PAPER Understanding the Potential Economic Impacts of Sinking Ships for SCUBA Recreation

AUTHOR ABSTRACT Linwood H. Pendleton Ships, planes, and other large structures are finding their way to the bottom of the Program in Environmental Science sea along coasts in North America, Europe, Australia, and elsewhere. More and more, and Engineering coastal communities and even not-for-profit organizations (e.g. the San Diego Oceans Department of Environmental Foundation and Artificial Reef Society of British Columbia) are actively promoting and Health Sciences financing “ships to reefs” projects as a means of providing new destinations for recre- University of California, Los Angeles ational SCUBA diving tourists. Creating a “ships to reef” site can be costly. The cost to prepare a ship for reefing can range from $46,000 to $2 million, depending on the size of the vessel (Hess et al., 2001). The benefits, however, can be equally large or larger. In order to get a better idea of the potential economic value of ships to reefs, I review the literature on the value of recreational diving to artificial reefs in the United States. Using data from the literature, I estimate that potential net present value of expenditures associated with the recently placed Yukon ship to reef site in Southern California could be on the order of $46 mil- lion and the potential net present non-market value of the sunken ship could be as high as $13 million. These estimates are within an order of magnitude of estimates based on a preliminary survey of divers at the Yukon.

INTRODUCTION The scale and pace of sinking ships to that the Persian Kingdoms built reefs across hips, planes, and other large structures create artificial reefs, especially reefs designed the Tigris River (Hess et al., 2001). In the are finding their way to the bottom of for recreational diving, is increasing rapidly. United States, artificial reefs have been Sthe sea along coasts in North America, Eu- In Florida, over 380 vessels have been sunk around for over 150 years; as long ago as rope, Australia and elsewhere. While many to create artificial reefs. In 2004 the U.S.S. 1830 log huts were sunk off the coast of purists see the scuttling of ships and planes Spiegel, a 510-foot naval vessel, was sunk in South Carolina to improve fishing (Hess et in coastal waters as something akin to dump- the Florida Keys National Marine Sanctu- al., 2001). What differentiates modern arti- ing, more and more coastal communities are ary. To date, over 700 vessels serve as artifi- ficial reefs from past reef making is the scale turning to these structures as a means of pro- cial reefs in the waters off the continental and cost of artificial reefs and the potential tecting shoreline, creating habitat for fish and U.S. coastline. The majority of these ships economic benefits that could be produced sea life, and providing new destinations for are found off the coast of Florida (380), New by the strategic placement and marketing recreational fishing and SCUBA diving tour- Jersey (129), South Carolina (100), and New of artificial reefs. ists (Baine, 2001). In many cases (e.g. the York (65) (http://njscuba.net/reefs/ Creating a ship to reef site can be costly. sinking of the Yukon off the San Diego index.html accessed 9.18.2004). Other states The cost to prepare a ship for reefing can coast), the goal of “ships to reefs” is exclu- lag far behind in the creation of artificial reef range from $46,000 to $2 million, depend- sively to create new destinations for non- structures. For instance, while steps have ing on the size of the vessel (Hess et al., consumptive SCUBA diving; in some cases been made to increase the use of artificial 2001). These costs represent direct outlays ships to reefs are even designated as “no fish- reefs in California, the state has only ten ships by cities, counties, states or not-for-profit ing zones”. Despite the success of these re- currently in place as artificial reefs intended organizations and are considered an invest- gional organizations in raising funds to sup- for recreational diving. ment that is expected to produce economic port ships to reefs, it is never certain that While the attention paid to artificial reef returns. For governments, especially local any one ship to reef site represents a good development has increased dramatically in governments, ships to reefs are intended as economic investment—especially when the the past decade, artificial reefs are not a new recreational revenue sources that will intended goal of a “ship to reef” is limited modern development. Two thousand years stimulate tourism, increase local expendi- to SCUBA recreation alone. ago, the Greek geographer Strabo recorded tures, and support new tax revenues. For

