ML17221A746

Annual Environ Rept (FPL-87) for 1987.

ML17221A746
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Site:	Saint Lucie
Issue date:	12/31/1987
From:	FLORIDA POWER & LIGHT CO.
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ML17221A747	List: L-88-193, Forwards Annual Environ Rept for Apr 1988 & Annual Environ Operating Rept for 1987 ML17221A746 ML17221A749
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FLORIDAPOWER8LIGHTCOMPANYST.LUCIEUNITNO.2ANNUALENVIRONMENTAL REPORT(FPL-87)APRIL1988gp-887>i~><>~g~gczoig5Coo.NI@t;,jii~A24 W6fOocumea4g",6JV<jOR7 OXRH7%4P~O+NfeSa+8805030185 8889k&'DR ADGCK05000389'R DCD 1

FLORIDAPOWER8LIGHTCOMPANYST.LUCIEUNITNO.2ANNUALENVIRONMENTAL REPORT(FPL-87)APRIL1988

~e~ClIll Page1of4ANNUALENVIRONMENTAL REPORTIntroduction TheSt.LuciePlantUnit2Environmental Protection Plan(EPP)requiresthesubmittal ofanannualreportforvariousactivities attheplantsiteincluding thereporting onseaturtlemonitoring

programs, andothermattersrelatedtoFederalandStateenvironmental permitsandcertifications.

Thisreportfulfillsthesereporting requirements.

II.SeaTurtleMonitoring andAssociated Activities Aquaticandterrestrial seaturtlemonitoring programstosatisfySections4.2.1(BeachNestingSurveys),

4.2.3(StudiestoEvaluateand/orMitigateIntakeCanalMortality) and4.2.5(CaptureandReleaseProgram)isconcurrently submitted inaseparatereport(AB-595)preparedbyAppliedBiology,Inc.Studiestoevaluateand/ormitigateintakeentrapment requiredbySection4.2.2oftheEPPhavebeenpreviously performed.

Afinalreportwassubmitted totheOfficeofNuclearReactorRegulation onApril18,1985.Withsubmittal ofthatreport,theEPPrequirement wasfulfilled andwillnotbereaddressed inthisorfuturereports.

III Page2of4FPLwillrequestmodification ofcertainsectionsoftheEnvironmental Protection Planrelatedtoseaturtleprograms, toreflectimplementation andsatisfaction ofthoserequirements whichhavebeencompleted asdescribed above.Requirements forreporting onthestatusofalightscreentominimizeturtledisorientation asrequiredbySection4.2.4oftheEPPisongoing.TheAustralian Pinelightscreen,locatedonthebeachdunebetweenthepowerplantandtheocean,isroutinely surveyedtodetermine itsoverallvitality.

Thetreelineissurveyedforanygapsoccurring fromtreemortality whichwouldresultinunacceptable lightlevelsonthebeach.Treesarereplacedasnecessary tomaintaintheintegrity oftheoveralllightscreen.III.OtherRoutineReportsThefollowing itemsforwhichreporting isrequiredarelistedbysectionnumberfromtheEnvironmental Protection Plan(EPP):5.4,.1(a)

EPPNONCOMPLIANCES ANDCORRECTIVE ACTIONSTAKENNononcompliances underEPPSection5.4.1(a)weredetermined tohaveoccurredduring1987.

Page3of4541(b)STATIONDESIGNANDOPERATION CHANGESgTESTSgANDEXPERIMENTS AFFECTING THEENVIRONMENT Noplantsiteactivities weredetermined tobereportable underSection5.4.1(b)during1987.5.4.1(c)NONROUTINE REPORTSSUBMITTED TOTHENRCFORTHEYEAR1987INACCORDANCE WITHEPPSUBSECTION 5.4.2:1.Reportconcerning anoverflowfromtheSt.LucieUnit1SewageTreatment PlantreportedtoEPAonFebruary24,1987andtheNRConMarch18,1987.2.Reportconcerning receiptofthefinalNPDESPermitfortheSt.LuciePlant.(TheStateofFlorida401Certification andtheStateofFloridaSiteCertification forSt.LucieUnit2areattachments totheNPDESPermit.)Permiteffective dateSeptember 30,1987.Thefollowing reportsweresubmitted totheNRCforinformational purposesalthoughnotrequiredunderprovisions of5.4.2:1.Reportconcerning anexceedance ofthemaximumtemperature difference (dT)fortheSt.LucieUnits Cl Page4of41and2oncethroughcoolingwatersystemwhichwasreportedtotheEPAonFebruary25,1987andtotheNRConMarch18,1987.2.Seaturtleactivities quarterly reportdatedApril2,1987forthefirstquarter1987.3.Seaturtleactivities quarterly reportdatedJuly8,1987forthesecondquarter1987.4.Seaturtleactivities quarterly reportdatedOctober6,1987forthethirdquarter1987.5.Seaturtleactivities reportdatedJanuary5,1988forthefourthquarter1987.

APPLIEDBIOLOGY,INC.AB-595FLORIDAPOWER8LIGHTCOMPANYST.LUCIEUNIT2ANNUALENVIRONMENTAL OPERATING REPORT198702968ANORTHDECATURROAD~ATLANTA,GEORGIA30033~404-296-3900

)

0 AB-595FLORIDAPOWER5LIGHTCOMPANYST.LUCIEUNIT2ANNUALENVIRONMENTAL OPERATING REPORT1987APRIL1988FLORIDAPOWER5LIGHTCOMPANYJUNOBEACH,FLORIDAAPPLIEDBIOLOGY,INC.ATLANTA,GEORGIA

~i'f/Itlt ENVIRONMENTAL OPERATING REPORTTABLEOFCONTENTSTABLEOFCONVERSION FACTORSFORMETRICUNITSEXECUTIVE SUMMARYIntroduction TurtleNestingSurveyIntakeCanalMonitoring-OtherRelatedActivities INTRODUCTION-

Background

AreaDescription--

PlantDescription

~Pae1v1v1VvvTURTLESIntroduction IMaterials andMethods-NestingSurveyIntakeCanalMonitoring StudiestoEvaluateand/orMitigateIntakeEntrapment

---

LightScreentoMinimizeTurtleDisorientation

---

ResultsandDiscussion NestingSurveyDistribution ofLoggerhead NestsAlongHutchinson IslandNumberofNestsandLoggerhead Population Estimates

---TemporalLoggerhead NestingPatternsPredation onLoggerhead TurtleNestsGreenandLeatherback TurtleNestingIntakeCanalMonitoring SpeciesNumberandTemporalDistribution-Size-Class Distributions-SexRatios-CaptureEfficiencies RelativeCondition MortalitiesRecapture IncidentsSummary-LITERATURE CITEDFIGURESTABLES-11ll1316161616162325262729303234363842464752598111 TABLEOFCONVERSION FACTORSFORMETRICUNITSToconvertcentigrade (degrees) centigrade (degrees) centimeters (cm)centimeters (cm)centimeters/second (cm/sec)cubiccentimeters (cm3)grams(g)grams(g)hectares(ha)kilograms (kg)kilograms (kg)kilograms (kg)kilometers (km)kilometers (km)liters(1)liters(1)meters(m)meters(m)meters(m)microns(9)milligrams (mg)milligrams/liter (mg/1)milliliters (ml)millimeters (mm)millimeters (mm)squarecentimeters (cm2)squaremeters(m2)squaremillimeters(mm2)Multiplyby)(Cx1.8)+32C+273.18,3.937x103.281x10"3.281x101.0x102.205x103.527x10"2.4711.0x1032.20463.5274x1016.214x10-11.0x1061.0x102.642x103.2813.937x10l.0941.0x1061.0x10"31.01.0x103.937x10"23.281x101.550x101.076x101.55x10Toobtainfahrenheit (degrees) kelvin(degrees) inchesfeetfeetpersecondliterspoundsounces(avoirdupois)acresgramspoundsounces(avoirdupois) miles(statute) mi11imeterscubiccentimeters (cm3)gallons(U.S.liquid)feetinchesyardsmetersgramspartspermi11ionliters(U.S.liquid)inchesfeetsquareinchessquarefeetsquareinches

EXECUTIVE SUMMARYINTRODUCTION TheSt.LuciePlantisanelectricgenerating stationonHutchinson IslandinSt.LucieCounty,Florida.Theplantconsistsoftwonuclear-fueled850-MWunits;Unit1wasplacedon-lineinMarch1976andUnit2inMay1983.Thisdocumenthasbeenpreparedtosatisfytherequirements contained intheUnitedStatesNuclearRegulatory Commission's Appendix8Environmental ProtectionPlan(EPP)toSt.LucieUnit2FacilityOperating LicenseNo.NPF-16.Thisreportdiscusses environmental pro-tectionactivities relatedtoseaturtlesasrequiredbySubsection 4.2oftheEPP.TURTLENESTINGSURVEYTherehavebeenconsiderable year-to-year fluctuations inseaturtlenestingactivityonHutchinson Islandsincemonitoring beganin1971.Lownestingactivityin1975and1981-1983inthevicinityofthepowerplantwasattributed toconstruction ofplantintakeanddischarge struc-tures.Nestingreturnedtonormalorabovenormallevelsfollowing bothperiodsofconstruction.

Powerplantoperation exclusive ofconstruction hashadnosignificant effectonnestingneartheplant.Datacollected through1987haveshownnolong-term reductions intotalnesting,totalemergences ornestingsuccessontheisland.Formalrequirements tocon-ductthisprogramexpiredin1986butwerevoluntarily continued in1987withagreement fromfederalandstateagencies.

0 INTAKECANALMONITORING Sinceplantoperation beganin1976,1,748seaturtles(including 79recaptures) representing fivedifferent specieshavebeenremovedfromtheintakecanal.Eighty-six percentofthesewereloggerheads.

Differences inthenumbersofturt'lesfoundduringdifferent monthsandyearswereattribute'd tonaturalvariation intheoccurrences ofturtlesinthevicinityoftheplant,ratherthantoanyinfluence oftheplantitself.Themajority(about92percent)oftheturtlesremovedfromtheintakecanalwerecapturedaliveandreleasedbackintotheocean.TurtlesconfinedbetweentheA1Abarriernetandintakeheadwalls usuallyresidedinthecanalforarelatively shortperiodoftime,andmostwereingoodtoexcellent condition whencaught.Drowningwasthoughttoberesponsible formostrecentcanalmortalities andappropriate

measures, including theinstallation ofanewbarriernet,weretakentominimizefuturemortalities.OTHERRELATEDACTIVITIES Theintegrity ofavegetative lightscreenalongthedunelineattheSt.LuciePlantisassessedonacontinuing basis.During1987,routineinspections ofthescreenweremadeandreplantings conducted asneeded.Studiestoevaluatevariousintakedeterrentsystems,asrequiredbytheNRC'sUnit2Environmental Protection Plan,wereconducted during1982,and1983.Resultsandevaluations ofthosestudieswerepresented toregulatory agenciesduring1984,andtherequirement isnowconsidered completed.

INTRODUCTION BACKGROUND Thisdocumenthasbeenpreparedtosatisfytherequirements con-tainedintheUnitedStatesNuclearRegulatory Commission's (NRC)AppendixBEnvironmental Protection PlantoSt.LucieUnit2FacilityOperating LicenseNo.NPF-16.In1970,FloridaPower5LightCompany(FPL)wasissuedPermitNo.CPPR-74bytheUnitedStatesAtomicEnergyCommission, nowtheNuclearRegulatory Commission, thatallowedconstruction ofUnit1oftheSt.LuciePlant,an850-HWnuclear-powered electricgenerating stationonHutchinsonIslandinSt.LucieCounty,Florida.St.LuciePlantUnit1wasplacedon-lineinHarch1976.InHay1977,FPLwasissuedPermitNo.CPPR-144bytheNRCfortheconstruction ofasecond850-HWnuclear-poweredunit.Unit2wasplacedon-lineinHay1983andbegancommercial operation inAugustofthatyear.St.LuciePlantUnits1and2usetheAtlanticOceanasasourceofwaterforonce-through condenser cooling.Since1971,thepotential environmental effectsresulting fromtheintakeanddischarge ofthiswaterhavebeenthesubjectofFPL-sponsored bioticstudiesatthesite.

Baselineenvironmental studiesofthemarineenvironment adjacenttotheSt.LuciePlantweredescribed inaseriesofreportspublished bytheFloridaDepartment ofNaturalResources (Campetal.,1977;FutchandDwinell,1977;Gallagher, 1977;Gallagher andHollinger, 1977;WorthandHollinger, 1977;MofflerandVanBreedveld, 1979;TesterandSteidinger, 1979;Walker1979;Walkeretal.,1979;WalkerandSteidinger, 1979).TheresultsofUnit1operational andUnit2preoperational bioticmoni-toringattheSt.~LuciePlantwerepresented insixannualreports(ABI,1977,1978,1979,1980a,1981b,1982).InJanuary1982,aNationalPollutant Discharge Elimination System(NPDES)permitwasissuedtoFPLbytheU.S.Environmental Protection Agency(EPA).TheEPAguidelines fortheSt.Luciesitebiological studieswerebasedonthedocumententitled"Proposed St.LuciePlantPreoperational andOperational Biological Monitoring Program-August1981"(ABI,198lc).Findingsfromthesestudieswerereportedinthreeannualreports(ABI,1983,1984a,1985a).TheEPAbioticmonitoring requirements weredeletedfromtheNPDESpermitin1985.Jurisdiction forseaturtlestudiesiswiththeNRC,whichiscon-sideredtobetheleadfederalagencyrelativetoconsultation undertheEndangered SpeciesAct.Previousresultsdealingexclusively withseaturtlestudiesarecontained infourenvironmental operating reports(ABI,1984b,1985b,1986,1987).Thisreportdescribes the1987environ-mentalprotection activitiesrelatedtoseaturtles,asrequiredbySubsection 4.2oftheSt.LuciePlantUnit2Environmental Protection Plan.

AREADESCRIPTION TheSt.LuciePlantislocatedona457-hasiteonHutchinson IslandonFlorida's eastcoast(FiguresIand2).Theplantisapproximately midwaybetweentheFt.PierceandSt.LucieInlets.ItisboundedonitseastsidebytheAtlanticOceanandonitswestsidebytheIndianRiverLagoon.Hutchinson Islandisabarrierislandthatextends36kmbetweeninletsandobtainsitsmaximumwidthof2kmattheplantsite.Eleva-tionsapproach5matopdunesbordering thebeachanddecreasetosealevelinthemangroveswampsthatarecommononmuchofthewesternside.Islandvegetation istypicalofsoutheastern Floridacoastalareas;densestandsofAustralian pine,palmetto, seagrapeandSpanishbayonetarepresentatthehigherelevations, andmangroves aboundatthelowerele-vations.Largestandsofblackmangroves, including someontheplantsite,havebeenki11edbyfloodingformosquitocontroloverpastdecades.TheAtlanticshoreline ofHutchinson Islandiscomposedofsandandshellhashwithintermittent rockypromontories protruding throughthebeachfacealongthesouthernendoftheisland.Submerged coquinoid rockformations parallelmuchoftheislandofftheoceanbeaches.Theoceanbottomimmediately offshorefromtheplantsiteconsistsprimarily ofsandandshel1sediments.

