14Coral Reefs: Their Functions,Threats and Economic ValueHERMAN S. J. CESARABSTRACTCoral reef ecosystems provide many functions, services andgoods to coastal populations, especially in the developingworld. A variety of anthropogenic practices threatens reef healthand therefore jeopardises the benefits flowing from theseservices and goods. These threats range from local pollution,sedimentation, destructive fishing practices and coral mining toglobal issues like coral bleaching. Economic valuation can helpto shed light to the importance of the services and goods bygetting some of the numbers on the table. Valuation tech-niques are discussed and a summary of economic studies oncoral reefs is presented. The concepts of Total Economic Valueand Cost Benefit Analysis are used to illustrate the valuation ofmarine protected areas (national parks, etc.) and of threats.1. INTRODUCTIONCoral reefs are the flowers of the sea, surrounded by fasci-natingly coloured fish with remarkable diversity. Reefs arealso rather productive shallow water marine ecosystems(Odum and Odum, 1955) that are based on rigid limeskeletons formed through successive growth, depositionand consolidation of the remains of reef-building coralsand coralline algae. The basic units of reef growth are thecoral polyps and the associated symbiotic algae that liveinthecoraltissues.Thissymbioticrelationshipisthekey factor explaining both the productivity of reefs andthe rather strict environmental requirement of corals.Differentstructuraltypesofcoralreefsaredistin-guished:(i) fringing reefs;(ii) patch reefs;(iii) barrier reefs; and(iv) atolls.Fringingreefsarethemostcommontypeofcoralreefs.They develop adjacent to the shore usually along rockycoasts of uplifted islands or along the shores of exposedlimestone islands.Patchreefsareisolatedanddiscontinuouspatchesoffringing reefs.Barrier reefs develop sometimes rather far away fromcoastlines in areas where coral growth has kept up withgradual drop of the sea-bed.Finally,atollsarecircularreefsthatarisefromdeep-sea platforms such as submerged volcanic seamounts.Coralreefshaveimportantecosystemfunctions,which provide crucial goods and services to hundreds ofmillions of people. The goods and services form an im-portantsourceofincometothelocalpopulation(fish-ery, mariculture, etc.), often living at subsistence levels.Also, they are a potential tourist attraction, thereby con-tributingtolocalincomegenerationandforeignex-change. Besides, they form a unique natural ecosystem,withimportantbiodiversityvalueaswellasscientific15andeducationalvalue.Andcoralreefsformanaturalprotection against wave erosion.Currently,however,coralreefsarebeingdepletedrapidlyinmanylocationsintheworldduetodestruc-tivefishingpractices(poisonfishing,blastfishing,muro-ami,etc.),coralmining,marinepollutionandsedimentation among others. Besides, at the global level,coral bleaching has recently become an additional majorthreat. Often, these threats are the result of externalities:peoplecausingthethreatbenefitfromunsustainableeconomicactivities,butthecostsarebornebyothersdepending in some way or another on coral reefs.HodgsonandDixon(1988)describeaclearexter-nalitysituationwhereloggingcausessedimentationresulting in reef degradation (tourism) and fishery loss-es.Fortheloggingcompany,thesetourismandfisherylossesarenotpartoftheirprofitcalculation.Intheabsence of government policy and/or public outcry, log-ging would continue even if the external costs to societyweremuchhigherthanthenetprofitsoftheloggingindustry, as was the case in the example of Hodgson andDixon.This example shows the importance of obtaining eco-nomic values for the various reef goods and services, e.g.afisheryvalueandacoastalprotectionvalue.Thesegoodsandservicescandealwithconcretemarketableproducts,suchasshellfish,forwhichthevaluecanbedeterminedbasedonthedemand,supply,priceandcosts. Other services depend on the possible future usesofyetunknownbiodiversityonreefs. Thevaluesofallthesegoodsandservicestogetherformsthe TotalEco-nomicValue(TEV)(e.g.Spurgeon,1992).ThisTEVcan be calculated for a specific area or for alternative uses(e.g.preservationarea,tourismarea,multipleusearea,etc.).Wecanalsouseeconomicvaluationtocalculatethe economic losses due to destruction of reef functions,as in blast fishing (Pet-Soede et al. 1999)Inthisoverviewchapter,thefunctions,goodsandservices of coral reefs are described first in Section 2. Thethreatstocoralreefsandtheirimpactsonthevariousreef functions will be discussed in Section 3. In Section4,economicvaluationofcoralreefsisdescribedinde-tail, followed by an enumeration of valuation techniquesin Section 5. The paper ends with a discussion.2. FUNCTIONS, GOODS AND SERVICESOF CORAL REEFSAND ASSOCIATED ECOSYSTEMSEcosystems provide a great many functions, services andgoods. The terms functions, goods and services have,in this context, slightly different meanings, though theseterms are used interchangeably by many in the environ-mentaleconomicsliterature.Costanzaetal.(1997,p. 253) define functions, services and goods in the fol-lowing way: Ecosystem functions refer variously to thehabitat,biologicalorsystempropertiesorprocessesofecosystems. Ecosystem goods (such as food) and services(suchaswasteassimilation)representthebenefitshu-man populations derive, directly or indirectly, from eco-system services. For example, a forest provides the func-tion of storage and retention of water, with the associat-ed service of water supply. Table 1 (next page) summa-risesthefunctionsandtheircorrespondinggoodsandservices that Costanza et al. (1997) investigated for coralreefs.ThedescriptionoftheexamplesistakenfromMoberg and Folke (1999).InarecentpaperbyMobergandFolke(1999),themost important goods and services of coral reef ecosys-temsaresystematicallypresented(seeTable2onnextpage).Theauthorsdistinguishgoodsintorenewableresources (fish, seaweed, etc.) and mining of reefs (sand,coral,etc.).Theservicesofcoralreefsarecategorisedinto:(i) physicalstructureservices,suchascoastalprotec-tion;(ii) biotic services, both within ecosystems (e.g. habitatmaintenance) and between ecosystems (e.g. biologi-cal support through mobile links);(iii) biogeochemical services, such as nitrogen fixation;(iv) information services (e.g. climate record); and(v) social and cultural services, such as aesthetic values,recreation and gaming.16Table 1. Ecosystem functions and corresponding goods and services of coral reefsEcosystem functions Corresponding Goods Examples for coral reefsand ServicesCapacitance, damping and integrity of ecosystem Disturbance regulation Coastal protection andresponse to environmental fluctuations sediment retentionRecovery of mobile nutrients and removal or breakdown Waste treatment Nitrogen fixation, waste ofexcess or xenic nutrients and compounds assimilation and CO2and Ca budget controlTrophic-dynamic regulations of populations Biological control Feeding placesboth within ecosystemand between ecosystemsHabitat for resident and transient populations Refugia Nurseries and habitatsThat portion of gross primary production extractable as food Food production Fish and other seafoodproductsThat portion of gross primary production extractable Raw materials Seaweed, materials foras raw materials medicine curio, jewellery,coral blocks, sandProviding opportunities for recreational activities Recreation Tourism, recreation,game-fishingProviding opportunities for non-commercial use Cultural Aestetic, cultural, religiousand spiritual valuesSource: adapted from Costanza et al. (1997) and Moberg and Folke (1999)Table 2. Goods and ecological services of coral reef ecosystems identified in Moberg & Folke (1999)Goods ____________________ Ecological services _____________________________________________________________Renewable Mining of reefs Physical Biotic Biotic Biogeo- Information Social andresources structure services services chemical services cultural servicesservices (within (between servicesecosystem) ecosystems)Sea food Coral blocks, Shoreline Maintenance Biological sup- Nitrogen Monitoring Supportproducts rubble/sand protection of habitats port through fixation and pollution recreationfor building mobile links recordRaw materials Raw materials Build up Maintenance Export organic CO2/Ca Climate Aesthetic valuesand medicines for lime and of land of biodiversity production etc. budget control and artisticcement and a to pelagic control inspirationproduction genetic library food websOther Mineral oil Promoting Regulation of Waste Sustaining theraw materials and gas growth of ecosystem assimilation livelihood of(e.g. seaweed) mangroves and processes and communitiesseagrass beds functionsCurio and Generation of Biological Support of cultural,jewellery coral sand maintenance religious andof resilience spiritual valuesLive fish andcoral collectedfor aquariumtradeSource: adapted from Moberg and Folke (1999)HERMAN S. J. CESAR:171Sometimes,whatappearslikeanaturalthreatisreallytheresultofanthropogenicthreats. Thesanderosioninareefareaisnaturalbutmaybetheresultofcoralmining,anchoring,andblastfishing.Alsovarious coral diseases can be seen as natural even though they may beexacerbated by human induced stress to the corals.2Some of the descriptions of the threats come from Cesar et al. (1997).CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUENotethatthiscategorisationisslightlydifferentthanthatofCostanzaetal.