Giglio-2015-Recreational-Diver-Behavior-and-Contacts
Transcrição
Giglio-2015-Recreational-Diver-Behavior-and-Contacts
Environmental Management DOI 10.1007/s00267-015-0628-4 Recreational Diver Behavior and Contacts with Benthic Organisms in the Abrolhos National Marine Park, Brazil Vinicius J. Giglio1,2 • Osmar J. Luiz3 • Alexandre Schiavetti4 Received: 23 April 2015 / Accepted: 17 November 2015 ! Springer Science+Business Media New York 2015 Abstract In the last two decades, coral reefs have become popular among recreational divers, especially inside marine protected areas. However, the impact caused by divers on benthic organisms may be contributing to the degradation of coral reefs. We analyzed the behavior of 142 scuba divers in the Abrolhos National Marine Park, Brazil. We tested the effect of diver profile, reef type, use of additional equipment, timing, and group size on diver behavior and their contacts with benthic organisms. Eightyeight percent of divers contacted benthic organism at least once, with an average of eight touches and one damage per dive. No significant differences in contacts were verified among gender, group size, or experience level. Artificial reef received a higher rate of contact than pinnacle and fringe reefs. Specialist photographers and sidemount users had the highest rates, while non-users of additional equipment and mini camera users had the lowest contact rates. The majority of contacts were incidental and the highest rates occurred in the beginning of a dive. Our findings highlight the need of management actions, such as & Vinicius J. Giglio [email protected] 1 Programa de Pós-graduação em Ecologia e Conservação da Biodiversidade, Universidade Estadual de Santa Cruz, Ilhéus, Brazil 2 Present Address: Programa de Pós-graduação em Ecologia, Universidade Federal do Rio de Janeiro, Rio De Janeiro, Brazil 3 Department of Biological Sciences, Macquarie University, Sydney 2109, NSW, Australia 4 Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil the provision of pre-dive briefing including ecological aspects of corals and beginning dives over sand bottoms or places with low coral abundance. Gathering data on diver behavior provides managers with information that can be used for tourism management. Keywords Dive tourism ! Marine protected area ! Management ! Scuba divers ! South Atlantic ! Tourism management Introduction Coral reefs are important habitats along tropical coastlines, providing humans with economic resources and services through cultural values, fishing, coastal protection, and tourism (Moberg and Folk 1999). This ecosystem is also a popular destination for scuba diving, one of the world’s fastest growing recreational sports (Van Treeck and Schuhmacher 1998; Hasler and Ott 2008). Scuba diving is considered to be a low-impact activity and provides an economic alternative to fishing through a non-extractive use of marine wildlife (Davis and Tisdell 1995; Tapsuwan and Asafu-Adjaye 2008). However, coral reefs are globally threatened by a wide range of anthropogenic activities, such as fishing, pollution, and unplanned tourism (Bellwood et al. 2004). These activities act in synergy with the high vulnerability of corals to climate change (Hughes et al. 2003), rendering the sustainable use of coral reefs a complex task. The recent growth of diving tourism has raised concern among managers and scientists regarding its impacts. For instance, in Eilat reefs, Israel, visitation rates account for 250,000–300,000 divers and 400,000 instances of coral damage per year (Zakai and Chadwick-Furman 2002). 123 Environmental Management No-take Marine Protected Areas (MPAs) have recently become widely recognized as a key tool for biodiversity conservation and fisheries management, especially in coral reefs (Jones 2001). The reduction in fishing pressure through the closure of selected areas has led to the reappearance of rare or absent species and substantially increases the biomass of apex predators (Anderson et al. 2014; Edgar et al. 2014). There are also positive effects for coral reefs, such as increase of coral cover and structural complexity (Selig and Bruno 2010). Increases in fish abundance and coral cover make MPAs highly attractive to the diving industry. Today, scuba diving is one of the most important commercial uses of MPAs (Green and Donnelly 2003). However, in some cases, large numbers of dives have resulted in decline in the health of coral reefs (Davis and Tisdell 1995; Uyarra and Côté 2007). Divers can damage corals through direct (physical contact) or indirect contact (via sediment deposition) with their hands, body, scuba gear, and fin kicks (Harriot et al. 1997; Rouphael and Inglis 1997). Due to the delicate structure of corals, contacts often result in breakage, abrasion, or tissue removal (Hawkins et al. 1999). Damaged corals are more susceptible to