COASTALCONSERVATIONPROJECTANASSESSMENTOFTHE
CORALREEFSOFTOBAGO
PreparedbyKahlilHassanali
September2009
INSTITUTEOFMARINEAFFAIRSRESEARCHREPORT
COASTALCONSERVATIONPROJECTANASSESSMENTOFTHE
CORALREEFSOFTOBAGO
Prepared byKahlil Hassanali
Jr.Research Officer
September 2009
InstituteofMarine AffairsHilltop Lane,Chaguaramas
P.O. Box 3160, Carenage Post OfficeTrinidad andTobago,W.I.
Tel. (868) 634-4291-4
Fax. (868) 634-4433
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Institute of Marine Affairs
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OR
ABSTRACT
In2004,whilepreparingtheStateoftheMarineEnvironmentReport,itbecameapparentthattherewasalackofrecentinformationonthestateofreefsinTobagoexceptforBuccooReefwhichhasbeenmonitoredundertheCARICOMPproject.Inaddition,thereweremanyrequestsfromthepublicforinformationonthestateofreefs.Thisprojectsoughttobridgethisknowledgegapand entailedare-surveyingofreefsatBuccoo,Culloden,ArnosValeandSpeyside.SurveyswerealsoconductedatLaGuiraBay.
ResultsfromtheassessmentofthevariousareasaroundTobagoshowedthefatesofreefstobemixedintermsofcomparativeextentofhardcoralcoveroverthelasttwoandahalfdecades.Meanhardcoraldeclineswereseeninsomearease.g.BuccooandCulloden,whereasimprovementswereobservedinotherse.g.ArnosValeandSpeysideReefs.ReefsinMan-o-WarBay,showednooveralltrendwithslightimprovementsinmeanhardcoralcoveratthemidandlowerforereefzoneswhiletherewasalargereduction incoverat theupper fore reefs.Surveyscarried outat thereefsinLaGuiraBaywerenovelandthuscomparisonscouldnotbemade.However,macroalgaecoverisofmajor concern especiallyat theCoveLedge dive site.
Coralbleachingwasnotobservedduringsurveyswhichwasnotsurprisingastheywerenotconductedduringan‘ElNiño’period.However,highincidenceofyellowbanddiseasewasobservedespeciallyontheBuccooandCullodenReefs.Also,therapidassessmentmethodrevealedthatDiademaantillarumnumbersremainlowcomparedtopre die off densityestimates.
TABLE OF CONTENT
Page
ABSTRACTi
1.0INTRODUCTION1
2.0METHODOLOGY8
3.1RESULTS19
3.2ARNOSVALE19
3.3BUCCOO23
3.4CULLODEN33
3.5MAN-O-WAR BAY43
3.6SPEYSIDE50
3.7LA GUIRA BAY60
3.8RAPIDASSESSMENT68
4.0DISCUSSION69
5.0CONCLUSIONS78
6.0REFERENCES80
7.0ACKNOWLEDGEMENTS83
LIST OFFIGURES
Page
Figure 2.1: / Map ofTobago / 8Figure 2.2: / Map ofArnos Vale Reefshowinggeneral location ofsurveysites / 10
Figure 2.3: / Map ofBuccooReefshowing generallocationofsurveysites / 11
Figure 2.4: / Map ofCulloden Bay showinggenerallocationofsurveysites / 12
Figure 2.5: / Map ofMan-o-War Reefshowinggenerallocationofsurveysites / 13
Figure 2.6: / Map ofLa Guira Bay showinggenerallocationofsurveysites / 14
Figure 2.7: / Map ofSpeyside Reefshowinggenerallocationofsurveysites / 15
Figure 2.8: / Speciesrecoverycurvesforeight photoquadrats at 9mCulloden West(SiteA) and16mBuccoo Western Reef(SiteB). / 17
Figure 4.1: / Hard coral covercomparisons betweenthe Laydoo(1985a-e)surveys and the currentassessments / 70
LIST OFTABLES
Page
Table 1.1:
Table 1.2:
Table 2.1:
Table 3.1.1:
Table 3.1.2:
Table 3.1.3:
Table 3.1.4:
Table 3.2.1:
Table 3.2.2:
Table 3.2.3:
Table 3.2.4:
Table 3.2.5:
Table 3.2.6:
Table 3.2.7:
Number ofspecies foundin varyingbenthic categories in3
surveys of Tobago’sreefs(excludingthose donebyLaydoo,1985 a-e).
Number ofspecies foundin varyingbenthic categories in4
Laydoo(1985a-e) surveysof Tobago’sreefs.
Depthssurveyedat thevarious samplingsites located in the9
differentreefareas studied around Tobago. Number ofsurveydepthswasdependent upon the fore-reef slopestructureat thesites.
Speciescover on reef crest (3m) atArnos Valesurveysite.19
Speciesmean densityand frequencyon reefcrest(3m) at20
ArnosVale surveysite.
Speciescover on theupper fore reef(9m)at Arnos Vale21
surveysites.
Speciesmean densityand frequencyon the upperfore reef22
(9m) atArnos Vale surveysites.
Speciescover on thereefcrest (3m)atBuccoo surveysites.24
Speciesmean densityand frequencyon the reefcrest (3m) at25
Buccoo surveysites.
Species cover on theupper fore reef(9m)at Buccoo survey26
sites.
Speciesmean densityand frequencyon the upperfore reef28
(9m) atBuccoo surveysites.
Speciescover on themid fore reef(16m) atBuccoo survey29
sites
Speciesmean densityand frequencyon themid fore reef30
(16m) atBuccoo surveysites
Speciescover on thelower fore reef(21m)at Buccoo survey31
sites
LIST OFTABLES
Page
Table 3.2.8:
Table 3.3.1:
Table 3.3.2:
Table 3.3.3:
Table 3.3.4:
Table 3.3.5:
Table 3.3.6:
Table 3.3.7:
Table 3.3.8:
Table 3.4.1:
Table 3.4.2:
Table 3.4.3:
Speciesmeandensityandfrequencyonthelowerforereef32
(21m) atBuccoo surveysites.
Speciescover on the reefcrest (3m)atCulloden surveysite34
Speciesmeandensityandfrequencyonthereefcrest(3m)at35
Culloden surveysite.
Speciescoverontheupperforereef(9m)atCullodensurvey36
sites.
Speciesmeandensityandfrequencyontheupperforereef37
(9m) atCulloden surveysites
Speciescoveronthemidforereef(16m)atCullodensurvey39
sites.
Speciesmeandensityandfrequencyonthemidforereef40
(16m) atCulloden surveysites
Species cover on the lower fore reef (21m) at Culloden41
surveysite.
Speciesmeandensityandfrequencyonthelowerforereef42
(21m) atCulloden surveysite
Speciescoveronthereefcrest(3m)attheMan-o-WarBay44
surveysites
Speciesmeandensityandfrequencyonthereefcrest(3m)at45
Man-o-WarBaysurveysites
Speciescoverontheupperforereef(9m)atMan-o-WarBay47
surveysites
LIST OFTABLES
Page
Table 3.4.4:
Table 3.4.5:
Table 3.4.6:
Table 3.4.7:
Table 3.4.8:
Table 3.5.1:
Table3.5.2:
Table 3.5.3:
Table 3.5.4:
Table 3.5.5:
Table 3.5.6:
Table 3.5.7:
Speciesmeandensityandfrequencyontheupperforereef48
(9m) at Man-o-War Baysurveysites
Speciescoveronthemidforereef(16m)atMan-o-WarBay49
surveysite
Speciesmeandensityandfrequencyonthemidforereef49
(16m) at Man-o-War Baysurveysite
Speciescoveronthelowerforereef(21m)atMan-o-War50
Baysurveysite
Speciesmean densityand frequencyon the lowerfore reef50
(21m) at Man-o-War Baysurveysite
Speciescover on thereefcrest (3m)atAngel Reef, Speyside52
surveysites
Speciesmean densityand frequencyon the reefcrest (3m) at53
AngelReef,Speyside surveysites
Speciescover on theupper fore reef(9m)at Angel Reef,54
Speyside surveysites
Speciesmean densityand frequencyon the upperfore reef55
(9m) atAngel Reef, Speyside surveysites
Speciescover on themid fore reef(16m) at Angel Reef,57
Speyside surveysites
Speciesmean densityand frequencyon the mid fore reef58
(16m) atAngel Reef, Speyside surveysites
Speciescover on thelower fore reef(21m)at Angel Reef,59
Speyside surveysites
LIST OFTABLES
Page
Table 3.5.8:
Table 3.6.1:
Table 3.6.2:
Table 3.6.3:
Table 3.6.4:
Table 3.6.5:
Table 4.1:
Speciesmean densityand frequencyon the lowerfore reef60
(21m) atAngel Reef, Speyside surveysites
Speciescover on theupper fore reef(9m)at CoveLedge,La62
Guirasurveysites
Speciescover on theupper forereef(9m)at Majeston,La63
Guirasurveysites
Speciesmean densityand frequencyon the upperfore reef64
(9m) at theCoveLedge and Majeston,La GuiraBay
Speciescover on theupper fore reef(9m)at FlyingReef,La66
GuiraBay
Speciesmean densityand frequencyon the upperfore reef67
(9m) at FlyingReef,LaGuirasurvey
Siderastreasidereapercentagecover change between the76
Laydoo(1985 a,b,c,e)surveys andthe presentsurveys
LIST OFPLATES
Page
Plate 2.1:Photoquadrat from16mdepth at Western Reef, Buccoo16
1.0INTRODUCTION
CoralreefsareanintegralpartoftheCaribbeanenvironment,providingover100millionpeopleinmorethan25countriesandterritorieswithfood,coastalprotection, andrevenuefromtourism(PopulationReferenceBureau1996).Tourismistheregion’smostimportanteconomicsector,andreefsprovidemuchofthesandfortheregion’sbeaches,wheremosttouristsspendtheirtime(BurkeMaidens2004).TouristarrivalstotheCaribbeanwereestimatedatnearly28millionin1999(CaribbeanTourismOrganisation2001)andtourismrevenuealonebringsinoverUS$25billionayeartotheregion(Burke Maidens 2004).
Inspiteoftheirimportance,Caribbeancoralreefsareunderseverepressuremainlyfromhumanactivitiessuchascoastaldevelopment,landclearanceandintensiveagricultureamongothers(Mora2008).Inadditiontothis,thereareimpactsfromglobalphenomenasuchasclimatechange(Johannes1970;Rogers1985,1990;Woodley1992;Glynn1997;UNEP2002).Thus,seventy-fivepercentofCaribbeanreefsareinseriousdeclineorunderthreat(Hinrichsen1996).Therehasbeenamajorlossofcoralcoveranddiversity(Hoegh-Guldberg1999;Wilkinson2000;Gardneretal.2003),coupledinmanyareaswithanincreaseinalgalbiomassandshiftinalgalcommunitystructure(Littleretal.1992;Lapointe 1997; Hughes 1994).
