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Home , Recreational diving, Sipadan

Impacts of Recreational Divers on Palauan Reefs and Options for Management1

Chris Poonian,2,4 Patricia Z. R. Davis,2 and Colby Kearns McNaughton2,3

Abstract: Recent growth in the popularity of recreational has gen- erated concerns about resulting impacts to coral reefs, particularly in locations such as the Republic of Palau, a world-renowned dive destination with rapidly increasing numbers of visitors. Divers were observed in-water at three of the most visited dive sites in the Rock –Southern Lagoon Area: German Channel, Ngerchong, and Big Drop-off. Dive guides were interviewed about diver impacts at German Channel and Ngerchong. Divers’ contact rates with hard coral ranged from 0.87 e 0.27 to 2.98 e 0.59 contacts diver1 10 min1 (mean e SEM). Three instances of obvious physical damage were observed. Holding and fin contacts were the most common potentially damaging behav- iors of divers, particularly those with cameras or gloves. Guides identified natu- ral impacts (63% of respondents) and divers (34% of respondents) as the primary causes of damage to coral. Proactive management is essential to miti- gate any negative impacts of on coral reefs and to ensure resilience against other increasing threats. Long-term monitoring of dive sites, controls on the use of gloves and , and training of guides are suggested to minimize damage caused by divers to coral reefs in Palau and elsewhere.

Dive tourism is a major recreational activ- Africa have been negatively affected by inten- ity worldwide (Buckley 2004), but this popu- sive recreational diving (e.g., Rou- larity has caused concern due to the potential phael and Inglis 2001, Walters and Samways of physical damage to reefs from anchoring, 2001, Zakai and Chadwick-Furman 2002, trampling, kicking, and breaking of by Barker and Roberts 2004, Di Franco et al. divers and tour boats. Although tourism is 2009), and the transition from pristine to often perceived as a low-impact alternative ‘‘diver-damaged’’ can occur very quickly for coastal management, a number of studies where dive tourism is allowed to grow in an have confirmed that coral reefs and other unregulated manner (Hawkins and Roberts sensitive substrates in the Red , the 1992). Divers may also be less willing to pay Caribbean, Australia, the Mediterranean, and a conservation access fee as the quality of a dive site declines in terms of , species diversity, and coral cover (Parsons and Thur 1 Funding for this work was generously provided by the U.S. National and Wildlife Foundation and 2008). The continued growth of recreational Koror State Government. Manuscript accepted 31 De- diving is thus a threat to both the ecological cember 2009. and economic sustainability of reefs (Davis 2 Community Centred Conservation (C3), 17 North- and Tisdell 1995) and should be considered cliffe Drive, London, N20 8JX, United Kingdom (e-mail: in the planning of effective marine resource [email protected]). 3 University of Hawai‘i at Hilo, 200 West Ka¯wili management strategies. Considering that Street, Hilo, Hawai‘i. coral reefs are seriously threatened world- 4 Corresponding author. wide, primarily from the consequences of climate change (Hughes et al. 2003, Hoegh- Guldberg et al. 2007), urgent action is Pacific Science (2010), vol. 64, no. 4:557–565 doi: 10.2984/64.4.557 necessary to reduce the effects of controllable : 2010 by University of Hawai‘i Press impacts, such as those associated with recre- All rights reserved ational divers.