Theunstablesubstrate limitstheestablishmentofrootedmacrophytes.

TheFloridaCurrent,whichflowsparalleltothecontinental shelfmargin,beginstodivergefromthecoastline atWestPalmBeach.AtHutchinson Island,thecurrentisapproximately 33kmoffshore.

Oceanicwaterassociated withthewesternboundaryofthecurrentperiodically meanders.

overtheinnershelf,especially duringsummermonths.PLANTDESCRIPTION TheSt.LuciePlantconsistsoftwo850-HWnuclear-fueled electricgenerating unitsthatusenearshore oceanwatersfortheplant'soncethroughcondenser coolingwatersystem.Waterfortheplantentersthroughthreesubmerged intakestructures locatedabout365moffshore(Figure2).Eachoftheintakestructures isequippedwithavelocitycaptominimizefishentrainment.

Horizontal intakevelocities arelessthan30cm/sec.Fromtheintakestructures, tliewaterpassesthroughsubmerged pipes(two3.7mandone4.9mindiameter) underthebeachanddunesthatleadtoa1500-mlongintakecanal.Thiscanaltransports thewatertotheplant.Afterpassingthroughtheplant,theheatedwaterisdischarged intoa670-mlongcanalthatleadstotwoburieddischarge pipelines.Thesepassunderneath thedunesandbeachandalongtheoceanfloortothesubmerged discharges, thefirstofwhichisapproximately 365moffshoreand730mnorthoftheintake.Heatedwaterleavesthefirstdischarge linefromaY-shapednozzle(diffuser) atadesignvelocityof396cm/sec.Thishigh-momentum jetentrainsambientwaterresulting inrapidheatdissipation.

Theoceandepthintheareaofthefirstdischarge isabout6m.Heatedwater leavestheseconddischarge linethroughaseriesof48equallyspacedhighvelocityjetsalonga323-mmanifold(multiport diffuser).Thisdiffuserstarts168mbeyondthefirstdischarge andterminates 856mfromshore.Theoceandepthatdischarge alongthisdiffuserisfromabout10to12m.Aswiththefirstdiffuser, thepurposeoftheseconddiffuseristoentrainambientwaterandrapidlydissipate heat.Fromthepointsofdischarge atbothdiffusers, thewarmerwaterrisestothesurfaceandformsasurfaceplumeofheatedwater.Theplumethenspreadsoutonthesurfaceoftheoceanundertheinfluence ofwindandcurrentsandtheheatdissipates totheatmosphere.

TURTLESTheNRC'sSt.LucieUnit2AppendixBEnvironmental Protection PlanissuedApril1983containsthefollowing technical specifications:

4.2Terrestrial/A uaticIssuesIssuesonendangered orthreatened seaturtlesraisedintheUnit2FES-OL[NRC,1982jandintheEndangered SpeciesBiological Assessment (March1982)[Bellmund etal.,1982]willbeaddressed byprogramsasfollows:4.2.1BeachNestinSurvesBeachnestingsurveysforallspeciesofseaturtleswillbeconducted onayearlybasisfortheperiodof1982through1986.Thesesurveyswillbecon-ductedduringthenestingseasonfromapproximately mid-April throughAugust.TheHutchinson Islandbeachwillbedividedinto36one-km-long surveyareas.Inaddition, thenine1.25-km-long surveyareasusedinpreviousstudies(1971-1979) willbemaintained forcomparison pur-poses.Surveyareaswillbemarkedwithnumberedwoodenplaquesand/orexistinglandmarks.

Theentirebeachwillbesurveyedsevendaysaweek.Allnewnestsandfalsecrawlswillbecountedandrecordedineacharea.Aftercounting, allcrawltrackswillbeobliterated toavoidrecounting.

Predation onnestsbyraccoonsorotherpredatorswillberecordedasitoccurs.Recordswillbekeptofanyseasonalchangesinbeachtopography thatmayaffectthesuitability ofthebeachfornesting.4.2.2StudiestoEvaluateand/orMitiateIntakeAprogramthatemployslightand/orsoundtodeterturtlesfromtheintakestructure willbeconducted.

Thestudywilldetermine withlaboratory andfieldexperiments ifsoundand/orlightwillresultina'reduction oftotalturtleentrapment rate.Thestudyshallbeimplemented nolaterthanafterthefinalremovalfromtheoceanofequipment and structures associated withconstruction ofthethirdintakestructure andtheexperiments shallterminate 18monthslater.Fourmonthsaftertheconclusion oftheexperimental period,areportontheresultsofthestudywillbesubmitted toNRC,EPA,NationalMarineFisheries Service(NMFS),andtheU.S.FishandWildlifeService(USFWS)fortheirevaluation.

Ifastatistically significant reduction inannualtotalturtleentrapment rateof80percentorgreatercanbedemonstrated, usingthedeveloped technology anduponFPLreceiving writtencon-currencebyNRC,EPA,NMFS,andUSFWSthenpermanent installation ofthedeterrent systemshallbecompleted andfunctioning nolaterthanI(monthsaftertheagencies'oncurrence.

Thedesignofthisstudyneedstotakeintoaccountthesignificant annualvariationinturtleentrapment observedinthepast.Ifan80percentreduction ofturtleentrapment can-notbeprojected toallthreeintakestructures, thenaninteragency taskforcecomposedofHRC,EPA,NMFS,USFWS,andFPLshallconvene18monthsaftercompletion ofthethirdintakeanddetermine ifothercoursesofactiontomitigateand/orreduceturtleentrapment arewarranted (suchasphysicalbarrier,emergence ofnewtechnology ormethodstodeterturtles).

4.2.3StudiestoEvaluateand/orMitiateIntakeAlternative methodsorprocedures forthecaptureofseaturtlesentrapped intheintakecanalwillbeevaluated.

Ifamethodorprocedure isconsidered feasibleandcosteffective andmayreducecapturemortality rates,itwillbefieldtestedintheintakecanal.4.2.4LihtScreentoMinimizeTurtleDisorienta-tion[N:1s1sasoSection4.2otheNRCSt.LucieUnit1AppendixBTechnical Specifications issuedMay1982]Australian pine"orothersuitableplants(i.e.,nativevegetation suchasliveoak,nativefigs,wildtamarindandothers)shallbeplantedandmain-tainedasalightscreen,alongthebeachdunelinebordering theplantproperty, tominimizeturtledisorientation.

4.2.5CatureandReleaseProramSeaturtleremovalfromtheintakecanalwillbeconducted onacontinuing basis.Theturtleswi11becapturedwithlargemeshnets,orothersuitablenondestructive device(s),

ifdeemedappropriate.

Aformalized dailyinspection, fromtheshoreline, ofthecapturedevice(s) willbemadebyaqualified individual whenthedevice(s) aredeployed.

Theturtleswillbeidentified tospecies,measured, weighed(ifappropriate),

taggedandreleasedbackintotheocean.Recordsofwounds,freshorold,andasubjective judgement onthecondition oftheturtle(e.g.,barnaclecoverage, underweight) wi11bemaintained.

Methodsofobtaining additional biological/physiological data,suchasbloodanaly-sesandparasiteloads,fromcapturedseaturtleswillbepursued.Deadseaturtleswillbesubjected toagrossnecropsy, iffoundinfreshcondition.

INTRODUCTION Hutchinson Island,Florida,isanimportant rookeryfortheloggerhead turtle,Carettacaretta,andalsosupportssomenestingoftheCh1l~,dh1hkcoriacea(Caldwell etal.,1959;Routa,1968;Gallagher etal.,1972;WorthandSmith,1976;Williams-Walls etal.,1983).Allthreespeciesareprotected bystateandfederalstatutes.

Thefederalgovernment classifies theloggerhead turtleasathreatened species.Theleather-backturtleandtheFloridanestingpopulation ofthegreenturtlearelistedbythefederalgovernment asendangered species.Becauseofreductions inworldpopulations ofmarineturtlesresulting fromcoastaldevelopment andfishingpressure(NMFS,1978),maintaining thevitalityoftheHutchinson Islandrookeryisimportant.

0jf IthasbeenaprimeconcernofFPLthattheconstruction andsub-sequentoperation oftheSt.LuciePlantwouldnotadversely affecttheHutchinson Islandrookery.Becauseofthisconcern,FPLhassponsored monitoring ofmarineturtlenestingactivityontheislandsince1971.Daytimesurveystoquantifynesting,aswellasnighttime turtletaggingprograms, wereconducted inoddnumberedyearsfrom1971through1979.Duringdaytimenestingsurveys,nine1.25-km-long surveyareasweremonitored fivedaysperweek(Figure3).TheSt.LuciePlantbeganoperation in1976;therefore, thefirstthreesurveyyears(1971,1973and1975)werepreoperational.

Thoughthepowerplantwasnotoperating during1975,St.LuciePlantUnitNo.1oceanintakeanddischarge struc-tureswereinstalled duringthatyear.Installation ofthesestructures includedconstruction activities conducted offshorefromandperpen-diculartothebeach.Construction hadbeencompleted andtheplantwasinfulloperation duringthe1977and1979surveys.Amodifieddaytimenestingsurveywasconducted in1980duringthepreliminary construction oftheoceandischarge structure forSt.LuciePlantUnit2.Duringthisstudy,fourofthepreviouslyestablished 1.25-km-long surveyareasweremonitored.

Additionally, eggsfromturtlenestspotentially endangered byconstruction activities wererelocated.

Everyyearfrom1981through1987,thirty-six 1-km-long surveyareascomprising theentireislandweremonitored sevendaysaweekduringthenestingseason(Figure3).TheSt.LuciePlantUnit2discharge struc-turewasinstalled duringthe1981nestingseason.Offshoreandbeachconstruction oftheUnit2intakestructure proceeded throughout the1982nestingseasonandwascompleted neartheendofthe1983season.Construction activitiesassociated withinstallation ofbothstructures weresimilartothoseconducted whenUnit1intakeanddischarge struc-tureswereinstalled.

Eggsfromturtlenestspotentially endangered byconstruction activities wererelocated duringallthreeyears.Requirement

.4.2.1oftheNRC'sSt.LucieUnit2AppendixBEnvironmental Protection Planwascompleted withsubmission ofthe1986nestingsurveydata(ABI,1987).Thenestingsurveywascontinued volun-tarilyin1987withagreement fromfederalandstateagencies.

Resultsarepresented inthisreportanddiscussed inrelationtopreviousfin-dings.Inadditiontomonitoring seaturtlenestingactivities andrelo-catingnestsawayfromplantconstruction areas,monitoring ofturtlesintheintakecanalhasbeenanintegralpartoftheSt.LuciePlantenvironmental monitoringprogram.Turtlesenteringtheoceanintakestructures arerapidlytransported withcoolingwaterthroughtheintakepipesandintotheenclosedcanalsystemwheretheyareentrapped.

Sincetheplantbecameoperational in1976,turtlesentrapped intheintakecanalhavebeencaptured,

measured, taggedandreturnedalivetotheocean.10

Previouspublications andtechnical reportshavepresented findingsofthenestingsurveys,nestrelocation activitiesandcanalcaptureprogram(Gallagher etal.,1972;WorthandSmith,1976;ABI,1978,1980a,1981a,1982,1983,1984b,1985b,1986,1987;Williams-Walls etal.,1983;Proffittetal.,1986;Ernestetal.,inpress;Martinetal.,inpress).Resultsofstudiestoassesstheeffectsofthermaldischargesonhatchling swimmingspeedhavealsobeenreported(ABI,1978;O'ara,1980).Thepurposeofthisreportisto1)present1987seaturtlenestingsurveydataandsummarize observedspatialandtemporalnestingpatternssince1971,2)documentandsummarize predation onturtlenestssince1971,and3)present1987canalcapturedataandsummarize relateddatacollected since1976.MATERIALS ANDMETHODSNestinSurveMethodologies usedduringpreviousturtlenestingsurveysonHutchinson Islandweredescribed byGallagher etal.(1972),WorthandSmith(1976)andABI(1978,198la,1982,1987).Methods.usedduringthe1987surveyweredesignedtoallowcomparisons withthesepreviousstu-dies.From16Aprilthrough29April1987,eightpreliminary nestsurveyswereconducted alongHutchinson IslandfromtheFt.PierceInletsouthtotheSt.LucieInlet.After29April,surveyswereconducted dailythrough11September.

Severaladditional surveyswereconducted after11September toconfirmthatnestinghadceased,thelastsurveybeingcon-ductedon18September.

Biologists usedsmalloff-roadmotorcycles tosurveytheislandeachmorning.Newnests,non-nesting emergences (falsecrawls),andnestsdestroyed bypredators wererecordedforeachofthethirty-six 1-km-long surveyareascomprising theentireisland(Figure3).Thenine1.25-km-long surveyareasestablished byGallagher etal.(1972)alsoweremonitored socomparisons couldbemadewithpreviousstudies.Duringthedailynestmonitoring, anymajorchangesintopography thatmayhaveaffectedthebeach'ssuitability fornestingwererecorded.

Inaddition, eachofthethirty-six1-km-long surveyareashasbeensystematically analyzedandcategorized basedonbeachslope(steep,moderate, etc.),widthfromhightidelinetothedune,presenceofbenches(areasofabruptverticalrelief)andmiscellaneous charac-teristics (packedsand,scattered rock,vegetation onthebeach,exposedrootsontheprimarydune,etc.).Inacooperative effort,theFloridaDepartment ofNaturalResources (DNR)wasnotifiedofallgreenturtlenests.Eggsfromsomeofthesenestswerecollected aspartoftheFloridaDNRHeadstart Program.Additionally, datafromstrandedturtlesfoundduringbeachsurveyswereroutinely providedtotheNationalMarineFisheries ServicethroughtheSeaTurtleStranding andSalvageNetwork.12

IntakeCanalMonitorin RoutinecaptureofseaturtlesfromtheSt.LuciePlantintakecanalcontinued during1987.Turtleswereremovedfromthecanalwithlarge-meshtanglenetsfishedbetweentheintakeheadwalls andabarriernetlocatedattheHighwayA1Abridge(Figure2).ThesenetswereusuallydeployedonMondaymorningandretrieved onFridayafternoon.