Tobagoreefsarenotexemptfromthesedeleteriousimpactsandchanges.However,theextenttowhichtheyarebeingaffectedisnotquiteknown.MoststudiesoncoralreefsherehaveconcentratedontheBuccooandSpeysideReefecosystems.ReefsatMan-O-War Bay, Culloden andArnosVale have also received some attention.
BuccooReef,designatedamarineprotectedarea(MPA) in1973andwith itslong historyofbeingoneofTobago’smajortouristattractions,isthemoststudiedreefsysteminTobago.Goreau(1967)carriedoutlargelyqualitativeworkwithinthecontextofpotentialimpactsonthereeffromplannedtouristdevelopmentonthesouth-western
coastoftheisland.Aerialandunderwaterobservationsweremadeofthereef,thelatterbeingdoneontheeasternsideoftheecosystemnotinggeneralfloralandfaunalzonationandspeciesdiversitypatterns.BonAccordLagoonandassociatedmangrovehabitatwasalso similarlyobserved.Goreaucommentedandspeculatedupon the trophicrelationshipsamongstandbetweentheBuccooReef-BonAccordLagooncomplexnotingthecloseinterdependencebetweenthereefandmangrovelagoon,andactuallyconsideringthemasasingleecologicalunit.Recommendationswerealsomadeforthepreservationoftheentirewetlandecosysteminthefaceofwhatwasthenproposeddevelopment.Theseincluded the creation ofamarineparkandinitiatinglongterm studyon theecologyof theBuccooarea with particularreference to the mangroves and reefs.
SeveralyearslaterKenny(1976)conductedapreliminarystudyoftheBuccooReef/BonAccordcomplexinresponsetothegeneralquestionofdevelopmentandmanagementofcoastalresources.Thispreliminarystudyentailedahydrographicsurveywithaviewtoproducinganup-datedmapofthereefandlagoon,afaunalassessmentsothatacomprehensivespecieslistcould bemadeandlastly,adelineationoftheextentofdamage to the reef.
Inthepurelyqualitativedamageassessmentitwasfoundthat,generallyspeaking,theseawardslopesandthereefcrest,excludingthetouristarea,wereonlyslightlydamaged.Damagesobservedintheseareaswereattributedtonaturalcausesandmorespecificallystormsurge.Thetouristarea(thereefcrestandbackreefofOuterReef)however,wasextensivelydamagedalthough,dueto compoundinghistoricaldata,it wasuncertainwhetherthedamageherewascausedbyhumanactivity.Kennydidsuggestthatstormsinitiallydamagedthetourist areaandsubsequent activityonthereefpreventedthenaturalregeneration that might be expected.
WithregardstothefloraandfaunaofthereefandlagoonKenny(1976)concludedthatcomparedwithotherreefsinTobago,BuccooReefissomewhatimpoverished.Hecitedsub-oceanicconditionse.g.lowsalinityduringtherainyseason,highturbidityandhigh
turbulence, as being possible reasons for this. His investigations yielded 1 spongespecies, 2 hydrozoans,21hexacoralspecies and8octocoral species (Table1.1).
Table1.1: NumberofspeciesfoundinvaryingbenthiccategoriesinsurveysofTobago’sreefs(excludingthosedone by Laydoo,1985a-e)
Reef Location / BENTHICCATEGORYStudyAuthor / Sponges / Hydrozoans / Octocorals / Zoanthids / Hexacorals / BlackCorals
Man-O-WarBay / Ramsaroop(1981) / 4*(4) / 3 / 21 / 2 / 24 / 2*(2)
BuccooReef / Kenny(1976) / 1*(1) / 2 / 8 / 2 / 21 / undetermined
Speyside / IMA (2002) / 3*(2) / 2 / 9*(6) / 1 / 26 / undetermined
*(#)- no.undeterminedatspecieslevel
Laydoo’s(1985a)benthicspeciesnumbercountsonBuccooReef(Table1.2)differslightlyfromthosereportedbyKenny(1976).TheformersurveysatdifferentreefsitesthroughoutTobagohowever,didvalidateclaimsbythelatter thatbenthicspeciesnumberinBuccooislessthanmostother reefareasinTobago.ThemappingandbenthicsamplingstudiesdonebyLaydooremaintodaythemostcomprehensivequantitativesurveyevercarriedoutontheBuccooReefecosystem,gatheringinformationonmean
speciescover(%m-2),meandensity(col.m-2)andfrequencyofoccurrence(%)ofthe
benthic community.
Intheaforementionedecologicalsurveys,theauthorsallhighlightedtheneedtomonitor,assessandmitigatetheimpactsofsewagepollutionandlandrun-off.LittlequantitativeworkwasdoneuntilLapointeetal.(2003)whodidprovideactualevidenceofsewagedriveneutrophicationintheBuccooReefComplex(BRC).LaydooandHeileman(1987)inastudyoftheenvironmentalimpactsofsewagetreatmentplantsinBuccooandBonAccorddidfindthatimproperlyfunctioningplantsexhibiteddirectimpactsonthequalityofthe downstream and receivingmarineenvironment, includingtheBRC.
Table1.2:NumberofspeciesfoundinvaryingbenthiccategoriesinLaydoo(1985a-e)surveysofTobago’sreefs
BENTHICCATEGORYReef Location / Algae / Sponges / Hydrozoans / Octocorals / Zoanthids / Hexacorals / BlackCorals
BuccooReef / 3*(3) / 2*(2) / 3 / 14 / 1 / 21 / 1
Speyside / 4*(4) / 1** / 4*(1) / 16 / 2 / 24 / 2*(1)
Man-O-WarBay / 3*(3) / 4*(4) / 5*(2) / 19 / 3 / 27 / 3
Culloden / 1*(1) / (undet.) / 4 / 16 / 1 / 27 / 0
ArnosVale / 2*(2) / 3*(3) / 3*(1) / 13 / 1 / 20 / 0
*(#)- no.undeterminedatspecieslevel
** - distinguishedupto levelofclass
SeveralyearslaterLapointeetal.(2003)reportedthatdissolvedinorganicnitrogen(DIN)andchlorophyll-awithintheBRCwerehighcomparedtootherfringingreefsaroundTobagoandwereindicativeofeutrophication. Inaddition,valuesforδ15Nratios
(=15N/14N)formacroalgaeintheBRCwerewithintherangereportedforthosegrowing
onsewagenitrogen.Theyalludedtothefactthatrelativelylowcoverofhermatypiccoralsandhighcoverofmacroalgae,turfalgae,octocoralsandPalythoawasevidenceofcumulative impacts of land basednutrient enrichment.
TwoextensivesurveyswereconductedonthereefsinSpeyside,thefirstbeingLaydoo(1985e)andthesecondbyIMA(2002).Laydoo’sstudy–apreliminaryinvestigationofthenatureanddistributionofthereefsatSpeyside–foundthatspeciesdistributionandabundanceappearedtoberelatedtothestructuralzonationofthereefs.Hydrozoansandzoanthidswerecommonontheshallowreefflats,octocoralsandstonycoralsdominantontheforereefslopesandblackcoralsandspongesabundantonthelowerforereefareas.Intotal48speciesofhydrozoans,octocorals,zoanthids,stonycoralsandblackcorals wererecorded in his surveys(Table 1.2).
IMA(2002)alsofoundscleractinians,gorgoniansandspongestobethedominantorganismsobservedonthereefs.Thisstudy,whichalsoincorporatedphysicaloceanography,waterandsedimentqualityandmicrobiologicalanalysiswiththebiological/ecological components found that cover of live substrate did not change
significantlysincetheLaydoo1985survey.However,manydiseasedcoralswereobserved,especiallythereefbuildingcorals–Montastreaannularis,SiderastreasidereaandDiploriastrigosa.Infectionincoralswasobservedatalldepths.InadditiontothisthepopulationofDiademawasstilllowfollowingmassmortalitythatoccurredregionwide(Lessiosetal.1984,Laydoo1985f).AlgalmatsobservedcoveringdeadcoralsatBigReefandLucyValeReefintheSpeysideareaweremostlikelyasignofthestrainedpopulations.
Alongwith BuccooandSpeyside, thenature anddistribution of reefsat Man-O-WarBay,CullodenBay andArnosValewasalsodeterminedbyLaydoo(1985b-d).ThecoralreefsinMan-O-WarBaywerepreviouslysurveyedbyRamsaroop(1981).HecarriedoutobservationsandidentifiedbenthicinhabitantsatBoobyIslandReef,RestHouseReefandPirate’sBayReef.Noquantitativeinvestigationswerecarriedout,butanideaofspeciesnumber in varyingbenthicclasses andsubclasseswasascertained(Table1.1).
Although,reefsatMan-O-WarBaylacklagoons-whichsuggestthatthesereefsareyoungerthantheBuccooReef-RamsarooppostulatedthatbeingfurtherremovedfromtheeffectsoftheOrinocoRivereffluent,especiallylowersalinityandhigherturbiditylevels,allowedreefsatMan-O-WartobemorespeciesrichthantheBuccooReef.BothheandLaydoo(1985b)endorsedthehugepotential,especiallyofRestHouseandTurpin’sReef,formarinetourism,duetotheiraccessibility.Theydidstresshowever,thatthischaracteristiccouldalsoprovedisadvantageousifproperconservationprecautions werenot taken.
Man-O-WarBayreefswereimpactedby themortalityofDiademaantillarumwhichwasfirstofficiallydocumentedonTobago’sreefsinMarch1984atMan-O-War’sBoobyreef(Laydoo1985f).Pre-mortalityestimatesherewereapproximatelyfive(5)urchins.m-2.Asalludedtoearlier,thismassmortalitywasaregionwidephenomenonintheCaribbean(Lessioset al. 1984)with all reefs in Tobagoeventuallybeing affected.
SurveysatCullodenBay,onTobago’sleewardcoast,indicatedthatthereefsystemwasinayouthfulandvigorousstageofdevelopment(Laydoo1985c).Thiswasinferred
throughthepresenceofadiversebenthicfauna(Table1.2)andmoreso,a‘spurandgroove’fore-reefmorphology.Thereefcomprisedofnumeroussedimentchannels,atrightanglestothecoastline,separatedbybuttressesmadeofmainlylarge,hermatypicstonycorals.Atthetime,anthropogenicimpactswerenegligibleapartfromsomefishingactivityinthemarineareaadjacenttothereef.HoweverevidenceofstormdamageandwhitebanddiseasewasobservedintheshallowwaterAcroporapalmata.LikeDiademadieoff,highmortalityofA.plamataduetowhitebanddiseasewasalsoreportedinTobago(Laydoo1985g),andbyextension,aregionwidephenomenon.Nonetheless,thediversemarinelifeandrelativelyundisturbedenvironmentatCullodenBayledLaydoo(1985h)tosuggestthatthereefsystemcanrepresentacontrolsiteinmonitoringenvironmentalimpacts atotherreeflocalities in Tobago.