Summer 2005 Volume 39, Number 2 47 diving groups and not-for-profits, the returns and gray literature are easily available on the expenditures do not represent net benefits from these investments need not be so obvi- Web. The National Ocean Economics Pro- to the economy, gross expenditures do cap- ous. Acting on behalf of the diving public, gram provides a literature portal that includes ture the magnitude of importance that arti- these groups seek to create new recreational a searchable bibliographic database of ma- ficial reefs may have in the overall local resources that increase the quantity and qual- rine non-market valuation studies economy. Further, gross expenditures rep- ity of dive opportunities for their members. (www.oceaneconomics.org). Similarly, the resent the base upon which tax revenues can The benefits these users derive may not be National Oceanic and Atmospheric Admin- be generated. The promise of increased tax apparent in the market and include the value istration (NOAA) has a Web site that con- revenues may lead local, state, and even fed- of these ship-based dive experiences beyond tains many technical reports on the eco- eral agencies (e.g. National Marine Sanctu- what divers spend in the market. These latter nomic valuation of marine resources aries) to approve the sinking of ships and values, known as non-market values, can be (www.marineeconomics.noaa.gov). Econo- the creation of other artificial reef structures. significant, but often are difficult to measure. mists can use data from these studies and The lure of increased expenditures on dive To better understand the potential eco- on-site data regarding environmental and charters and hotel stays can encourage local nomic benefits of artificial reefs generally, a socio-economic conditions to estimate the businesses to support such endeavors. number of studies have been undertaken to economic value of marine resources that have The non-market value of recreational estimate both the market and non-market not yet been valued rigorously. Less formally, diving is more difficult to determine. Non- values of artificial reefs. In the late 1970s, these studies can be used by non-economists market values represent the value reef users studies began to quantify the economic ben- to better understand the potential range of place on a reef, beyond what they have to efit of recreational fishing and diving on ar- values that may be associated with a marine pay to use the reef. Non-market values are tificial reefs (Daniel, 1976). Over time, the resource or policy. often associated with outdoor recreational accuracy and comprehensiveness of these In this paper, I assess the state of the art resources, including dive sites, and have been studies have grown to provide a more com- in the quantification of the recreational val- shown to generate substantial economic plete picture of the potential economic ben- ues of artificial reefs that may provide recre- value beyond the expenditures generated by efit of artificial reefs. ational experiences that are similar to ships these resources (see Cesar, 2000 and Ships to reefs potentially could support to reefs. I provide an overview of the litera- Pendleton, 1995). These non-market values a number of diverse uses and values includ- ture, describe the kinds of estimated values represent a true net economic value of reefs ing shoreline protection and fishery enhance- in the literature, and provide a non-techni- to divers; these values capture the increase ment or concentration. Nevertheless, ships cal demonstration of how these values could in economic well-being that divers enjoy as to reefs projects are increasingly undertaken be used to gain a better knowledge of the a result of access to reefs. At a minimum, with the primary purpose of supporting rec- potential economic returns of sinking ships funds raised directly from divers to support reational, non-consumptive diving. I focus for SCUBA tourism. the creation of artificial reefs reflect a lower on this limited use of ships to reefs as a con- bound for these non-market values. These servative estimate of their value. (Further, I funds are only a lower bound, however, be- limit the scope of the research to diving in cause most artificial reefs, including ships to order to keep the demonstration of values II. The Economic Value of reefs, are open access public resources; many straightforward and clear.) Recreational div- Artificial Reefs for SCUBA reef users will be able to “free ride” on the ing is a rapidly growing industry and increas- Recreation creation of ships to reefs. ingly artificial reefs are being prepared, sunk, Artificial reefs yield economic benefits In the literature, two primary methods and maintained for the express use of recre- through the enhancement of shoreline pro- are used to estimate the non-market value ational diving. Leeworthy et al. (2005) esti- tection, fishery resources, and recreational of artificial reefs. Travel cost methods are used mate that 2.86 million people over the age fishing and diving opportunities. The val- to estimate a demand curve for recreational of sixteen years participated in SCUBA div- ues of these benefits are difficult to quantify diving to artificial reefs by modeling the in- ing activities in 2000. Of nineteen settings/ because they involve both market and non- fluence of travel cost and travel time on the activities for which participation was esti- market values. The market impact of a reef frequency of visitation by divers. Travel cost mated, SCUBA diving was estimated to be resource usually is assessed by examining methods use real diver behavior to estimate the fastest growing recreational activity in how much money artificial reef users con- the consumer surplus of recreational diving the United States. tribute to the local economy by spending (the value divers place on a reef visit beyond In the paper that follows, I review the money to participate in activities on the reef what they have to pay), but the method can literature to develop a better understanding (such as recreational fishing and diving). only estimate the value of current uses by of the potential economic value of ships to Commonly, the focus of market-based stud- non-resident divers. When travel cost meth- reefs for recreational SCUBA diving. Increas- ies is on gross expenditures with fewer stud- ods are inappropriate, authors have used ingly, studies from both the peer reviewed ies focusing on profits or taxes. While gross contingent methods to estimate values for