(1997).Besides,MobergandFolke additionally identify information services, such asclimate and pollution records.In the next two sections, the threats to reefs and theeconomicvalueofreefswillbediscussed.Ineachofthese, the goods and services presented above will be thebuilding blocks of the discussion.3. THREATS TO CORAL REEFSThreats or over-uses can be divided into human-inducedthreatsandnaturalthreats. Thelatter,includinghurri-cane damage, will not be discussed here further1. Thereare several categories of anthropogenic threats. Many ofthe threats to coral reefs are extensively discussed in theeditedvolumebySalvat(1987).IntheAppendix,aconcisesummaryoftherecentliteratureonthreatsisgiventhroughanannotatedbibliography.Threatscanbedividedintolocalandglobalthreats.Themainthreats at the local level are:(i) destructiveandnon-sustainablefisherypractices,such as poison fishing, blast fishing, muro-ami fish-ing among others;(ii) sedimentation, pollution, and waste;(iii) mining and dredging activities; and(iv) non-sustainable tourism practices.Currently,themainglobalthreatiscoralbleaching(Wilkinson et al. 1999). Below, seven major threats willbe discussed2. In subsequent chapters, a number of theseand other threats will be presented in detail.Poison FishingWith Hong Kong restaurant prices as high as US$ 60180perkiloforcertaintypesofgroupersandNapoleonwrasse,thewild-caughtlive-fishtradehasagoldrush-like character. Both in the restaurant retail business and inthe older aquarium fishery, cyanide is nearly exclusivelyused as the cost-effective way of harvesting live fish. Large-scalepoisonfishingvesselsoperateinremoteandun-populated areas of Indonesia and elsewhere, leaving behinda mosaic of coral destruction. Besides, the use of cyanideand other poisons for the aquarium fish has a long tradi-tion,thatisstillcontinuing,notwithstandingattemptstocurbthisactivity,forinstanceinthePhilippinesthrough the International Marinelife Alliance (IMA).In this monograph, the chapter by Mous et al. pointsout that the habitat destruction through poison fishing isnot as large as earlier anticipated. However, the overfishingaspectsofpoisonfishingandthelivereeffishtradeingeneral are very large. In another chapter, Cesar et al. de-scribe how the currently unsustainable and destructive livereef fish trade could be transformed into one that is sustain-able and non-destructive, through well-managed introduc-tion and expansion of grouper aquaculture and of regulatedsustainable fishery of live fish (both juveniles and adults).Blast FishingThoughforbiddennearlyinallcountriesintheworld,and despite the inherent dangers, home-made bombs arestill a very popular fishing gear used to catch schools ofreef fish and small pelagics and thereby earning moneytheeasyway.Inthepast,theexplosivechargecamefrom World War II bombs, though fertilisers and illegallypurchaseddynamite,oftenfromcivilengineeringprojects,arecurrentlyused. Theexplosionshattersthestonycoralsandkillsfishandinvertebratesinalargesurrounding area. Over time, blast fishing damages thewholereefandtherebydestroystheresourcebaseofmany subsistence fishers. The chapter by Pet-Soede et al.in this edited volume describes in detail the economicsof this destructive activity both from the perspective ofthe blast fisher and of society.OverfishingThoughnotnecessarilyasdestructiveastheotherthreatsdescribedabove,overfishingdoesdamagecoral18kg of TrochusFigure 1. Yield of Trochus Shells in Noloth (Central Maluku)in 1969-1992.Source: Cesar (1996)localadministrativeoffices.Coralminingnotonlyde-stroys reef flats, and thereby its coastal protection func-tion, but leads indirectly to logging of secondary forests,whichisusedforlimeburning.Notwithstandingthenegative impacts of coral mining on the coastal protec-tion service of reefs, as well as on other ecosystem servic-es, coral mining is still extensive practised in many partsof the world. Two examples of coral mining are workedout in the paper by hman and Cesar in this volume.SedimentationSedimentation, both from urban areas and from loggingactivities,smotherscoralsasitpreventsthesymbioticalgae and the coral polyps from capturing sun light andplankton respectively their primary sources of energyandnutrition.Theseproblemsareparticularlyacuteclose to estuaries of rivers and urban centres. The chap-ter by Hodgson and Dixon in this volume describe theeconomicimpactoflogging-inducedsedimentationontourismandfisheries.TheseestimatesshowthatgrossrevenuesassociatedwithlogginginthePhilippinesare2.8 lower than those of tourism and fisheries. For urban-induced sedimentation, economic costs are much moredifficult to calculate. The reason is that such dischargeshave many sources, and the reduction of these discharg-esoftenhasmanyothereconomicbenefits(suchaswater treatment benefits, etc.) making the costs to coralsprobably minor.Urban Pollution and WastePollution, both from agro-chemicals and industrial dis-charges,canalsokillcorals.Aneconomicanalysisofpollution in urban areas is presented by Russell (1992).Thispaperdescribesthecostsandbenefitsofcoastalwaste management in urban areas. As stated above, humanandindustrialwasteareresponsibleformuchofthesedimentation in urban coastal areas. Russell takes tour-ism(divingandothercoastalrecreation),fisheryandhealth (decreased incidence of dysentery and other water-bornediseases)asprimebenefitsofcoastalwasteman-agement.Annualcostspresentedofadditionalwastemanagement (sewage and solid waste) for urban centresHERMAN S. J. CESAR:reefs, mainly through a reduction in fish diversity. It alsodecreases the value to recreational divers, who are eagerto see both large predators and abundance of small col-ourful fish. In general, the necessary reduction in efforttoavoidoverfishingandachieveoptimalsustainableyieldsisinroughlyestimatedatintheorderof60percent (McManus et al, 1992). Alternative income gen-eration, for instance in eco-tourism, could be one poten-tialwayofbringingaboutthisreductionineffort.Be-sides lowering the total effort, fisheries management ef-forts should also focus on the creation of sanctuaries andestablishment of closed seasons. A number of papers onoverfishing are described in the annotated bibliographyon threats in the Appendix. In figure 1, a typical case ofoverharvestingorareefresourceisillustrated.Inthepast,mother-of-pearlshellswerecollectedinathree-year cycle following a traditional sasi-system. Since thatsystem collapsed, total yields over time have been signif-icantly lower (see Cesar, 1996).Coral MiningCorals have long been used for building material and fortheproductionoflime,aswellasintheornamentalcoraltrade. Thelimeisoftenusedasplasterormixedwithcementtoreducecostsforprivatedwellingsand05001000150020002500300035004000450069 71 73 75 77 79 81 83 85 87 89 91YearThree Year CycleOne Year Cycle19inIndonesiaareUS$987million.Thebenefitsare:tourism(US$101million),fishery(US$221),andhealth(US$4.8).HencetotalannualbenefitsareUS$327 million, or one-third of the costs.Coral BleachingDuring the period February to June 1998, a significantriseinthesurfacewatertemperatureintheIndianOcean and elsewhere was observed. Especially alarmingaboutthe1998bleachingeventwasthescopeoftheevent and the fact that many reefs previously regarded asnear pristine were seriously affected. The bleaching andsubsequentmortalitymayresultinserioussocio-eco-nomicimpacts,particularlyforthosenationswhoseeconomies are heavily dependent on the revenues gener-atedbyreef-basedtourism,andreef-basedfisheries.HardhitwerelargeareasofcoralreeffromSriLankaandtheMaldivesinSouthAsiatotheEastAfricancoastalline.ThechapterbyWestmacottetal.inthisvolume deals extensively with these socio-economic im-pacts.Compatible UsesMany of the goods and services that coral reefs provideto humans can lead to incompatibilities: the concurrentuse of the all goods and services is not possible. This isbecausecertainecosystemfunctionsexcludetheuseofotherecosystemresourcesatthesametimeandinthesameplace,e.g.biodiversityresearchandresourceex-traction. This becomes even more obvious