Laydoo(1985d)providestheonlyliteraturetodateonthenatureanddistributionofreefsinArnosVale.ItwasfoundthatreefsherehadlowerspeciesdiversitycomparedtootherreeflocalitiesaroundTobago(Table1.2).Thesmallerhorizontalandverticalextentofthereefareasinthebaywasproposedasareasonforthis.Nonetheless,itwasapopularareaforsnorkellersalthoughitwasfoundthatthereefsremainedgenerallyundisturbedbytheiractivities.Inadditiontothis,environmentalfactorsthatcouldbedetrimentaltomarinelife, suchas sedimentation and pollution,wereminimal.
InanexecutivesummaryoftheecologicalsurveyofreefsaroundTobago(Laydoo1985h)severalconclusionswerearrivedat.Theseincludedthefactthatextensivedistributionofcoralrubble,observedinmanyshallowreefareas,couldbeattributedtotheeffectsofstormsandhurricanes.Thisrubbleframeworkinturncontributedtoanenhancedhabitatthatledtohighfishdiversityandabundanceonthereefs.Laydoo(1985h)alsoconcludedthatconflictsexistedinspaceutilizationatmanyofthelocalitiesinvestigated,especiallybetweenartisanalfishingactivitiesandmarinetourismandrecreation activities. Similarconflicts still remaintoday.
In2004,whilepreparingtheStateoftheMarineEnvironmentReport,itbecameapparentthattherewasalackofrecentinformationonthestateofreefsinTobagoexceptfor
BuccooReefwhichhasbeenmonitoredundertheCARICOMPproject.Inaddition,therehavebeenmanyrequestsfromthepublicforinformationonthestateofreefs.Thus,commencinginlate2007,throughtheIMA’sCoralReefMonitoringProject,whichisacomponentofthelargerCoastalConservationProject,are-surveyingofthemajor reefs in Tobago took place.
Thisresearchprojectwasdesignedtoaddressthelackofinformationonthehealthofthemajorreefsystems.ReefsatBuccoo,Culloden,ArnosVale,Man-o-WarBayandSpeyside,whichwerequalitativelyandquantitativelysurveyedinthe1980s,werere-surveyed.Theaimwastoidentifychanges/impactstotheseareas.Inaddition,thefringingreefsofLaGuira Baywerealsosurveyed.Littlequalitativeandmore so,quantitativecoralreefresearchhasbeencarriedouthere(IMA1990)althoughitiswellknown thatdiversereefs,increasingin popularityas dive sites,can befound in this area.
2.0METHODOLOGY
SurveysofreefsinsixareasofTobago(Figure2.1)wereconductedusingabelt-quadratmethod (Dodge et al. 1982) to quantitativelydescribethe non-living and livingbenthos intermsofspeciesfrequency,densityandcover.Infiveofthereefareas,theirassociatedsamplingsitesweredeterminedusingmapsfromLaydoo(1985a-e).Asixthareawithreefs,LaGuiraBay–locatedontheAtlanticsideofsouthwestTobago–wasnotpreviouslysurveyedbyLaydoobutthelackofquantitativedataofreefsinthisregionanditsincreasingimportanceindivetourismwarranteditsinclusioninthisstudy.Heremajordivespotsintheareawereselectedaslocationsforsamplesites.SurveydepthsateachofthesamplinglocalitiesthroughoutthereefareasinTobagowere3m,9m,16mand 21m, fore-reef slopestructurepermitting(Table2.1).
Figure2.1:Map ofTobago
Table2.1:DepthssurveyedatthevarioussamplingsiteslocatedinthedifferentreefareasstudiedaroundTobago.Numberofsurveydepthswasdependentuponthefore-reefslopestructureat thesites
Area / SamplingSite / SurveyingDepthsArnosValeBay(Figure2.2) / EasternsideofArnosValeBay / 3m,9m
WesternsideofArnosValeBay / 9m
Buccoo(Figure2.3) / EasternReef,Buccoo / 3m,9m
OuterReef,Buccoo / 3m,9m,16m
NorthernReef,Buccoo / 3m,9m,16m,21m
WesternReef,Buccoo / 3m,9m,16m,21m
CullodenBay(Figure2.4) / EasternsideofCullodenBay / 3m,9m,16m,21m
WesternsideofCullodenBay / 9m,16m
Man-o-WarBay(Figure2.5) / EasternsideofBoobyIsland / 3m,9m,16m,21m
WesternsideofBoobyIsland / 3m,9m
RestHouseReef / 3m
Pirate'sReef / 3m,9m
LaGuiraBay(Figure2.6) / DivesiteknownasCove Ledge(2sites) / 9m
DivesiteknownasMajeston(2sites) / 9m
FlyingReef(5sites) / 9m
Speyside(Figure2.7) / InlinewithconcreteJettyadjacenttowhitehouseonGoatIsland / 3m,9m,16m,21m
Approximately100mSouthofjetty / 3m,9m,16m,21m
Approximately100mNorthofjetty / 3m,9m,16m,21m
AmethodologysimilartothatadoptedbyLaydoo(1985a-e)wasappliedtoallowforeasiercomparisonofthetwostudies.Ateachsamplingdepthasequenceofeight1.0m2quadratswerephotographed.Asampleareaof8.0m2waspreviouslydeterminedtobeoptimumbyLaydoo(1985a-e)throughtheuseofaspeciesareacurve.Attherespectivedepthsateachsamplinglocalitythestartingpointforphotographsi.e.photoquadrat1,wasselectedatrandomwithsuccessivephotoquadratstakenthereafterat2mintervals
alongthecontours.
Figure2.2:Map ofArnosValeReefshowinggenerallocationofsurveysites
Figure2.3:Map of BuccooReefshowinggenerallocationofsurveysites
Figure2.4:Map ofCullodenBayshowinggenerallocationofsurveysites
Figure2.5:Map ofMan-o-WarReefshowinggenerallocationofsurveysites
Figure2.6:Map ofLaGuiraBayshowinggenerallocationofsurveysites
Figure2.7:Map ofSpeysideReefshowinggenerallocationofsurveysites
ThephotoquadratsweretakenusingaCanonS3-ISdigitalcamerawithanIKELITEW-
20underwaterwideangleconversionlens(magnification0.56x).ThecamerawasenclosedinanIKELITEunderwaterhousing.Theentiresetupwasattachedtoa1.3mrodwhichmaintainedafixeddistancebetweencameraandreeftoensureaminimumareaof1.0m2wascaptured in each photoquadrat(Plate2.1).
Plate2.1:Photoquadratfrom16mdepthatWesternReef,Buccoo
ThephotoquadratswereanalysedusingtheNationalCoralReefInstitute(NCRI)/NovaSouth-easternUniversityOceanographicCentre’sCoral Point Count with Excelextensionsprogram(CPCeV3.4).ThroughCPCeseventyfive(75)randompointswereappliedtoeachphotoquadrat.Laydooinhis1985studiesused450pointshoweveruseofthismanyintheseassessmentswasdeterminedtobeimpractical.Seventyfiverandompoints was found to be sufficientthrough the useofspecies recoverycurves(Figure 2.8).
Figure2.8:Speciesrecoverycurvesforeightphotoquadratsat9mCullodenWest(SiteA)and16mBuccooWesternReef(SiteB).Speciesrecoverycurveswereusedtodeterminetheappropriatenumberofrandompointstobeusedforanalysisofphotoquadratsin thisstudy
Sixteenphotoquadrats,eighteachfromwhatweredeemed,throughpreliminaryinvestigations,tobethetwomostspeciesdiversesamplingsites,wereoverlaidusinginitiallyfifty(50)randompoints.Thenumberofpointswasincreasedbyincrementsoffiveuntilallcoralspecieswithinphotoquadratfellunderatleastonerandompointovertheseriesofoverlays.Themaximumnumberofpointsneededtodothisduringthetestingofthesixteenphotoquadratswasthentakenasthenumbertobeusedinphotoquadratanalysis inthe study.
Inthestudy,thenon-living/livingbottomunderlyingeachrandompointwasidentified.Livingbottomwasidentifiedtospecieswherepossible,especiallyinthecaseofhardcorals,andtheresultsexpressedasmeanspeciescover(%m-2)andfrequency(%).Thenumberofcolonies,irregardlessofwhetherornottheyunderlayarandompoint,ofeachhardcoralspecies,gorgonian(familylevelprimarilyandgenuslevelinthecasesof
Pseudopterogorgia,ErythropodiumandBriareum)andsponges(familylevel)inthephotoquadratwasalso counted to obtain mean densities (col.m-2).
TheAGRRA(2005)rapidassessmentmethodwasalsoappliedtoobtaininformationonadditionalparameterssuchasrecruitment,presence/absenceofDiademaantillarumanddiseaseandbleachingoccurrence.Atwenty(20)metretransectlinewaslaidjustabovethereefsurfaceateachsampledepth.Indisease/bleachingassessment,anystonycoralforwhichanypartofitsskeletonunderlaythetransectlinewasobserved.Affectedcoralspeciesandpercentageofcoralsurfaceimpactedwasrecorded.Thetypeofcoraldisease/severityofdiscolouration(forbleaching)wasalsonoted.Recruitmentwasanalysedbyrecordinganyhardcoralspeciessmallerthan2cmindiameterwithinahalfmetrebeltoneithersideofthetransectline.AnyDiademaantillarumseenwithinthesehalfmetrezones were alsorecorded.
3.1RESULTS
3.2ARNOSVALE
ArnosVale’sreefsextendedtoamaximumdepthofabout10mallowingforsurveystobeconductedatonlytwodepths.Ataneasternlocality,thereefflatat3mandupperforereefat9mwassurveyedwhileonlyadepthof9mwassurveyedatawesternlocality(Figure 2.2).
At3mthetotallivebottomcoverwasveryhigh(97.8%)withencrustingcorallinealgae(41.2%cover)andthezoanthidPalythoacaribaeorum(39.3%cover)dominatingthespeciesassemblage(Table3.1.1).Hardcoralmadeuponly11.2%ofthebenthoswithMilleporacomplanata(6%cover,1.375col.m-2)and,toalesserextent,theknobbybraincoralDiploriaclivosa(2.1%cover,1.5col.m-2)dominatingamongthe7hardcoralspeciesrecorded(Table3.1.2). Incomparisontotheothermajorgroupsrecorded,
sponges(4.8%cover)andgorgonians(1.3%cover)coveredaverylimitedamountofthebenthos.