predation, competition interference, and disease, which can result in death of the colony (Guzner et al. 2010). Algal colonization on corals may soon follow tissue damage. Algae compete for space with corals and can act as a sediment trap, hindering coral recovery (Hall 2001). Fin kicks on the bottom disturb and re-suspend sediment that can settle nearby, including on corals (Zakai and Chadwick-Furman 2002). When sediment covers the coral surface in excess, coral recruitment, feeding, and photosynthesis are inhibited (Hasler and Ott 2008). Since the 1990s, studies have investigated the dynamics of diver and benthic organisms contacts (e.g., Hawkins and Roberts 1992; Hawkins et al. 1999; Plathong et al. 2000; Barker and Roberts 2004; Lucrezi et al. 2013). The characteristics that affected the rates of diver contacts on reefs were related to diver’s profile, such as their experience (Di Franco et al. 2009), gender (Rouphael and Inglis 2001), dive purpose (Uyarra and Côté 2007), use of additional equipment (e.g., cameras, gloves and lanterns; Rouphael and Inglis 2001; Uyarra and Côté 2007; Poonian et al. 2010), and biophysical characteristics of dive site (e.g., reef type and coral cover; Rouphael and Inglis 1997; Hawkins et al. 1999). Sites with complex topographies can make it difficult for divers avoid touching corals on vertical structures (Rouphael and Inglis 1995). However, the correlation between coral damage and reef topography is unclear (Zakai and Chadwick-Furman 2002). The lack of awareness by divers of their own impacts on reefs has contributed to a substantial amount of human-induced damage on corals (Rouphael and Inglis 1995). In Thailand, 123 Dearden et al. (2007) verified that only 30 % of divers were aware of negative environmental impacts created by their dive group. In summary, there is not a general pattern of relationships among diver behavior and rate of contacts on reefs. Patterns of diver impacts are generally site-specific, so further studies and dive site management should be narrowly focused to be of maximum practical use. Understanding diver behavior is important to subsidize the carrying capacity and verify management strategies to reduce impacts of recreational diving. Previous studies have demonstrated that underwater photographers inflicted high rates of damages to corals (Rouphael and Inglis 2001; Chung et al. 2013). Photographers stay close to the substrate and may accidentally come into direct contact with the reef or deliberately hold on the corals to stabilize themselves to photograph a subject. Rouphael and Inglis (2001) evaluate the behavior of specialist and non-specialist photographers and verified that specialists caused higher rates of damage than non-specialists. However, since then, several models of easy-to-use underwater cameras have recently been developed and the effect on diver behavior of these snapshot cameras has not yet been evaluated, as well as the use of new diving gear configurations. To mitigate diving impacts, studies have proposed the establishment of carrying capacity approaches (Davis and Tisdell 1995; Rı́os-Jara et al. 2013) and the use of predive educational briefings (Medio et al. 1997; Camp and Fraser 2012). However, diver’s behavior and compliance to the norms vary according to diver’s profile, objectives, and characteristics of the dive site (Smith et al. 2010; Giglio et al. 2015). For example, the use of pre-dive briefings reduced 60 % of diver’s contacts with corals in Egypt (Medio et al. 1997). On the other hand, in Santa Lucia (Lesser Antilles, Caribbean), group leader intervention was the only effective method to reduce coral damage (Barker and Roberts 2004). The use of artificial reefs has been proposed as a strategy to reduce impacts on natural reefs (Polak and Shashar 2012). Shipwrecks are often used as a diving attraction, mainly due to their esthetic appeal (Leeworthy et al. 2006). These structures generate revenue through diving tourism and consequently assist in local economic development (Pendleton 2005). Historical shipwrecks represent an important cultural heritage and are fragile, non-renewable resources, generally protected by law (Jewell 2004). However, the impact caused by scuba divers on its benthic fauna incrusted remains little understood. To implement and adequate artificial reef program, it is essential to understand diver impacts on historical structures and its fauna, and assessing potential impacts of artificial structures on marine biota, such as phase shifts of benthic assemblages (Work et al. 2008). Environmental Management Despite the increasing interest in coral reef conservation, assessments of recreational dive damage have not yet been carried out on benthic organisms (e.g., scleractinian corals, fire corals, gorgonians, and sponges), and how divers contributes to these impacts in Brazil. In this study, we examined