once the re-sourceusebecomesathreat.Infact,athreatcouldbeseen as the over-use of a specific service: water pollutioninacoastalzoneisbasicallyanover-useofthenaturalpurificationfunctionofwetlands.Andcoastalzones,whicharemoreandmoredevoidoffish,havefallenvictim to the threat of overfishing.ThiscompatibilityissuehasbeenworkedoutbySpurgeon (1992) and is demonstrated in the Chapter byCesaretal.inthisvolumeonJamaicasPortlandBightProtectedArea.ThisParkisacombinedmarineandterrestrial(coastal)parkonthesouthcoastofJamaica,just west of the capital, Kingston. Many of the servicesare not necessarily compatible. Especially the extractiveuses, such as charcoal burning, tend to be incompatiblewithotherservices,suchastourismandbiodiversitypreservation.Ontheotherhand,fisheriesandtourismcan well go together, especially if some zoning is applied.Thechallengeofmanagingaprotectedareaistoallowmultiple uses while conserving nature at the same time.Successfulareamanagementincludeszoningaswellasthreat regulation.4. ECONOMIC VALUE OF CORAL REEFSThe economic value of an ecosystem is often defined asthe total value of its instruments, that is the goods andecological services that an ecosystem provides. For coralreefs,wethereforeneedtoknowitsmajorgoodsandservicesaswellastheirinteractionswithotherecosys-tems. Next, these goods and services need to be quanti-fied and monetised. For goods sold in the market place,this is straightforward by looking at their market price,but for ecological services, this is not the case. Therefore,complexvaluationtechniquesareusedtoarriveataneconomicvalueoftheseservices. Thesetechniquesarepresented in the next section. The concept of Total Eco-nomicValueandthevaluationofaspecificareaandthreatarediscussedhere.Foradiscussionontheeco-nomic valuation of coral reefs, see Spurgeon (1992) andDixon (1998).Thevalueofallthecompatiblegoodsandservicescombined gives the Total Economic Value (TEV) for anecosystem.Theneo-classicalfoundationsofeconomicvalueanditsrelationshipwithwillingnesstopayandconsumer surplus are not discussed here (see Pearce andTurner, 1990 for a general discussion and Barton, 1994andPendleton,1995foraspecificdiscussionontheeconomicvalueofcoralreefs).Eachofthegoodsandservices of coral reefs presented in table 2 above generateeconomic value. Fishery resources can be harvested andsold, creating value added and likewise, the coastal ma-rineareaenablesseatransportationthatcreatesprofits.Similarly,preservationandeco-tourismcreatevalue.The mapping between the goods and services on the oneCORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE20Figure 2. Total Economic Value and Attributes of Economic Values for Coral ReefsTotal Economic Value Use Values Non-Use ValueDirect use value Indirect use value Option value Quasi-option value Bequest value Existence valueOutputs/services Functional benefits Future direct Expected new Value of leaving use Value from knowledge ofthat can be enjoyed indirectly and indirect use information from and non-use values continued existence,consumed directly avoiding irreversible to offspring based on e.g. morallosses of: convictionExtractive: Biological support to: *species *species *threatened reef habitatscapture fisheries sea birds *habitats *habitats *endangered speciesmariculture turtles *biodiversity *way of life *charismatic speciesaquarium trade fisheries connected to *aesthetic reefscapespharmaceutical other ecosystems traditional usesNon-Extractive: Physical protection to:tourism/recreation *other coastalresearch/education ecosystemsaesthetic *coastline*navigationGlobal life-support:carbon storeSource: Barton (1994).HERMAN S. J. CESAR:handandtheirvaluesontheotherhandisstraightfor-ward, as is shown in figure 2.Asindicatedinfigure2,therearesixcategoriesofvalues:(i) direct use value;(ii) indirect use value;(iii) option value;(iv) quasi-option value;(v) bequest value; and(vi) existence value.Direct use values come from both extractive uses (fisher-ies, pharmaceuticals, etc.) and non-extractive uses. Indi-rect use values are, for example, the biological support intheformofnutrientsandfishhabitatandcoastlineprotection. The concept of option value can be seen asthe value now of potential future direct and indirect usesof the coral reef ecosystem. An example is the potentialof deriving a cure for cancer from biological substancesfoundonreefs.Bio-prospectingisawayofderivingmoney from this option value. The quasi-option value isrelatedtotheoptionvalueandcapturesthefactthatavoiding irreversible destruction of a potential future usegives value today. The bequest value is related to preserv-ingthenaturalheritageforgenerationstocomewherethevaluetodayisderivedfromknowingthatthecoralreef ecosystem exists and can be used by future genera-tions. The large donations that are given to environmen-tal NGOs in wills are an example of the importance ofthe bequest concept. The existence value reflects the ideathat there is a value of an ecosystem to humans irrespec-tive of whether it is used or not.21 CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE3Note that some of the numbers presented in table 3 are outdated andmore recent data on blast fishing and coral mining are presented in thechapters by Pet Soede et al. and hman and Cesar in this volume.These values all are quite abstract and theoretical. Inthe next section, valuation methods are discussed to seehow the economic value of these uses can be measuredin practice. Measuring these values in monetary ways isnot straightforward, and in some cases (nearly) impossi-ble.Yet,itisimportanttotaketheseintoaccount.AsDixon(1989)states:Whetheracoastalresourceisagoodorservice,marketedornonmarketed,isnotim-portant in terms of its function in the coastal ecosystem.Theextent,towhichcoastalresourcesrepresenteasilymarketedgoods,however,heavilyinfluencesresourcemanagementdecisions.Nonmarketedgoodsandenvi-ronmentalorecosystemservicesarefrequentlyover-looked or their importance played down. This is one ofthefactorsleadingtoresourcemanagementconflictsand poor decisions.OnepurposeofobtainingtheTEVofcoralreefsandusingCost-BenefitAnalysis(CBA)istogetsomenumbersonthetableforpolicydiscussions.Forin-stance, a government might consider proclaiming a spe-cific bay a Marine Protected Area (MPA) or a Multiple-UseCoastalArea(MUCA).TherearesignificantmanagementcostsinvolvedinthemanagementofMPAsandMUCAsandthegovernmentmaywanttoknow in economic terms whether the management costsareeconomicallyjustified.OragovernmentmightgetcomplaintsfromNGOsaboutcertainunsustainablecoastal activities. These activities form a threat but theygeneratequitesomecashatthesametime,andthegovernment needs to be convinced that it is worthwhileto curb the threat. Both these issues will be briefly dis-cussed.Economic Value of an MPAEstablishing an MPA is a costly affair and a governmentneeds to be well informed about the pros and cons of anadditionalMPA(McClanahan,1999).ManyMPAsindeveloping countries are basically unprotected. Such ar-easarereferredtoaspaperparks.CyanidefishersinIndonesia allegedly know exactly where the parks are, astheseareashaverelativelyabundantfisheryresourceswhile enforcement is so weak that this does not form athreat to them. Determining the economic value for anMPA involves three important steps.First,thecompatibleusesand/orthezoningoftheareas has to be determined, as discussed above. See alsoBarton (1994). Secondly, the additional contribution ofparkprotectiontothegoodsandservicesoftheecosystem(s) need to be determined. And thirdly, a CBAiscarriedoutbycomparingthenetbenefitsinstep2withthecostsofmanagement. Theactualvalueoftheparkisthendefinedasthenetincreaseinthevalueoftheecosystemduetotheestablishmentandmanage-ment of the park minus the costs of managing the park.Pendleton (1995, p.119) states: Past valuations of trop-icalmarineparksinaccuratelymeasuretheireconomicvalue because they value the resource protected and notthe protection provided.In this monograph, three papers discuss the valuation ofacoastalarea.Whiteetal.discussthenetbenefitsofcoral reef and wetland management on Olango Island inthePhilippines.Dixonetal.discussavaluationoftheBonaire Marine Park in the Netherlands Antilles. Final-ly, Cesar et al. give an economic valuation of an integrat-edterrestrialandmarineprotectedareainJamaica.Ineach of these three valuation studies, the costs of manag-ing the park sustainably are economically justified.Economic Value of a ThreatSince the economic benefits from reef destruction are oftenused to justify continuation of this threat, quantifying thecosts associated with coral reef degradation is importantto make a balanced assessment of the ben-efits and costsof various threats. To do this, a CBA is carried out wherethenetbenefitsoftheharmfulactivitytothepeoplecausingthethreatarecomparedwiththenetsocietalcosts plus the enforcement costs of actually eliminatingthe threat. To illustrate the costs and benefits of a threat,table 3 on next page presents a CBA where the societalcostsarecalculatedperecosystemserviceofthereef3.22Table 3. Total Net Benefits and Losses due to Threats of Coral Reefs in Indonesia(present value; 10% discount rate; 25 y. time-span; in 1000 US$; per km2)Net Benefits to Individuals Net Losses to Society _____________________________________________Function: Total Net Benefits Fishery Coastal Tourism Others Total NetProtection Losses (quantifiable)ThreatPoison Fishing 33 40 0 3436 n.q. 43476Blast Fishing 15 86 9193 3482 n.q. 98761Coral Mining 121 94 2-260 3482 >67.0 176903Sedimentationfrom logging 98 81 192 n.q. 273Overfishing 39 109 n.q. n.q. 109Source: Adapted from Cesar et al. (1997).Table 4. Net Benefits to Individuals: Amount per km2 and per StakeholderBenefits per stakeholder in parentheses; present value; 10% discount rate; 25 y. time-span; in 1000 US$; per km2) Individuals: Fishermen Miners, Loggers Others (payments) Total per km2Threat:Poison Fishing 29 4 33(468.6 per boat) (317-1585 per person)(23.4 per diver)Blast Fishing 15 ? 