Table3.1.1: Speciescover onreefcrest(3m)at ArnosValesurveysite
ArnosVale3mMAJOR CATEGORY (% of transect) / Species(%of transect) / ArnosValeEast / MEAN
HARDCORAL / 11.17 / 11.17
Diploriaclivosa / 2.17 / 2.17
Diploriastrigosa / 0.83 / 0.83
Faviafragum / 0.33 / 0.33
Meandrinameandrites / 0.50 / 0.50
Milliporaalcicornis / 0.33 / 0.33
Milliporacomplanata / 6.00 / 6.00
Porites astreoides / 1.00 / 1.00
GORGONIANS / 1.33 / 1.33
Erythropodium / 0.33 / 0.33
Gorgonian(general) / 1.00 / 1.00
SPONGES / 4.83 / 4.83
ZOANTHIDS / 39.33 / 39.33
Palythoasp. / 39.17 / 39.17
Zoanthid(general) / 0.17 / 0.17
ENCRUSTINGCORALLINE ALGAE / 41.17 / 41.17
SAND, PAVEMENT, RUBBLE / 2.17 / 2.17
Table3.1.2:Speciesmean density andfrequency onreefcrest(3m)atArnosValesurveysite
ArnosVale3m / MeanDensity(col.m-2)(n=8) / Frequency(%)Species / ArnosValeEast / ArnosValeEast
Diploriaclivosa / 1.5 / 62.5
Diploriastrigosa / 0.5 / 37.5
Faviafragum / 0.75 / 25
Meandrinameandrites / 0.125 / 12.5
Milliporaalcicornis / 0.125 / 12.5
Milliporacomplanata / 1.375 / 62.5
Porites astreoides / 0.375 / 37.5
Erythropodium / 0.25 / 12.5
Gorgonian(general) / 0.5 / 25
Sponge / 3.5 / 87.5
At9mthetotalmeanlivecoverdroppedtoabout60%.Herearedmacroalgae(unknownspecies:tuftlike,growingonrubble)dominatedwithanaveragecoverof22.2±0.2%(Table3.1.3).Meanhardcoralcoverwas14±7.5%althoughcoveratthewesternsurveysitewasmorethantwicethatattheeasternlocality(19.3%and8.7%coverrespectively).Onaveragehowever, noonehardcoralspeciesdominatedoutofthe14recorded.Diploriastrigosa(4.5±0.7%)andMontastreacavernosa(3.7±4%)hadthehighestcoverages.Encrustingcorallinealgaealsohadafairmeanpercentagecover(12.9±17.3%)althoughthiswaslargelybecauseitmadeup25.2%ofthecoveratthewesternsurveysitewithonly0.7%coverrecordedattheeasternsite.Alltheothermajorcategorygroupings–sponges,gorgoniansandzoanthidseachhadapproximately5%or
lessmeancoveralthoughspongecoverwasrelativelyhigh(7.8%,4.25col.m-2)atthe
western locality(Table 3.1.4).
Table3.1.3:Speciescoveron the upperforereef(9m)atArnosValesurveysites
ArnosVale9mMAJOR CATEGORY (% of transect) / Species(%of transect) / ArnosValeEast / ArnosValeWest / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 8.67 / 19.33 / 14.00 / 7.54 / 5.33
Agariciaagaricites / 0.00 / 0.33 / 0.17 / 0.24 / 0.17
Dichocoeniastokesi / 0.00 / 0.50 / 0.25 / 0.35 / 0.25
Diplorialabyrinthiformis / 0.17 / 1.17 / 0.67 / 0.71 / 0.50
Diploriastrigosa / 5.00 / 4.00 / 4.50 / 0.71 / 0.50
Meandrinameandrites / 0.17 / 0.83 / 0.50 / 0.47 / 0.33
Milliporaalcicornis / 1.17 / 0.83 / 1.00 / 0.24 / 0.17
Milliporacomplanata / 0.00 / 1.50 / 0.75 / 1.06 / 0.75
Montastraeacavernosa / 0.83 / 6.50 / 3.67 / 4.01 / 2.83
Montastreafaveolata / 0.00 / 2.50 / 1.25 / 1.77 / 1.25
Mycetophylliaferox / 0.17 / 0.00 / 0.08 / 0.12 / 0.08
Porites astreoides / 0.17 / 0.50 / 0.33 / 0.24 / 0.17
Scolymiacubensis / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
Siderastrearadians / 0.50 / 0.17 / 0.33 / 0.24 / 0.17
Siderastreasiderea / 0.50 / 0.33 / 0.42 / 0.12 / 0.08
GORGONIANS / 6.00 / 2.00 / 4.00 / 2.83 / 2.00
Briareum / 0.83 / 0.00 / 0.42 / 0.59 / 0.42
Erythropodium / 1.33 / 0.33 / 0.83 / 0.71 / 0.50
Gorgonian(general) / 0.83 / 0.50 / 0.67 / 0.24 / 0.17
Pseudopterogorgia / 3.00 / 1.17 / 2.08 / 1.30 / 0.92
SPONGES / 3.00 / 7.83 / 5.42 / 3.42 / 2.42
ZOANTHIDS / 0.83 / 2.67 / 1.75 / 1.30 / 0.92
Palythoasp. / 0.83 / 2.67 / 1.75 / 1.30 / 0.92
MACROALGAE / 22.00 / 22.33 / 22.17 / 0.24 / 0.17
Macroalgae(general) / 22.00 / 22.33 / 22.17 / 0.24 / 0.17
ENCRUSTING CORALLINE ALGAE / 0.67 / 25.17 / 12.92 / 17.32 / 12.25
SAND, PAVEMENT, RUBBLE / 58.83 / 20.67 / 39.75 / 26.99 / 19.08
21
Table3.1.4: Speciesmeandensity andfrequencyon the upperfore reef(9m)at ArnosValesurveysites
)
3.3BUCCOO
TheforereefslopestructureontheBuccooReefallowedforsurveystobeconductedatallfourdepthsattwosites(NorthernreefandWesternreef),3mthrough16mdepthsatOuterreefandonlythe two shallowest depths atEastern reef (Figure2.3).
Thetotalmeanlivecoverat3mwasjustunder80%withPalythoacaribaeorum,azooanthid,makinguponaverage,32±40.9%outofthatlivecover(Table3.2.1).TherewasgreatvariabilityinPalythoacoverthroughoutthesurveylocalitieshowever,with86.3%and40.7%coveratOuterandNorthernreefsrespectively,whereastherewaslessthan1%coveratWesternreef.AtEasternreef noPalythoa wasrecorded.
Encrustingcorallinealgawasalsoadominantcomponentofthebenthosat3m(22.8±19.5%meancover)butlikePalythoawasalsohighlyvariableamongsurveysites.Meanmacroalgalcoverwas14.3±16.9%atthisdepth.However,macroalgaeandPalythoacoveragevariedinversely-macroalgalcoverwashigh(35%atWesternreefand21.3%atEasternreef)wherePalythoacoveragewaslowandviceversa.TherewasverylittletonomacroalgalcoverattheOuterandNorthernreefsites.Meanhardcoralcoverwasonly5.6±4.3%withMilliporasp.makingupoverhalfofthisfigure.Milliporacomplanatacoverage(9.3%)(Table3.2.1)and
density (6.25col.m-2)(Table3.2.2)wasparticularly highatEasternreef.Gorgonians(2.6±4.7%)
andsponges(1.4±1.3%)showed verylowcoverageat 3m.