557 558 PACIFIC SCIENCE . October 2010

The coral reefs of the Republic of Palau Thus, one of the proposed actions of the (07 30 0 N, 134 30 0 E) (Figure 1) are among management plan was to ‘‘regulate diving the most biologically diverse in the Indo- and activities in the Management Pacific (Maragos and Cook 1995) and consis- Area to reduce site congestion and damage tently rate as one of the world’s best diving to corals and increase site safety.’’ Such pro- locations (e.g., Halls 2008). Following a rapid active management of dive sites is clearly es- increase from only 4,000 visitors per annum sential to cope with the continued increase in during the 1980s (Graham et al. 2001), tour- visitation and to ensure that both economic ism is now the largest income source for the and recreational needs are met. In this study, nation’s private sector. In 2002, $66.1 million we employed in situ observation and self- were generated from the estimated 58,560 administered questionnaire surveys of dive visitors (Palau Visitors Authority 2003), 70% guides to evaluate actual occurrence and per- of whom were divers (Osman 2003), and ceptions of diver damage to coral reefs to Koror State collected approximately $505,000 generate effective, stakeholder-inclusive man- from Rock permit fees alone (Koror agement recommendations for recreational State Government 2004). The Palauan tour- diving on coral reefs. ism sector has continued to expand, generat- ing $111.9 million (U.S. Department of materials and methods State–Bureau of East Asian and Pacific Af- fairs 2009) from 88,175 visitors (Palau Visi- This study was conducted at three dive sites tors Authority 2008) in 2007. As an island in 2003 (before the Rock Islands–Southern nation, Palauan people have strong traditional Lagoon Area Management Plan was put into ties to the sea and are aware that this rapid action) within the Rock Islands–Southern development carries with it substantial eco- Lagoon Area: German Channel, Ngerchong, logical costs and impacts on marine re- and Big Drop-off (Figure 1). These sites source–based livelihoods with a potential for were selected by Koror State Department of conflict between tourism and artisanal fishing Conservation and Law Enforcement based activities (Ueki 2000, Matthews 2004). It has on a lack of biological data, popularity with also been demonstrated that the amount of recreational divers, and the need for im- live coral cover directly affects divers’ satisfac- proved management practices. All of these tion in Palau and consequently the potential sites have been ranked within the top 20 dive revenue from recreational diving (Graham sites in Palau; German Channel and Big et al. 2001). Drop-off are visited by almost every dive The unique natural resources of the Rock tourist and are in the top seven (Palau Con- Islands–Southern Lagoon Area (Figure 1), servation Society 2001). Ngerchong was a where most of Palau’s 75 dive sites are lo- popular site before the 1997/1998 coral- cated, are formally managed by Koror State bleaching event and, given its sheltered as- Department of Conservation and Law En- pect, is primarily dived in rough weather forcement. However, as dive tourism has (A. Eledui, pers. comm., 2002). Most dives at developed, congestion has become an issue German Channel are conducted along the at some dive sites, a concern that is com- seaward side of the opening of the channel, pounded by a lack of empirical data on and the reef slopes to a sandy bottom at which to establish a standard for diver impact around 25 m; Ngerchong is a sloping reef on that area (Ueki 2000). In 2004, the Rock with a maximum depth of 15 m, and Big Islands–Southern Lagoon Area Management Drop-off is a vertical wall that starts at 1 m Plan was adopted (Koror State Government and drops steeply to around 600 m. 2004), which identified ‘‘damage to reef Diver impacts were quantified using in- from divers and snorkelers touching water observation techniques based on Rou- and standing on corals or removing corals or phael and Inglis (1995). Daily selection of invertebrates’’ as a primary concern associ- sites depended on the choices of dive opera- ated with tourism and recreational activities. tors according to weather and sea conditions, Figure 1. Palau, showing location of study sites in the Rock Islands–Southern Lagoon Area. 560 PACIFIC SCIENCE . October 2010 and individual subjects were selected at ran- questionnaire surveys. Information was re- dom. Two underwater observers indepen- corded on perceived status and impacts to dently recorded the behavior of 124 divers (52 coral reefs and dive site usage. Questionnaires divers at German Channel, 35 at Ngerchong, in Japanese and English were distributed to and 37 at Big Drop-off ). Each subject was all marine tour operators in Koror. Eighteen observed for 10 min, and the following details companies of the 25 registered water-sports were recorded: number of contacts with the operators in Palau participated in the study, substratum; type of substratum contacted; and 35 questionnaires were completed. nature of the contact (e.g., fin contacts, holding); contact obviously damaging (visible results breakage) or nondamaging to substratum; type and size of substratum damaged and At German Channel, divers made contact additional notes on diver accessories (e.g., with hard coral most often of all substrata gloves, cameras). Each observer followed a and sites and also knelt or rested fins on the group of two to four subjects, dependent on at some point during the dive, usually group size and intragroup distance, and re- while waiting for manta rays; interactions mained approximately 5 m behind the sub- with soft corals and sea fans were rare (Table jects. Divers generally remained close to 1). Most interactions involved holding or other members of their party and did not ap- kicking coral with fins (Table 2), but divers pear to notice the observation process; data were also observed dragging gauges or octopus were disregarded for the few cases where the regulators over the substrata and kneeling subject appeared to be aware of the observer. indiscriminately on corals, often to take Student’s t-tests were employed to compare photographs. contact rates of divers using gloves and cam- At Ngerchong, hard coral was again the eras with those without. most commonly contacted substratum (Table Dive guides’ perceptions of environmental 1), the number of interactions with sand impacts at German Channel and Ngerchong was similar to that for German Channel, and were determined through self-administered there were no interactions with soft corals