scuba diver behavior through direct observations in order to identify factors that may influence their contacts with benthic organisms in the Abrolhos National Marine Park (ANMP), a no-take MPA in eastern Brazil. The ANMP is part of the largest and most biodiverse coral reef complex in the South Atlantic (Leão et al. 2003) and is considered one of the best diving destinations in Brazil. We verified the rate of scuba divers’ contacts with benthic organisms according to (1) divers’ profile (gender, age, and experience); (2) reef type; (3) use of additional equipment (e.g., camera and sidemount); (4) divers’ group size; and (5) dive time. We also estimated the rate of contacts under current visitation rates and suggested management measures to reduce coral reef damage in the ANMP. Materials and Methods Study Area Comprising an area of 965.67 km2, the ANMP was created in 1983 aiming to conserve biodiversity and to promote sustainable tourism, educational, and research activities. Eighteen coral species occur in ANMP and of these, eight are endemic to South Atlantic, and one endemic to eastern Brazil (Leão and Kikuchi 2001). In the 1990s, unofficial estimates suggested that ANMP received approximately 10,000 visitors per year. However, annual visitation has decreased by one-third when compared with 2002 estimate (Alvarenga and Fleck 2011). At the time of writing, ANMP received an average of 3500 visitors per year, peaking during the austral summer, due to good dive conditions and higher underwater visibility. Fishing or collection of organisms is forbidden within the ANMP, as well as the use of gloves and knives. The first dive in each tourism operation is restricted to shallow reefs (\10 m depth), focusing equipment and buoyancy control adjustments. Group leaders take a maximum of eight divers in a group. Diver Behavior The underwater behavior of scuba divers was assessed through direct observation. Observers sampled two divers at a time. Three distinct dive operators were sampled over 7 weeks during the austral summers (January to March) of 2012 and 2013. We sampled all divers on 20 liveaboards trips that performed generally eight dives along 3 days. Divers were unaware that they were being observed to avoid influencing their behavior. Observers blended in the dive party and remained inconspicuously behind their subjects, within visual contact (usually 2–4 m away). Each sample period began when divers approached the reef and ended when they return to the boat, moving away from the reef. We quantified four types of dive contacts, according to the part of the diver body or gear with which they touched, damaged, or raising sediment onto benthic organisms: fin, knee, hand, and scuba gear (e.g., spare regulator and air tank). Diver contacts were recorded on a PVC slate and classified as touch, damage (when physical damage occurs), or raising sediment onto corals. Timing was grouped into categories (e.g., 0–10, 11–20, 21–30, and [30 min). We recorded the number of divers in the group and the number of interventions made by the dive leader when divers contacted benthic organisms or raised sediment onto corals. Corals were categorized to one of three categories: (a) branching (e.g., fire coral Millepora alcicornis), (b) massive (e.g., Mussismilia braziliensis, M. hispida, M. harttii, and Favia leptophylla), and (c) gorgonians (e.g., Phyllogorgia dilatata). Contacts with other organisms (e.g., invertebrates) were also recorded. Diver behavior was classified as intentional or unintentional. An intentional contact is one the divers were clearly aware of. For instance, divers putting their hands on the coral to get closer to an organism near the substrate. Diver Profile Age, gender, certification level, and experience were recorded through registration forms required by the dive operator or by an interview at the end of the visit. We require to divers an oral authorization to include their data in the survey. The experience (number of dives completed in a lifetime) was grouped into four categories: (a) 1–25 dives; (b) 26–50 dives; (c) 51–100 dives; or (d)[100 dives. Certification was categorized as one of the follow categories: (a) open water; (b) advanced open water; (c) rescue diver; or (d) dive master or instructor. Reef Types The behavior of divers was quantified at six dive sites, each categorized as one of the following three reef types: (a) three shallow fringing reefs; Mato Verde, Portinho Sul, and Lı́ngua da Siriba sites, maximum depth of 7 m; (b) two pinnacle reefs: Faca Cega and Chapeirão da Sueste sites, maximum depth of 20 m; and (c) one artificial reef; the Rosalinda shipwreck, a 102 m length steel freighter wrecked in 1955 in good conservation status, maximum depth of 20 m. We do not verify reef complexity; however, there are obvious differences in the topography of the three 123 Environmental Management reef