48 Marine Technology Society Journal artificial reef maintenance or abundance. oil and gas structures in the Gulf of Mexico; iting artificial reefs in Northwest Florida. The Specifically, several authors use contingent the authors calculate that the average per authors find that divers spend $50 to approxi- valuation methods to ask divers to place a person-day expenditures at artificial reefs in mately $90 per person-day (for residents and value on their current recreational use of a) Alabama, Mississippi, and Louisiana was non-residents respectively), a value that lies existing artificial reefs and/or b) proposed $119, and total annual spending for the three within the range of the other studies; together, new artificial reefs. states combined was over $7.4 million. Fol- resident and non-resident divers visiting arti- Below I summarize studies that provide lowing a similar approach, McGinnis et al. ficial reefs spend more than $14 million an- estimates of both market values (expendi- (2001) calculate the average per person-day nually in Northwest Florida. Johns et al. find tures) and non-market values associated with expenditures of divers visiting decommis- even higher levels of expenditures by SCUBA recreational uses of artificial reefs. Most of sioned oil rigs in California to be $64, with divers and snorkelers visiting artificial reefs in the comparable studies focus on sunken a total annual spending of $10,700 for all Southeast Florida. The authors estimate the ships or oil rigs. It is important for the reader rig diving in the state. per person-day expenditures of $61 to $204 to note that the methods for finding these Expenditures by divers visiting artificial for residents and non-residents respectively. market and non-market values often differ reefs are similar to divers visiting oil rigs (see between studies. In the following I provide Table 1). Hess et al. (2001) provide gross these estimates (all converted to US$ in revenue estimates for a variety of artificial reef The Non-Market Value of 2004, all figures greater than $10 are sites made from sunken ships. The authors Recreational Diving At rounded to the nearest dollar) with brief find that these reef sites, located around the Artificial Reefs explanations of the basic methods. Further, world, generate an average of $3.4 million Artificial reefs, including sunken ships, when possible, I break down the value esti- annually per reef site. Ditton et al. (2001) can generate substantial non-market values mates based on the value per visitor per day. and Ditton and Baker (1999) find that non- for recreational divers (Table 2). Roberts et By doing so, I hope the reader will be able resident divers who visited an artificial reef al. (1985) use contingent valuation meth- to better compare these results across stud- on at least one dive trip each year spent just ods to estimate the mean annual per diver ies and also understand how these values may over $193 per person-day on their last trip to non-market value of oil rig diving in the Gulf compare to the values that would be gener- a dive site in coastal Texas waters; residents of Mexico to be $339, with a total annual ated by future artificial “ships to reefs” valu- spent over $184 per person-day. Brock (1994) value ranging from $905,216 to $1,264,640 ation studies. surveyed a dive-tour operator in Hawaii who for all sites. Other studies provide estimates conducted trips exclusively on a surplus yard of per person-day non-market values. Bell oiler and calculated the total gross annual in- et al. (1998) use both travel cost and con- The Market Value of come generated by these trips to be $494,840. tingent valuation methods (specifically Recreational Diving At Bell et al. (1998) also provide a breakdown Turnbull and Dichotomous Choice analy- Artificial Reefs of expenditures per person-day for divers vis- ses) to estimate per person-day non-market Gross expenditures by divers generate net revenues for local firms and businesses and also have substantial secondary impacts. TABLE 1 Expenditures by divers support jobs and Market Value (Expenditure) Estimates for Diving at Artificial Reefs wages for dive charter captains and crews, Author Location Habitat Type Market Value employees at local hotels and eateries, and Per Person-Day numerous other ancillary services. ($2004, figures While much of the literature focuses on are rounded) the economic value of recreational angling Hiett & Milon (2002) Gulf of Mexico Oil and Gas Structures $119 and diving combined, many of these stud- McGinnis et al. (2001) Southern California Platform Grace (Oil Rig) $64 ies also provide data on the independent Ditton and Baker (1999) Texas Various types of artificial reefs $185 for resident value of artificial reefs for recreational div- $194 for non-residents ing. (Of course, many recreational divers Ditton et al. (2001) may also spearfish. We do not attempt to Bell et al. (1998) North West Florida Ships, reef balls, and other $50 for residents differentiate between non-consumptive and private and public artificial reefs $90 for visitors consumptive recreational diving.) Two stud- Johns et al. (2003) South East Florida Ships, reef balls, and other $61 for residents ies estimate the expenditures associated with private and public artificial reefs $204 for visitors recreational SCUBA diving at oil rigs. Hiett Wilhelmsson et al. (1998) Eliat, Israel Navy Ship $28 & Milon (2002) surveyed divers that went diving or fishing within 300 feet of offshore Brock (1994) Waikiki Surplus yard oiler $26-$60