Encrustingcorallinealgaedominatedthelivingbenthosat9maccountingfor38.8±38.7%ofthetotalmeanlivingcover,whichwasabout71%(Table3.2.3).Variabilityincoveramongsiteswashigh,rangingfrom0%atEasternreefto82.3%atNorthernreef.Atthisdepth,meanhardcoralandgorgoniancoverwerebothabout14%eachwithMontastreafaveolatadominating(6.3±5.1%)thecoverforthe12hardcoralspeciesrecorded,andErythropodiumcaribaeorum(5.8±2.9%)doingthesameforthegorgoniancategory.Interestingly,hardcoralcoverdecreasedsteadilyfromsitetositeasonemovedinaneasttowestdirectionaroundthearcofreefplatformsthatmakeuppartoftheBuccooReefcomplex.Itwasalsoobservedthatonaverage,23.2±17.3%ofthecoralwasaffectedbyyellowbanddisease.Thehighestincidencestookplace
Table3.2.1:Speciescoveron thereefcrest(3m)atBuccoosurveysites
Buccoo3mMAJOR CATEGORY (% of transect) / Species(%of transect) / Buccoo EasternReef / BuccooOuterReef / BuccooNorthernReef / Buccoo WesternReef / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 11.50 / 2.33 / 2.50 / 6.17 / 5.63 / 4.30 / 2.15
Acroporapalmata / 0.00 / 0.00 / 0.00 / 2.33 / 0.58 / 1.17 / 0.58
Diploriaclivosa / 0.00 / 0.00 / 0.67 / 3.67 / 1.08 / 1.75 / 0.88
Diploriastrigosa / 0.00 / 0.00 / 0.17 / 0.00 / 0.04 / 0.08 / 0.04
Faviafragum / 0.00 / 0.00 / 0.17 / 0.17 / 0.08 / 0.10 / 0.05
Milliporaalcicornis / 1.33 / 1.83 / 0.67 / 0.00 / 0.96 / 0.80 / 0.40
Milliporacomplanata / 9.33 / 0.50 / 0.50 / 0.00 / 2.58 / 4.51 / 2.25
Montastraeaannularis / 0.33 / 0.00 / 0.00 / 0.00 / 0.08 / 0.17 / 0.08
Porites astreoides / 0.50 / 0.00 / 0.33 / 0.00 / 0.21 / 0.25 / 0.13
GORGONIANS / 0.83 / 0.00 / 9.67 / 0.00 / 2.63 / 4.71 / 2.36
Erythropodium / 0.83 / 0.00 / 0.67 / 0.00 / 0.38 / 0.44 / 0.22
Gorgonian(general) / 0.00 / 0.00 / 9.00 / 0.00 / 2.25 / 4.50 / 2.25
SPONGES / 1.50 / 0.33 / 3.17 / 0.67 / 1.42 / 1.27 / 0.63
ZOANTHIDS / 0.00 / 86.33 / 40.67 / 0.83 / 31.96 / 40.92 / 20.46
Palythoasp. / 0.00 / 86.33 / 40.67 / 0.83 / 31.96 / 40.92 / 20.46
MACROALGAE / 21.33 / 0.67 / 0.33 / 35.00 / 14.33 / 16.92 / 8.46
Halimeda / 0.00 / 0.00 / 0.33 / 0.17 / 0.13 / 0.16 / 0.08
Macroalgae(general) / 21.33 / 0.67 / 0.00 / 34.83 / 14.21 / 16.95 / 8.47
ENCRUSTING CORALLINE ALGAE / 2.17 / 10.00 / 40.17 / 38.67 / 22.75 / 19.52 / 9.76
SAND, PAVEMENT, RUBBLE / 62.67 / 0.33 / 3.50 / 18.67 / 21.29 / 28.72 / 14.36
Table3.2.2:Speciesmeandensity andfrequency onthe reef crest(3m)at Buccoosurveysites
Buccoo3mMeanDensity(col.m-2)(n=8)Frequency(%)
Species / BuccooEasternReef / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReef / BuccooEasternReef / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReefAcroporapalmata / 0 / 0 / 0 / 0.125 / 0 / 0 / 0 / 12.5
Diploriaclivosa / 0 / 0 / 0.375 / 2 / 0 / 0 / 37.5 / 100
Diploriastrigosa / 0.125 / 0 / 0.125 / 0 / 0 / 0 / 12.5 / 0
Faviafragum / 0 / 0 / 0.25 / 0.125 / 0 / 0 / 12.5 / 12.5
Milliporaalcicornis / 1.625 / 1.375 / 0.75 / 0 / 50 / 75 / 37.5 / 0
Milliporacomplanata / 6.25 / 0.375 / 0.25 / 0 / 75 / 12.5 / 25 / 0
Montastraeaannularis / 0.25 / 0 / 0 / 0 / 12.5 / 0 / 0 / 0
Porites astreoides / 0.25 / 0 / 0.125 / 0 / 12.5 / 0 / 12.5 / 0
Erythropodium / 0.5 / 0 / 0.5 / 0 / 37.5 / 0 / 25 / 0
Gorgonian(general) / 0 / 0 / 4 / 0 / 0 / 0 / 75 / 0
Sponge / 0.875 / 0.125 / 1.125 / 0.625 / 50 / 12.5 / 37.5 / 37.5
Table3.2.3:Speciescoveron the upperforereef(9m)at Buccoosurveysites
Buccoo9mMAJOR CATEGORY (%of transect) / Species(%of transect) / Buccoo EasternReef / BuccooOuterReef / BuccooNorthernReef / Buccoo WesternReef / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 20.50 / 17.67 / 10.00 / 7.00 / 13.79 / 6.34 / 3.17
Agariciaagaricites / 0.00 / 0.00 / 0.50 / 0.00 / 0.13 / 0.25 / 0.13
Colpophyllianatans / 0.00 / 1.33 / 0.00 / 0.83 / 0.54 / 0.66 / 0.33
Diplorialabyrinthiformis / 0.00 / 0.00 / 0.33 / 0.50 / 0.21 / 0.25 / 0.13
Diploriastrigosa / 0.00 / 0.00 / 1.17 / 1.67 / 0.71 / 0.84 / 0.42
Eusmiliafastigiata / 0.00 / 0.00 / 0.00 / 0.33 / 0.08 / 0.17 / 0.08
Milliporaalcicornis / 11.50 / 0.33 / 1.33 / 0.00 / 3.29 / 5.50 / 2.75
Milliporacomplanata / 5.33 / 0.50 / 0.17 / 0.00 / 1.50 / 2.56 / 1.28
Montastraeaannularis / 1.00 / 0.00 / 0.00 / 0.00 / 0.25 / 0.50 / 0.25
Montastreafaveolata / 2.33 / 13.50 / 6.17 / 3.00 / 6.25 / 5.11 / 2.56
Porites astreoides / 0.33 / 0.17 / 0.33 / 0.00 / 0.21 / 0.16 / 0.08
Porites porites / 0.00 / 0.00 / 0.00 / 0.67 / 0.17 / 0.33 / 0.17
Siderastreasiderea / 0.00 / 1.83 / 0.00 / 0.00 / 0.46 / 0.92 / 0.46
GORGONIANS / 4.17 / 12.33 / 5.67 / 32.83 / 13.75 / 13.21 / 6.60
Briareum / 0.00 / 0.00 / 0.00 / 18.00 / 4.50 / 9.00 / 4.50
Erythropodium / 4.17 / 7.50 / 2.50 / 8.83 / 5.75 / 2.92 / 1.46
Gorgonian(general) / 0.00 / 2.17 / 3.17 / 4.67 / 2.50 / 1.96 / 0.98
Pseudopterogorgia / 0.00 / 2.67 / 0.00 / 1.33 / 1.00 / 1.28 / 0.64
SPONGES / 4.50 / 0.33 / 0.00 / 0.00 / 1.21 / 2.20 / 1.10
ZOANTHIDS / 0.00 / 0.50 / 1.67 / 0.00 / 0.54 / 0.79 / 0.39
Palythoasp. / 0.00 / 0.50 / 1.67 / 0.00 / 0.54 / 0.79 / 0.39
MACROALGAE / 6.67 / 0.00 / 0.00 / 3.17 / 2.46 / 3.18 / 1.59
Halimeda / 0.00 / 0.00 / 0.00 / 2.67 / 0.67 / 1.33 / 0.67
Macroalgae(general) / 6.67 / 0.00 / 0.00 / 0.50 / 1.79 / 3.26 / 1.63
ENCRUSTING CORALLINE ALGAE / 0.00 / 59.67 / 82.33 / 13.17 / 38.79 / 38.70 / 19.35
SAND, PAVEMENT, RUBBLE / 64.17 / 9.50 / 0.33 / 43.83 / 29.46 / 29.77 / 14.88
attheOuterandNorthernreefssamplinglocationswith38.7%and36.7%ofcoralsaffectedrespectively.YellowbanddiseaseprimarilyaffectedMonatstreafaveolata.Meanmacroalgal(2.5±3.2%)andsponge(1.2±2.2%)coveratthisdepthwereverylow.However,atEasternreefin particular,macroalgalcover(6.67%)andspongecover(4.5%, 3.375 col.m-2)(Table 3.2.4)was especiallyabove the average.
At16mdepthmeanhardcoralcoverwashighest(30.4±1.4%)(Table3.2.5)whencomparedwithallothersurveydepthsontheBuccooreef.HardcoralcoverwasconsistentlyhighatallsurveysiteswithMontastreafaveolatadominatingatOuterreef(16.2%,2.5col.m-2)andNorthernreef(9.7%,3.125col.m-2)andColpophyllianatansatWesternreef(11.3%,1col.m-2)(Table3.2.6).FourteenhardcoralspecieswererecordedandthiswasthehighestnumberrecordedatanydepthinBuccoo.Encrustingcoralline
algaealsohadsubstantial,consistentcoveragethroughoutwith anaveragecoverof27.3±7%.Gorgoniansweretheonlyothermajorcomponentofthelivingbiota(14.5±8.5%meancover)withErythropodiumcaribaeorummakingupthevastmajority(8.9±2.7%)ofthisgrouping.Gorgoniancoverwasmorevariablethanthatofhardcoralsandcorallinealgaethough,with7.2%,12.5%and23.8%coveratOuterreef,NorthernreefandWesternreefrespectively.Asalludedtoearlier,outofthetotalmeanlivingcoverof74.2%,zoanthids(1.4±1.3%),sponge(0.4±0.5%)andmacroalgal(0.2±0.3%)coverwereall extremelylow.
Totalmeanlivecoverat21montheBuccooreefwasjustunder80%withmeanencrustingcorallinealgalcoveraccountingforabouthalfofthis(40.4±3.7%)(Table3.2.7).Althoughnotashighasat16m,meanhardcoralcoverwasstillgood(21.5±7.3%)withWesternreef(26.7%)having10%highercoveragethanNorthernreef(16.3%).
Montastreafaveolata(14.3%,2.25 col.m-2and 7.2%, 2 col.m-2respectively) (Table 3.2.8)
onceagaindominatedoutofthe12speciesidentifiedatthisdepth.Althoughvariable(23.2%atNorthernreefand9%atWesternreef)meangorgoniancoverwas16.1±10%withErythropodiumcaribaeorumlargelydominatingatbothsurveysites.Onceagain,sponges(1.2±0.5%cover),macroalgae (0.3±0.5%cover)andzoanthids(0.2±0.2%cover)wereminorities in thebenthic covermakeup.