15(7.3 per fisherman)Mining 67 54 121(1.4 per mining family) (18 - 54 per person)Sedimentation 98 ? 98due to logging (1990 per log. family)Overfishing 39 39(0.2 per fisher)Source: adapted from Cesar (1996) and Cesar et al. (1997).HERMAN S. J. CESAR:Notethattheanalysisfocusesononlythreeecosystemservices,leavingoutanumberofotherservices.Totalcostsshouldthusbeinterpretedasroughestimatesofthe lower range of true costs associated with reef destruc-tion.However,thislowerboundaryalreadyprovesthepoint that reef destruction is not economically justifiedfor each of the threats.Inthisvolume,fourexamplesofeconomicanalysesofthreatsaregiven:HodgsonandDixondescribethetrade-off between logging on the one hand and tourismand fisheries on the other hand. Mous et al. discuss theeconomics of cyanide fishing. Pet-Soede et al. discuss thecostsandbenefitsassociatedwithblastfishing.Finally,hmanandCesarcomparetwocasestudiesontheeconomics of coral mining. A recent overview of valua-tionstudiesforcoralreefsisgiveninRuitenbeekand234ThecolumnOtherspresentsthepaymentstothirdpersons,some-times referred to as political rents.CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUECartier(1999),seealsothechapterbyGustavsonandHuber in this book.Stakeholder AnalysisThoughitisusefultoknowthesocietalcostandtheprofits (benefits) of a threat, it is often from a man-agementperspectiveevenmoreimportanttoknowthe economic forces that are driving destructive practic-es.Astakeholderanalysisisthereforecalledfor.Thistype of analysis aims at getting insight into the followingtwo questions:(a) whoisgainingandwhoislosingfromthecurrentsituation and a prescribed future scenario;(b) what is the size of the stake in actual dollar terms foreach stakeholder.To illustrate this point, table 4 shows the private benefitsthataccruetothevariousgroupsofstakeholdersin-volvedincausingthethreataswellastoeachofthepersons/families/boats/companiesinvolved.4 Theaggre-gated numbers (last column of table 4) correspond withthe total benefits presented in table 3 (second column).Interestingly,netbenefitspersquarekilometretoindi-vidualsappeartobehighestforcoralmining.Yet,pri-vatebenefitsperstakeholder(person/boat/company/etc.), poison fishing and logging-induced sedimentationhave by far the highest private incentives, ranging fromUS$2millionpercompanyinthecaseofloggingtooverUS$0.4millionperboatinthecaseofpoisonfishing (in present value terms). Side-payments are alsoparticularlyhigh,veryroughlyestimatedatsomeUS$0.31.5millionforsomereceiversoflargepayments.On the other extreme, coral mining is a rather marginalactivityfortheminingfamiliesinvolved(foradiscus-sion, see Cesar et al. 1997).Benefit TransferIt is often quite costly to carry out studies to determinetheprecise TotalEconomic Valueofcoralreefsineachlocation,e.g.aspecificmarinepark.However,itissometimes possible to use a meta-analysis of studies car-ried out in other, comparable, areas. The values calculatedinthosestudiesmight,ifcarefullydone,sometimesbeusedforanotherarea.Ifanextensivestudyhasbeencarried out for the fisheries and tourism potential in onemarine reserve in the Philippines, than it is not unlikelythatthesevaluescanformaproxyforanothermarinereserve elsewhere in the Philippines. Put differently, be-cause of human or financial resource constraints, valuescansometimesbetakenoutofpreviousstudieswhichfocus on a different region or time period. This practiceoftransferringofmonetaryvaluesiscalledasbenefittransfer. An example is given in the article by White etal. in this monograph.5. VALUATION TECHNIQUESIn the environmental economics literature, a host of valua-tiontechniqueshavebeendevelopedoverthelastdec-ades.Standardtechniquesinmicroeconomicsandwel-fareeconomicsrelyonmarketinformationtoestimatevalue.However,theexternalitiesinherenttoenviron-mental issues prevent these techniques from being usedmost of the time. For an elaboration of this issue that isaccessable to non-economists, see Dixon (1998). Specif-icallyfortropicalcoastalecosystems,Barton(1994)givesadetailedoverviewof15differenttechniques.Spurgeon(1992)givesaninterestingsummaryofthistopic with many actual numbers. Table 5 gives a listingofthemostcommontechniquesusedforvaluingthegoods and services of coral reef ecosystems. Three gener-al categories are distinguished:(i) directly to obtain information about the value of theaffected goods and services or of direct expenditures;(ii) potentiallyapplicabletechniques,whichusethemarketindirectlytoobtaininformationaboutval-ues and expenditures;(iii) survey based methods, which use hypothetical mar-kets and situations through, for instance, question-nairesurveyssuchasthecontingentvaluationmethod (CVM).24Table 5. Valuation Techniques used for Valuing Goods and Services of Coral Reef EcosystemsGenerally Applicable Techniques Using conventional market value of goods and services directly affectedG Change in Productivity / Effect of production (EoP);G Stock (houses, infrastructure, land) at Risk (SaR)G Loss of earnings / Human capital approach (HC);G Opportunity cost approach (OC);Using the value of direct expenditures (cost based)G Preventive expenditures (PE);G Compensation payments (CP)Potentially Applicable Techniques Using implicit or surrogate market values indirect approachesG Property-value and other land-value approaches (PV);G Travel-cost approaches (YC);Using the magnitude of potential expenditures (cost based)G Replacement costs (RP);G Shadow-project costs (SPC)Survey-Based Methods Survey-Based MethodsG Contingent valuation meth. (CVM) hypothetical markets and situationsSource: Adapted and shortened from Dixon (1988), Barton (1994).Table 6. Correspondence between the Types of Value and the Valuation MethodsType of Value Valuation MethodDirect Use ValuesG tourism (consumer surplus) Travel Cost (TC)G tourism (producer surplus) Effect on Production (EoP)G fisheries Effect on Production (EoP)Indirect Use ValuesG coastal protection Replacement costs (RC); Damage Costs (DC)Option Values Contingent Valuation Method (CVM)Quasi-option Values Contingent Valuation Method (CVM)Bequest Values Contingent Valuation Method (CVM)Existence Values Contingent Valuation Method (CVM)HERMAN S. J. CESAR:Thesevaluationtechniquesenableustoestimateinmoney terms the direct and indirect use value, as well astheoption,quasi-option,bequestandexistencevalues.We will here specifically discuss five methods, which arealsousedinmanyofthechaptersthatfollow.Thesetechniques are:(i) Effect on Production (EoP);(ii) Replacement Costs (RC);(iii) Damage Costs (DC);(iv) Travel Costs (TC); and(v) the Contingent Valuation Method (CVM).25 CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUEThesetechniquescorrespondtothevarioustypesofvalues,asshownintable6.Fordetailsonothertech-niques, see Barton (1994). Note that both TC and CVMhave many shortcomings, including problems of design-ing,implementingandinterpretingquestionnaires.However,inthecaseswheretheyareused,theyaretypically the only techniques available, as table 6 shows.Effect on Production (EoP)Thistechnique,alsoreferredtoasthechangeinpro-ductivitymethod,looksatthedifferenceinoutput(production)asthebasisofvaluingreefservices.Thetechniquemainlyappliesheretofisheriesandtourism(producer surplus) to estimate the difference in value ofproductive output before and after the impact of a threator a management intervention. Coral bleaching may, forinstance, lead to fewer dive tourists and therefore