types surveyed. For instance, pinnacle is predominantly a ‘‘wall reef’’ and shipwreck is a ‘‘tridimensional’’ reef. The differences in topography can be an influential variable in diver behavior and contacts with the reefs because the reef angle with respect to the diver can vary (Rouphael and Inglis 1997). Table 1 Summary of diver profile Fringe Pinnacle Artificial reef Total Male 26.8 16.1 16.2 59.1 Female 14.1 18.3 8.5 40.9 1–25 dives 11.8 7.9 7.2 27 26–50 dives 15.1 9.9 2.6 27.6 51–100 dives 9.2 7.9 5.3 22.4 [100 dives 7.2 7.9 7.9 23 Gender (%) Experience (%) Use of Additional Equipment We assigned divers to one of five categories based on the type of equipment they used, in addition to the regular scuba set: (1) mini camera user (divers using small action cameras, e.g., GoPro); (2) non-specialist photographer (divers using compact digital cameras); (3) specialist photographer (divers using professional cameras with external flash greater bulk than compact cameras); (4) sidemount users (divers using a gear configuration in which two cylinders are mounted alongside the diver, below the shoulders and along the hips, instead of on the back of the diver); and (5) non-additional equipment users. Data Analysis Poisson regression and Kruskal–Wallis test were used to verify relationships between diver profile, dive site characteristics, and contact rates. A multivariate analysis of variance was used to explore relationships between both the rates of touches and breakages on benthic organisms per minute, using seven independent variables: (A) certification; (B) diver’s experience; (C) gender; (D) type of reef; (E) use of additional equipment; (F) group size: 2–4 divers; 5–6 divers, and 7–9 divers; and (G) dive timing 0–10, 11–20, 21–30, and [ 30 min. To find the best set of explanatory variables, we used the model selection procedure of stepwise backward elimination of non-significant factors. The selection started with a model with all variables, and then dropped one variable at a time to test if the variable deletion improved the model. We repeated this process until no further improvement was possible (Zuur et al. 2007). All tests were performed at a significance level of P \ 0.05. Statistical analyses were performed using R 2.15.0 software (R Development Core Team 2012). Results Diver Profile and Contacts with Benthic Organisms We observed 142 divers (57 on fringe reefs, 50 on pinnacles reefs, and 35 on the artificial reef). The total observation time was 87 h and 16 min. The majority of divers were male (59 %; Table 1). Seventy percent of divers possessed open water or advanced open water diving 123 Age (%) Certification level 10–20 6.8 Open water 63 21–30 23 Advanced open water 37 31–40 31.8 Rescue diver 19 41–50 20.3 Dive master [50 18.2 Instructor 9 14 certifications. Diver experience ranged between 2 and 700 dives. The modal diver experience category was 26 to 50 dives, followed by 1 to 25 dives (27.6 and 27 %, respectively; see Table 1). Fifty-eight percent (N = 83) of divers used additional equipment. Of these, 28.9 % were mini camera users, 32.5 % non-specialist photographers, 20.5 % were specialist photographers, and 18.1 % were sidemount users. The experience of mini camera users varied between 10 and 550 dives, with an average of 138 ± 18.5 (±SE), of non-specialist photographers varied between 6 and 1200 dives (average = 113 ± 23), of specialist photographers varied between 10 and 550 dives (average = 141 ± 17.1), and of sidemount users varied between 10 and 500 dives (average = 156 ± 19.2). Most divers (88 %, N = 126) contacted benthic organisms at least once during each dive. Of these, 46 % of divers touched, 37 % damaged, and 17 % raised sediment onto benthic organisms. The overall average of contacts per minute was 0.26 (SD = 0.25), and considering that a single dive lasted on average 39 min, each diver contacted benthic organisms 10.4 times per dive, represented by 8.19 touches, 1.04 damages, and 1.17 raising sediment. Additional equipment users accounted for 54 % of all contacts. Overall, a minority of divers accounted for the highest contact rates (Fig. 1). Ninety-two percent of all contacts (N = 1324) were unintentional. Most of contacts occurred during the first 20 min of dive (69 %, N = 67). Divers contacted benthic organisms with their fins (79 % of total, 7.5 ± 0.6 contacts per dive); hands (11 %, 1.06 ± 0.09), scuba gear (6.5 %, 0.55 ± 0.04 contacts per dive); and knees (3.6 %, 0.36 ± 0.04 contacts per dive). Intentional contacts were caused mainly with hands (85 %, Environmental Management Fig. 1 Frequency of diver contact rate with benthic organisms (N = 142) N = 94). Table 2 details the number of contacts and how they occurred. Massive corals were the most touched, and branching corals the most damaged (74 and 59 %, respectively). Both were contacted mainly by fin kicks. All events