27
Table3.2.4:Speciesmeandensity andfrequency onthe upperfore reef(9m)atBuccoo survey sites
Buccoo9mMeanDensity(col.m-2)(n=8)Frequency(%)
Species / BuccooEasternReef / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReef / BuccooEasternReef / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReefAgariciaagaricites / 0 / 0.125 / 0.375 / 0 / 0 / 0 / 25 / 0
Colpophyllianatans / 0 / 0.5 / 0 / 0.5 / 0 / 37.5 / 0 / 25
Diplorialabyrinthiformis / 0 / 0 / 0.125 / 0.125 / 0 / 0 / 12.5 / 12.5
Diploriastrigosa / 0 / 0 / 0.625 / 0.875 / 0 / 0 / 25 / 37.5
Eusmiliafastigiata / 0 / 0 / 0 / 0.25 / 0 / 0 / 0 / 25
Milliporaalcicornis / 5.375 / 0.375 / 1 / 0 / 100 / 12.5 / 25 / 0
Milliporacomplanata / 2.75 / 0.375 / 0.125 / 0 / 62.5 / 12.5 / 12.5 / 0
Montastraeaannularis / 0.625 / 0 / 0 / 0 / 12.5 / 0 / 0 / 0
Montastreafaveolata / 1.375 / 2.625 / 1.375 / 1.125 / 37.5 / 50 / 50 / 75
Porites astreoides / 0.25 / 0.125 / 0.375 / 0 / 12.5 / 12.5 / 25 / 0
Porites porites / 0 / 0 / 0 / 0.125 / 0 / 0 / 0 / 12.5
Siderastreasiderea / 0 / 0.5 / 0 / 0 / 0 / 12.5 / 0 / 0
Briareum / 0 / 0 / 0 / 3.25 / 0 / 0 / 0 / 62.5
Erythropodium / 0.875 / 2.75 / 2.875 / 1.625 / 37.5 / 62.5 / 75 / 37.5
Gorgonian(general) / 0 / 0.75 / 1.125 / 4.125 / 0 / 37.5 / 37.5 / 87.5
Pseudopterogorgia / 0 / 0.5 / 0.125 / 0.375 / 0 / 37.5 / 0 / 25
Sponge / 3.375 / 0.375 / 0 / 0.125 / 100 / 25 / 0 / 0
Scolymiacubensis0000.125n/an/an/an/a
Table3.2.5:Speciescoveron themidforereef(16m) atBuccoosurveysites
Buccoo16mMAJOR CATEGORY (% of transect) / Species(%of transect) / BuccooOuterReef / BuccooNorthernReef / Buccoo WesternReef / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 31.00 / 31.33 / 28.83 / 30.39 / 1.36 / 0.78
Agariciaagaricites / 0.00 / 0.50 / 0.50 / 0.33 / 0.29 / 0.17
Colpophyllianatans / 2.00 / 8.83 / 11.33 / 7.39 / 4.83 / 2.79
Diplorialabyrinthiformis / 0.33 / 0.67 / 0.33 / 0.44 / 0.19 / 0.11
Diploriastrigosa / 1.00 / 2.50 / 5.00 / 2.83 / 2.02 / 1.17
Madracisdecactis / 0.33 / 0.17 / 0.33 / 0.28 / 0.10 / 0.06
Meandrinameandrites / 0.17 / 0.83 / 0.17 / 0.39 / 0.38 / 0.22
Milliporaalcicornis / 1.00 / 1.50 / 0.83 / 1.11 / 0.35 / 0.20
Milliporacomplanata / 1.67 / 1.17 / 0.33 / 1.06 / 0.67 / 0.39
Montastraeacavernosa / 0.00 / 2.50 / 1.33 / 1.28 / 1.25 / 0.72
Montastreafaveolata / 16.17 / 9.67 / 6.67 / 10.83 / 4.86 / 2.80
Porites astreoides / 2.83 / 0.33 / 0.50 / 1.22 / 1.40 / 0.81
Porites porites / 0.00 / 0.00 / 0.33 / 0.11 / 0.19 / 0.11
Siderastrearadians / 0.33 / 0.33 / 0.00 / 0.22 / 0.19 / 0.11
Siderastreasiderea / 5.17 / 2.33 / 1.17 / 2.89 / 2.06 / 1.19
GORGONIANS / 7.17 / 12.50 / 23.83 / 14.50 / 8.51 / 4.91
Briareum / 0.00 / 2.00 / 0.00 / 0.67 / 1.15 / 0.67
Erythropodium / 6.83 / 7.83 / 12.00 / 8.89 / 2.74 / 1.58
Gorgonian(general) / 0.00 / 1.83 / 0.83 / 0.89 / 0.92 / 0.53
Pseudopterogorgia / 0.33 / 0.83 / 11.00 / 4.06 / 6.02 / 3.48
SPONGES / 0.00 / 0.17 / 1.00 / 0.39 / 0.54 / 0.31
ZOANTHIDS / 0.00 / 2.67 / 1.50 / 1.39 / 1.34 / 0.77
Palythoasp. / 0.00 / 2.67 / 1.50 / 1.39 / 1.34 / 0.77
MACROALGAE / 0.00 / 0.00 / 0.50 / 0.17 / 0.29 / 0.17
Halimeda / 0.00 / 0.00 / 0.50 / 0.17 / 0.29 / 0.17
ENCRUSTING CORALLINE ALGAE / 25.00 / 35.17 / 21.83 / 27.33 / 6.97 / 4.02
SAND, PAVEMENT, RUBBLE / 36.83 / 18.17 / 22.50 / 25.83 / 9.77 / 5.64
Table3.2.6:Speciesmeandensity andfrequency onthemidforereef(16m)atBuccoosurveysites
Buccoo16m / MeanDensity(col.m-2)(n= / 8) / Frequency(%)Species / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReef / BuccooOuterReef / BuccooNorthernReef / BuccooWesternReef
Agariciaagaricites / 0.125 / 1.125 / 0.625 / 0 / 25 / 37.5
Colpophyllianatans / 0.125 / 0.625 / 1 / 12.5 / 50 / 62.5
Diplorialabyrinthiformis / 0.125 / 0.25 / 0.125 / 12.5 / 25 / 12.5
Diploriastrigosa / 0.25 / 0.75 / 0.75 / 25 / 50 / 50
Madracisdecactis / 0.125 / 0.125 / 0.25 / 12.5 / 12.5 / 25
Meandrinameandrites / 0.125 / 0.125 / 0.5 / 12.5 / 12.5 / 12.5
Milliporaalcicornis / 0.875 / 1.5 / 0.625 / 25 / 50 / 25
Milliporacomplanata / 0.5 / 0.25 / 0.25 / 25 / 25 / 12.5
Montastraeacavernosa / 0 / 0.5 / 0.625 / 0 / 25 / 62.5
Montastreafaveolata / 2.5 / 3.125 / 2.25 / 75 / 100 / 87.5
Porites astreoides / 1.5 / 0.125 / 1.125 / 75 / 12.5 / 25
Porites porites / 0 / 0 / 0.125 / 0 / 0 / 12.5
Siderastrearadians / 0.375 / 0.125 / 0 / 25 / 12.5 / 0
Siderastreasiderea / 1.125 / 1.375 / 0.5 / 62.5 / 62.5 / 50
Briareum / 0 / 0.5 / 0 / 0 / 25 / 0
Erythropodium / 1.25 / 2.25 / 3.125 / 87.5 / 100 / 100
Gorgonian(general) / 0 / 1 / 0.75 / 0 / 62.5 / 37.5
Pseudopterogorgia / 0.25 / 0.25 / 2.5 / 12.5 / 12.5 / 87.5
Sponge / 0.125 / 0.25 / 0.5 / 0 / 12.5 / 37.5
Scolymiacubensis / 0.125 / 0 / 0.125 / n/a / n/a / n/a
Table3.2.7: Speciescover on thelowerfore reef(21m)atBuccoosurveysites
Buccoo21mMAJOR CATEGORY (% of transect) / Species(%of transect / BuccooNorthernReef / Buccoo WesternReef / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 16.33 / 26.67 / 21.50 / 7.31 / 5.17
Agariciaagaricites / 0.33 / 0.50 / 0.42 / 0.12 / 0.08
Colpophyllianatans / 4.83 / 0.00 / 2.42 / 3.42 / 2.42
Diplorialabyrinthiformis / 0.17 / 0.17 / 0.17 / 0.00 / 0.00
Diploriastrigosa / 0.00 / 6.00 / 3.00 / 4.24 / 3.00
Eusmiliafastigiata / 0.17 / 0.67 / 0.42 / 0.35 / 0.25
Madracisdecactis / 0.17 / 1.00 / 0.58 / 0.59 / 0.42
Milliporaalcicornis / 1.17 / 0.00 / 0.58 / 0.82 / 0.58
Milliporacomplanata / 0.50 / 0.33 / 0.42 / 0.12 / 0.08
Montastraeacavernosa / 0.17 / 1.33 / 0.75 / 0.82 / 0.58
Montastreafaveolata / 7.17 / 14.33 / 10.75 / 5.07 / 3.58
Porites astreoides / 0.17 / 1.50 / 0.83 / 0.94 / 0.67
Siderastreasiderea / 1.50 / 0.83 / 1.17 / 0.47 / 0.33
GORGONIANS / 23.17 / 9.00 / 16.08 / 10.02 / 7.08
Erythropodium / 20.33 / 7.33 / 13.83 / 9.19 / 6.50
Gorgonian(general) / 1.33 / 0.67 / 1.00 / 0.47 / 0.33
Pseudopterogorgia / 1.50 / 1.00 / 1.25 / 0.35 / 0.25
SPONGES / 0.83 / 1.50 / 1.17 / 0.47 / 0.33
ZOANTHIDS / 0.33 / 0.00 / 0.17 / 0.24 / 0.17
Palythoasp. / 0.33 / 0.00 / 0.17 / 0.24 / 0.17
MACROALGAE / 0.67 / 0.00 / 0.33 / 0.47 / 0.33
Macroalgae(general) / 0.67 / 0.00 / 0.33 / 0.47 / 0.33
DEADCORALWITHALGAE / 0.33 / 0.00 / 0.17 / 0.24 / 0.17
ENCRUSTING CORALLINE ALGAE / 37.83 / 43.00 / 40.42 / 3.65 / 2.58
SAND, PAVEMENT, RUBBLE / 20.50 / 19.83 / 20.17 / 0.47 / 0.33
Table3.2.8: Speciesmeandensity andfrequencyon thelowerforereef (21m) atBuccoosurveysites
%)
32
3.4CULLODEN
ReefsateasternlocalityofCullodenwerequiteextensiveandallowedforsurveystotakeplaceatallfoursamplingdepths(Figure2.4).Atthewesternsite,however,duetoforereef slope structure,surveyswere conductedatonlytwo depths; 9m and 16m.
Oftheapproximate98%livecoverobservedat3mintheCullodenarea,encrustingcorallinealgaemadeupabout50%andPalythoacaribaeorummadeupabout32%coverage(Table3.3.1).Incomparison,spongecoveratthisdepthwas6.3%howeverthiswasthehighestmeanspongecoverforalldepthssurveyedinCulloden.Similarly,thespongedensityof4.25col.m-2wasalsothehighestobservedwhencomparedtoalltheotherlocalitiessurveyed(Table3.3.4).Nonetheless,inthisreefcrestzone,likespongecover,coverageofhardcorals(4.5%)andgorgonians(4.8%)wasrelativelylow.Theywereallhigherthanmacroalgalcover(1.3%)though,whichforthemost partwasidentified asHalimeda sp.
Totalmeanlivecoverat9mwaslower(71.2%)thanat3mbutdominancewasmoreevenlydistributedamongthemajorcategories.Encrustingcorallinealgawasonceagainmostdominantwithjustunder31±12.2%meancover(Table3.3.3).The16speciesofhardcoralsrecordedhadanaveragecoverof16.3±4.7%withMontastreafaveolataaccountingforaboutathirdofthis(5.7±7.5%).Thisspecieswasespeciallyabundantatthewesternlocality–11%(0.75col.m-2density)outof20%hardcoralcovercompared
to0.3%(0.25col.m-2 density)outof13%hardcoralcoverattheeasternsite(Table
3.3.4).Consequently,sowasthenotedoccurrenceofyellowbanddiseasewhichhasanaffinitytothisspeciesinparticular.Itaffectednearly13%ofthehardcoralscapturedinthephotoquadratstakenatthiswesternsitewhilenonewereaffectedintheEasternsite’sphotoquadrats.
Gorgoniansat9mhadameancoverofabout13±10.8%butcoverageattheeasternsurveysitewasmuchhigher(20.8%)comparedtothatofthewesternsite(5.5%)(Table3.3.3).Thiswasalsothe casewithspongecoverwhere,althoughthemeancoverwaslow(3.8±4.5%),7%coveragewasrecordedattheeasternlocalitycomparedwith0.7%atthe
westernsite.Aboutfivepercent(4.9±2.5%)meanzoanthidcoverandjustunder2%meanmacroalgal covermadeup the remainderof thetotalmean livecover.