Todetectcaptures, formaldailyinspections ofthenets(mornings andafternoons) weremadeeachdayofdeployment.

Varioussizes,numbersandlocations oftanglenetshavebeenusedtodateascapturetechniques havebeenrefined.Netsinrecentusewerefrom32to61minlength,2.7to3.7mindepthand30to40cminstretchmesh.Largefloatskeptthenetsatthesurface,andbecausenetswerenotweightedwithleadlines,turtleswhichbecameentangled remainedatthewater'ssurfaceuntilremoved.ThebarriernetattheA1Abridgeisintendedtoconfineturtlestotheeasternmost sectionoftheintakecanal,wherecapturetechniques havebeenmosteffective.

However,theintegrity ofthebarriernetoccasionally hasbeencompromised, andturtleshavebeenabletoswimoverorunderit.PriortoDecember1986,mostturtlescircumventing thebarrierneteventually emergedintheintakewellsofUnits1and2(Figure2),wheretheywereretrieved bymeansoflargemechanical rakesorspecially designednets.However,during1986,asecurityintrusion barrierwasconstructed acrossthenorth-south armoftheintakecanal.Afteritsemplacement, turtleslargerthan30.5cmincarapacewidthwere13 impededfromreachingtheintakewellsbyalarge-mesh chainnet.TanglenetsweresetwestoftheA1Abarriernettocapturetheseturtles.Turtlessmallerthan30.5cmcanpassthroughthemeshofboththebarriernetandtheintrusion barrier.Personnel ofAppliedBiology,Inc.wereoncall24hoursadaytoretrievecapturedturtlesfromboththeintakewellsandturtlenets.Theutmostcarewastakeninhandlingcapturedturtlestopreventinjuryortrauma.Afterremovalfromthecanal,turtleswereidentified tospecies,measured, weighed,tagged,examinedforoverallcondition (wounds,abnor-malities,parasites, etc.)andreleasedbackintotheocean.Althoughbothstraight-li neandcurvedcarapacelengthsweremeasured, onlystraight-line measurements wereusedinanalysespresented inthisreport.Straight-line carapacelength(SLCL)wasmeasuredfromthepre-centralscutetothenotchbetweenthepostcentral scutes(minimumcara-pacelengthofPritchard etal.,1983).Since1982,bloodsampleshavebeencollected andanalyzedtoinvestigate thepotential occurrence andsignificance ofanemiaincap-turedanimalsandtodetermine thesexofimmatureturtles.Bloodwasremovedfromthepaireddorsalcervicalsinusesofsubjectturtlesusingthetechnique described byOwensandRuiz(1980).Asmallsubsample ofwholebloodwashemolyzed andhemoglobin measuredingramsper100mlbycolorimetry usinganA.O.10100hemoglobinometer.

Theremainder ofthe~~

lli bloodsamplewascentrifuged for15minutestoseparatecellsandserum.Sexdeterminations weresubsequently madebyresearchers atTexasA5MUniversity usingradioimmunoassay forserumtestosterone (Owensetal.,1978).During1984and1985,bloodcellsampleswerealsoprovidedtotheNationalMarineFisheries Serviceforthepurposeofdeveloping andrefiningmethodsforuseinconducting turtlestockanalysis.

Sickorinjuredturtlesweretreatedandoccasional lyheldforobservation priortorelease.Whentreatment waswarranted, injections ofantibiotics andvitaminswereadministered byalocalveterinarian.

Resuscitation techniques wereusedifaturtlewasfoundthatappearedtohavediedrecently.

Beginning in1982,necropsies wereconducted ondeadturtlesfoundinfreshcondition; twoindividuals, oneKemp'sridleyandoneloggerhead, werefoundsuitablefornecropsyin1987.FloridaPower5LightCompanyandAppliedBiology,Inc.continued toassistotherseaturtleresearchers in1987.InadditiontotheFloridaDNR'sHeadstart Program,data,specimens and/orassistance havebeengiventotheNationalMarineFisheries

Services, U.S.ArmyCorpsofEngineers, Smithsonian Institution, SouthCarolinaWildlifeandMarineResources Division,CenterforSeaTurtleResearch(UniversityofFlorida),

TexasA&MUniversity, University ofRhodeIsland,University ofSouthCarolina, University ofIllinois, University ofGeorgiaandtheWesternAtlanticTurtieSymposium.

15 StudiestoEvaluateand/orMitiateIntakeEntramentAprogramthatassessedthefeasibility ofusinglightand/orsoundtodeterturtlesfromenteringtheSt.LuciePlantintakestructures wasconducted in1982and1983andcompleted inJanuary1984.Asrequired, testresultsandevaluations werewrittenupandapresentation wasmadetotheNRC,NationalMarineFisheries ServiceandtheFloridaDepartment ofNaturalResources onllApril1984.Requirement 4.2.2oftheNRC'sSt.LucieUnit2AppendixBEnvironmental Protection Planisconsidered completed withsubmission ofdeterrent studyfindings.

LihtScreentoMinimizeTurtleDisorientation Avegetative beachdunelightscreencreatedtominimizeturtledisorientation attheSt.LuciePlantwasroutinely inspected byFPLper-~~sonnelduring1987.Replantings wereconducted asrequiredtomaintainitsintegrity.

RESULTSANDDISCUSSION NestinSurveDistribution ofLoerheadNestsAlonHutchinson IslandWhenseaturtlenestingsurveysbeganonHutchinson Island,nine1.25-km-long surveyareaswereusedtoestimateloggerhead nestingacti-vityfortheentireisland.Since1981,all361-km-long segmentscomprising theisland'scoastline havebeensurveyed.

-Regardless oftechnique, loggerhead nestdensities haveshownconsiderable annualvariation withinindividual surveyareas(Figures4and5).Yet,theannualspatialdistribution ofthosenestsamongsurveyareashaspro-16 ducedaratheruniformgradient, nestdensities consistently increasing fromnorthtosouth(ABI,1987).Thegradientappearstobelinearwhenonlythenine1.25-km-long surveyareasareused(Figure4),butbecomescurvilinear whenall361-km-long surveyareasareincludedintheanaly-sis(Figure5).During1987thedistribution ofloggerhead nestsalongtheislandfollowedthesamegeneralpatternaspreviously

reported, nestdensities increasing abruptlyfromnorthtosouthalongthenorthernpor-tionoftheisland,reachingmaximumdensities incentralsurveyareasandthendecreasing slightlytowardthesouthernportionoftheisland(Figure5).Inthepast,thepronounced gradientobservedonthenorthernendoftheislandwasoccasionally influenced byphysicalprocesses occurring there;periodsofheavyaccretion reducedthegradient, whileperiodsoferosionaccentuated it(WorthandSmith,1976;Williams-Walls etal.,1983).However,duringrecentyearsnoconsistent relationship wasapparentwhenfieldobservations ofbeachwidthswerecomparedtothe-spatialdistribution ofnestsalongtheisland(ABI,1987).Thus,eventhoughbeachdynamicsmaysometimes affecttheselection ofnestingsites1byloggerhead turtles,otherfactorsmustalsocontribute totheselec-tionprocess.Offshorebottomcontours, spatialdistribution ofnearshore reefs,typeandextentofdunevegetation, anddegreeofhumanactivityonthebeachatnighthavebeenidentified assomeofthefac-torsaffecting nesting(Caldwell, 1962;Hendrickson andBalasingam, 1966;Bustard,1968;BustardandGreenham, 1968;Hughes,1974;DavisandWhiting,1977;Mortimer, 1982).Relationships betweenspatialnesting17 patternsandspecificenvironmental conditions areoftendifficulttoestablish becauseoftheinterrelationship ofthefactorsinvolvedandmaybeobscuredbynestsitetenacity.

Schulz(1975)suggested thatnestsitetenacitymayforceadultfemalestomaintaintheirnestingsiteaslongaspossible, eventhoughthosesitesmaybeundergoing environmental changes.Notallventuresontothebeachbyafemaleturtleculminate insuc-cessfulnests.These"falsecrawls"(non-nesting emergences) mayoccurformanyreasonsandarecommonlyencountered atotherrookeries (BaldwinandLofton,1959;Schulz,1975;DavisandWhiting,1977;Talbertetal.,1980;Raymond,1984).DavisandWhiting(1977)suggested thatrelatively highpercentages offalsecrawlsmayreflectdisturbances orunsatisfac-torynestingbeachcharacteristics.

Therefore, certainfactorsmayaffectaturtle'spreference toemergeonabeach,whileotherfactorsmayaffectaturtle'stendencytonestafterithasemerged.Anindexwhichrelatesthenumberofneststothenumberoffalsecrawlsinanareaisusefulinestimating thepost-emergence suitability ofabeachfornesting.Inthepresentstudythisindexistermed"nestingsuccess"andisdefinedasthepercentage oftotalemergences thatresultinnests.Historically, thepatternofloggerhead emergences ontheislandhasparalleled thedistribution ofnests(ABI,1987),andthissametrendwasapparentin1987(Figure6).Incontrast, nestingsuccessbyloggerheads alongtheislandhastypically lackedgradients (Figure7).Thus,the18 0

relatively highnumbersofloggerhead nestsusuallyobservedalongthesouthernhalfoftheislandhaveresultedprimarily frommoreturtlescomingashoreinthatarearatherthanfrommorepreferable nestingcon-ditionsbeingencountered bytheturtlesaftertheyemerged.Hughes(1974)andBustard(1968)foundthatloggerheads preferred beachesadjacenttooutcropsofrocksorsubtidalreefs.Williams-Walls etal.(1983)suggested thatthenestinggradientonHutchinson Islandmaybeinfluenced bytheoffshorereefsiffemaleturtlesconcentrate onthereefsclosesttothebeachtorestorfeed.Theproximityofoffshorereefswouldputthegreatestconcentration ofturtlesnearthesouthernhalfoftheislandwherecoincidentally nestingishighest.Loggerhead nestingdensities during1987weregenerally withintherangeofvaluespreviouslyrecorded(Figures4and5).Twonotableexceptions includerecordlownestinginAreaFandrecordhighnestinginAreaJJ.LownestinginAreaFwasapparently duetopre-emergent aswellaspost-emergent factorssinceboththenumberofemergences andnestingsuccesswerelowduring1987(Figures6and7).Theremovalofconsiderable beachfront vegetation inAreaFbetweenthe1986and1987nestingseasonsoffersoneexplanation.

BaldwinandLofton(1959)indi-catedthatnestingturtlesshowapreference forbeachesbackedbyhighdunesorvegetation andahesitancy toemergeonbarrenbeaches.Anotherexplanation involvestheuseofthebeachatnightbyoffroadvehicles.

Althoughillegal,vehicular trafficonthebeachinArea19 Fwasconsiderable during1987.Turtlesareverysensitive toalarmingstimulibothpriortoemergingontoabeach(Schulz,1975)andduringtheirascentofthebeach(Hirth,1971).Amongthesealarmingstimuli,movinglightswillfrightennestingseaturtlesofallspecies(Mortimer, 1982).Lightsassociated withvehiclesonthebeachmayhavecontributed todecreases inboththenumberofemergences andnestingsuccess.Recordhighloggerhead nestinginAreaJJduring1987(Figure5)maybeattributable tounfavorable nestingconditions ontheadjacentnorthernsectionofbeach.Sandbagsinstalled inAreaIIbetweenthe1986and1987nestingseasonswereapparently responsible forahighnumberoffalsecrawlswhichaccounted fortherecordlownestingsuccessobservedinthatareaduring1987(Figure7).Thehighnumberofemergences inAreaII(Figure6)probablyreflectsrepeatedunsuccessful nestingattemptsbyindividual turtles.Manyoftheseturtlesprobablyreemerged inAreaJJwhere,becauseofmorefavorable beachconditions, theynested.In1987asinpreviousyears,loggerhead emergences wereleastnumerousinAreaAand.increased steadilyinasoutherly direction toaboutAreaK(Figure6).Thepresenceofdeepwaterclosetoshorehasbeensuggested asafactorwhichmightinfluence seaturtlestoemergeonparticular beaches(Hendrickson andBalasingam, 1966;Mortimer, 1982).Thedistancefromshoretothethirty-foot waterdepthcontourdecreases continuously fromAreaAthroughAreaF,andthismaypartially accountfortheobservedpatternofincreased emergences fromnorthtosouth20 alongthenorthendoftheisland.Furthermore, 1argepublicbeachaccessesinAreasAthroughC,combinedwithconsiderable artificial lightinginthoseareas,providethepotential forextensive andhighlyvisiblehumanactivityonthebeachatnight.Aspreviously stated,turtlesareverysensitive toalarmingstimulijustpriortoandduringemergences ontobeaches.Nighttime humanactivityintheseareasmaydeterturtlesfromemergingorfromnestingaftertheyemergeontothebeach,andmayhavecontributed tothesomewhatlowernestingsuccessobservedthere(Figure7).Historically, lownestingsuccessinthenorthernmost areashasbeenattributed tobeachcharacteristics suchaspersistent andextensive areasofverticalrelief(benches),

accumula-tionsofrocksandshells,andcompactsand.Apparently, acombination offactorsaffecting bothemergence andnestingsuccesshasbeenrespon-siblefortheextremely lownestdensities usuallyobservedalongthatpartoftheisland.Numbersofloggerhead emergences andconsequently nestdensities haveremainedrelatively lowinAreaZfrom1981through1987(Figures5and6).Sincethisareaincludesalargepublicbeachaccess,amotelandconsiderable artificial

lighting, nighttime humanactivitymaydeterturtlesfromcomingashore.NestingsurveysonHutchinson Islandwereinitiated inresponsetoconcernsthattheoperation oftheSt.LuciePlantmightnegatively impactthelocalseaturtlerookery.Previousanalyses, usinglog-likelihood testsofindependence (G-test;SokalandRohlf,1981)21 demonstrated thattheconstruction oftheplant'soffshoreintakeanddischarge structures significantly reducednestingattheplantsiteduringconstruction years(1975,1981,1982and1983;Proffittetal.,1986;ABI,1987).However,nestingattheplantconsistently returnedto1evelssimi1artoorgreaterthanthoseatacontrolsiteinyearsfol1owingconstruct ion(Figure8).TheG-testwasalsousedtoassesstheimpactsofpowerplantopera-tion,exclusive ofconstruct ion(ABI,1987).Thistestindicatedasignificant difference intherelativeproportion ofnestsbetweentheplantsite(Area4)andacomparable controlsite(Area5)whenbaselineyears(1971and1973)andoperational yearswithoutconstruction werecompared.