of raising sediments were caused by fin kicks, mainly in massive corals (79 %). Sixty-six percent of damages occurred in branching corals and 21 % in massive corals. Dive leader intervention was observed in only 2 % (N = 29) of contacts. Effects of Reef Type, Additional Equipment Use, Timing, and Group Size on Diver Behavior The highest rates of diver contacts with benthic organisms were observed on the artificial reef, followed by pinnacle reefs (Table 3). Artificial reefs had the shorter dive time average (* 4 min) than dives on the natural reefs, but received the highest rates of touch, damage, and raising sediment events per dive. No significant relationship was verified between diver experience and contact rates per Table 2 Diver contact rate with benthic organisms in the Abrolhos National Marine Park minute on fringe reefs (Poisson regression I = -1.57, P = 0.7), pinnacle reefs (I = -1.51, P = 0.9), and on the artificial reef (I = -0.86, P = 0.6; Fig. 2). However, in the artificial reef, the rate of contacts tended to increase with greater experience. For all reef types, specialist photographers and sidemount users obtained significantly more contact rates than mini camera users and nonspecialist photographers (Kruskal–Wallis test P \ 0.01) and non-additional equipment users (P \ 0.001; Fig. 3a). Mini camera users caused the lowest contact rates, (0.15 min-1 ± 0.02), even lower than non-additional equipment users (0.18 min-1 ± 0.02). Specialist photographers and sidemount users caused highest contact rates (0.38 min-1 ± 0.06 and 0.50 min-1 ± 0.07). A similar pattern was verified when contact type was analyzed according to additional equipment. For instance, specialist photographers and sidemount users caused the highest rates of touch and damage over all reef types. Multiple analysis of variance revealed that reef type, use of additional equipment, and dive timing were important Branching coral Massive coral Gorgonians Other organisms N Per dive N Per dive N Per dive N Per dive 164 1.15 720 5.07 23 0.16 77 0.54 14 0.10 4 0.03 Touch Fin Hand 17 0.12 108 0.76 3 0.02 Knee 1 0.01 44 0.31 0 0 Scuba gear 4 0.03 53 0.37 3 0.02 3 0.02 186 1.31 925 6.51 29 0.20 98 0.69 Fin 88 0.62 16 0.11 1 0.01 8 0.06 Hand 86 0.04 0 0 0 0 2 0.01 Knee 1 0.01 0 0 0 0 0 0 Scuba gear 2 0.01 9 0.06 0 0 4 0.03 97 0.68 25 0.18 1 0.01 14 0.10 Total Damage Total 123 Environmental Management Table 3 Diver contact rate with benthic organisms according to reef types Frequency (per minute) Average number of contacts over a dive Fringe (mean ± SE) Pinnacle (mean ± SE) Artificial reef (mean ± SE) Fringe (average dive time of 41 min) Pinnacle (average dive time of 39 min) Artificial reef (average dive time of 37 min) Touch 0.13 ± 0.013 0.17 ± 0.02 0.33 ± 0.04 5.33 6.63 12.21 Damage 0.01 ± 0.003 0.02 ± 0.004 0.05 ± 0.009 0.41 0.78 1.85 Raising sediment 0.03 ± 0.006 0.02 ± 0.006 0.05 ± 0.02 1.23 0.78 1.48 (X2 = 24.5, df = 3, P \ 0.05), pinnacle (X2 = 56.8, P \ 0.05), and the artificial reef (X2 = 14.4, P \ 0.05). Divers in the first 10 min caused more than four times as many contacts as fringe and pinnacle reef types, and more than twice compared with the end stage of the dive (Fig. 3b). Group size did not reveal significant differences to contact rates. Discussion In this study of diver contacts on benthic organisms, we found that on an average dive, divers contacted the reef 10.4 times. However, our analysis indicates that variability in contact rates was influenced mainly by additional equipment use, reef type, and timing. In the sections below we discuss the influence of each variable on diver contacts with benthic organisms. Reef Type Fig. 2 Relationship between diver contacts rates with benthic organisms and diver experience according reef type factors explaining touch and raising sediments rates (Table 4, ANOVA F = 15.44, P \ 0.001, R2 = 0.188) and damage rates (F = 7.721, P \ 0.001, R2 = 0.097). More specifically, the combination of factors that predicted the highest rate of touches and damaged was specialist photographers, sidemount users, diving in the artificial reef during the beginning of their dive (Table 4). The diving time between 11 and 20 min was also negatively correlated with touch rate. The significant difference in the end stage of diving (21 min upward) on diver contacts with benthic organisms was consistent over the three reef types: fringe 123 The artificial reef obtained twice the rate of diver contacts with benthic organisms than fringe or pinnacle reefs. The Rosalinda shipwreck has a complex structure, with a high abundance of corals along its extension. The high complexity and high abundance of corals in the parts of wreck most visited by divers (e.g., the command deck and vessel edges) make these areas susceptible to higher contact rates. Another reason for the high rate of contact in the artificial reef is that