Summer 2005 Volume 39, Number 2 49 values. The authors find that the value for “option” values.” Milon finds that estimates reefs was much higher than that of dives visitors may be as high as $11/ person-day for the option value of new artificial reefs conducted on artificial reefs. In an unpub- for non-residents and $4.30/ person-day for range from $4.48 to $128 per visitor per lished manuscript (personal communica- residents. Ditton and Baker (1999) estimate year, depending on the method used. In tion), Ditton also finds that artificial reefs the non-market value of diving in Texas these cases, reef diving opportunities are not are not as highly valued as natural reefs; waters, for divers that visited at least one ar- as scarce as in other locations (e.g. Southern Ditton estimates the per trip value for artifi- tificial reef in the past year, to be between California or the Mid-Atlantic United cial reefs is $76 lower than that of natural $45 and $75 per person-day for non-resi- States). Where reef diving opportunities are reefs ($114 and $190 respectively). dents. The values estimated by Ditton and scarce, it is likely that the non-market value Baker, however, are not exclusively for arti- of new artificial reefs will be relatively higher ficial reef divers. initially, but the value of additional artificial III. Conclusion Johns et al. estimate the value of main- reefs should be expected to decline (a com- Our base of knowledge regarding the taining artificial reefs and creating new arti- mon tenet of economics known as declin- economic value of dive recreation at ship- ficial reefs; the authors conclude that the ing marginal returns). based artificial reefs is still limited. In the non-market use value per person-day for At least two studies find that artificial published literature, only a handful of stud- maintaining existing artificial reefs ($3.41- reefs are not perfect recreational substitutes ies examine the economic impacts of ship- $14 for residents and non-residents respec- for natural reefs when both types of reefs based artificial reefs and most of those stud- tively) was generally higher than for creat- exist together. Johns, et al. found a prefer- ies focus on ship-based artificial reefs in ing new artificial reefs ($0.80 - $5.61 for ence among boaters, fishers, and divers for coastal Florida. Clearly, there is a need to residents and non-residents respectively); the natural reefs; the per person-day use value know more about the economic impacts of finding suggests that there are declining for natural reefs averaged $14 compared to the more than 300 ship-based artificial reefs marginal returns to increasing the supply of the value for artificial reefs that averaged in place around North America, but out- reefs in an area in which reefs (artificial or $9.18. In addition to the higher willingness side of Florida. The potential economic value natural) already were abundant. Milon to pay for natural reefs, the Johns et al. study of a ship-based artificial reef depends both (1989) also estimates the economic value of also shows that in most counties in Florida, on the value of a reef to the individual diver new artificial reefs, what the author calls the percent of dives conducted on natural (which is a function of diver interest, the

TABLE 2 Non-Market Value Estimates for Diving at Artificial Reefs

Author Method Location Habitat Type Market Value Per Person-Day ($2004, figures are rounded)

STUDIES OF DIVING ON ARTIFICIAL REEFS Ditton and Baker (1999) Contingent Valuation: Texas Various types of artificial reefs 1. $752. $45 Ditton et al. (2001) 1.dichotom-ous choice 2. open-ended Bell et al. (1998) Travel Cost North West Florida Ships, reef balls, and other $11 structures Contigent Valuation Residents: $3.50 - 4.30 Visitors: $6.30-7.70 Roberts et al. (1985) Contingent Valuation Gulf of Mexico Petroleum Structures ($339 annually per diver) Johns, et al. (2003) Contingent Valuation Southeast Florida Ships, reef balls, and other Residents: (dichotomous choice) private and public artificial reefs $3.40 (to maintain existing artificial reefs) $0.80 (new artificial reefs) Visitors: $14 (to maintain existing artificial reefs) $5.60 (new artificial reefs) STUDIES OF DIVING AND FISHING ON ARTIFICIAL REEFS Milon (1988) Contingent Valuation Florida Network of 7 different reefs $29.04 to $42.77 per year from various materials Milon (1989) Contingent Valuation Florida Ships and steel debris $4.48 to 127.56 per year