However,thisdifferenceresultedfromadisproportionately highnumberofnestsinArea4duringasingleyear(1986)ratherthanfromanylong-term declineinnestingresulting frompowerplantopera-tion.Whendatafrom1986wereexcluded, nosignificant difference be-tweenbaselineandoperational periods'eredetected.

Thesameresultswereobtainedwhen1987datawereincludedintheanalyses.

Datacollected through1987haveshownnolong-term reduction inloggerhead nestdensities, totalemergences ornestingsuccessineitherthenine1.25-km-long surveyareasorthe361-km-long surveyareas'Table1;Figure9).-22 NumberofNestsandLoerheadPoulationEstimates Variousmethodswereusedduringsurveyspriorto1981toestimatethetotalnumberofloggerhead nestsonHutchinson Islandbasedonthenumberofnestsfoundinthenine1.25-km-long surveyareas(Gallagher etal.,1972;WorthandSmith,1976;ABI,1980a).Eachofthesemethodsweresubsequently foundtoconsistently overestimate islandtotals(ABI,1987).Sincewhole-island surveysbeganin1981,ithasbeenpossibletodetermine theactualproportion of'otalnestsdeposited inthenineareas.Thishasthenallowedextrapolation fromtheninesurveyareastotheentireislandforyearspriorto1981.From1981through1987thetotalnumberofnestsinthenineareasvariedfrom33.1to35.6percentofthetotalnumberofnestsontheisland(Table1).Thisisslightlyhigherthanthe31.3percentwhichwouldbeexpectedbasedstrictlyontheproportion oflinearcoastline comprised bythenineareas.Usingtheseven-year meanof33.9percent,estimates ofthetotalnumberofnestsonHutchinson Islandcanbecalcu-latedbymultiplying thenumberofnestsinthenineareasby2.95.Thistechnique, whenappliedtotheninesurveyareasduringthesevenyearsinwhichtheentire'islandwassurveyed, producedwhole-island estimates withinfivepercentoftheactualnumberofnestscounted.Becausetheproportion ofnestsrecordedintheninesurveyareasremainedrelatively constantoverthelastsevenyears,thisextrapolation procedure shouldprovideafairlyaccurateestimateoftotalloggerhead nestingforyearspriorto1981.23 Itisclearthatloggerhead nestingactivityonHutchinson Islandfluctuates considerably fromyeartoyear(Table1);Annualvariations innestdensities alsoarecommonatotherrookeries (Hughes,1976;DavisandWhiting,1977;Ehrhart,1980)andmayresultfromtheoverlapping ofnon-annual breedingpopulations.

Duringthelastsixye'ars,however,annualnestproduction hasremainedrelatively high.Totalnestingacti-vitywasgreatestduring1986when5,483loggerhead nestswererecordedontheisland.During1987,4,623nestswerecounted.Norelationships betweentotalnestingactivityandpowerplantoperation orintake/di s-chargeconstruction wereindicated byyear-to-year variations intotalnestingonHutchinson Island.Inordertodetermine thetotalnumberoffemaleloggerhead turtlesnestingonHutchinson Islandduringagivenseason,anestimateofthenumberofnestsproducedbyeachfemalemustbedetermined.

Acomparison ofthenumberofnestsproducedbytaggedturtlesduringthe1975,1977and1979surveysindicated thatanaverageoftwonestsperfemalewastproducedduringanestingseason(ABI,1980a)..Thus,estimates ofthetotalnumbersoffemalesnestingduringprevioussurveyyearsmaybeobtainedbydividingthecalculated totalnumberofnestsbytwo.Basedonextrapolation estimates oftotalnesting,thenumberoffemaleloggerhead turtlesnestingonHutchinson Islandvariedfromapproximately 1,400to2,200individuals duringsurveyyears1971through1979.Usingwhole-island nestcounts,theestimated totalnumberofnestingfemalesvariedfrom1,558to2,742individuals between1981and1987.24

TemoralLoerheadNestinPatternsTheloggerhead turtlenestingseasonusuallybeginsinearlyMay,whenoceantemperatures reach23'o24'C,attainsamaximumduringJuneorJuly,andendsbylateAugustorearlySeptember (ABI,1987).Nestingactivityduring1987followedthissamepattern(Figure10).ShiftsinthetemporalnestingpatternonHutchinson Island.maybeinfluenced byfluctuations inwa'tertemperature.

Thiswasobservedduring1975and1982whenearlynestinginAprilcoincided withaverageoceantem-peratures above24"C(ABI,1983;Williams-Walls etal.,1983).Coolwaterintrusions frequently occuroverthecontinental shelfofsoutheast Floridaduringthesummer(TaylorandStewart,1958;Smith,1982).WorthandSmith(1976),Wil1iams-Walls etal.(1983)andABI(1982,1983,1984b,1985b,1986,1987)suggested thattheseintrusions mayhavebeenresponsible forthetemporary declinesinloggerhead turtlenestingactivitypreviously observedonHutchinson Island.Considerable decreases inoceantemperatures wererecordedattheSt.LuciePlantduringJuneandearlyAugust1987(Figure10).Asubstantial decreaseinnestingontheislandcorresponded withthelatterofthesecoolwaterintrusions.

Todetermine ifplantoperation hasaffectedthetimingofnestingactivity, seasonalnestingpatterns(nestdensityonamonth-to-month basis)forArea4(plantsite)andArea5(controlsite)werecomparedstatistically duringeachstudyyear(Kolmogorov-Smi rnovtest;SokalandRohlf,1981).Nosignificant (P<0.05)differences weredetectedbetween~~25

areasduringanystudyyear,eitherbeforeorafterthepowerplantbeganoperating.

Theresultsoftheseanalysesindicatethatplantoperation hasnotsignificantly affectedtemporalnestingpatternsadjacenttotheplant.Predation onLoerheadTurtleNestsSincenestsurveysbeganin1971,raccoonpredation probablyhasbeenthemajorcauseofturtlenestdestruction onHutchinson Island.Researchers atotherlocations havereportedraccoonpredation levelsashighas70tonearly100percent(DavisandWhiting,1977;Ehrhart,1979;Hopkinsetal.,1979;Talbertetal.,1980).Raccoonpredation ofloggerhead turtlenestsonHutchinson Islandhasnotapproached thislevelduringanystudyyear,thoughlevelsforindividual 1.25-km-long areashavebeenashighas80percent(Figure11).Overallpredation ratesfor-surveyyears1971through1977werebetween21and44percent,withthehighof44percentrecordedin1973.Apronounced decreaseinraccoonpredation occurredafter1977,andoverallpredation ratesforthenineareashavenotexceeded10percentsince1979.Adeclineinpredation ratesonHutchinson Islandhasbeenvariously attributed totrappingprograms, construction activities, habitatlossanddisease(Williams-Walls etal.,1983;ABI,1987).During1987,sevenpercent(304)oftheloggerhead nests(n=4,623) ontheislandweredepredated byraccoons.

Asinpreviousyears(ABI,1987),predation ofturtienestswasprimarily restricted tothemostundeveloped portionoftheisland(i.e.,AreasfthroughU)andthesouthernmost areas(AreasIIandJJ;Figure12).26 Ghostcrabshavebeenreportedbynumerousresearchers asimportant predators ofseaturtlenests(BaldwinandLofton,1959;Schulz,1975;Diamond,1976;Fowler,1979;Hopkinsetal.,1979;Stancyk,1982).ThoughturtlenestsonHutchinson Islandprobablyhavebeendepredated byghostcrabssincenestingsurveysbeganin1971,thissourceofnestdestruction didnotbecomeapparentuntil1983.guantification ofghostcrabpredation wasinitiated thesameyear.Overallpredation ratesbyghostcrabshavevariedfrom0.3to2.1percentduringthelastfiveyears(ABI,1987).During1987,0.3percent(15)oftheloggerhead nests(n=4,623) ontheislandweredestroyed byghostcrabs(Figure12).Nestsdestroyed byacombination ofraccoonandghostcrabpredation havebeenincludedasraccoonpredations inpreviousdiscussions.

Whenthesecombination predations areincludedascrabpre-dations,theoverallpredation ratesbyghostcrabsrangefrom1.5to3.2percent.During1987,1.5percent(71nests)weredestroyed byeitherghostcrabsoracombination

'ofghostcrabsandraccoons.

GreenandLeatherback TurtleNestinGreenand,leatherback turtlesalsonestonHutchinson Island,butinfewernumbersthanloggerhead turtles.Priorto1981,bothsurvey(nine1.25-km-long sections) andinter-survey areasweremonitored forthepre-senceofgreenandleatherback nests.Thirty-one kilometers ofbeachfromArea1southtotheSt.Lucieinletwereincludedinthateffort.Duringwholeislandsurveysfrom1981through1987,onlytwoof101leatherback nestsandonlyfourof350greennestswererecordedonthe27

fivekilometers ofbeachnorthofArea1.Therefore, previouscountsofgreenandleatherback nestswithinthe31kilometers surveyedwerepro-bablynotappreciably differentfromtotaldensities fortheentireisland.Basedonthisassumption, greenandleatherback nestdensities maybecomparedamongallsurveyyears,except1980,whenlessthan15kilometers ofbeachweresurveyed.

Priorto1987,thenumberofnestsobservedontheislandrangedfrom5to68forgreenturtlesandfrom1to20forleatherbacks (Figure13).Duringthe1987survey,72greenturtleand18leatherback turtlenestswererecordedonHutchinson Island.Temporalnestingpatternsforthesespeciesdifferfromthepatternforloggerhead turtles.Greenturtlestypically nestonHutchinson Islandfrommid-JunethroughthefirstorsecondweekofSeptember.

During1987,greenturtles.nestedfrom15Junethrough9September.

Leatherback turtlesusuallynestontheislandfrommid-April throughearlytomid-July.

During1987thisspeciesnestedfrom3Maythrough20July.Considerable fluctuations ingreenturtlenestingontheislandhaveoccurredamongsurveyyears(Figure13).Thisisnotunusualsincetherearedrasticyear-to-year fluctuations inthenumbersofgreenturtlesnestingatotherbreedinggrounds(Carretal.,1982).Despitethesefluctuations, greenturtlenestinghasremainedrelatively highduringthelastsixyears(1982through1987)andmayreflectanincreaseinthe28 numberofnestingfemalesintheHutchinson Islandarea.During1987,greenturtlesnestedmostfrequently alongthesouthernhalfoftheisland.Thisisconsistent withresultsofprevioussurveys.Leatherback turtlenestdensities haveremainedlowonHutchinson Island;however,densities duringthelasteightsurveyyearshavebeenhigherthanduringthefirstfoursurveyyears(Figure13).ThismayreflectanoverallincreaseinthenumberofnestingfemalesintheHutchinson Islandarea.During1987,leatherback turtlesprimarily nestedonthesouthernhalfoftheislandbetweenAreasBBandGG(Figure3).IntakeCanalMonitorin Entrainment ofseaturtlesattheSt.LuciePlanthasbeenattri-butedtothepresumedphysicalattractiveness oftheoffshorestructures housingtheintakepipesratherthantoplantoperating characteristics (ABI,1980band1986).Evenwhenbothunitsareoperating atfullcapa-city,turtlesmustactivelyswimintooneoftheintakepipesbeforetheyencounter currentvelocities sufficiently strongtoeffectentrainment.

Consequently, aturtle'sentrapment relatesprimarily totheprobability thatitwilldetectandsubsequently enteroneoftheintakestructures.

Assumingthatdetection distances donotvaryappreciably overtimeandthatallturtles(oraconstantproportion) areequallyattracted tothestructures, capturerateswillvaryproportionately tothenumberofturtlesoccurring inthevicinityofthestructures.

Ifthisassumption istrue,datafromthecanalcaptureprogramshouldreflectnaturalvariability inthestructure ofthepopulation beingsampled.29 SeciesNumberandTemoralDistribution During1987,218seaturtlecapturestookplaceintheintakecanaloftheSt.LuciePlant(Table2).Fourofthefivespeciesofseaturtlesoccurring incoastalwatersofthesoutheastern UnitedStateswererepresented inthecatches,including 175loggerheads, 35greens,2hawksbills and6Kemp'sridleys.Sinceintakecanalmonitoring beganinHay1976,1,497loggerhead (including 79recaptures),

227green(including 1recapture),

8leatherback, 6hawksbill and10Kemp'sridleycaptureshavebeenreportedfromtheSt.LuciePlant.Annualcatchesofloggerheads increased steadilyfromalowof33in1976(partialyearofplantoperation andmonitoring) to173in1979~~(Figure14).Afterdeclining between1979and1981,yearlycatchesof1oggerheads againrosesteadily, reachingahighof195during1986.Capturesin1987weredownslightlyfrom1986.Twooffshoreintakestructures wereinplacepriortoUnit1start-upin1976;thethirdandlargeststructure wasinstalled during1982-1983.

Eventhoughallthreestructures areinrelatively closeproximity, theadditionofanotherpipemayhaveincreased theprobabi1-ityofaturtlebeingentrained.

Becausethischangecannotbequan-tified,datacollected priorto1982maynotbecomparable withthatcollected after1983.Nevertheless, thegeneralriseincanalcapturessince1981,evenafterthethirdstructure wascompleted, suggestsagenuine,long-term increaseinthenumberofturtlesoccurring neartheplant.30 i

During1987,themonthlycatchof1oggerheadsrangedfrom3(October) to26(JanuaryandJune),withamonthlymeanof14.6(+8.9;Table3).CapturesduringApril,MayandJuneweremuchhigherthanhistorical averagesforthosemonths,whilecapturesduringSeptember andOctoberweremuchlowerthanaverage(Figure15).Overtheentiremoni-toringperiod,monthlycatcheshaverangedfrom0to39;thegreatestnumberofcapturesoccurredduringJanuary1983.Whendatafromallfullyearsofmonitoring (1977-1987) werecom-bined,themajorityof1oggerheadswerecapturedinJanuary(13.2percent);

fewestcapturesoccurredduringNovemberandDecember(Table3).However,monthlycatcheshaveshownconsiderable annualvariability.

~~Monthshavingrelatively lowcatchesoneyearoftenhavehadrelatively highcatchesinanother..Catchesofgreenturtlesalsohavevariedwidelyamongyears,rangingfrom0in1976(partialyearofsampling) to69in1984(Table4).During1987,35individuals werecaptured.