lowertourismrevenues.Hence,thechangeinnetprofit(i.e.effect on production) can be calculated, and this can beused as a proxy for the loss in tourism value. For fisher-ies,thetechniqueisusedtocalculatethelossinthefisheries value from a specific threat, such as coral min-ing or the gain in the fisheries value from a managementintervention,suchastheintroductionofamarinere-serve.Themainchallengeisthecalculationofthechangesinproductivityinphysicaltermsbetweenthewith and without scenario.AnexampleoftheEoPmethodisAlcalaandRuss(1990),whoreportonadeclineofUS$54,000inthetotal yield of reef fishes off Sumilon Island (Philippines)afterbreakdownofprotectivemanagement.McAllister(1998)givesestimatesofreefproductivityforreefsinexcellent condition (18 mt/km2/yr) as well as good con-dition(13mt/km2/yr),andfaircondition(8mt/km2/yr).Basedonchangesinconditionovertimeandesti-mates of net profits associated with these yields, McAl-listerestimatesthefisherieslossinthePhilippinesatUS$ 80 million per year.Replacement Costs (RC)Thereplacementcostapproachisusedtovaluetheecosystem service of coastal protection. Data on invest-ments to control coastal erosion are used as a proxy forthecoastalprotectionserviceofahealthcoralreef.Hence, the cost of replacing the coral reef with protec-tiveconstructions,suchasrevetmentsandunderwaterwave breakers are used.A study quoted in Spurgeon (1992) indicates that onTarawaAtollinKiribati,coastaldefencescostingUS$90,720 had to be built to prevent coastal erosion. Berget al. (1998) give a detailed analysis of the replacementcosts following years of coral mining in Sri Lanka. TheaveragecostvariesbetweenUS$246,000andUS$836,000km-1ofprotectedcoastline.Cesar(1996)quotes a case in Bali, Indonesia where coastal protectionexpendituresofUS$1millionwerespentoverseveralyears for 500 m of coastline protection. Finally, Riopelle(1995)citesinformationonahotelinWestLombokwhich has spent US$ 880,000 over a seven year periodto restore their beach stretch of around 250 m, allegedlydamaged by past coral mining.Damage Costs (DC)In the absence of coastal protection, the monetary dam-agetopropertyandinfrastructurefromsurgeandstormscanbeenormous.Hence,thedamagecostap-proach uses the value of the expected loss of the stock atrisk as straightforward proxy for the value of the coastalprotection service.Berg et al. (1998) use the cost of land loss as a proxyfor the annual cost of coastal erosion due to coral min-inginSriLanka.Dependingonlandpriceanduse,these costs are between US$ 160 and US$ 172,000 perkm of reef per year. Cesar (1996) uses a combination ofthe value of agricultural land, costs of coastal infrastruc-ture and houses to arrive at a range of US$ 90 up to US$110,000 per km of reef per year.Travel Costs (TC)This approach is often used to estimate the welfare asso-ciatedwiththerecreationaluseofaNationalPark,wherethetraveltimeortravelcostsareusedasanindicator of the total entry fee, and therefore, a personswillingness to pay for visiting a Park. The further away26 HERMAN S. J. CESAR:people live from the Park, the higher the costs are to visitthe Park. Because of the variation in these costs amongvisitors,thedemandfordifferentpricescanbedeter-minedandademandcurvefortheParkcanbecon-structedandtheassociatedconsumerssurpluscanbedetermined. Thissurplusrepresentsanestimateofthevalueoftheenvironmentalgoodinquestion(e.g.theNational Park). Both the Travel Cost method as well asthe Contingent Valuation method below have a numberof drawbacks that will be discussed later in this section.An example of TC is Pendleton (1995) who uses thismethodtoestimatethevalueoftheBonaireMarinePark. To obtain the welfare estimate, Pendleton dividesthenumberofvisitorsfromeachstate/countrybythepopulationofthecorrespondingorigin. Thisvisitationrateisthenregressedupontravelcosts,givingthede-mand curve for reef-oriented vacations to Bonaire (visi-tation rate = 0.07250.0000373 * travel costs). Based onthis estimated demand curve, the travel costs from eachregion and assuming annual visits to the marine park tobe 20,000, the total consumer surplus of visitors to theBonaire Marine Park is approximately US$ 19.2 millionannually.AnotherexampleisaTC-studyreportedinHundloeetal.(1987),withavalueofA$144millionper year for tourists visiting the Great Barrier Reef.Contingent Valuation Method (CVM)Intheabsenceofpeoplespreferencesasrevealedinmarkets,thecontingentvaluationmethodtriestoob-taininformationonconsumerspreferencesbyposingdirect questions about willingness to pay and/or willing-nesstoaccept.Itbasicallyaskspeoplewhattheyarewilling to pay for a benefit, or what they are willing toacceptbywayofcompensationtotoleratealoss. Thisprocessofobtaininginformationmaybecarriedouteither through a direct questionnaire/survey or by exper-imental techniques in which subjects respond to differ-entstimuliinlaboratoryconditions.Soughtareper-sonalvaluationsoftherespondentforincreasesorde-creases in the quantity of some goods, contingent upona hypothetical market.An example of CVM is the chapter by Spash in thismonograph.VisitorstoMontigoBay(Jamaica)andCuraao (Netherlands Antilles) were surveyed to investi-gate the consumer surplus, or individual utility, of coralreef improvement. The survey instrument was designedto capture the non-use benefits of marine biodiversity,for both local residents and for visitors. The question torespondentsdealtwiththeirwillingnesstopayforanincreaseincoralcoverinthePark.ExpectedWTPforcoralreefimprovementwasUS$3.24perpersoninasampleof1058respondentsforMontigoBay.ForCuraao, the number was US$ 2.08 per person. But thisvaluewasheavilydependentonwhetherrespondentsbelievedthatmarinesystemspossessedinherentrights,orthathumanshadinherentdutiestoprotectmarinesystems. Such preferences would increase WTP by up toa factor of three. Another example is Dixon et al.s paperinthismonograph. TheyarriveatanaverageWilling-ness to Pay for a consumer surplus of US$ 325,000 forBonaire Marine Park.ThereareanumberofbiasesassociatedwithCVMthatareimportanttonote.ThesebiaseshavegivenCVM in the eyes of some a bad name. The careful use ofCVM is therefore necessary. Barton (1994) summarisesthe following biases, described in the literature:G hypotheticalbias:Thisreferstothepotentialerrorinherent in the process that is not an actual situation.Respondentsmaynottaketheinterviewseriouslyenough to give bids reflecting their true preferences;G strategicbias:Peoplemayanswerstrategicallyiftheyfeelthattheirreplywillinfluencerealevents,i.e.ifthey feel that their willingness-to-pay bid may entailactual payment when values will be lower than other-wise;G information bias: The way in which the hypotheticalsituationisdescribedcanhaveapowerfuleffectonthe reply, involving several aspects. Design bias referstohowthequestionsarestructured.Instrumentbiaswillresultiftherespondentreactseitherwaytothehypothetical instrument or vehicle of payment that issuggested (e.g. entry fee). Starting-point bias refers totheobservationthatthestartingbidmayaffectthefinal outcome in a converging bidding process.27Table 7. System of Classifying Marine Biodiversity Valuation MethodologiesBiodiversity Production Biodiversity Utility Biodiversity Rent CaptureValuation Method Valuation Methods Valuation MethodsEconomic Basis Supply-Oriented Demand Oriented Profit-OrientedDescription Values biodiversity within an Values biodiversity within an Values biodiversity as aeconomic production function economic utility function distribution of profits or value-addedValuation Target Measures the contribution of Measures the contribution Measures one or morebiodiversity to the value of of biodiversity to the utility components of the distributionoutput in a produced good of an individual or society. of Use Values, focusing onor service. Can estimate and Can estimate aggregated captured rents, profits or valueisolate direct or indirect Use and Non-Use Values, added. Can isolate value ofUse Values, including including consumers embedded informationecological functions or surplusembedded informationExamples of Methods Cobb-Douglas production Contingent Valuation Royalty evaluationsfunction Hedonic Pricing Patent system evaluationsLinear Transforms Value of life measures Joint venture evaluationsNon-linear TransformsSource: adapted from Ruitenbeek and Cartier (1999).CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUETable 5 above gave a classification of valuation tech-niques, using three categories:(i) generally applicable techniques using direct marketinformation on values and expenditures;(ii) potentiallyapplicabletechniques,whichusethemarket indirectly, such as the TC-method; and(iii) survey based methods, such as the contingent valua-tion method (CVM).RuitenbeekandCartier(1999)giveaninterestingnewclassification