dive leaders often deliberately contacted corals. This behavior was frequently repeated by visitors, resulting in a higher rate of contacts. It is well known that divers tend to mimic the behavior of their dive leaders (Barker and Roberts 2004). When asked to justify this behavior, dive leaders explained that they were not as concerned about corals in the shipwreck, as they perceived the artificial reef as a non-natural environment. The Rosalinda shipwreck is one of the main attractions of ANMP and diving may continue to occur there with or without the coral presence. However, after a period between 8 and 25 years, artificial reefs, if undisturbed, Environmental Management Fig. 3 a Number of dive contact rates of non-users of additional equipment (white box), users of photographic cameras (light gray boxes), and users of sidemount (dark gray box). b Contacts made according dive timing. Boxes represent the interquartile range, containing 50 % of the figures. The line across the box indicates the median. The dashes represent the 5th and 95th percentiles and the filled circles are the extreme figures have demonstrated the same level of biodiversity and productivity as other natural reef ecosystems (Burt et al. 2009; Perkol-Finkel et al. 2006). Frequent diver contact on shipwrecks not only cause impact on benthic organisms but may also expose the metal framework of the ship to the seawater, accelerating corrosion (Jewell 2004; McKinnon 2015). Environmental education training for dive leaders and other management interventions are needed to conserve the benthic organisms of ANMP. A successful initiative that should be used to inspire similar action is the National Oceanic and Atmospheric Administration’s (NOAA) Blue Star programme in Florida, which trains and incentivizes dive leaders to include conservation education into their dive briefing, aiming to reduce diver impacts on the reefs (Camp and Fraser 2012). Dive shops also benefit from this endeavor, because its positive results (see Camp and Fraser 2012; Krieger and Chadwick 2012) can be used as marketing tool as the society is becoming more environmentally aware. Additional Equipment Use It is not surprising that specialist photographers inflicted most of the damage to benthic organisms in this ANMP, since this diver type has previously been shown to cause more damages to benthic organisms elsewhere (Worachananant et al. 2008; Luna et al. 2009). Specialist photographers are often too distracted with their subjects to paying attention to the reef. They also use the reef to steady themselves and get closer to their subjects. The contacts they made caused more damage than those made by nonphotographers (Rouphael and Inglis 2001; Barker and Roberts 2004; Krieger and Chadwick 2012). On the other hand, mini camera users obtained the lowest contact rates. Mini cameras have become popular in underwater videography due of its small size, low-cost, standardized housing, and widespread availability. Mini camera’s users usually have a rod with the camera attached at the tip, and so the diver does not need to approach the bottom to capture a subject. 123 Environmental Management Table 4 Multivariate analysis of variance results showing factors with significant influence on divers’ contact rates with benthic organisms Unstandardzed coefficients Standardised coefficients b b SE t P Touch (Intercept) 6.892 <0.001 0.228 5.424 <0.001 0.035 0.853 0.4 -0.017 -0.409 0.7 0.064 1.554 0.12 0.146 3.566 <0.001 0.235 5.724 <0.001 -0.124 -2.687 0.007 -0.207 -4.472 <0.001 -0.323 -6.949 <0.001 3.620 <0.001 0.180 4.076 <0.001 0.027 0.626 0.5 0.014 0.330 0.7 0.024 0.557 0.5 0.129 2.994 0.002 0.123 2.834 0.004 -0.041 -0.852 0.4 -0.192 -3.921 <0.001 -0.235 -4.796 <0.001 0.252 0.036 Reef type Artificial reef 0.198 0.036 Pinnacle 0.027 0.032 Additional equipment Mini camera user -0.016 0.040 Non-specialist photographer 0.062 0.040 Specialist photographer 0.165 0.046 Sidemount user 0.274 0.047 Dive timing 11–20 min -0.107 0.039 21–30 min -0.178 0.039 [31 min -0.281 0.040 Damage (Intercept) 0.027 0.007 Reef type Artificial reef 0.030 0.007 Pinnacle 0.004 0.007 Additional equipment Mini camera user 0.003 0.008 Non-specialist photographer 0.004 0.008 Specialist photographer 0.028 0.009 Sidemount user 0.028 0.009 Dive timing 11–20 min -0.007 0.008 21–30 min -0.032 0.008 [31 min -0.049 0.008 The best model for touch and damage used the variables reef, additional equipment, and timing. The table shows the coefficient’s estimates of variables (b), standard error (SE), t statistic (t), and probability (P). Coefficients in bold indicate significance (P \ 0.05). Reference level for this regression was set as ‘fringe’ for reef type, ‘non-user’ for use of additional equipment, and ‘0–10 min’ to dive timing. For the analyses purpose, we added raising sediments rates to the category touches 123 Environmental