Theaverageannualcatchofgreenturtles,excluding 1976,was20.6(+19.4).Noconsistent trendsinannualcatchesareevidentfromthedata(Figure14).Green,turtleshavebeencaughtduringeverymonthoftheyear,withaveragemonthlycatchesforallyearscombinedrangingfrom0.3inMayto7.1inJanuary(Table4).However,seasonalabundance patternsofgreensaremuchmorepronounced thanforloggerheads, nearly75percentofallcapturesoccurring betweenNovemberandMarch.During1987,thelargest.31 0

numberofgreens(11)werecapturedinDecember.

caughtinonemonthwas37inJanuary1984.ThemostgreenseverCatchesofleatherbacks, hawksbills andKemp'sridleyshavebeeninfrequent andscattered throughout theelevenyearstudyperiod(Table2).Eachspecieshasshownratherpronounced seasonaloccurrences; allbutoneoftheeightleatherbacks werecollected betweenFebruaryandMay,fiveofthesixhawksbills werecollected betweenJuneandSeptember, andallbutoneofthe10Kemp'sridleyswerecaughtbetween~DecemberandApril.Size-Class Distributions Todate,liveloggerheads removedfromtheintakecanalhaverangedinlength(SLCL)from40.4to112.0cm(x=65.2+12.3cm)andinweightfrom10.9kgto154.7kg(Figures16and17).About75percentofallliveloggerheads capturedwere70cmorlessinlengthandweighedlessthan100pounds.Acarapacelengthof70cmapproximates thesmallestsizeofnestingloggerhead femalesobservedalongtheAtlanticeastcoast(Hirth,1980).However,adultscanonlybereliablysexedonexternalmorphological characteristics (e.g.,relativetaillength)afterobtaining alengthofabout80cm.Basedonthesedivisions,dataweresegregated intothreegroups:juvenile/sub-adults

(<70cm;thedemarcation betweenthesetwocomponents isnotwellestablished intheliterature),

adults(>80cm)andtransitional (70-80cm).Thelattergroupprobablyincludessome32 JIL matureandsomeimmatureindividuals.

Ofthe1,348capturesforwhich1engthdatawerecollected, 75percentwerejuveni1es/sub-adul ts,themajorityofthesemeasuring between50and70cmSLCL(Table5).Theremaining 25percentwasdividednearlyequallybetweenadultsandindi-vidualsinthetransitional sizeclass.Similarsize-frequency distribu-tions,indicating apreponderance ofjuveniles, havebeenreportedfortheMosquito/Indi anRiverLagoon(Mendonca andEhrhart,1982),theCanaveral shipchannel(OgrenandMcVea,1982),GeorgiaandSouthCarolina(Hi1lestadetal.,1982)andsuggestthatcoastalwatersofthesoutheastern UnitedStatesconstitute animportant developmental habitatforCarettacaretta.Seasonalpatternsofabundance forvarioussizeclassesindicated thatjuveniles andsub-adult loggerheads wereslightlymoreabundantduringthewinterthanatothertimesoftheyear(Table5).About37percentofjuvenile/sub-adult loggerheads werecapturedbetweenJanuaryandMarch,theremainder beingratherevenlydistributed amongothermonths.Theseasonaldistribution ofadult.loggerheads wasmuchmorepronounced, 60percentofallcapturesoccurring betweenJuneandAugust.Thisrepresents theperiodofpeaknestingonHutchinson Island.Ifothernestingmonthsareincluded(MayandSeptember),

75percentofalladultswerecapturedduringthenestingseason.Greenturtlesremovedalivefromtheintakecanalovertheentirestudyperiodrangedinsizefrom20to108cmSLCL(x=36.9+15.1cm)and0.9kgto177.8kg(Figures18and19).Nearlyall(96percent)were33 juveniles orsub-adults.

Over75percentwere40cmorlessinlength,and60percentweighedlessthan10pounds.Theseimmatureturtlesexhi-biteddistinctwinterpulsessuggesting migratory behavior(Table4).However,someimmaturegreenturtleswerepresentthroughout theyear.Todate,onlysixadultgreenturtles(SLCL>83cm;Witherington andEhrhart,inpress)havebeenremovedfromthecanal;allwerecapturedduringorshortlyafterthenestingseason.Fiveofthesixhawksbills andalltenKemp'sridleysremovedfromthecanalwereimmature, ranginginsizefrom34to46cmSLCL(6.4-12.7 kg)and27to47cmSLCL(3.2-15.4 kg),respectively; theadulthawksbill (SLCL>53cm;Hirth,1980)hadaSLCLof70cmandweighed52.2kg.Theeightleatherbacks removedfromthecanalrangedinlengthfrom112.5to150cm,andatleastsixwereadults(SLCL>121cm;Hirth,1980).Thelargestleatherback forwhichanaccurateweightwasobtained, amalewithaSLCLof134.5cm,weighed233.6kg.SexRatiosSinceintakecanalmonitoring beganin1976,198adultloggerheads havebeensexed.Thesmallestwas75.5cminlengthandwasobservednestingonHutchinson Islandsubsequent toher.captureinthecanal.Femalespredominated malesbyaratioof4.9:1.0,whichsignificantly departsfroma1:1ratio(X2,P<0.05).Consequently, temporalpatternsinthenumberofadultloggerhead capturesareheavilyinfluenced bythenumbersoffemalespresent.Whensexeswereseparated, itisevidentthatmaleswererelatively evenlydistributed amongdifferent

months,

[1I whereasnearly80percentofthefemalesweretakenduringthenestingseason(MaythroughSeptember; Figure20).Thenumberofadultloggerheads capturedattheSt.LuciePlantincreased appreciably after1982.Between1976and1982,anaverageof7.4adultloggerheads

(+4.4;range=2-15)wereentrapped eachyear,whereasoverthelastfive.years,anaverageof30.0adultsperyear(+8.9;range=19-40)werecaptured.

Thisincreasecorresponds toageneralriseinloggerhead nestingneartheplant(Figure21).Theyear1986represented thehighestnumberofnestseverrecorded, bothfortheentireislandandattheplantsite(Area4),andmoreadultfemales(35)wereentrapped inthecanalthaneverbefore.Thisassociation isnotunexpected, becauseincreased nearshore movementassociated withnestingbehaviorincreases theprobability ofaturtledetecting oneoftheintakestructures andhencetheprobability ofentrainment.-

Theadditionofthethirdoffshoreintakestructure, thelargestofthethreestruc-tures,in1982alsomayhavecontributed toincreased entrainment ofadults.SinceSeptember 1982,258juvenileandsub-adult loggerhead turtlescapturedinthecanalhavebeensexedbyTexasA8NUniversity researchers usingabioimmunoassay technique forbloodserumtestosterone.

Forthepurposeoftheseanalyses, Dr.Owensandhisasso-ciatesused76cmasthecutofflengthbetweenimmatureandadultturtles.Bioimmunoassay resultsindicatethatforimmatureloggerheads removedfromtheSt.LuciePlantintakecanal,femalesoutnumbered ma'les35 I

byaratioof2.7:1.0.Thesexratiosofimmatureloggerheads capturedintheCapeCanaveral shipchannel(1.7:1.0) andtheIndianRiverLagoon(1.4:1.0)arealsoreportedtobesignificantly skewedinfavoroffema-les(X2,P<0.05;Wibbelsetal.,1984).Ofthesixadultgreenturtlescapturedsincemonitoring began,fourweremalesandtwowerefemales.Siximmaturegreenturtleshavebeensexedthroughbloodwork;allhavebeenfemales.Ofthefiveadultleatherback turtlesforwhichsexwasrecorded, twowerefemalesandthreeweremales.Theonlyhawksbill thusfarsexedwasafemale.Nosexinformation existsforKemp'sridleys.CatureEfficiencies Capturemethodologies evolvedoverthefirstseveralyearsofintakecanalmonitoring asnetmaterials, configurations andplacement werevariedinanefforttominimizeseaturtleentrapment times.Concurrently, alternative capturetechniques wereevaluated andpotential deterrent systemstestedinthelaboratory.

Duringthisperiod,captureefficiencies variedinrelationtonettingeffortandtheeffectiveness ofthesystemsdeployed.

Acapture/recapture studyconducted intheintakecanalbetweenOctober1980andJanuary1981indicated thatmostturtlesconfinedbe-tweentheAIAbridgeandtheintakeheadwalls werecapturedwithintwoweeksoftheirentrainment (ABI,1983).Basedonmorerecentformaldailyinspections, itappearsthatcaptureefficiencies havefurther36 improved.

Mostturtlesenteringthecanalarenowcaughtwithinafewdaysoffirstsighting, andinmanyinstances, turtleshavebeencaughtinthetanglenetswithoutanypriorsighting, suggesting residency timesoflessthan24hours.Betterutilization ofcurrentsandeddies,adjustments totethering linesandmulti-net deployments havecontributed toreducedentrapment times.Entrapment timesmaybeextendedforturtlesswimmingpasttheA1Abarriernet(ABI,1987).Occasionally, thetopofthenethasbeensub-mergedortheanchorcablepull,edfreefromthebottom,allowinglargerturtlestopass;turtleswithcarapacewidthslessthanabout30.5cmcanswimthroughthelargemesh.BecausecaptureeffortswestoftheA1Abridgehavegenerally beenlesseffective thanthoseneartheintakeheadwalls, mostturtlesbreaching thebarriernetwerenotcaughtuntiltheyenteredtheintakewellsofUnits1and2.Sincethecanalcaptureprogrambegan,about15percentofallturtlesentrapped inthecanalhavebeenremovedfromtheintakewells.Becauseoftheirrelatively smallsizes,agreaterproportion ofgreens(47.6percent)reachedtheplantthanloggerheads (9.4percent).

Aftercompletion ofthesecurityintrusion barrierinDecember1986,mostturtleslargerthan30.5cmincarapacewidthwereprevented fromreachingtheintakewells.During1987,onlysevenloggerheads wereremovedfromtheplant,allduringJanuaryandFebruary.

Theseturtleswerepresumably trappednorthoftheintrusion barrier(Figure2)beforeitwascompleted.

Anadditional 15loggerheads wereremovedfromthe37 canalwestoftheA1Abarriernetduring1987;12werehand-captured atorneartheintrusion barrier,twowerecaughtintanglenetssetwestoftheA1Abridge,andonewashedupalongthebank.Atotalof11greenturtlesmadeitpasttheA1Abarriernetduring1987.Ninewereremovedfromtheintakewells,onewashand-captured neartheintrusion barrierandonewascaughtinatanglenetsetwestoftheA1Abridge.FourKemp'sridleyswerealsocapturedwestoftheA1Abarriernetduring1987,allattheUnit1and2intakewells.Tomaximizeconfinement oflargerturtlestotheeasternmost sectionoftheintakecanal,andtherebyincreaseoverallcaptureefficiency, theA1Abarriernethasbeenperiodically surveyedand,asrequired, appropriate measurestakentoensureitsintegrity.

Suchanadjustment wasmadeduringAugust/September 1985(ABI,1987).During1987,thebarriernethadtobedismantled betweenAprilandJunebecauseofconstruction activities inthecanal.Itwasultimately replacedwithanewnetinNovember1987.RelativeCondition Turtles"capturedaliveintheintakecanaloftheSt.LuciePlantwereassignedarelativecondition basedonweight,activity, parasiteinfestation, barnaclecoverage, wounds,injuriesandanyotherabnor-malitiess whichmighthaveaffectedoverallwell-being (Table6).During1987,86.3percent(151)ofallloggerheads foundinthecanalwerealiveandingoodtoexcellent condition.

Only7.5percent(13)ofloggerhead capturesinvolvedindividuals infairorpoorcondition; 6.3percent(11)oftheloggerheads removedfromthecanalweredea'd.38 Ofthe35greenturtlesremovedfromtheintakecanalduring1987,85.7percent(30)wereingoodtoexcellent condition, whileonly14.3percent(5)wereinfairorpoorcondition.

ThreeofthesixKemp'sridleyscaughtduring1987wereingoodtoexcellent condition, onewasinfaircondition andtwoweredead.Bothhawksbills capturedduring1987wereinexcellent condition.

Overtheentiremonitoring period,about70and80percent,respec-tively,ofal1loggerhead andgreencaptureshaveinvolvedturtlesingoodtoexcellent condition (Table6).Capturesofindividuals infairtopoorcondition haveoccurredabout22percentofthetimeforlogger-headsand13percentofthetimeforgreens.Allofthehawksbil1sandallbutone1eatherback havebeenremovedfromthecanalingoodtoexcellent condition.,

Although60percentoftheKemp'sridleyshavebeeningoodtoexcellent condition, allcategories havebeenrepresented inthecatches.Relativecondition ratingscanbeinfluenced byanumberoffactors,somerelatedandothersunrelated toentrainment and/orentrapment intheintakecanal.Ratingsofgoodtoexcellent indicatethatturtleshavenotbeennegatively impactedbytheirentrapment inthecanal,atleastasevidenced byphysicalappearance.

Althoughratingsoffairorpoorimplyreducedvitality, theextenttowhichentrainment/entrapment isresponsible isoftenindeterminable.

Insomeinstances, conditions responsible forlowerratings,suchasinjuries, obviouslyweresustained priortoentrainment.

39

During1987,about13percentofallcapturesinvolvedindividuals withsevereinjuries, including missingappendages, brokenormissingpiecesofcarapaceordeeplacerations.

However,nearlyallofthesewereold,wel1-healedwounds.Sharkattacksappearedtohavebeenresponsible foralargepercentage oftheinjuries, asevidenced bycrescent-shaped bitemarks.Oneturtlehadobviouspropeller scarsonthecarapace.

Althoughmanyturtlesremovedfromthecanalduring1987hadoneormorerecentsuperficial abrasions tothecarapaceorskin,onlytwoindividuals appearedtohavesustained seriousinjuriesasaresultoftheirentrainment/entrapment.

Bothweretreated,heldforobservation andsubsequently released.

Onceinthecanal,anindividual's relativecondition appearstoberelatedtothelengthoftimeitremainsentrapped (ABI,1987).Asindi-catedearlier,entrapment periodsarerelatively shortforturtlesremaining betweentheA1Abarriernetandintakeheadwalls, whileresi-dencytimesincreaseforthoseindividuals breaching thebarriernet.Previouscomparisons havedemonstrated thattheproportion ofloggerheads ingoodtoexcellent condition isgreaterforindividuals caughtinthetanglenetsthanforindividuals removedfromtheintakewells(ABI,1987).Loggerheads haveatendencytoorientagainstcurrentsinthecanal,oftenrestingnearsubmerged structures.

Forindividuals westoftheA1Abridge,thisbehaviorprolongstheirtransport totheintakewellsandtherebyextendstheirresidency times.40 Becausegreenturtlesentrapped inthecanalarerelatively small,theirmovements aremoreeasilyinfluenced bycurrents.

Individuals passingthroughthebarriernetprobablyarriveattheintakewellsinarelatively shortamountoftime.Consequently, themeanrelativecon-ditionofgreenturtlescaughtbytanglenetsdoesnotdifferappreciably fromthemeancondition ofindividuals removedfromtheintakewells(ABI,1987).Therelativecondition assignedtoaturtleisasubjective assess-mentpronetosomevariation amongobservers andisbasedsolelyonphy-sicalappearance.