TABLE 1 Diver Contact Rates (mean e SEM) for Each Substratum at Each Study Site

Contact Rates Diver1 10 min1

Study Site Hard Coral Sand Rock Soft Coral Sea Fan Other

German Channel 2.98 e 0.59 1.62 e 0.26 0.79 e 0.26 0.19 e 0.07 0.04 e 0.03 0.79 e 0.24 Ngerchong 1.86 e 0.39 1.23 e 0.38 0.54 e 0.20 0 0.03 e 0.03 0.20 e 0.09 Big Drop-off 0.87 e 0.27 0 0.95 e 0.27 0.08 e 0.05 0 0

TABLE 2 Diver Contact Rates (mean e SEM) with Hard Coral for Each Type of Contact at Each Study Site

Contact Rates Diver1 10 min1

Study Site Holding Fins Gauge Kneeling Tank

German Channel 1.25 e 0.29 0.98 e 0.26 0.38 e 0.11 0.31 e 0.12 0.06 e 0.04 Ngerchong 0.66 e 0.22 0.83 e 0.25 0.20 e 0.11 0.14 e 0.12 0.03 e 0.03 Big Drop-off 0.43 e 0.16 0.43 e 0.14 0 0 0 Recreational Divers on Palauan Coral Reefs . Poonian et al. 561 and few with sea fans. As at other sites, most pact (34% of respondents), anchor damage interactions involved kicking coral with fins (23% of respondents), trash (3% of respon- or holding (Table 2), and there were also in- dents), and triggerfishes (3% of respondents). stances of divers bumping into corals with Kicking (‘‘sometimes’’ observed by 58% of their air cylinders as a result of problems respondents) and holding (‘‘sometimes’’ ob- with control. served by 48% of respondents) coral were Interactions at Big Drop-off differed from thought to be the greatest impacts of divers those at other sites in that rock was the most at German Channel. At Ngerchong, kicking commonly contacted substratum and hard coral was again the most commonly identified coral was less frequently affected (Table 1). impact (‘‘sometimes’’ observed by 55% of There was no sand at Big Drop-off within respondents). In general, guides ‘‘rarely’’ saw the depth range usually dived, therefore no coral being broken (71% of respondents at interactions were recorded. Interactions with German Channel and 68% of respondents at soft coral were rare, and no contacts with sea Ngerchong). fans were observed. Of the interactions with Guides (66% of respondents) expressed coral, half involved divers touching or kicking concern about boat and diver congestion at coral with their fins and the other half in- German Channel, and several made com- volved divers holding coral (Table 2). Half ments about boats speeding through the div- of the interactions with rock also involved ing area and causing a to both divers touching or kicking with fins; the majority of and manta rays. Guides generally felt that other interactions involved holding, although there were sufficient mooring buoys at the there were also cases of divers kneeling on dive sites (71% of respondents at German and hitting rocks with their air cylinders. Channel, 68% of respondents at Ngerchong) If data from all sites are combined (all and reported that most or all operators figures given as mean e SEM), divers wear- used them at German Channel (94% of re- ing gloves touched hard coral more often spondents) and at Ngerchong (97% of re- (4.1 e 0.6 interactions diver1 10 min1) spondents). It was noted that both sites were than those not wearing gloves (1.3 e 0.3 visited by divers throughout the year, but interactions diver1 10 min1)(t ¼ 3.88, there were noticeable peaks of usage during df ¼ 44, P a .0005), and divers using January–March at German Channel and dur- cameras touched hard coral more often ing June–August at Ngerchong. Guides re- (3.1 e 0.7 interactions diver1 10 min1) ported that they usually saw two or three than those not using cameras (1.8 e 0.3 inter- other dive boats while they were visiting ei- actions diver1 10 min1), but the difference ther site. was not found to be significant (t ¼ 1.70, df ¼ 34, P a .1). Only three instances of ob- discussion vious physical damage caused by two divers were recorded during the course of this Based on a conservative estimate that 70% of study, out of a total of 124 divers observed. tourists in Palau in 2007 were divers, as in One interaction involved a diver scraping an 2002 (61,723), and that 80% of these divers air cylinder against a coral head at German (49,378) conducted a 40-min dive at German Channel, and the other occurred at Big Channel, extrapolation of the results gener- Drop-off, where a diver kicked and broke off ated by this study demonstrates that this den- two pieces of a branching hard coral. sity of recreational divers may be responsible From the questionnaire survey, dive guides for 589,000 e 117,000 coral contacts and reported hard coral damage at both German approximately 400 coral breakages annually. Channel and Ngerchong (62% and 71% of This level of impact could clearly have a respondents, respectively), mainly due to nat- long-term effect on coral health at the site, ural causes (63% of respondents), and 71% and these visitation rates far exceed the were aware of coral-bleaching phenomena. 4,000–6,000 (Dixon et al. 1993, Hawkins Other factors mentioned included diver im- and Roberts 1994) or 7,000 (Schleyer and 562 PACIFIC SCIENCE . October 2010

