonofwheretheturtlesrecapturedinthe2014Corozalitoarribabaswereoriginallytagged.

•  9weretaggedinCorozalito•  Another8weretaggedattheother3PRETOMAprojects,whichisatotalcoastal

spanof20km….

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•  InaddiAon,10turtleswerefromBuenavista(ASVO),Camaronal(MINAET),Montezuma(ASVO),andCocalito(RefugioRomelia).

•  Thereforetheturtlesmigratedfromdistancesupto45kmalongthecoasttoparAcipateintheCorozalitoarribadas.

•  Thisismuchfurtherthanthedistancesreportedinpreviousstudies,whichfoundanaveragedistanceofunder10kmbetweenthe2same-seasonnesAnglocaAons.(Matosetal2012,Hameletal2008)

•  Howeverthe2008HamelstudyinAustraliashowed2oliveridleysswamgreatdistancesduringtheinternesAngperiodofupto200km.SoweknowoliveridleysarecapableofmovingfromevenfurtherbeachestoparAcipateintheCorozalitoarribada.

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•  OliveridleystaggedwhilenesAngsolitarilyatthefourPRETOMAprojectshavebeenreportedtore-nestinOsAonalandLaFlor,NicaraguawithinanesAngseason.

•  ThereforeitispossiblethatthisnesAngpopulaAonregularlymigratesbetweenbeachesallalongtheNicoyaPeninsulabetweeninternesAngperiods.

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•  CorozalitohaspeaksofacAvitymuchhigherthanothernearbynesAngbeaches.•  Thesepeakscanbehardtodefinebecausetheyvarybetweenpeaknights(>100

females),smallevents(>1000females),andlargerarribadaevents(upto10000females).

•  Theretendstobeapabernemerginginthepeaksinthelastcoupleofyears,withpeaksoccurringatmonthlyintervals

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Althoughthearribadaeventshavegreatlyfluctuatebetweentheyearswe’vebeenmonitoringCorozalito,theeventsappeartobegrowinginsizeandfrequency

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TurtlesappeartobebothswitchingnesAngbehavioursandbeachestoparAcipateintheCorozalitoarribadas.

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•  WehavesecuredincreasedfundsfromtheRiesterFoundaAontoextendmonitoringunAltheendofFebruary

•  WewillconAnuetoimprovethearribadamethod,inaddiAontocollecAngmoretagdataduringfuturearribadas.

•  WehopetocollaboratewithotherbeacheswithsimilarnesAngacAvity.InparAcularwehopetogetmoreinformaAonfromCamaronal,whichhasreportedsimilararribadaevents.

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I’dliketothankthefollowingorganizaAonsandpeopleformakingthispresentaAonpossible:•  Riester(forfundingtheCorozalitoyearaferyearandcoveringmytravelexpenses

forgoingtothissymposium)•  AlloftheTurtleTraxvolunteers,researchassistants,andcoordinatorswho

workedhardtocollectthedataandprotecttheseaturtlenests•  AndPRETOMAandTurtleTraxforcoveringISTSexpenses.

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