50 Marine Technology Society Journal quality of the artificial reef, and substitute conservative estimate of the potential non- Original valuation studies and technical dive sites) and the total number of divers market value, but they still provide a guide benefits transfer analyses are beyond the that are expected to use a ship to reef site. for considering the potential non-market eco- means of many organizations that might like Individual value, individual expenditures, nomic value of the site to divers. The non- to finance and promote ships to reefs. This and the total numbers of visitors will vary market value of artificial reefs to local divers paper demonstrates that estimates of mar- from region to region. may explain the increasing role of diver-based ket and non-market values, taken from the In 2000, The San Diego Oceans Foun- “not-for-profit” organizations in the creation literature, may provide a reasonable approxi- dation (SDOF), paid $238,000 to acquire of new artificial reefs. mation of the potential economic benefits the 366 foot, Canadian Destroyer Escort The value of sinking ships to create reefs from creating new ships to reefs, artificial Yukon. The Foundation also paid an addi- depends on the degree to which the new reefs, or other marine and coastal projects. tional $97,000 to prepare the vessel and artificial reef site generates increased diver $100,000 for towing, mooring, and sink- expenditures and non-market values. The ing. Can the values taken from the litera- values from the literature only indicate the Acknowledgments ture give us an idea of the potential economic potential value of trips to a new reef site like Funding for this research was provided by benefit of this “ship to reef” project? that which would be created by a ship to a grant from the San Diego Oceans Founda- The San Diego Oceans Foundation es- reef project. For the Yukon, the analyst would tion. The author wishes to thank numerous timates that 10,000 divers made 26,700 day need to know how the provision of the Yukon reviewers for their excellent comments. Vernon visits to the Yukon “ship to reef” site between as a recreational destination for divers effec- (Bob) Leeworthy provided invaluable help in August 2002 and August 2003; roughly tively changed the level of expenditures and understanding values from studies in Florida. 6,000 of these diver trips were made by out- total non-market values enjoyed by these of-town visitors accounting for 15,600 per- divers. If we consider all of these trips as an son-days (Pendleton, 2005). Conservative upper-bound estimate of the incremental References estimates from diving in Florida (Bell et al., effect of the Yukon, we can use the literature Baine, M. 2001. Artificial reefs: a review of 1998 and Johns et al., 2003) suggest that to estimate the maximum value of the Yukon. their design, application, management and divers to the Yukon might spend on the or- The literature suggests that the potential performance. Ocean Coast Manage. 44:241-259. der of $50 per dive day for residents and magnitude of annual expenditures by all $200 for non-residents. A non-random sur- divers to the Yukon could be $3.5 million Bell, F., Bonn, M., and Leeworthy, V. 1998. vey of 814 divers to the Yukon revealed that ($3 million by non-residents and over $0.5 Economic Impact and Importance of Artificial expenditures associated with trips to the million for residents; note that this figure is Reefs in Northwest Florida. NOAA Paper wreck were approximately $95 for dive-re- almost exactly equal to the average estimated Contract Number MR235. lated expenditures with out-of-town divers expenditures per site from Hess et al. [2001]) Brock, R. 1994. Beyond Fisheries Enhance- spending an additional $580 on food and for a Net Present Value of $46 million at a ment: Artificial Reefs and Ecotourism. lodging. The literature provides estimates of discount rate of 4% over twenty years— B Mar Sci. 55(2-3):1181-1188 potential expenditures that are well within roughly one hundred times the costs of buy- an order of magnitude of what are likely to ing, preparing, and sinking the ship. Of Cesar, H. S.J. 2000. Collected Essays on the be the actual expenditures by divers. course, only a fraction of these expenditures Economics of Coral Reefs, pp. 250, CORDIO, A similar transfer of values from the lit- represents true economic benefits (net rev- Kalmar University, Kalmar, Sweden. erature can also be used to estimate the po- enues). Nevertheless, the values from the lit- Daniel, D.L., 1976. Empirical and theoretical tential non-market value of visits to the erature suggest that the fiscal impact of the Observations on the Potential Economic sunken Yukon. Bell et al. (1998) and Johns et Yukon could well exceed the costs of creat- Benefits and Costs Associated with Mississippi- al. (2003) find only modest non-market val- ing the new dive site. Alabama Liberty Ship Reef Program. ues for artificial reef diving (ranging from A similar analysis could be conducted Hattiesburg: Bureau of Business Research, approximately $3/person-day for residents to to estimate non-market value of the Yukon. University of Southern Mississippi. $13/person-day for non-residents) while other The literature suggests that the annual value authors find much more substantial values of non-market benefits of the Yukon are likely Ditton, R.B. and T.L. Baker. 1999. Demo- for diving on rigs (on the order of $50 per to be between $80,000 and $1.3 million for graphics, Attitudes, Management Preferences, person-day). A travel cost study by Pendleton a Net Present Value of between $1 million and Economic Impacts of Sport Divers using (2005), using a non-random sample of 4,256 and $13 million dollars. Again, the non- Artificial Reefs in Offshore Texas Waters, diver day trips to the Yukon over 3 years, esti- market values from the literature provide Report prepared for the Texas Parks and mated that the non-market value of diving at evidence that the economic returns from Wildlife Department through a research the Yukon was on the order of $110/person- creating a new reef site in Southern Califor- contract with Texas A&M University day. Estimates from the literature are clearly a nia could justify the creation of the site.