Tomalin 2000) dives per year per site consid- guides as supported by in-water observations. ered to be a reliable rule of thumb to estimate Dive guides’ briefings (Medio et al. 1997) and carrying capacity for scuba divers, depend- close underwater supervision (Barker and ing on the biophysical characteristics of the Roberts 2004) have been shown to reduce site (West 2001). Although occasional con- coral damage caused by groups of divers. tacts are unlikely to cause permanent damage Effective training of dive guides, through to corals, cumulative effects in conjunction means such as the recently introduced, com- with other stressors may be more serious pulsory Marine Tour Guide Certification (Hawkins et al. 1999, Plathong et al. 2000, Programme (Davis and Kearns 2005), and as- Zakai and Chadwick-Furman 2002). Isolated sociated legislation are pragmatic tools to ad- breakages are unlikely to result in the death dress these issues. of a large coral colony because corals can re- Overcrowding at dive sites, one of the generate tissue over small injuries (Hall 2001, main concerns voiced by dive guides, reduces Rouphael and Inglis 2002), although small the ‘‘wilderness experience’’ (Davis and Tis- coral colonies take longer to regenerate and dell 1995, Musa 2002), with impact on enjoy- may be completely killed by physical damage ment being significantly correlated with alone (Kramarsky-Winter and Loya 2000, group size (Barker 2003). It has also been Oren et al. 2001). demonstrated that sites with human-made Most studies of diver behavior have con- structures such as buoys are much less appeal- cluded that fin kicks were the most prevalent ing to divers (Inglis et al. 1999), which is per- type of contact (e.g., Medio et al. 1997, Rou- haps the reason that guides generally believed phael and Inglis 1997) as in this study, where that installation of further buoys was not divers often appeared unaware that they had an acceptable to overcrowding. even touched the reef. Divers were also However, committed use of mooring buoys, observed intentionally holding onto coral to as evident in this study, has been shown to steady themselves in a or to get closer effectively mitigate anchor damage to coral to the substratum to see something or take reefs ( Jameson et al. 2007). Introduction of photographs. Divers wearing gloves made limits for diver numbers within the Rock contact with hard coral more often as previ- Islands–Southern Lagoon Area may not be ously noted (e.g., Medio et al. 1997, Schleyer completely effective in limiting diver damage and Tomalin 2000, Walters and Samways to coral reefs; there is substantial literature 2001). Bans on the use of gloves have been from terrestrial research that suggests that successfully enforced in a number of Marine a single, objectively estimated level of use Protected Areas globally and may also be to maintain resource condition is unrealistic a useful mitigation measure in the Rock (e.g., McCool and Lime 2001, Farrell and Islands–Southern Lagoon Area. Marion 2002). As demonstrated by this work All guides were observed deliberately and previous studies, diver behavior, in-water keeping away from the substratum, although activities, and the biophysical characteristics few paid attention to coral contacts by their of the reef will substantially affect the level clients because the guide tended to remain of impact. In addition, the resilience of coral at the front of the group, looking ahead. reefs can vary substantially, even within the Guides’ perceptions that coral damage was same Marine Protected Area (Done 1992, a result of natural events are supported by Hughes and Connell 1999). the absence of fresh breaks, typical of diver Long-term monitoring of coral damage damage, and the obvious