of valuation methodologies, specifically formarine biodiversity. This classification, shown in table 7,is also summarised in the article by Gustavson and Hu-berinthisbook. Thisclassificationcanbedirectlyap-plied for coral reefs.6. DISCUSSIONWhy do economists want to value something as invalua-bleascoralreefs?Theanswercouldwellbe:Becausecoralreefsaresobeautifulthatwewanttomakesurethat our grandchildren can enjoy them as well. Yet, weseemanycoastalpopulationswhoareunawareofthegoods and services that coral reef ecosystems provide andwho areunable tosee through thecomplexlinkagesofthe natural world. We see people using coral reefs unsus-tainablyandevendestructively.Andweseepoliticiansunwilling to look beyond their short-sighted lenses, andconsequently we see a lack of funds for coral reef man-agement,eventhoughthelong-termcostsofinactionare typically much higher than the funds needed.Dixon(1998)givesabeautifulillustrationofwhatcouldhappenifwewouldalllookbeyondourshort-sighted own interests: In Hawaii, for example, the tra-ditional land management unit was called the ahupuaa,which was a slice of land that went from the top of themountain down to the edge of the coral reef. Thus, theindividual or group who owned the ahupuaa owned anentire functioning ecosystem, a self-contained economicand environmental unit. Any externalities were therebyinternalised, and the land managers realised that actionstaken in the upper watershed (such as agricultural pro-28ductionorlogging)wouldhaveaneffectbothonthewater quality on the taro fields in the lower watershed aswell as in the coral reef and the coastal fish ponds. Sinceallimpactswerecontainedwithinthesystem(withclearlydefinedintegratedpropertyrights),decisionswere being made taking these impacts into account andthereby balancing any tradeoffs involved. The Hawaiianahupuaasystemistheidealworld;itveryrarelyexiststoday. Usually externalities are present, and they lead totheresultsthatweobserve:mismanagement,overuse,needless destruction of precious resources.One important issue in economic valuation studies isto whom the benefits will accrue and whether these arereal or virtual. Travel costs for National Parks form thekeywelfaremeasureforthetourismfunctionofcoralreefecosystems.Someofthesecostsareactuallypaidandaccruetolocalorforeignbusinessoperators.Mostcostsare,however,virtual.Theydescribeapotentialwillingness-to-payforaspecificimprovementinreefqualityinaNationalPark.InthecaseofCVM,allvaluesarevirtualinthesensethattherearenoactualcash transactions associated. It is also important, for theeconomicanalysisofaspecificcountry,todistinguishbetweenlocalandforeigntouristsandbetweenactualexpenditures on travel costs and virtual figures. For theeconomic value of a National Park for a specific country,onlytheconsumersurplusoflocaltouristsshouldbeused. And of the actual expenditures, only those accru-ingtothehostcountry.. 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C., Rajasuriya, A., & Lindn, O., (1993), HumanDisturbances on Coral Reefs in Sri Lanka: A Case Study.AMBIO, Vol. 22, No. 7, pp. 474480.hman, M. C., Rajasuriya, A., & Olafsson, E., (1997) Reef FishAssemblages in North-Western Sri Lanka: DistributionPatterns and Influences of Fishing Practices. EnvironmentalBiology of Fishes, Vol. 49, pp. 4561.Pauly, D., & Chua, T.-E. (1988) The Overfishing of MarineResources: Socioeconomic Background in Southeast Asia.AMBIO, Vol. 17, No. 3, pp. 200206.HERMAN S. J. CESAR:31Pauly, D., Silvestre, G., & Smith, I. R., (1989) On Develop-ment, Fisheries and Dynamite: A Brief Review of TropicalFisheries Management. Natural Resources Modelling, Vol. 3,No. 3, pp. 307329.Pearce, D. W., & Turner, K. R., (1990) Economics of naturalresource and the environment. 1 ed., London: HarvesterWheatsheaf.Pendleton, L. H., (1995) Valuing Coral Reef Protection. Ocean& Coastal Management, Vol. 26, No. 2, pp. 119131.Pet-Soede, C., Cesar, H. S. J., & Pet, J. S. 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Marine Pollution Bulletin, Vol. 24, No. 11, pp. 529536.Sybesma, J., (1988) Marine Resource Protection versus MarineTourism in Curacao: a Management Problem in Proceedings ofthe International Coral Reef Symposium Australia, Vol. 2, pp.411414.CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE32 HERMAN S. J. CESAR:Appendix. Bibliography of Human-Induced Coral Reef Threats and Management IssuesAuthors Threats Mgt. DescriptionIssuesAblong et al. (1998) All Yes Description of the Coastal Resource Management Project(CRMP) to establish a sustainable resource along 2,000 km ofthe Philippine coast, using participatory methods.Alcala (1988) Overfishing No Assessment of coral fish abundance and yields at four islands inthe Philippines to compare marine reserves with non-reserveand control sites; significant differences in catch per unit effortwere found.Alcala & Russ (1990) Overfishing No Test of the effects of removal of protective marine managementat Sumilon Island, Philippines, 1984; found a 54% decline intotal yield of reef fishes in a 2 year period that also affectedareas adjacent to the reserve.Alder et al. (1994) Overfishing, Yes Compares management of 3 Indonesian marine reserves:coral mining, Kepulauan Seribu, Bunaken Manado Tua and Taka Bone Rate;blasting, discusses common issues facing the reserves and stresses thepoison, need for education, community development programmes, andpollution, attention to the socio-economic needs of the residents.tourismAlvarez (1995) Poison No Short description of the live fish trade in the Philippines and itseffects on coral reef systems.Andersson & Ngazi (1995) Overfishing, No Examines the socio-economic relationship between indigenousblasting, resource users and their coastal environment; concludes thatcoral mining participation from local resource-users can greatly benefitplanning and management decision-making.Andrews (1998) All Yes Assesses the process and motives for establishment of the Park,with critical reference to the transposition of developed countryconservation and management paradigms to a developingcountry.Thorhaug, A., (1992) Oil Spills in the Tropics and Sub-Tropicsin Connell, D. W., & Hawker D. W., (eds.) Pollution inTropical Aquatic Systems. CRC Press, Boca Raton, FL, pp.101127.Wantiez, L., Thollot, P., & Kulbicki, M., (1997) Effects ofMarine Reserves on Coral Reef Fish Communities from FiveIslands in New Caledonia. Coral Reefs, Vol. 16, No. 4, pp.215224.White, A. T., (1979) Sumilon Island: Philippine Marine ParkPilot Site Enjoys Early Success. ICLARM Newsletter, Vol. 2,No. 4, pp. 1012.White, A. T., (1989) Two Community-Based Marine Reserves:Lessons for Coastal Management in Chua, T.-E., and Pauly,D., (eds.) Coastal Area Management in Southeast Asia: Policies,Management Strategies and Case Studies. ICLARM ConferenceProceedings 19, pp. 8596.White, A. T., Barker, V., & Tantrigama, G., (1997) UsingIntegrated Coastal Management and Economics to ConserveCoastal Tourism Resources in Sri Lanka. AMBIO, Vol. 26,No. 6, pp. 335344.Wilkinson, C. R., Lindn, O., Cesar, H., Hodgson, G., Rubens,J., & Strong, A. E., (1999) Ecological and SocioeconomicImpacts of 1998 Coral Mortality in the Indian Ocean: AnENSO Impact and a Warning of Future Change?. AMBIO,Vol. 28, No. 2, pp. 188196.33Authors Threats Mgt. DescriptionIssuesBakus (1982) General Yes Provides criteria by which to select coral reef reserves, andidentifies mechanisms through which multiple-user conflicts canbe resolved.Bell & Galzin (1984) General No Empirical study in French Polynesia on the effect of differencesin percentage live cover on the number of fish species andindividuals.Berg et al. (1998) Coral mining No Analysis of the ecological services provided by reefs in Sri Lankain terms of their potential long-term economic benefits; over a20 year period, reefs were found to value US$ 140,000-7.5 m.km-2, and the costs of coral mining were found to exceed netbenefits by US$ 6 m.Bjork et al. (1995) Pollution No Study examining the levels of coralline algae on coral skeletonsat four reefs in Tanzania, in order to assess the impact ofwastewater exposure on algae distribution; calcification ratedecreased with proximity to wastewater outlet, as well as withincreased exposure to phosphates, but not ammonia or nitrates.Bohnsack & Ault (1996) All Yes Evaluates management strategies to protect marine biodiversityand promote the sustainable use of resources; propose newmanagement tools based upon marine reserves, with referenceto application to Florida Keys National Marine Sanctuary.Brown (1997) Temperature No Review of recent data related to the physical and biologicalfactors associated with coral bleaching, including environmentaltriggers, the