Summer 2005 Volume 39, Number 2 51 Ditton, R. B., C.E. Thailing, R. Riechers and Pendleton, L. 2005. Towards A Better H. Osburn. 2001. The Economic impacts of Understanding of the Economic Value of Ship sport divers using Artificial Reefs in Texas to Reef Scuba Diving in Southern California. Offshore Waters. Proceedings of the Annual Gulf San Diego Oceans Foundation. and Caribbean Fisheries Institute 54:349- 360. Roberts, K. Thompson, M., and Pawlyk, P. Ditton, R. personal communication. Valuing 1985. Contingent Valuation of Recreational Recreational SCUBA Diving Use of Natural Diving at Petroleum Rigs, Gulf of Mexico. and Artificial Reef Habitats. Abstract only. Transactions of the American Fisheries Society 114: 214-219. Hess, R., Rushworth, D., Hynes, M., Peters, J. Disposal Options for Ships National Defense Wilhelmsson, D., Ohman, M.C., Stahl, H., Research Institute RAND 2001. 59-80. Shlesinger, Y. 1988. Artificial Reefs and Dive Tourism in Eilat, Israel. AMBIO. 27(8):764-766. Hiett, R. and Milon, J.W. 2002. Economic Impact of Recreational fishing and Diving Associated with Offshore Oil and Gas Structures in the Gulf of Mexico. DOI Minerals Management Service Document MMS Study 2002-010.

Johns, G., Leeworthy, V., Bell, F. and Bonn, M. 2003. Socioeconomic Study of Reefs in Southeast Florida, Final Report for Broward County, Florida, Fort Lauderdale, October 19, 2001.

Leeworthy, V.R., Bowker, J.M., Hospital, J.D., and Stone. E.A. 2005. Projected Participation in Marine Recreation: 2005 & 2010. U.S. Department of Commerce, National Oceanic and Atmospheric Adminis- tration, National Ocean Service, Special Projects, Silver Spring, MD. March 2005.

McGinnis, M. Fernandez, L. and Pomeroy, C. 2001. The Politics, Economics, and Ecology of Decommissioning Offshore Oil and Gas Structures. DOI Minerals Management Service Document. MMS Publication 2001-006.

Milon, J.W. 1988. The Economic Benefits of Artificial Reefs: An Analysis of the Dade County, Florida Reef System. Gainesville, Fla.: Sea Grant Extension Program, University of Florida, 1988. Report / Florida Sea Grant College; no. 90

Milon, J.W. 1989. Contingent valuation experiments for strategic behavior. J Environ Econ Manag. 17:293-308.

Pendleton, L. 1995. “Valuing Coral Reef Protection.” Ocean Coast Manage. 26:119-131

52 Marine Technology Society Journal