my name’s maddie beange & i’m responsible for the research ... · • my name’s maddie...
TRANSCRIPT
• 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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ReferencesDornfeld,T.C.,Robinson,N.J.,Tomillo,P.S.,Paladino,F.V.(2015)EcologyofsolitarynesAngoliveridleyseaturtlesatPlayaGrande,CostaRica.Mar.Biol.162,123–139.FonsecaL.G.,VillachicaW.N.,MatarritaE.R.,ArguelloY.,OrregoC.M.,QuirosW.,SeminoffJ.A.,ValverdeR.A.(2015)PreliminarydataontheoliveridleytaggingprogramatNancitebeach,CostaRica.In:Tucker,T.,Belskis,L.,Panagopoulou,A.,Rees,A.,Frick,M.,Williams,K.,LeRoux,R.,andStewart,K.compilers.2013.ProceedingsoftheThirty-ThirdAnnualSymposiumonSeaTurtleBiologyandConservaAon.NOAATechnicalMemorandumNOAANMFS-SEFSC-645:177pGates,C.E.,Valverde,R.A.,Mo,C.L.,Chaves,A.C.,Ballestero,J.&Peskin,J.(1996)EsAmaAngarribadasizeusingamodifiedinstantaneouscountprocedure.JournalofAgricultural,BiologicalandEnvironmentalStaAsAcs1(3):275–87.HamelMA,McMahonCR,BradshawCJA(2008)Flexibleinter-nesAngbehaviorofthegeneralistoliveridleyinAustralia.JExpMarBiolEcol359:47–54KalbHJ(1999)BehaviorandphysiologyofsolitaryandarribadanesAngoliveridleyseaturtles(Lepidochelysolivacea)duringtheinternesAngperiod.DissertaAon,TexasA&MUniversity,CollegeStaAon,TXKot,C.Y.,DiMabeo,A.(2015)NesAngBiologyofSeaTurtlesinCostaRicaFeatureMap.SWOTReport–StateoftheWorld’sSeaTurtles,vol.X:22-23Matos,L.,Silva,A.C.,CasAlhos,J.C.,Weber,M.I.,Soares,L.S.,Vicente,L.(2012)StrongsitefidelityandlongerinternesAngintervalforsolitarynesAngoliveridleyseaturtlesinBrazil.Mar.Biol.159,1011–1019.PlotkinPT,RostalDC,BylesRA,OwensDW(1997)ReproducAveanddevelopmentalsynchronyinfemaleLepidochelysolivacea.JHerpetol30(1):17–22