biological responses of corals, and their scope foradaptation.Brown & Dunne (1988) Coral mining No Describes mining activities on coral reefs around North MaleAtoll (Maldives) and environmental impacts; suggests alternatives for the construction industry to protect the reefs.Brown et al. (1990) Dredging No Assesses the impact on coral cover of increased sedimentationcaused by a 9 month dredging operation in 1986-1987, Phuket,Thailand; at Ko Phuket, a measurable decrease in coral coverand species diversity was noted, although corals recoveredrapidly, with complete restoration noted 22 months after theonset of the dredging.Bunce et al. (1999) Yes The article describes the socio-economics of reef managementthrough a case study of the Montego Bay Marine ParkButler et al. (1993) Overfishing Yes Describes the fishery on the Bermuda platform and the govern-ments historical efforts to manage the fishery, including the1990 ban on pot fishing and its results.Campos et al. (1994) Overfishing No Estimates catch, fishing effort and yield of the fishery at CapeBolinao specific to different types of gear (spear, traps, corrals,gill nets); compares data with other fisheries in the region to con-clude that current rates of extraction should not be increased.Christie et al. (1994) Blasting, Yes Overview of community-based Marine Conservation Project forpoison, San Salvador Island (IMCPSS) including means of implementa-fish collecting tion and results; shows that community-based protection andmanagement is a feasible solution.CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE34Authors Threats Mgt. DescriptionIssuesDavis & Tisdell (1995) Tourism Yes Examines the critical thresholds of marine protected areas forrecreational scuba diving in view of the potential impact ofdivers on the reef systems.Davis & Tisdell (1996) Tourism Yes Uses economic instruments to assess the most effectiveallocation of scuba divers between recreational dive sites;suggests management strategies to allocate divers amongstmultiple sites.Dennis & Bright (1988) Grounding No Results of a two-year study examining re-colonisation of coralcommunities following a ship grounding; found significantdifferences in species composition, community structure andbiomass.Dixon et al. (1993) Tourism Yes Discusses the trade-offs between the economic and protectionbenefits of marine parks in the context of the need for theintegrated management of coastal areas; economic analysis ofthe benefits and costs of protecting Bonaire Marine Park toisolate its maximum sustainable use level and draw lessons forpark management.Dixon et al. (1995) Tourism Yes Examines the feasibility of achieving joint ecological andeconomic benefits in marine protected areas through the casestudy of Bonaire Marine Park in the Caribbean; assessesecological sustainability and compares tourism revenue withprotection costs; draws lessons for park management.Dulvy et al. (1995) Coral mining Yes Results of a study showing impact of coral mining on reefcommunities at Mafia Island, Tanzania; live coral cover and fishabundance and diversity were substantially lower than at theunmined site; assesses management issues surrounding themining of coral.Fiske (1992) General Yes Results of a study comparing the establishment of two marinesanctuaries: La Parguera, Puerto Rico and Fagatele Bay,American Samoa, in light of sociocultural variables influencingthe process; identifies key sociocultural variables and argues infavour of planned social change.Gabri et al. (1994) Overfishing, Yes Assesses the state of the coral reefs of Bora-Bora (Frenchtourism, Polynesia) and analyses the conflicting multiple uses of the reefurbanisation to enable the design of a sustainable management plan;management recommendations are provided.Galvez et al. (1989) Blasting, poison Yes Results of ethnographic studies of two villages in the LingayenGulf, Philippines to assess how and due to what factors cyanideand blast fishing continue to take place despite legal restric-tions; describes villager perceptions of the practices andprovides recommendations for management of the reef re-source.Gittings et al. (1988) Grounding No Results of a 27-month study detailing the recruitment andrecovery of Molasses Reef, Key Largo National Marine Sanctu-ary, following a freighter grounding; results point to specificmeasures that can be taken to expedite coral recovery.HERMAN S. J. CESAR:35Authors Threats Mgt. DescriptionIssuesHarriott et al. (1997) Tourism No Results of a study assessing the potential impacts of divers atfour dive sites in Eastern Australia via. comparing diver contactswith corals with diver training and experience levels; suggestsmanagement strategies to limit the damage caused by diving.Hatcher et al. (1989) General Yes Review of recent research related to anthropogenic impacts oncoral reef systems, including management issues.Hatcher et al. (1990) Lobster fishing Yes Combines ecological and anthropological approaches todescribe the patterns of usage and resources at the HoutmanAbrolhos reefs of Western Australia; aims to identify areas ofconflict between the user groups in order to contribute to asustainable management strategy for the area.Hawker & Connell (1992) Pollution No Discusses pollution threats to coral reef systems and describesstudies pointing to tolerance levels for each type of pollution.Hawkins & Roberts (1993) Tourism No Study examining the impact of reef trampling by scuba diversand snorkellers near Sharm-el-Sheikh, Egypt; found that coralcommunities were significantly altered in size, species composi-tion, and abundance in locations of heavy diver trampling.Hawkins & Roberts (1994) Tourism No Examines the impact of tourism on coral reefs through a casestudy on the Red Sea; evaluates present and planned develop-ment and potential growth in impact; proposes sustainabledevelopment strategies.Hingco & Rivera (1991) Poison, No Overview of the fish collecting industry in Bolinao, Philippinesfish collecting with a focus on the use of cyanide, including local attitudestoward its use and mechanisms that support the practice; policyrecommendations are made.Hughes (1994) Overfishing, No Analysis of phase-shift in Jamaican coral reef communityhurricanes, structures due to anthropogenic and natural causes, includingdisease implications and future prospects.Jennings & Polunin (1995) Overfishing No Study of six Fijian fisheries to compare catch-per-unit-effort(CPUE) and value-of-catch-per-unit-effort (VPUE); resultssuggest that the fisheries are sustainable since fishermenfrequently fail to maximise their efficiency.Jennings & Polunin (1997) Overfishing No Study of ten Fijian fisheries to measure the indirect effects offishing on the biomass and diversity of reef fish; a negativerelationship was found between the biomass of piscivorousfishes and fishing intensity, but increases in the biomass of theirpotential prey species were not noted.Johannes & Riepen (1995) Poison, No Overview of all aspects of the live fish trade in Asia and theoverfishing Western Pacific including impacts on fishing communities andcoral reef systems; provides policy recommendations.McAllister (1988) Sedimentation, No Details the economic, social and environmental costs of coralpoison, blasting, reef destruction in the Philippines.overfishing,pollution,coral miningCORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE36Authors Threats Mgt. DescriptionIssuesMcClanahan (1995) Overfishing Yes Presents a coral reef simulation model which calculates theeffect of fishing various species at different levels of intensity onthe coral reef ecology; results in the design of a managementstrategy based upon the highest and most stable yield of fishery.McClanahan & Overfishing Yes Study analysing fish numbers and weights at two older marineKanda-Arara (1996) protected areas in comparison with a newly created marine park(with an adjacent marine reserve) in Kenya; total fish landing inthe reserve decreased by 35% due (in part) to a flawed parkdesign with low edge-to-area ratio.McClanahan & Sedimentation No Results of a study testing the effects of sedimentation on coralObura (1997) reef communities in the Watamu and Malindi National MarineParks, Kenya; the biological diversity and ecological health ofthe sediment-affected reefs remained stable throughout thestudy.McClanahan et al. (1999) Yes Paper discusses the proliferation of MPAs in Kenya and else-where in the world where management is relatively poor. Thearticle argues that there is an economic rationale to have fewer,but better managed MPAs.McClanahan (1999) Overfishing Yes Tests a previously-designed overfishing model at protected reefsites in Kenya