Table3.3.1: Speciescover on thereefcrest(3m)atCullodensurveysite
Culloden3mMAJOR CATEGORY (% of transect) / Species(%of transect) / CullodenEast / MEAN
HARDCORAL / 4.50 / 4.50
Diploriaclivosa / 0.67 / 0.67
Diplorialabyrinthiformis / 0.33 / 0.33
Diploriastrigosa / 1.33 / 1.33
Faviafragum / 0.17 / 0.17
Meandrinameandrites / 0.50 / 0.50
Milliporaalcicornis / 0.17 / 0.17
Milliporacomplanata / 0.50 / 0.50
Montastraeacavernosa / 0.17 / 0.17
Montastreafaveolata / 0.33 / 0.33
Porites astreoides / 0.33 / 0.33
GORGONIANS / 4.83 / 4.83
Briareum / 0.17 / 0.17
Erythropodium / 0.17 / 0.17
Gorgonian(general) / 3.83 / 3.83
Pseudopterogorgia / 0.67 / 0.67
SPONGES / 6.33 / 6.33
ZOANTHIDS / 31.67 / 31.67
Palythoasp. / 31.67 / 31.67
MACROALGAE / 1.33 / 1.33
Halimeda / 1.33 / 1.33
ENCRUSTINGCORALLINE ALGAE / 49.50 / 49.50
SAND, PAVEMENT, RUBBLE / 1.83 / 1.83
Table3.3.2: Speciesmean density andfrequency onthe reefcrest(3m)at Cullodensurveysite
Culloden3m / MeanDensity(col.m-2)(n=8) / Frequency(%)Species / CullodenEast / CullodenEast
Diploriaclivosa / 0.25 / 25
Diplorialabyrinthiformis / 0.125 / 12.5
Diploriastrigosa / 0.25 / 12.5
Faviafragum / 0.125 / 12.5
Meandrinameandrites / 0.125 / 12.5
Milliporaalcicornis / 0.125 / 12.5
Milliporacomplanata / 0.625 / 37.5
Montastraeacavernosa / 0.125 / 12.5
Montastreafaveolata / 0.125 / 12.5
Porites astreoides / 0.625 / 25
Briareum / 0.125 / 12.5
Erythropodium / 0.125 / 12.5
Gorgonian(general) / 2.125 / 100
Pseudopterogorgia / 0.125 / 12.5
Sponge / 4.25 / 75
Table3.3.3: Speciescover on theupperforereef(9m)atCullodensurveysites
Culloden9mMAJOR CATEGORY (% of transect) / Species(%of transect) / CullodenEast / CullodenWest / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 13.00 / 19.67 / 16.33 / 4.71 / 3.33
Agariciaagaricites / 2.00 / 0.00 / 1.00 / 1.41 / 1.00
Colpophyllianatans / 1.33 / 0.67 / 1.00 / 0.47 / 0.33
Diplorialabyrinthiformis / 0.50 / 0.17 / 0.33 / 0.24 / 0.17
Diploriastrigosa / 0.83 / 2.50 / 1.67 / 1.18 / 0.83
Eusmiliafastigiata / 0.50 / 0.00 / 0.25 / 0.35 / 0.25
Isophylliarigida / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
Madracisdecactis / 0.83 / 0.33 / 0.58 / 0.35 / 0.25
Meandrinameandrites / 0.50 / 2.33 / 1.42 / 1.30 / 0.92
Milliporaalcicornis / 1.67 / 0.17 / 0.92 / 1.06 / 0.75
Milliporacomplanata / 1.17 / 0.67 / 0.92 / 0.35 / 0.25
Montastraeacavernosa / 2.00 / 0.83 / 1.42 / 0.82 / 0.58
Montastreafaveolata / 0.33 / 11.00 / 5.67 / 7.54 / 5.33
Porites astreoides / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
Scolymiacubensis / 0.17 / 0.00 / 0.08 / 0.12 / 0.08
Siderastrearadians / 0.33 / 0.33 / 0.33 / 0.00 / 0.00
Siderastreasiderea / 0.83 / 0.33 / 0.58 / 0.35 / 0.25
GORGONIANS / 20.83 / 5.50 / 13.17 / 10.84 / 7.67
Erythropodium / 2.33 / 3.67 / 3.00 / 0.94 / 0.67
Gorgonian(general) / 7.67 / 0.00 / 3.83 / 5.42 / 3.83
Pseudopterogorgia / 10.83 / 1.83 / 6.33 / 6.36 / 4.50
SPONGES / 7.00 / 0.67 / 3.83 / 4.48 / 3.17
ZOANTHIDS / 3.17 / 6.67 / 4.92 / 2.47 / 1.75
Palythoasp. / 3.00 / 6.67 / 4.83 / 2.59 / 1.83
Zoanthid(general) / 0.17 / 0.00 / 0.08 / 0.12 / 0.08
MACROALGAE / 1.83 / 1.83 / 1.83 / 0.00 / 0.00
Halimeda / 1.83 / 1.50 / 1.67 / 0.24 / 0.17
Macroalgae(general) / 0.00 / 0.33 / 0.17 / 0.24 / 0.17
DEADCORALWITHALGAE / 0.83 / 0.00 / 0.42 / 0.59 / 0.42
ENCRUSTING CORALLINE ALGAE / 22.00 / 39.33 / 30.67 / 12.26 / 8.67
SAND, PAVEMENT, RUBBLE / 31.33 / 26.33 / 28.83 / 3.54 / 2.50
36
Table3.3.4:Speciesmean density andfrequency onthe upperforereef(9m)atCullodensurveysites
%)
Totalmean livecover at16mwas just over88%.Here,meanencrusting corallinealgae covercontinued to dominatethe benthos.Itsmeancoverwas morethan threetimes higher than thatofthenexthighestmajorcategory,hardcorals(55±18.2%comparedto17.9±8.1%)(Table3.3.5).Likeat9mthough,outofthe15speciesofhardcoralsdocumentedMontastreafaveolatawasonceagainmostabundantwithanaveragecoveranddensityof9.9±6%and
1.75 col.m-2 respectively (Table 3.3.6). Gorgonians had a mean cover of just under
11.8±5.4%withPseudeopterogorgiasp.(5.6±4.1%cover)makingupabouthalfthatnumber.
Interestingly,thesurveylocalityontheeasternsideofCullodenhadalmosttwicethehardcoralandgorgoniancoverthanthewesternside.However,YellowBanddiseaseoccurrencewasalsomuchhigherherewith30.3%ofthehardcoralsaffectedcomparedto6.9%atthewesternsite.Theremainingcategories–sponges(1.3±0.2%),macroalgae(1.2±0.7%)andzoanthids (0.9±1.3%) – had verylow mean coverageat this depth.
Highcoverageofencrustingcorallinealgaewasagainobservedat21mmakingupjustover61%ofthebenthiccover(Table3.3.7).Hardcoralshadsimilarcoveragetothatobservedat9mand16mabout16%.Atthisdepthhowever,Montastreafaveolata(4.5%cover)shareditshardcoraldominancewithMeandrinameandrites(3.8%cover).Theformerwasclearlyencounteredmorefrequentlyhowever(Table3.3.8).Gorgonianshadabout10%coverwithErythropodiumcaribaeorum(5.3%)accountingforjustoverhalfofthis.Spongesmadeup4%outoftheapproximate92%livecoverdocumentedwithalmostnegligiblecontributionmadefrommacroalgae (0.5%) and nonefrom zoanthids.
Table3.3.5: Speciescover on themidfore reef(16m)atCullodensurveysites
Culloden16mMAJOR CATEGORY (% of transect) / Species(%of transect) / CullodenEast / CullodenWest / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 23.67 / 12.17 / 17.92 / 8.13 / 5.75
Agariciaagaricites / 0.33 / 0.17 / 0.25 / 0.12 / 0.08
Dichocoeniastokesi / 0.00 / 0.33 / 0.17 / 0.24 / 0.17
Diplorialabyrinthiformis / 0.17 / 0.00 / 0.08 / 0.12 / 0.08
Diploriastrigosa / 0.67 / 0.00 / 0.33 / 0.47 / 0.33
Madracisdecactis / 1.17 / 2.83 / 2.00 / 1.18 / 0.83
Meandrinameandrites / 0.83 / 0.33 / 0.58 / 0.35 / 0.25
Milliporaalcicornis / 0.33 / 0.00 / 0.17 / 0.24 / 0.17
Milliporacomplanata / 0.50 / 0.00 / 0.25 / 0.35 / 0.25
Montastraeacavernosa / 1.17 / 0.83 / 1.00 / 0.24 / 0.17
Montastreafaveolata / 14.17 / 5.67 / 9.92 / 6.01 / 4.25
Mycetophylliaaliciae / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
Porites astreoides / 0.00 / 0.33 / 0.17 / 0.24 / 0.17
Scolymiacubensis / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
Siderastrearadians / 0.00 / 0.50 / 0.25 / 0.35 / 0.25
Siderastreasiderea / 4.33 / 0.83 / 2.58 / 2.47 / 1.75
GORGONIANS / 15.67 / 8.00 / 11.83 / 5.42 / 3.83
Briareum / 0.00 / 0.33 / 0.17 / 0.24 / 0.17
Erythropodium / 2.83 / 3.83 / 3.33 / 0.71 / 0.50
Gorgonian(general) / 4.33 / 1.17 / 2.75 / 2.24 / 1.58
Pseudopterogorgia / 8.50 / 2.67 / 5.58 / 4.12 / 2.92
SPONGES / 1.50 / 1.17 / 1.33 / 0.24 / 0.17
ZOANTHIDS / 1.83 / 0.00 / 0.92 / 1.30 / 0.92
Palythoasp. / 1.83 / 0.00 / 0.92 / 1.30 / 0.92
MACROALGAE / 1.67 / 0.67 / 1.17 / 0.71 / 0.50
Halimeda / 1.67 / 0.50 / 1.08 / 0.82 / 0.58
Macroalgae(general) / 0.00 / 0.17 / 0.08 / 0.12 / 0.08
DEADCORALWITHALGAE / 0.17 / 0.00 / 0.08 / 0.12 / 0.08
ENCRUSTING CORALLINE ALGAE / 42.17 / 67.83 / 55.00 / 18.15 / 12.83
SAND, PAVEMENT, RUBBLE / 13.33 / 10.17 / 11.75 / 2.24 / 1.58
39
Table3.3.6: Speciesmeandensity andfrequencyon themidforereef(16m)at Cullodensurveysites
%)
Table 3.3.7:Speciescover on the lowerfore reef(21m)at Cullodensurveysite.