Aturtle'sphysicalappearance mayormaynotrelatetoitsphysiological health.Thus,measuresofphysiological condition aredesirable.

Bloodhemoglobin levelshavebeenmeasuredinturtlesremovedfromtheintakecanalsinceSeptember 1982.During1987,valuesrangedfromlessthan4.0to14.9g/100ml(n=80).Themeanforturtlesinexcellent condition was10.1g/100ml(+1.52;n=38),whilethemeanvalueforindi-vidualsinfaircondition wasonly8.2g/100ml(+2.36;n=3).Althoughpreviousanalyseshavealsoindicatedageneralassociation betweenrela-tivecondition andhemoglobin value,theoverlapinrangesbetweengroupshasbeenconsiderable (ABI,1987).Todate,therehavebeennosignificant differences inthemeanHbvaluesbetweenrelativecondition categories.

Frair(1977)reportedthatmanyfactors,suchastemperature, sex,sizeandactivity, canaffectanindividual turtle'sbloodchemistry irrespective ofgeneralhealth.Thus,hemoglobin datatakencollectively fromtheentirepopulation overdifferent seasonsandenvironmental con-ditionsprobablymasksdifferences whichmightotherwise beattributable todifferences inhealthamongindividuals withindistinctsegmentsofthepopulation.

Asthedatabasecontinues togrow,hemoglobin valuescanbepartitioned bysizeclasses,sexandseasontoreducevariability andthusproduceabettergaugeofrelativehealthwithineachsub-group.

Mortalities During1987,11loggerhead mortalities (6.3percentofallloggerhead captures) wererecordedintheintakecanal.Eightoftheseturtleswereremovedfromthesecurityintrusion barrier,twowerefoundfloatingagainsttheA1AbarriernetandonewasheduponthecanalbankwestofA1A.TwoKemp'sridleymortalities alsooccurredintheintakecanalduring1987;onewasremovedfromtheintakewellsandthe,otherfromaturtlenet.Nomortalities tootherspecieswererecordedduring1987.Overtheentire12yearmonitoring period,116(7.7percent)ofthe1,322loggerheads and16(7.0percent)ofthe227greenturtlesentrapped inthecanalwerefounddead(Table2).Mortalities spannedtherangeofsizeclassesforloggerheads (SLCL=47.5-125cm),whileallgreenturtlemortalities involvedjuveniles lessthan41cminlength.Thetwojuve-nileKemp'sridleymortalities documented attheplantduring1987were42 theonlydeathsforthisspeciessincemonitoring began;noleatherback orhawksbill mortalities haveoccurredattheSt.LuciePlant.Mortalities havebeencloselymonitored throughout thelifeofthecanalcaptureprograminanattempttoassignprobablecausesandtake'ppropriate corrective measurestoreducefutureoccurrences.

Previousanalysesofdatacollected fromturtlescapturedbetween1976and1986identified drowninginnets,drowningintheintakepipesduringperiodsofreducedintakeflow,injuriessustained fromdredgingoperations andinjuriessustained fromthemechanical rakesusedintheintakewellsasprobablemortality factors(ABI,1987).Althoughdifficult toquantify, theentrapment andsubsequent demiseofinjuredorsickturtlesalsopro-bablyaccountsforaportionofobservedmortalities.

Overtheyears,materials andprocedures havebeenmodifiedtoreducethepotential foraturtledrowningduringcapture.Leadlineshavebeenremovedfromthenetsanddeployment techniques alteredtoallowturtleseasiermovementafterentanglement.

Surveillance ofthenetshasalsoincreased.

However,evenwiththeseprecautions, aturtlehasoccasionally drowned.Inrecentyears,thishasoccurredprimarily whenasmallturtlehasbecomeentangled withoneormorelargerindivi-duals,apparently restricting itsmovementandabilitytosurface.Suchanincidentoccurredon10June1987,asajuvenileKemp'sridleybecameentangled inanetatnightwithtwolargerloggerheads.

Overthe12yearhistoryofthecanalcaptureprogram,onlyeightofthemorethan1,700turtlesentrapped inthecanalhavedrownedasaresultofnettingactivities.

Mostrecentmortalities intheintakecanalapparently resultedfromdrownings attheA1Abarriernetandthenewlyconstructed securityintrusion barrier.Adramaticincreaseinloggerhead mortalities between1985and1986(Table2)wasthoughttohavebeenrelatedtoadjustments madetotheA1Abarriernetduringthelatterpartof1985(ABI,1987).Presumably, theseadjustments increased theprobability ofaturtledrowning.

Asapreventive measure,largeholeswerecutinthebarriernettoprovideescapehatchesforturtlestrappedagainstitbystrongcurrents.

Concurrently, plansweremadetoinstallanewbarriernet,usingadifferent methodofdeployment.

Asaresultofthebarriernet'sgeneralineffectiveness duringmuchof1987,largerturtleswhichotherwise wouldhavebeenconfinedeastoftheAlAbridgewerepermitted freeaccesstothatportionofthecanalwherecaptureeffortsarelesseffective.

Twelveoftheseturtleswereeventually removedfromthecanalatthesecurityintrusion barrier;eightweredead.Theliveindividuals removedfromtheintrusion barrierweretangledinitsmeshorotherwise pinnedagainstitbystrongcurrents, andgenerally showedsignsofinjuriesorweakenedcondition.

Sickorinjuredturtlescontacting thenetbelowthewater'ssurfacemaybeunabletosurfaceandthusareprobablymoresusceptible todrowningthanhealthyindividuals.

Concurrent withtheremovaloftheA1Abarriernet,surveillance andcaptureeffortsinthecanalwereintensified, including multi-net deployments westofA1Aanddeployment ofnetsovertheweekends.

Nologgerhead capturesoccurredwestoftheA1AbridgeafterAugust1987andanewbarriernetwasinstalled duringNovemberofthatyear.

Inadditiontothe11loggerhead mortalities recordedduring1987,twoturtlesremovedfromthecanalinpoorcondition laterdied.Bothwereveryemaciated andweresolethargic theycouldbehand-captured.

Onehadnumerousoldwounds.Anecropsyperformed ontheindividual withoutwoundsprovidednocluesastothecauseofdeath.However,both'fturtleshadbeeninthecanalforarelatively shortperiod(basedondailyobservations),

indicating theyweresickbeforetheirentrapment.

Bothwereheavilyencrusted withbarnacles andhadnumerousparasites.

Thisisacondition oftenseeninstrandedindividuals wherenoapparentwoundsorinjuriesarepresentandmaybeindicative ofpoorhealth.Thecaptureofterminally illturtlesinthecanallendssupporttotheideathatatleastaportionofthemortalities occurring inthecanalmaybearesultofpre-entrainment conditions.

Undoubtedly, pre-existing injuriesandillnesses contribute tosomeofthecanalmortalities.

TwoKemp'sridleymortalities occurredintheintakecanalduring1987.Thedrowninginthetanglenetwasdiscussed earlier.Theothermortality wasrecordedattheplantintakewells.Similartothecon-ditionofmanyoftheloggerheads removedfromtheintrusion barrier,thisindividual wasemaciated andapparently inillhealth.Strongcurrentsinthevicinityoftheintakewellsmayhaveresultedinitsdrowning.

Althoughanecropsywasperformed, causeofdeathcouldnotbepositively determined.

45 0

RecatureIncidents SincetheSt.LuciePlantcaptureprogrambegan,mostturtlesremovedalivefromtheintakecanalhavebeentaggedandreleasedintotheoceanatvariouslocations alongHutchinson Island.Consequently, individual turtlescanbeidentified aslongastheyretaintheirtags.Overthe12yearhistoryofturtleentrapment attheSt.LuciePlant,48individuals (47loggerheads and1green)'havebeenremovedfromthecanalmorethanonce.Severalotherturtleswithtagscarshavealsobeenremoved,indicating thattheactualnumberofrecaptures maybehigher.Ofthe47individual loggerheads knowntohavebeencaughtmorethanonce,33werecaughttwice,sixwerecaughtthreetimes,fourwerecaughtfourtimes,twowerecapturedsixtimesandtwowerecaughtonsevenseparateoccasions, yieldingatotalof79recapture incidents.

Releasesitedidnotappeartohaveanyeffectonaturtle'sprobability ofbeingrecaptured.

Turtlesreleasedbothnorthandsouthoftheplantreturned.

Recaptures alsodidnotappeartoberelatedtosize,asbothjuveniles andadultswerecapturedmorethan.once(rangeofSLCL=47-89cm).However,themajorityofrecapture incidents involvedjuveniles andsub-adults(SLCL<70cm).Recapture intervals forloggerheads rangedfromfourto858days,withameanof143days(+161.5days).Theonlygreenturtlecaughtmorethanoncewascapturedontwooccasions, returning tothecanal59daysafterfirstbeingreleasedintotheocean.About57percentofallloggerhead recapture incidents occurredwithin90daysofpreviouscap-46 tureand91percentwithinoneyear(Figure22).Theaverageintervalbetweenfirstandlastcapturewas245days(+267.4days).Thesedatasuggestthatresidency timesofloggerheads withinthenearshore habitatadjacenttotheSt.LuciePlantarerelatively short.Similarfindingshavebeenreportedforloggerheads inhabiting theMosquito/Indian RiverLagoonsofeast-central Florida(Mendonca andEhrhart,1982).SUMMARYAgradientofincreasing loggerhead turtlenestdensities fromnorthtosouthalongthenorthernhalfofHutchinson Islandhasbeenshownduringallsurveyyears.Thisgradientmayresultfromvariations inbeachtopography, offshoredepthcontours, distribution ofnearshore reefs,onshoreartificial lightingandhumanactivityonthebeachatnight.Lownestingactivityinthevicinityofthepowerplantduring1975andfrom1981through1983wasattributed toconstruction ofpowerplantintakeanddischarge systems.Nestingreturnedtonormalorabovenormallevelsfollowing bothperiodsofconstruction.

Powerplantopera-tion,exclusive ofintake/discharge construction, hashadnosignificant effectonnestdensities.

Therehavebeenconsiderable year-to-year fluctuations inloggerhead nestingactivityonHutchinson Islandfrom1971through1987.Fluctuations arecommonatotherrookeries andmayresultfromoverlapping ofnon-annual breedingpopulations.

Despitethesefluc-tuations, loggerhead nestingactivityhasremainedrelatively highduringthelastsixyears.Norelationship betweentotalnestingandpowerplantoperation orintake/discharge construction wasindicated.

47

ResultsofthreeyearsoftaggingstudiesonHutchinson Islandindi-catedthatanaverageoftwonestsperyearwereproducedbyeachnestingloggerhead turtle.Basedonthisaverage,thenestingpopulation ofloggerhead turtlesontheislandhasvariedfromapproximately 1,400individuals in1977toover2,700in1986.Thoughtemporalnestingpat-ternsoftheHutchinson Islandpopulation maybeinfluenced byfluc-tuationsinwatertemperature, nosignificant effectsduetopowerplantoperation havebeenindicated.

Sincenestsurveysbeganin1971,raccoonpredation wasconsidered themajorcauseofturtlenestdestruction onHutchinson Island.From1971through1977,overallpredation ratesintheninesurveyareaswerebetween21and44percent.However,apronounced decreaseinraccoonpredation occurredafter1977,andoverallpredation ratesintheninesurveyareashavenotexceededtenpercentsince1979.Decreased preda-tionbyraccoonsprobablyreflectsadeclineintheraccoonpopulation.

During1987,.72greenturtleand18leatherback turtlenestswererecordedonHutchinson Island.Greenturtlenestingactivityexhibited considerable annualfluctuations, ashasbeenrecordedatotherrookeries, buthasremainedrelatively highduringthelastsixyears.Annualleatherback nestdensities duringthelasteightsurveyyearswerehigherthanthepreviousfoursurveyyears.During1987,175loggerheads, 35greenturtles,2hawksbills and6Kemp'sridleyswereremovedfromtheSt.LuciePlantintakecanal.Since48 monitoring beganinMay1976,1,497loggerhead, 227green,8leatherback, 6hawksbill and10Kemp'sridleyturtleshavebeencaptured.

Overthelifeofthemonitoring program,annualcatchesforloggerhead turtleshaverangedfrom33in1976(partialyearofplantoperation andmonitoring) to-ahighof195in1986.Yearlycatchesofgreenturtleshaverangedfrom0in1976to69in1984.Differences inthenumberofturtlesentrapped duringdifferent yearsandmonthswereattributed tonaturalvariation intheoccurrence ofturtlesinthevicinityoftheoffshoreintakestructures, ratherthantoanyinfluence oftheplantitself.Size-class distributions ofloggerhead turtlesremovedeachyearfromthecanalhaveconsistently beenpredominated byjuveniles andsub-adultsbetween50and70cminstraightlinecarapacelength.Mostgreenturtlesentrapped inthecanal(over75percent)werejuveniles 40cmorlessinlength.Forbothspecies,thelargestnumberofcapturesforallyearscombinedoccurredduringthewinter,buttheseseasonalpeaksweremuchmorepronounced forgreenturtles.Sexratiosofbothadultandimmatureloggerheads caughtinthecanalcontinued tobebiasedtowardsfemales.During1987,about86percentofallloggerheads andgreenturtlesremovedfromthecanalwerecategorized byphysicalappearance asbeingingoodtoexcellentcondition.

Overtheentire12yearmonitoring period,about70and80percent,respectively, ofallloggerhead andgreenturtlecaptureshaveinvolvedindividuals inthesecategories; 22 percentoftheloggerheads and13percentofthegreenturtlesremovedfromthecanalhavebeeninfairorpoorcondition.

About13percentoftheturtlesremovedfromtheintakecanalduring1987hadsevereinjuries.

However,itappearedthatallbuttwooftheseinjuriesweresustained priortoentrapment.

Onceinthecanal,turtlesconfinedeastofA1Ausuallyhadverybriefresidency timesandthustherelativecondition ofmostturtleswasnotaffectedbytheirentrapment.

During1987,22loggerheads, 11greenturtlesan'd4Kemp'sridleysswamwestoftheA1Abridge.Themajorityoftheloggerheads wereretrieved atarecentlyinstalled securityintrusion barrier,whileallbuttwoofthegreenturtlesandalloftheKemp'sridleyswereremovedfromthecanalattheintakewells.Sincemonitoring began,about9percentofallloggerhead and48percentofallgreenturtlecaptureshaveoccurredattheintakewells.During1987,twoKemp'sridleyandelevenloggerhead mortalities wererecordedfortheintakecanal.Thisrepresented asubstantial decreaseinloggerhead mortalities from1986.Themajorityofdeathsduring1987appearedtohaveresultedfromdrowning, althoughtheexactcausesofdeathcouldnotbedetermined.