presence of rubble and visitation rates to a representative sample resulting from the coral-bleaching event in of dive sites is one means to effectively assess 1998 (Community Centered Conservation diver impact and introduce regulations as 2003), particularly on the outer, exposed reefs necessary. Monitoring should primarily focus of Palau (Bruno et al. 2001, Golbuu et al. on early and easily identifiable symptoms of 2007). Kicking and holding onto corals were coral community decline, including increases the most common diver impacts according to in coral injuries such as broken branch tips Recreational Divers on Palauan Coral Reefs . Poonian et al. 563 and tissue abrasions (Rouphael and Inglis Scuba diver behaviour and the manage- 1995, Nelson and Mapstone 1998). These ment of diving impacts on coral reefs. site-specific data would be useful for wider, Biol. Conserv. 120:481–489. ecoregional spatial planning and zoning strat- Bruno, J., C. Siddon, J. Witman, P. Colin, egies (e.g., in Palau: Hinchley et al. 2007) and and M. Toscano. 2001. El Nin˜ o related a definition of limits of acceptable change coral bleaching in Palau, western Caroline (Roman et al. 2007). This approach would Islands. Coral Reefs 20:127–136. ensure that controllable impacts on coral Buckley, R. 2004. Skilled commercial adven- reefs such as diver damage are minimized ture: The edge of tourism. Pages 37–48 and could capitalize on site-specific resilience in T. V. Singh, ed. New horizons in tour- to natural impacts such as coral bleaching and ism: Strange experiences and stranger acidification, which are predicted to practices. CABI Publishing, Wallingford. increase considerably in the near future Community Centered Conservation. 2003. (Hughes et al. 2003, Hoegh-Guldberg et al. Baseline surveys and threat assessment of 2007). Although protected area managers are dive sites in Koror State, Palau: A report often required to balance the apparently con- submitted to the Department of Conserva- flicting objectives of tourism promotion and tion and Law Enforcement, Koror State natural resource protection, regulations im- Government. C3 Technical Report Series posed by the Rock Islands–Southern Lagoon No. 1. ISSN 1754-5188. Community Cen- Area Management Plan, including a permit tred Conservation (C3), London, United system for tourists visiting the area and zon- Kingdom. ing (Koror State Government 2004), are a Davis, D., and C. Tisdell. 1995. Recreational major step forward to monitoring and ulti- scuba-diving and carrying capacity in ma- mately controlling recreational diver impacts rine protected areas. Ocean Coastal Man- on coral reefs in Palau. age. 26:19–40. Davis, P. Z. R., and C. M. Kearns. 2005. acknowledgments Koror State Government marine tour guide certification manual. Final edits by Thanks are due to the Koror State Depart- The Environment, Inc., The Nature Con- ment for Conservation and Law Enforce- servancy, Palau Conservation Society, and ment, particularly Adalbert Eledui and Ileb Koror State Department of Conservation Olkeriil; Rengechel Dlutaoch and Mista and Law Enforcement and the Moros; Dr. Kathy Chaston (Coastal Manage- Research Foundation. ment Officer); Mica Hirose ( Japan Interna- Di Franco, A., M. Milazzo, P. Baiata, A. tional Cooperation Agency volunteer); the Tomasello, and R. Chemello. 2009. Scuba diver support team: Mike Kearns and Blake diver behaviour and its effects on the biota McNaughton (U.S. Peace Corps volunteer); of a Mediterranean marine protected area. Dr Patrick Colin (Coral Reef Research Foun- Environ. Conserv. 36:32–40. dation); and all the marine tour operators and Dixon, J. A., L. F. Scura, and T. van’t Hof. dive guides who participated in this study. 1993. 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