Culloden21mMAJOR CATEGORY (% of transect) / Species(%of transect) / CullodenEast / MEAN
HARDCORAL / 15.67 / 15.67
Agariciaagaricites / 0.33 / 0.33
Dichocoeniastokesi / 0.50 / 0.50
Diploriastrigosa / 0.67 / 0.67
Leptoseriscucullata / 0.17 / 0.17
Madracisdecactis / 1.67 / 1.67
Meandrinameandrites / 3.83 / 3.83
Montastraeacavernosa / 1.33 / 1.33
Montastreafaveolata / 4.50 / 4.50
Porites astreoides / 0.50 / 0.50
Scolymiacubensis / 0.17 / 0.17
Siderastrearadians / 0.17 / 0.17
Siderastreasiderea / 1.83 / 1.83
GORGONIANS / 10.17 / 10.17
Briareum / 2.00 / 2.00
Erythropodium / 5.33 / 5.33
Gorgonian(general) / 2.67 / 2.67
Pseudopterogorgia / 0.17 / 0.17
SPONGES / 4.00 / 4.00
MACROALGAE / 0.50 / 0.50
Macroalgae(general) / 0.50 / 0.50
ENCRUSTINGCORALLINE ALGAE / 61.33 / 61.33
SAND, PAVEMENT, RUBBLE / 8.33 / 8.33
Table3.3.8: Speciesmean density andfrequency onthelowerforereef(21m)atCullodensurveysite
Culloden21m / MeanDensity(col.m-2)(n=8) / Frequency(%)Species / CullodenEast / CullodenEast
Agariciaagaricites / 0.375 / 25
Dichocoeniastokesi / 0.125 / 12.5
Diploriastrigosa / 0.25 / 12.5
Leptoseriscucullata / 0.125 / 12.5
Madracisdecactis / 1.125 / 75
Meandrinameandrites / 0.375 / 37.5
Montastraeacavernosa / 0.75 / 37.5
Montastreafaveolata / 1.5 / 87.5
Porites astreoides / 0.25 / 12.5
Scolymiacubensis / 0.25 / 12.5
Siderastrearadians / 0.125 / 12.5
Siderastreasiderea / 0.375 / 37.5
Briareum / 0.75 / 50
Erythropodium / 2.25 / 75
Gorgonian(general) / 1.75 / 50
Pseudopterogorgia / 0.125 / 12.5
Sponge / 0.75 / 25
3.4MAN-O-WAR BAY
ThereefsinMan-o-WarBaywerenotdeepwiththeexceptionofBoobyIsland,wheretheeasternsidewassurveyedat21m.Reefsatthethreeremainingsitesextendedtodepthsofjustover10mexceptforRestHouseReefwhosereefshadamaximumdepthofabout7m(Figure2.5).
At3mzoanthidswerethedominantgroupaccountingfor,onaverage,23.6±24.7%ofthetotalmeanlivecoverofabout61%(Table3.4.1).PalythoacaribaeorumcoverwasveryhighattheBoobyIslandwest(54.3%)andPirate’sreef(32.8%)sitesleadingtothishighmeanzoanthidcover.Atthetworemainingsitesverylittletonozoanthidswererecorded.Meanhardcoralcoverwas20.3±15.1%andthisfigureisthehighestrecordedatany3mreefareasurveyedduringthisstudy.Thismeancoverfigureisdeceptivethough,asthevariabilityamongthefourreefcrestsitessurveyedinMan-O-Warbaywashigh.WhilethehardcoralcoverattheBoobyIslandeastandwestsitesandPirate’sreefsitewereabovetheTobagowidenorm(about12%,14%and13%coverrespectively),itwasthe42.8%coverattheRestHousereeflocalitythatreallyincreased the hardcoral cover average.
TheRestHousereefsiteat3mwasdominatedalmostentirelybytheyellowpencilcoralMadracismirabilis(42.3%cover,2.375col.m-2density)(Table3.4.2)andwiththefragilenatureofthisspeciesthehighpercentagecoverofcoralrubblewithalgaehere(41.7%)wasexpected.Milliporasp.wascommonatthePirate’sreefsitebutespeciallysoatthewesternsideofBoobyIslandwhereallhardcoralrecordedwasMilliporaalcicornis.TotheeastofBoobyIslandhardcoralspeciesdiversitywashigherbutwasdominatedbyMilliporacomplanata(3.2%cover,0.5col.m-2density)andMontastreafaveolata(3%cover,0.625col.m-2density)(Table3.4.2).Intotal11speciesofhardcoralwererecordedat3minMan-o-WarBayamongthesitessurveyed.Meangorgoniancoverat3mwas 7±3%whileencrustingcorallinealgaeandspongeshadaveragecoversof4.8±4.7%and3.7±4.7%respectively.Averagemacroalgalcoverwaslowmakingup just 1.3±1.5%of thetotal benthic cover.
Table3.4.1:Speciescover onthereefcrest(3m) attheMan-O-WarBay surveysites
Man-o-WarBay3mMAJOR CATEGORY (% of transect) / Species(%of transect) / BoobyIs.East / BoobyIs. West / Pirate'sReef / RestHouseReef / MEAN / STD.DEV. / STD.ERROR
HARDCORAL / 11.67 / 13.67 / 13.00 / 42.83 / 20.29 / 15.05 / 7.53
Agariciaagaricites / 0.17 / 0.00 / 0.00 / 0.00 / 0.04 / 0.08 / 0.04
Diploriaclivosa / 0.67 / 0.00 / 0.00 / 0.00 / 0.17 / 0.33 / 0.17
Diploriastrigosa / 1.67 / 0.00 / 1.33 / 0.00 / 0.75 / 0.88 / 0.44
Madracismirabilis / 0.00 / 0.00 / 0.00 / 42.33 / 10.58 / 21.17 / 10.58
Meandrinameandrites / 1.17 / 0.00 / 0.00 / 0.00 / 0.29 / 0.58 / 0.29
Milliporaalcicornis / 0.00 / 13.67 / 3.67 / 0.50 / 4.46 / 6.35 / 3.17
Milliporacomplanata / 3.17 / 0.00 / 3.00 / 0.00 / 1.54 / 1.78 / 0.89
Montastraeacavernosa / 1.00 / 0.00 / 2.00 / 0.00 / 0.75 / 0.96 / 0.48
Montastreafaveolata / 3.00 / 0.00 / 0.00 / 0.00 / 0.75 / 1.50 / 0.75
Porites astreoides / 0.50 / 0.00 / 1.67 / 0.00 / 0.54 / 0.79 / 0.39
Siderastreasiderea / 0.33 / 0.00 / 1.33 / 0.00 / 0.42 / 0.63 / 0.32
GORGONIANS / 7.33 / 4.33 / 5.33 / 11.17 / 7.04 / 3.02 / 1.51
Briareum / 0.00 / 0.00 / 0.50 / 3.00 / 0.88 / 1.44 / 0.72
Erythropodium / 4.17 / 3.00 / 0.50 / 0.00 / 1.92 / 1.99 / 1.00
Gorgonian(general) / 1.67 / 1.33 / 0.83 / 3.00 / 1.71 / 0.93 / 0.46
Pseudopterogorgia / 1.50 / 0.00 / 3.50 / 5.17 / 2.54 / 2.26 / 1.13
SPONGES / 10.67 / 0.50 / 2.67 / 0.83 / 3.67 / 4.76 / 2.38
ZOANTHIDS / 3.67 / 54.33 / 32.83 / 3.50 / 23.58 / 24.71 / 12.35
Palythoasp. / 3.67 / 46.33 / 32.83 / 0.00 / 20.71 / 22.53 / 11.27
Zoanthid(general) / 0.00 / 8.00 / 0.00 / 3.50 / 2.88 / 3.79 / 1.90
MACROALGAE / 3.00 / 0.17 / 2.00 / 0.00 / 1.29 / 1.46 / 0.73
Macroalgae(general) / 3.00 / 0.17 / 2.00 / 0.00 / 1.29 / 1.46 / 0.73
DEADCORALWITHALGAE / 0.17 / 0.00 / 0.33 / 41.67 / 10.54 / 20.75 / 10.38
ENCRUSITNG CORALLINE ALGAE / 11.33 / 4.00 / 4.00 / 0.00 / 4.83 / 4.73 / 2.36
SAND, PAVEMENT, RUBBLE / 52.17 / 23.00 / 39.83 / 0.00 / 28.75 / 22.59 / 11.29
Table3.4.2:Speciesmean density andfrequency onthe reefcrest(3m)atMan-O-Warsurveysites
Man-o-WarBay3mMeanDensity(col.m-2)(n=8)Frequency(%)
SpeciesAgariciaagaricites / BoobyIs.East
0.125 / BoobyIs.West
0 / Pirate'sReef
0 / RestHouseReef
0 / BoobyIs.East
12.5 / BoobyIs.West
0 / Pirate'sReef
0 / RestHouseReef
0
Diploriaclivosa / 0.5 / 0 / 0 / 0 / 25 / 0 / 0 / 0
Diploriastrigosa / 0.625 / 0 / 0.875 / 0 / 50 / 0 / 50 / 0
Madracismirabilis / 0 / 0 / 0 / 2.375 / 0 / 0 / 0 / 100
Meandrinameandrites / 0.25 / 0 / 0 / 0 / 25 / 0 / 0 / 0
Milliporaalcicornis / 0 / 4.625 / 2.75 / 0.375 / 0 / 87.5 / 62.5 / 25
Milliporacomplanata / 0.5 / 0 / 1.625 / 0 / 37.5 / 0 / 100 / 0
Montastraeacavernosa / 0.625 / 0 / 1.25 / 0 / 37.5 / 0 / 37.5 / 0
Montastreafaveolata / 0.625 / 0 / 0 / 0 / 25 / 0 / 0 / 0
Porites astreoides / 0.125 / 0 / 1 / 0 / 12.5 / 0 / 50 / 0
Siderastreasiderea / 0.125 / 0 / 0.375 / 0 / 12.5 / 0 / 37.5 / 0
Briareum / 0 / 0 / 0.25 / 1.875 / 0 / 0 / 25 / 62.5
Erythropodium / 1.625 / 0.625 / 0.5 / 0 / 62.5 / 37.5 / 25 / 0
Gorgonian(general) / 1.125 / 0.75 / 1.125 / 2.25 / 75 / 37.5 / 25 / 37.5
Pseudopterogorgia / 0.5 / 0.125 / 1 / 1.75 / 25 / 0 / 62.5 / 62.5
Sponge / 6.375 / 0.625 / 3.5 / 1.75 / 87.5 / 25 / 62.5 / 37.5
Faviafragum0.125000n/an/an/an/a