Theintrusion barrierwaspro-bablyresponsible foreightoftheelevenloggerhead mortalities, butthesedeathsappearedtobeconfinedprimarily toindividuals withinjuriesorinaweakenedcondition.

50 Sinceintakecanalmonitoring beganin1976,7.7percentoftheloggerheads and7.0percentofthegreenturtlesremovedfromthecanalweredead.ThetwoKemp'sridleymortalities in1987werethefirstrecordedforthisspeciessincemonitoring began.Alloftheleather-backsandhawksbi11scapturedattheSt.LuciePlanthavebeenreleasedaliveintotheocean.51 LITERATURE CITEDABI(AppliedBiology,Inc.)1977.Ecological monitoring attheFloridaPower&LightCo.St.LuciePlant,annualreport1976.VolumesIandII.AB-44.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1978.Ecological monitoring attheFloridaPower&LightCo.St.LuciePlant,annualreport1977.VolumesIandII.AB-101.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1979.FloridaPower&LightCompany,St.LuciePlantannualnon-radiological environmental monitoringreport1978.VolumesIIandIII,Bioticmonitoring.

AB-177.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,fliami.1980a.FloridaPower&LightCompany,St.LuciePlantannualnon-radiological environmental monitoring report1979.VolumesIIandIII,Bioticmonitoring.

AB-244.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1980b.Turtleentrainment deterrent study.AB-290.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1981a.Successful relocation ofseaturtlenestsneartheSt.LuciePlant,Kutchinson Island,Florida.AB-317..PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1981b.FloridaPower&LightCompany,St.LuciePlantannualnon-radiological environmental monitoring report1980.VolumesIIandIII,Bioticmonitoring.

AB-324.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1981c.ProposedSt.LuciePlantpreopera-tionalandoperational biological monitoring program-August1981.AB-358.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1982.FloridaPower&LightCompany,St.LuciePlantannualnon-radiological environmental monitoring report1981.VolumesIIandIII,Bioticmonitoring.

AB-379.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.1983.FloridaPower&LightCompany,St.LuciePantannualnon-radiological aquaticmonitoring report1982.VolumesIandII.AB-442.PreparedbyAppliedBiology,Inc.forFloridaPower&LightCo.,Miami.52 LITERATURE CITED(continued)

ABI(AppliedBiology,Inc.).1984a.FloridaPower8LightCompany,St.LuciePlantannualnon-radiological environmental monitoring report1983.VolumesIandII.AB-530.PreparedbyAppliedBiology,Inc.forFloridaPower8LightCo.,Miami.1984b.FloridaPower8LightCompany,St.LuciePlantannualenvironmental operating report1983.AB-533.PreparedbyAppliedBiology,Inc.forFloridaPower5LightCo.,Miami.1985a.FloridaPower8LightCompany,St.LuciePlantannualnon-radiological environmental monitoring report1984.AB-553.PreparedbyAppliedBiology,Inc.forFloridaPower8LightCo.,JunoBeach.1985b.FloridaPower8LightCompany,St.LuciePlantannualenvironmental operating report1984.AB-555.PreparedbyAppliedBiology,Inc.forFloridaPower8LightCo.,JunoBeach.1986.FloridaPower8LightCompany,St.LuciePlantannualenvironmental operating report1985.AB-563.PreparedbyAppliedBiology,Inc.forFloridaPower8LightCo.,JunoBeach.1987.FloridaPower8LightCompany,St.LuciePlantannualenvironmental operating report1986.AB-579.PreparedbyAppliedBiology,Inc.forFloridaPower8LightCo.,JunoBeach.Baldwin,W.P.,Jr.andJ.P.Lofton,Jr.1959.Theloggerhead turtlesofCapeRomain,SouthCarolina.

Previously unpublished manuscript abridgedandannotated byD.K.Caldwell, withouttheauthors.InD.K.CaldwellandA.Carr,coordinators, TheAtlanticloggerhead seaturtle,Carettacarettacaretta(L.),inAmerica.BulletinoftheFloridaStateMuseum,Biological

Sciences, 4(10):319-348.

Bellmund,S.,M.T.MasnikandG.LaRoche.1982.Assessment oftheimpactsoftheSt.Lucie2NuclearStationonthreatened orendangered species.U.S.NuclearRegulatory Commission, OfficeofNuclearReactorRegulation.

Bustard,H.R.1968.Protection forarookery:Bundaberg seaturtles.WildlifeinAustralia 5:43-44.Bustard,H.R.andP.Greenham.

1968.Physicalandchemicalfactorsaffecting hatchinginthegreenseaturtle,Chelnnia~mdas(L.).Ecology49(2):269-276.

53 LITERATURE CITED(continued)

Caldwell, D.K.1962.CommentsonthenestingbehaviorofAtlanticloggerhead seaturtles,basedprimarily ontaggingreturns.quarterly JournaloftheFloridaAcademyofSciences25(4):287-302.Caldwell, D.K.,A.CarrandL.H.Ogren.1959.Nestingandmigration oftheAtlanticloggerhead turtle.InD.K.CaldwellandA.Carr,coor-dinators, TheAtlanticloggerhead seaturtleCarettacarettacaretta(L.),inAmerica.BulletinoftheFloridaStateMuseum,Biological

Sciences, 4(10):295-308.

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V.Arthropods.

FloridaMarineResearchPublications 25:1-63.Carr,A.,A.Meylan,J.Mortimer, K.BjorndalandT.Carr.1982.Surveysofseaturtlepopulations andhabitatsintheWesternAtlantic.

NOAATechnical Memorandum NMFS-SEFC-91:

1-82.Carr,A.,L.OgrenandC.McVea.1981.Apparenthibernation bytheAtlanticloggerhead turtleCarettacarettaoffCapeCanaveral,

~~~~~~~Florida.Biological Conservat>on 19:7-14.Davis,G.E.,andM.C.Whiting.1977.Loggerhead seaturtlenestinginEverglades NationalPark,Florida,U.S.A.Herpetologica 33:18-28.

Diamond,A.W.1976.Breedingbiologyandconservation ofHawksbil1L.,CiI1,Syh11BiologicalConservation 9:199-215.

Ehrhart,L.M.1979.Reproductive characteristics andmanagement poten-tialoftheseaturtlerookeryatCanaveral NationalSeashore, Florida.Pages397-399inLinn,R.M.,ed.Proceedings oftheFirstConference onScientific ResearchintheNationalParks,9-12November, 1976,NewOrleans,La.NPSTrans.andProc.SereNo.5.Ernest,R.G.,R.E.Martin,B.D.Peery,D.G.Strom,J.R.WilcoxandN.W.Walls.InPress.Seaturtleentrapment atacoastalpowerplant.Proceedings ofSoutheastern WorkshoponAquaticEcological EffectsofPowerGeneration, 3-5December, 1986,Sarasota, Florida.Fowler,L.E.1979.Hatchingsuccessandnestpredation inthegreenseaturtle,Chelonia~mdasatTortuguero, CostaRica.Ecology60(5):945-955.Frair,W.1977.Turtleredbloodcel1packedvolumes,sizes,andnumbers.Herpetologica33:167-190.54

LITERATURE CITED(continued)

Futch,C.R.andS.E.Dwinel1.1977.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

IV.LanceletsandFishes.FloridaMarineResearchPublications 24:1-23.Gallagher,R.M.1977.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

II.Sediments.

FloridaMarineResearchPublications 23:6-24.Gallagher, R.M.andM.L.Hollinger.

1977.Nearshore marineecologyatHutchinsonIsland,Florida:1971-1974.

I.Introduction andrationale.

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1966.Nestingbeachpreferences of.Malayanseaturtles.BulletinoftheNationalMuseumSingapore 33(10):69-76.

~~~~~~~~~Hi11estad,H.O.,J.I.Richardson,C.McYea,Jr.andJ.M.Watson,Jr.1982.Worldwide incidental captureofseaturtles.Pages489-496inBjorndal, K.A.,ed.Biologyandconservation ofseaturtles.SmithsonianInstitutionPress,Washington, D.C.Hirth,H.F.1980.Someaspectsofthenestingbehaviorandreproductive biologyofseaturtles.AmericanZoologist 20:507-523.

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Zoologica Africana11I2~285-291.

Martin,R.E.,R.G.Ernest,N.W.WallsandJ.R.Wilcox.InPress.Sizedistribution andseasonalabundance ofloggerhead andgreenturtlesinnearshore watersoffHutchinson Island,Florida;Posterabstract.

InProceedings ofSecondWesternAtlanticTurtleSymposium.

Hayaguez, PuertoRico,12-16October1987.55

LITERATURE CITED(continued)

Mendonca, M.T.andL.M.Ehrhart.1982.Activity, population sizeandstructure oftheimmatureChelonia~mdasandCarettacarettainMosquitoLagoon,Florida.Copeia1982:161-167.Moffler,M.D.andJ.F.VanBreedveld.

1979.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

X.Benthicalgaespecieslist.FloridaMarineResearchPublications 34:118-122.Mortimer, J.A.1982.Factorsinfluencing beachselection bynestingseaturtles.Pages45-51inBjorndal, K.A.,ed.Biologyandconserva-tionofseaturtles.Smithsonian Institution Press.Washington, D.C.NMFS(National MarineFisheries Service).

1978.FinalEISlistingandprotecting thegreenseaturtle(Chelonia

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1982.Finalenvironmental statement relatedtotheoperation ofSt.LuciePlantUnit2.DocketNo.50-389.O'ara,J.1980.Thermalinfluences ontheswimmingspeedofloggerhead turtlehatchlings.Copeia1980(4):773-780.

Ogren,L.andC.McVea,Jr.1982.Apparenthibernation byseaturtlesinNorthAmericanwaters.Pages127-132inBjorndal, K.A.,ed.Biologyandconservation ofseaturtles.Smithsonian Institution Press,Washington, D.C.Owens,D.W.,J.R.Hendrickson, V.LanceandI.P.Cal1ard.1978.Atechnique fordetermining sexofimmatureChelonia~mdasusingaradioimmunoassay.

Herpetologica 34:270-273.

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Pritchard, P.C.,P.R.Bacon,F.H.Berry,A.F.Carr,J.Fletemeyer, R.M.Gallagher, S.R.Hopkins,R.R.Lankford, R.MarquesM.,L.H.Ogren,W.G.Pringle,Jr.,H.A.ReichartandR.Witham.1983.Manualofseaturtleresearchandconservation techniques.

PreparedfortheWesternAtlanticTurtleSymposium, SanJose,CostaRica,July1983.126pp.Proffitt,C.E.,R.E.Martin,R.G.Ernest,B.J.Graunke,S.E.LeCroy,K.A.Muldoon,B.D.Peery,J.R.WilcoxandN.Williams-Walls.

1986.Effectsofpowerplantconstruction andoperation onthenestingofthe1oggerhead seaturtle(Carettacaretta):1971-1984.

Copeia1986(3):813-816.

LITERATURE CITED(continued)

Raymond,P.W.1984.Theeffectsofbeachrestoration onmarineturtlesnestinginsouthBrevardCounty,Florida.M.S.thesis,University ofCentralFlorida.Routa,R.A.1968.SeaturtlenestsurveyofHutchinson Island,Florida.quarterly JournalFloridaAcademyofSciences30(4):287-294.

Schulz,J.'P.1975.SeaturtlesnestinginSurinam.Zoologische Verhandeli ngen,uitgegeven doorhetRijksmuseum vanNatuurlijke HistoricteLeiden,No.143:1-144.

Smith,N.P.1982.Upwelling inAtlanticshelfwatersofsouthFlorida.FloridaScientist 45(2):125-138.

Sokal,R.R.andF.J.Rohlf.1981.Biometry.

Theprinciples andprac-ticeofstatistics inbiological research.

W.H.FreemanandCompany,SanFrancisco.

859pp.Stancyk,S.E.1982.Non-human predators ofseaturtlesandtheircon-trol.Pages139-152inBjorndal, K.A.,ed.Biologyandconserva-tionofseaturtles.Smithsonian Institution Press.Washington, D.C.Talbert,O.R.,S.E.Stancyk,J.M.DeanandJ.M.Will.1980.Nestingactivityoftheloggerhead turtle(Carettacaretta)inSouthCarolina.

I:Arookeryintransition.

Copeia1980:709-718.

Taylor,C.B.,andH.B.Stewart.1958.Summerupwelling alongtheeastcoastofFlorida.JournalofGeophysical Research64(1):33-40.

Tester,L.A.andK.A.Ste'idinger.

1979.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

VII.Phytoplankton, 1971-1973.FloridaMarineResearchPublications 34:16-61.Walker,'.M.1979.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

IX.Dielplankton,1973-1974.

FloridaMarineResearchPublications 34:99-117.Walker,L.M.,B.M.GlassandB.S.Roberts.1979.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

VIII.Zooplankton, 1971-1973.

FloridaMarineResearchPublications 34:62-98.Walker,L.M.'andK.A.Steidi,nger.

1979.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

VI.Planktondynamics,1971-1973.

FloridaMarineResearchPublications 34:1-15.

LITERATURE CITED(continued)

Wibbels,T.,D.Owens,Y.MorrisandM.Amoss.1984.Sexratiosofimmatureloggerhead seaturtlescapturedalongtheAtlanticcoastoftheUnitedStates.FinalReporttotheNationalMarineFisheries Service.,

ContractNo.NA81-GA-C-0039.

47pp.Williams-Walls, N.,J.O'ara,R.M.Gallagher, D.F.Worth,B.D.PeeryandJ.R.Wi1cox.1983.SpatialandtemporaltrendsofseaturtlenestingonHutchinson Island,Florida,1971-1979.

BulletinofMarineScience33(1):55-66.

Witherington, B.E.andL.M.Ehrhart.InPress.Statusandreproductive characteristics ofgreenturtles(Chelonia

~mdas)nestinginFlorida.Posterabstract.

InProceedings ofSecondWesternAtlanticTurtleSymposium.

Mayaguez, PuertoRico,12-16October1987.Worth,D.F.andM.L.Hollinger.1977.Nearshore marineecologyatHutchinson Island,Florida:1971-1974.

III.Physicalandchemicalenvironment.

FloridaMarineResearchPublications 23:25-85.Worth,D.F.,andJ.B.Smith.1976.MarineturtlenestingonHutchinson Island,Florida,in1973.FloridaMarineResearch.