and Zanzibar in comparison with unprotectedsites; found that fishing led to a reduction in the abundance ofcertain fish species and an increase in the sea urchin population.McManus (1994) Military, Yes Argues in favour of the establishment of an international marineoil drilling park at the Spratly Islands as a strategy to resolve conflictingclaims over the region by China, Taiwan, the Philippines,Malaysia and Vietnam.McManus (1996) General Yes Overview of social scientific issues and research approachesrelated to the management of coral reef systems; discussesreefs as common property, Malthusian overfishing, and includesmanagement options.McManus et al. (1992) Blasting, Yes Describes four-year programme of monitoring the ecology andpoison, harvest patterns of a coral reef system in Bolinao, Philippines, toanchoring assess the effects of harvest on fish diversity; includes recommendations for management of the reef.McManus et al. (1997) Blasting, No Assess the effects of blasting, cyanide and anchor damage on apoison, coral reef in Bolinao, Philippines, between 1987 and 1990.anchoringNowlis et al. (1997) Sedimentation No Studies the impact of sediment on coral reefs in St. Luciafollowing a tropical storm; sediment resulting from intensiveland-use practices and road construction was found to have aconsiderably damaging effect on nearshore reefs.Nzali et al. (1998) Blasting No Results of a study comparing coral recruitment patterns at twosites at Taa Reef, Tanzania, one of which had been severelydamaged by blasting; findings suggest that recolonisation isnegatively affected by a reduction in viable seed populations, asreflected in coral cover levels.HERMAN S. J. CESAR:37Authors Threats Mgt. DescriptionIssueshman et al. (1993) Mining, No Study comparing three adjacent coral reefs in Sri Lanka: Barblasting, Reef, Talawila Reef, and Kandakuliya Reef, in terms of thepoison, diversity and abundance of fish and coral, and anthropogenicpollution, impacts.tourism,fish collecting,anchoring,nylon netshman et al. (1997) Blasting, No Assesses the distribution and abundance of reef fish within Barpoison, Reef Marine Sanctuary, Sri Lanka in comparison with annylon nets adjacent, unprotected reef; the organisation of fish assemblageswas related to habitat type, indicating that habitat destructionhas a significant impact upon reef fish communities.Pauly & Chua (1988) Overfishing No Provides a historical and socio-economic background to themarine fishery in Southeast Asia; analyses current problemsincluding stagnating catches, environmental problems, andpopulation growth.Pauly et al. (1989) Overfishing, Yes Assesses fishery management in the Third World in relation toblasting rural poverty in these regions; contends that Malthusianoverfishing describes the third world fishery, which is qualitativelydifferent from overfishing in the developed world; suggestsmanagement strategies.Polunin & Roberts (1993) Overfishing Yes Assesses the result of protective fishery management through acomparison of Saba Marine Park (Netherlands Antilles) and HolChan Marine Reserve (Belize) with adjacent unprotectedfisheries; analysis of abundance, size and biomass of commontarget species.Rakitin and Kramer (1996) Overfishing Yes Examines the distribution of sedentary vs. mobile and catchablevs. less-catchable species of fish in reserve and nearby non-reserve areas in Barbados; the marine reserve was found toprotect the fish community, but evidence for the emigration offish from the reserve was insufficient and inconsistent.Richmond (1993) Sedimentation, No Comparison of natural and anthropogenic disturbances to coralpollution, reef communities; describes key anthropogenic impacts.temperature,blasting,poisonRoberts (1994) Overfishing Yes Describes the benefits of establishing marine reserves for theprotection of fish stocks, sustenance of adjacent fisheries,protection of biodiversity; addresses several questions related toreserve set-up and effective management.Roberts (1995a) Overfishing No Assesses the effects of overfishing on reef community structureand reef processes, including a discussion of losses in speciesdiversity, keystone species, predator species, and functionalgroups of species.CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE38Authors Threats Mgt. DescriptionIssuesRoberts (1995b) Overfishing Yes Study assessing the response of fish populations to the creationof a marine reserve in the Caribbean; abundance, size andbiomass was greater in comparison with neighbouring areas; itwas concluded that reserves play an important role in theprotection of fish stocks.Roberts & Polunin (1991) Overfishing Yes Examines available evidence to assess whether marine reservesprotect nearby fisheries, and/or supplement these fisheriesthrough the emigration of fish from the reserve; concludes thatalthough fish abundance and sizes increase within protectedreserves, little evidence supports the theory of fishery recruit-ment and immigration.Roberts & Polunin (1993) Overfishing Yes Argues in favour of marine reserves as a low-cost alternative toconventional methods of fisheries management; assesses recentstudies of reserve function in replenishing fish stocks.Rogers (1990) Sedimentation No Examines the effect of sedimentation (due to dredging, runoff,sewage) on coral reef communities at the ecosystem andorganism level, including a discussion of interactions betweenfishes and their habitat.Rogers et al. (1988) Tourism Yes Results of a study assessing the damage caused to coral reefsas a result of recreational activities in Virgin Islands NationalPark and Biosphere Reserve; concludes with recommendationsfor monitoring and management of tourist activity.Ruitenbeek et al. (1999) General Impacts Yes The paper discusses cost-effective mitigation options for coralreef degradation using fuzzy logic procedures with empiricalresults from Montego Bay, Jamaica.Russ & Alcala (1996) Overfishing Yes Results of a study assessing the rates and patterns of increasein density and biomass of large predatory marine fish followingthe creation of marine reserves at Sumilon and Apo Islands,Philippines; over time, significant, positive linear correlations werefound between fish density with years of protection in reserves.Saila et al. (1993) Blasting, No Modelling of reef system in Lingayen Gulf, Philippines, assessinganchoring, fish diversity and coral re-growth over time and under certainpoison conditions; found that a 30% reduction in current destructivefishing practices (through halting use of poison) would enableslow reef recovery.Savina & White (1986) All Yes Assessment of two communities in the Philippines in whichmarine resource management projects were implemented;describes and discusses differences between the communitiesand presents implications for resource management.Smith et al. (1988) Overfishing Yes Results of a study testing whether the abundance and mean sizeof three species of invertebrate coral organisms increased as aresult of the creation of a marine protected area at the ArnavonIslands, Solomon Islands.Sybesma (1988) Tourism Yes Assesses the management of Curaao Underwater Park,Netherlands Antilles as a model for the sustainable use ofresources in marine systems.HERMAN S. J. CESAR:39Authors Threats Mgt. DescriptionIssuesThorhaug (1992) Pollution No Discusses major impacts of oil spill on tropical systems andcurrently used clean-up methods; policy recommendations aremade.Wantiez et al. (1996) Overfishing No Results of a study assessing the effect of marine reserveprotection on the species richness, density, and biomass ofcoral reef fish communities in New Caledonia; statisticallysignificant results confirm the efficacy of marine reserves.White (1979) All Yes Assessment of the implementation and management of SumilonMarine Park, Philippines as a model for marine resourcemanagement.White (1989) All Yes Results of a study comparing two community-based marineresource management projects in the Philippines; includesassessment of implementation, economic benefits accrued, andlessons for the management of coastal marine resources.White et al. (1997) General Yes Proposes an integrated coastal management approach toresolve tourism development/coastal protection conflicts inHikkaduwa, Sri Lanka; provides an economic evaluation of theproposed management plan.Wilkinson et al. (1999) Temperature No Discusses and assesses the extent and impact of bleachingdamage caused by the warming event of 1998 to coral reefsystems in the Indian Ocean; discusses the potential forrecovery in various locales and includes socio-economicimpacts on reef-dependent communities.CORAL REEFS: THEIR FUNCTIONS, THREATS AND ECONOMIC VALUE