Management Sidemount users also inflict a high rate of damages. This diving configuration, previously restricted primarily to the technical diving community, is becoming popular among recreational divers in Brazil relatively recently and most users may still lack the skills necessary to avoid reef contacts. Clearly, further research is needed to understand the effects of this equipment in divers’ behavior and impacts in the marine biota. Dive Timing For all of the reef types analyzed in this study, contact rates were higher during the first 10 min of the dive. Previous studies have verified that the beginning of the dive is considered critical with respect to diver-coral contact rates (Di Franco et al. 2009; Camp and Fraser 2012; Krieger and Chadwick 2012). In this stage, divers are performing adjusts to establish neutral buoyancy and navigation (Di Franco et al. 2009), and organizing pair formation (VJ Giglio, personal observation). Starting dives over sandy bottom areas or in sites with low coral cover could help mitigate the impacts of recreational diving. The rate of diver’ contacts with benthic organisms decreased as the time of dive increased, because over time then divers usually established better buoyancy control and navigation. Diver Profile and Group Size Experienced divers are more familiar with marine environment and have undertaken more extensive training. This in turn increases their diving skills, such as buoyancy and swimming control (Ong and Musa 2012; Davis and Tisdell 1995). In this context, we predicted that experienced divers would make fewer contacts with corals. However, we did not observe a negative relationship between diver experience and contact rates. A similar finding was reported by Rouphael and Inglis (2001), who did not verify such correlation either. This can be explained by inexperienced divers being more fearful of getting close to the bottom during scuba diving activities and touching what they assume to be harmful. On the other hand, experienced divers may feel more comfortable to get close to the substratum and handle organisms. However, our results must be interpreted carefully because the relationship between diver experience and contacts with benthic organisms may vary according to additional equipment type. It was not possible to assess this parameter because we did not have a wide range of experiences for all additional equipment and reef types. Our results highlight a contradiction in the relationship between diver experience and their behavior. Diving management strategies with constraints based only on certification and experience may be inefficient. The higher individual contact rates were influenced mainly by the use of additional equipment, not experience. Group size did not have influence on diver contact rates with the reef. In a scenario where dive leader intervenes when observe divers touching reefs, we expected that smaller groups cause lower contact rates. However, in ANMP, dive leaders intervene or warn divers when they touch organisms only in 2 % of the events. In a previous study, interventions made by dive leaders were successful to reduce diver-coral contacts by as much as 80 % (Barker and Roberts 2004). However, in dive sites in Florida (Krieger and Chadwick 2012) and in the ANMP, dive leaders serve primarily as tour guides and tend to stay at the front of the group, looking ahead. Recreational diving can be more sustainable in the ANMP if dive leaders observe divers more closely, and intervening when seeing they are damaging benthic organisms. Contacts with Benthic Organisms The high percentage of divers that contacted benthic organisms observed in this study (88 %) was consistent with findings at other sites, where most divers made one or more contacts per dive. On Australia’s Great Barrier Reef, 70 % of surveyed divers contacted with corals (Rouphael and Inglis 2001). In the Florida,USA, and Bonaire, 75 % of divers contacted the reef (Krieger and Chadwick 2012; Uyarra and Côté 2007). Overall, in ANMP, contact rates occur at an average of 0.26 min-1, 8.72 touches and 0.9 damages per dive. This result is lower than observed in Florida, US (0.33 contacts min-1 and 17.9 per dive) and Hong Kong (0.87 contacts min-1 and 14.6 per dive) (Chung et al. 2013). In Australia, Roberts and Harriot (1994) observed an average of 35 contacts and 2.45 damages per dive. The ANMP has a relatively low abundance of benthic organisms when compared with dive sites surveyed described above that covers between 30 to 70 %. The benthic organisms cover in ANMP is of approximately 10 % for the main coral species, M. braziliensis, 3.5 % for Siderastrea sp and 1 % for M. harttii (Francini-Filho et al. 2013). On the other hand, the lower abundance of benthic organisms in the ANMP may explain the apparent lower rate of diver contacts because they simply have fewer opportunities