Publications 18:1-17.58

GULFOFMEXICO0dOOVASSSKILOMDERS SCALE~~-N-St.LuciePlantFigure1.LocationoftheSt.LuciePlant.

l gegI~~P,::HUTCHINSON V\h~'La7~~V~OdVgH~ISLANDC~'I~tqP~'DISCHARGE

@G'.:PIPES~qS'i.0v'9INTAKE'<:.

INTAKE0+HEADWALL',

WELLSINTAKESTRUCTURES INTRUSION BARRIER:BARRIER,.NET;7";;':.':S',,Cl'vINTAKECANAL0250500METERS~~rFigure2.St.LuciePlantcoolingwaterintakeanddischarge system.

L1 "i0'e~~'tPierceInletAAlgQQbb,eC7EaStateHwyA'0eH23LMN40FPLpSTLUCIEPLANTU.S.HwyI~n1eg4I0SkmR(VE,Rw/6YzQBBCCDDEE8FFHHGG~\ped1>.':e9~~St.LucleInletFigure3.Designation andlocationofnine1.25-kmsegmentsand~~~~~~thirty-six 1-kmsegmentssurveyedforseaturtlenesting,Hutchinson Island,1971-1987.

3000329250z0200z15010050123456789NORTHPOWERPLANTSOUTHFigure4.Heanannualnumberofloggerhead turtlenestsineachofthenine1.25-km-long surveyareas,Hutchinson Island,1971-1986, comparedwithnumberofnestsduring1987.Horizontal linesaremeans,boxesencloseplusorminusonestandarddeviation, verticallinesareranges,andclosedcirclesare1987values(1980datawereexcludedbecausenotallareasweresurveyed).

0300250200R150Dz10050ABCDEFGHIJKLMNOPQRSTUVWXYZABCDE FGHIJABCDEFGHIJNORTH0POWERPLANTSOUTHFigure5.Heanannualnumberofloggerhead turtlenestsineachofthethirty-six 1-km--long surveyareas,Hutchinson Island,1981-1986, comparedwithnumberofnestsduring1987.Horizontal linesaremeans,boxesencloseplusorminusonestandarddeviation, verticallinesareranges,andclosedcirclesare1987values.

500g)400Oz300200100NORTHABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHI JABCDEFGHIJPOWERPLANTSOUTHFigure6.Heanannualnumberofloggerhead turtleemergences ineachofthethirty-six 1-km-long surveyareas,Hutchinson Island,1981-1986, comparedwithnumberofemergences during1987.Horizontal linesaremeans,boxesencloseplusorminusonestandarddeviation, verticallinesareranges,andclosedcirclesare1987values.

10080g(0COUJOOg60C9Z(0I-IIJz4020ABCDEFGHIJKLMNOPQRSTU VWXYZABCDEFGHIJABCDEFGHIJNORTHf'OWERPLANTSOUTHFigure7.Neanannualloggerhead turtlenestingsuccess(percentage ofemergences thatresultedinnests)foreachofthethirty-six 1-km-long surveyareas,Hutchinson Island,1981-1986, comparedw'ithnestingsuccessduring1987.Horizontal linesaremeans,boxesencloseplusorminusonestandarddeviation, verticallinesareranges,andclosedcirclesare1987values'

250o~Area4(PowerPlantSite)X--XArea5(ControlSite)200z150z100~XXX////XXx~N<x/K///X5071737577798081828384858687Figure8.Numberofloggerhead turtlenestsinAreas4and5,Hutchinson Island,1971-1987.

Arrowsdenoteyearsduringwhichintake/discharge construction occurredinArea4.

COI-COzDz50004000300020001000o10000z8000600040002000gCOCOLljOODCO(9zI-COUj8060402019811982198319841985198619879.Annualnumberofnests,numberofemergences andnestingsuccessalongtheentire36.0-km-long Atlanticcoastline ofHutchinson Island,1981-1987.

~OujKDI-IZIllQ.ILjI-2826242220906030015305APR1530515305153051530515MAYJUNJULAUGSEPFigure10.Dailyloggerhead turtlenestingactivityandwatertemperature, Hutchinson Island,1987.

50ALLAREASAREA150AREA250AREA3500-0W'o)50I-COLLIZAREA4AREA550I-Z50AREA650AREA750AREA8AREA9501971197319751977197919801981198219831984198519861987Figure11.Percentage ofloggerhead turtlenestsdestroyed byraccoonsinthenine1.25-km-long surveyareas,Hutchinson Island,1971-1987.

QDestroyed byghostcrabsgDestroyed byraccoonsandghostcrabsDestroyed byraccoons50CIg40CO30z20z2?%1001%1%1%1A-BCDEFGHIJKLMNOPQRS TUVWXYZABCDEFGHIJABCDEFGHIJNORTH0POWERPLANTSOUTHFigure12.Numberofloggerhead turtlenestsdes'troyed byraccoonsandghostcrabsandpercentage ofnestsdestroyed ineach1-km-long surveyarea,Hutchinson Island,1987.

60co45Zm30Z15p---pGreen(Chelonia mydas)8-+9Leatherback (Dermochelys coriacea) rrpW-/Fs/Ii/I/I//I/Ix/~/IIIIIIIIIII19711973197519771979198119821983.1984198519861987Figure13.Numberofgreenturtleandleatherback turtlenests,Hutchinson Island,1971-1987.

~,

200~LOGGERHEAD (Carettacaretta)0---E3GREEN(Chelcnia midas)80175I-0150O125(901007550Z25I///0/I/I0////0x/0--000I)I5/\00070M6055040030.gD2010197619771978197919801981198219831984198519861987Figure14.Numberofloggerhead andgreenturtlesremovedeachyearfromtheintakecanal,St.LuciePlant,1976-1987.

5050Pv40030mZZ204030201010JANFEBMARAPRMAYJUNJULAUG.SEPOCTNOVDECMONTHOFCAPTUREFigure16.Heannumberofloggerheads capturedeachmonth,St.LuciePlantintakecanal,1977-1986, comparedwithnumberofmonthlycapturesduring1987.Horizontal linesaremeans,boxesencloseplusorminusonestandarddeviation, verticallinesareranges,andclosedcirclesare1987values.

300200DO00z0KILJKlz100200.100c4041-4546-5051-5556-6061-6566-7071-7576-8081-8586-9091-9596-101-106-111-116-100105110115120STRAIGHTLINECARAPACELENGTH(cm)Figure16.Lengthdistribution (SLCL)ofliveloggerhead seaturtles(N=1,278)removedforthefirsttimefromtheintakecanal,St.LuciePlant,1976-1987.

18018016016014O0120Oz100Km8OD60140120100806040402020~2021-3031-4041-5051-6061-7071-8081-9091-100WEIGHT(Ibs)101-151-201-251-301-5350150200250300350figure17.Weightdistribution ofliveloggerhead seaturtles(N=1,140)removedforthefirsttimefromtheintakecanal,St.LuciePlant,1976-1987.

8080COD060CIz0KlU40z60402020-1516-21-26-31-36-41-46-51-56-61-66-71-76-81-86-91-96-101-106-11120253035404550556065707580'859095100105110115STRAIGHTLINECARAPACELENGTH(cm)Figure18.Lengthdistribution (SLCL)oflivegreenturtles(N=209)removedforthefirsttimefromtheintakecanal,St.LuciePlant,1976-1987.

125125~100D00750K03D50.10075502525s1011-2021-3031-4041-5051-6061-7071-8081-9091-100WEIGHT(Ibs)101-151-201-251-i300150200250300Figure19.Weightdistribution oflivegreenturtles(N=205)removedforthefirsttimefromtheintakecanal,St.LuciePlant,1976-1987.

'-'-.MALESFEMALES4040MDO30Clz0KujK20Dz30201010JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECMONTHOFCAPTUREFigure20.Numbersofadultloggerheads (N=202),including recaptures, removedeachmonthfromtheintakecanal,St.LuciePlant,1976-1987.

400-0CANALCAPTURES300OKDOCOI-DO0KIDzDZZ3020100--~NESTS0Z'25PZ15075197619771978197919801981198219831984198519861987Figure21.Comparison ofcapturesofadultfemaleloggerheads intheintakecanal,St.LuciePlant,1976-1987, andnumbersofloggerhead nestsinArea4adjacenttotheplant.Nonestingdatawerecollected in1976and1978.

80z0.60)I-DDo4020/0//r00//0III0I0II0III0III0III0/J~0-----oIntervalbetweensuccessive capturesIntervalbetweenfirstandlastcapture.806040201002003004005006007008009001000110012001300RECAPTURE INTERVAL(days)Figure22.Cumulative percentage ofallloggerhead recaptures occurring withinvarioustimeintervals betweensuccessive captures(N=77)andfirstandlastcapture(N=45),St.LuciePlantintakecanal,1976-1987.

ESTIMATES OFTHENUMBERSOFLOGGERHEAD TURTLENESTSONHUTCHINSON ISLANDBASEDONSURVEYSOFNINE1.25-KM-LONG SURVEYAREAS,1971-1987, COMPAREDTOTHEACTUALNUMBEROFNESTSONTHEISLAND,1981-1987 Year197119731975197719791981198219831984198519861987Numberofnestsinthenine1.25-km-long surveyareas14201260149393214491031163415921439162318391645Extrapolation fromthenine418937174404274942753041482046964245478854254853surveyareastotheentireisland(seetext)Actualnumberofnestsontheentireisland3115469047434277487754834623 T2TOTALNUMBEROFSEATURTLEURESAND(NUMBEROFDEAD)TURTLESREMOVEDFROMTHEINTAKECANALST.LUCIEPLANT1976-1987Year1976197719781979198019811982198319841985loerhead33(4)8o(s)138(19)173(13)116(5)62(s)101(16)119(4)148(3)157(4)Seciesreenleatherback s(2)6(1)3(1)1O(3)32(2)23(4)69(2)14hawksbill Kem'sridleTotal33(4)86(7)148(20)176(14)126(8)97(7)110(16)142(8)22O(S)172(4)19861987195(27)175(11)22(1)35Total1497(116) 227(16)8(o)6(o)6(2)10(2)220(28)218(13)1748(134)

AnnualMeana133.120.60.70.50.9158.9aExcludes1976(partialyearofplantoperation).

TABLETOTALNUMBERAND(NUMBEROFD0)LOGGERHEAD TURTLESREMOVEDEACHMONTHFROMTHEINTAKECANALST.LUCIEPLANT1976-1987Month19761977197819791980198119821983JanuaryFebruary131924(3)1611(1)6(2)398(1)11(2)29(1)21(2)11(3)1113(1)MarchAprilMay727(2)11145(2)19(5)17213(1)0761411014617(4)June05103(1)8(3)677(1)July7(1)4027(2)017August231217(2)12September 115(l)18(1)19OctoberNovemberDecember9541079(1)17(2)15(3)75(3)515(7)12462(1)62(1)9(1)8(2)09(5)1704(2)531(1)12Total33(4)80(5)138(19)173(13)116(5)62(5)101(16)119(4)

TABL(continued)

TOTALNUMBERAND(NUMBEROFDEAD)LOGGERHEAD TURTLESREMOVEDEACHMONTHFROMTHEINTAKECANALST.LUCIEPLANT1976-1987Month1984198519861987TotalMonthlyPercentofMeanTotalCatchaJanuaryFebruaryMarchApril111516(4)11157(14)14.362014(4)8(1)128(7)11.62(1)1320(2)24(3)124(13)11.3131115(2)26(3)193(11)17.513.210.78.78.5May7161223(1)98(6)8.26.6JuneJulyAugustSeptember OctoberNovemberDecemberTotal16149(4)10711(2)938210106(10)8.8112(13)9.375(12)6.381(1)6.7148(3)157(4)195(27)175(11)1497(116) 28(1)1720(1)26(1)137(8)11.412(1)20(3)26(2)19(1)130(10)10.82619(1)34(6)17(1)156(11)13.09.48.410.57.27.24.84.9aExcludes1976(partialyearofplantoperation).

TOTALNUMBERAND(NUMBEROFDEAD)GREENTURTLESREMOVEDEACHMONTHFROMTHEINTAKECANALST.LUCIEPLANT1976-1987MonthJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember OctoberNovemberDecember197619771978197919801981210020(1)2(1)215(1)70204(1)1(1)01(1)001(1)02(1)198219838(1)3(2)4(1)Total5(2)6(1)3(1)10(3)32(2)23(4)

TA4(continued)

TOTALNUMBERAND(NUMBEROFDEAD)GREENTURTLESREMOVEDEACHMONTHFROMTHEINTAKECANALST.LUCIEPLANT1976-1987MonthJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember OctoberNovemberDecember1011116(1)34(1)198419851986198737(l)414Total78(3)34(2)20(4)13(2)4(1)10(1)9(1)1018(2)19MonthlyMean7.13.11.81.20.30.80.60.70.40.81.51.6PercentofTotalCatch34.415.08.85.71.84.43.14.02.2447.98.4Total69(2)1422(1)35227(16)

NUMBEROFMONTHLYCAPTURESBYSIZECLASSFORLIVELOGGERHEAD TURTLESREMOVEDFROMTHEINTAKECANALST.LUCIEPLANT1976-1987aMonthSizeclassesSLCLincmJuveniles/Sub-Adults Transition Adults41-5051-6061-70TotalPercentae71-80Percentae81-9091-100>100TotalPercentaeJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember OctoberNovemberDecember3419363172214323631474591478615112075143101103637839342366443338023431676434190239317214.612.010.18.36.68.06.79.07.27.24.36.3221416161010181513.78.710.010.05.06.36.311.35.69.48.75.0232210200030105010115213162113020101435403614125.41.61.63.37.619.021.719.67.66.53.32.7Total76504424100474.516011.911661718413.6aNodatawerecollected for33individuals.

T6RELATIVECONDITION SEATURTLESREMOVEDFROMTHEINTAKECANALST.LUCIEPLANT1976-1987Relativecondition LoerheadsNumberGreensNumberkNumberXNumberHawksbills NumberAllseciesNumberTOTAL26017.434022.743829.325817.2765.11167.790.614976830.03917.27231.72310.162.6167.031.3227675.0112.522033011011022010112.5110466.633419.1116.638221.9116.652029.728316.2834.71347.7120.717481Excellent

-normalorabovenormalweight,active,veryfewornobarnacles orleeches,nowounds.2Verygood-intermediate goodtoexcellent.

3Good-normalweight,active,lighttomediumcoverageofbarnacles and/orleeches,woundsabsent,healedordonotappeartodebilitate theanimal.4Fair5Poor-intermediate poortogood.-emaciated, sloworinactive, heavybarnaclecoverageand/orleechinfestation, debilitating woundsormissingappendages.

6Dead7Alivebutcondition otherwise unknown.