to contact them. The majority of contacts with benthic organisms in the ANMP were through unintentional fin kicks, caused by poor swimming techniques and lack of buoyancy control, indicating poor diving proficiency. Fin kicks are the main cause of scuba diving coral damages (Medio et al. 1997; Rouphael and Inglis 1995, 1997; Luna et al. 2009; Chung 123 Environmental Management et al. 2013). Many divers are not aware that they had touched the reef, particularly with their fins (Poonian et al. 2010) or do not know about diving impacts on corals (Walters and Samways 2001). Unfortunately, most dive tourism destinations lack information on acceptable levels of contacts with the reef. Sites with higher densities of branching corals are more susceptible to diving damage because they break easily (Worachananant et al. 2008). A lower visitation rate is recommended for sites with a greater abundance of branching corals than sites that mainly consist of massive corals (Riegl and Riegl 1996; Schleyer and Tomalin 2000). Is Diving Pressure in the ANMP Sustainable? Approximately, 1300 scuba divers annually visit the ANMP and each diver performing on average seven dives, totalling 9100 dives per year divided between 15 dive sites. Using this visitation rate and the contact rates determined in this study, we estimate that divers touch on corals 74,529 times cause damage 9464 times and raising sediment onto corals 10,647 times per year. Diving pressure in ANMP lies below limits considered to be sustainable (5000–6000 dives per year; Hawkins and Roberts 1997), with a maximum of approximately 2500 annual dives per site. However, despite the wide adoption of proposed diving carrying capacity for reefs worldwide, this number varies according to diver behavior and site-specific biophysical characteristics of the reef. These characteristics include use intensity, coral growth, the presence of vulnerable species, and reef topography (Hawkins and Roberts 1997; Zakai and Chadwick-Furman 2002; Barker and Roberts 2004). Thus, the resilience of coral reefs can vary substantially, even within the same MPA (Hughes and Connell 1999). Coral reefs of ANMP consist of a relic coral fauna with Brazilian endemic forms dating back to the Tertiary time (Leão and Kikuchi 2005). Some species have adapted to water turbidity caused by carbonate and siliciclastic sedimentation (Leão and Ginsburg 1997; Leão et al. 2003). Therefore, the determination of a carrying capacity that considers site-specific characteristics is an essential strategy to managing diving tourism. Diver pressure and contacts with benthic organisms made by ANMP divers are lower than observed in other studies. Despite this, it is evident that the promotion of sustainable use is a necessary approach within dive tourism management. Long-term monitoring of corals health and visitation rates is one way to effectively assess diver impacts and to introduce regulation as necessary. We suggest the adoption of five management measures to reduce coral damage caused by divers in ANMP: (1) establishment of a diving carrying capacity, through a study that considers diver profile and site-specific biophysical characteristics of the reef; (2) provide pre-dive briefings that include ecological aspects of corals, alerting divers on impacts that diving can cause, and alerting specialist photographers and sidemount divers to take extra care; (3) increase the number of dive leader interventions when divers contacted corals, especially careless or unskilled divers; (4) conduct trainings with dive leader with focus on recreational diver impacts and cultural and environmental importance of historical artificial reefs; and (5) start dives over sand bottom or areas of low coral abundance. Sites with the highest coral vulnerability (ex. high cover of branching corals) should be visited when divers have demonstrated good buoyancy control. These strategies could be implemented with cooperation and support of recreational diving stakeholders such as governmental agencies, MPAs managers, and diving operators. The future of recreational diving is largely dependent on the health of reef resources and their management is essential to conserve the biodiversity of coral reefs. Acknowledgments We thank dive shops Horizonte Aberto, Apecatu Expedições, and Parú Divers for the support; dive guides V. Albanez, M. Lana, J. Andrade, M. Affonso, T. Ramon, T. Bonelli, R. Santoro, D. Cajueiro, M. Kipgem, and E. Said. J. Adelir-Alves for support in data collection; Abrolhos National Marine Park (through R. Jerozolimski) for research permission and support; and C. Sampaio, C. Cassano, and W. Goodell for suggestions on manuscript. The first author was supported by the Brazilian Ministry of Education (CAPES) and AS was supported by Ministry of Science and Technology (CNPq). 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